LT July 2016

LEONARDO TIMES Journal of the Society of Aerospace Engineering Students ‘Leonardo da Vinci’

1996

2016

ECO-RUNNER

Emirates’ A380s Big airline, big planes Page 12 Year 20 | N°3 | July 2016

G-Waves Einstein was right Page 17

Interview Matt Taylor About Rosetta and his career Page 44

KLM ROYAL DUTCH AIRLINES

Biofuel. You won’t notice the difference, but nature will KLM has proven that aviation can be more sustainable. As a pioneer we operated the world’s first commercial flight with biofuel. However, KLM will only use biofuels with no negative effects on food production and nature. Together with partners we stimulate the development of biofuel, only when used on a large scale biofuel will make the difference - klmtakescare.com

EDITORIAL Dear reader, Not long ago I read an article entitled: “Why Europe needs the EURO 2016”. The bottom line was that we need an event like a football tournament to restore a feeling of unity and safety in Europe, given that the tournament would be spared from any attacks.

After the EURO 2016, I was left with a sober feeling, not just because I am German, but also because I felt the whole event was rather underwhelming. The event's intention to restore these feelings failed in my eyes. Coincidently, the very same newspaper published an article after the final with the title: “And suddenly it is Monday again in France”.

The title sounded as dreary as the article described the mood in Europe.

Now how could someone possibly think that a sport event would restore what five years of crisis has caused? A feeling of safety has to be developed. It takes little to destroy, but a lot more to rebuild. Think of how security at airports has changed since 9/11 or the Paris attacks.

In an earlier issue of the Leonardo Times, Sushant Gupta wrote about the “Pax Technologica”, a restoration of peace brought by technology and in times like this I ask myself if this is truly possible. If peace means the absence of war, perhaps. Though, if peace includes a feeling of safety, I am not so sure.

Take a look at the NSA for example. Using modern technology they tap into our lines of communication and store data about everyone, not just potential threats. With this

method they might have prevented physical attacks; however, when their methods were revealed, did it make us feel safer?

In Afghanistan the U.S. flies drones to combat terror. In effect, it allowed the U.S. to remove troops from active combat; thereby sparing lives, avoiding the otherwise necessary physical fight, at least to a certain extent.

Nonetheless, if you would ask an Afghan child whether he or she felt safe with a drone over their head, they would say no.

Our technological progress is a mixed blessing and in the end we, as a society, have to decide on how to responsibly use it. Sadly, as it appears, people are more concerned with catching nearby Pokémon and sending selfies over Snapchat. Many of us couldn’t care less about the liberties we have in a democratic society as long as the phone reception is good, and all this while behind our backs the military is performing a coup (Turkey) or the government is mass spying on their own citizens (USA, UK).

I know this editorial is marginally concerned with Aerospace or what is in this magazine but instead of lying in the sun, I spend this summer checking the news and finding a place that is still safe to travel to. Reading about the events that are going on in the world I felt like I had to express my concerns and thoughts.

I personally strongly believe that education is key to combating the problems that arise with technology and that we, the educated, have a responsibility to pass on our knowledge and make it accessible to enable a broader understanding and discussion. With these thoughts I would like to leave you to reading the third edition of the Leonardo Times in 2016.

Sorry for the slight delay.

Despite all horrible events happening this summer, I hope that all of you are safe and enjoying your holiday, and eventually also this magazine. My thoughts are with the people in France, Turkey and Germany.

Last edition ...

LEONARDO TIMES Journal of the Society of Aerospace Engineering Students ‘Leonardo da Vinci’

1996

2016

JUICE

MISSION EUROPA

Scalar Drone A student-made drone Page 10

Ionic Propulsion Future of micro-propulsion Page 41

A320 NEO Aviation Department Page 44

Year 20 | N°2 | April 2016

If you have remarks or opinions on this issue, let us know by dropping an email at: LeoTimes-VSV@student.tudelft.nl

LT www.leonardotimes.com

Victor Gutgesell

Likes us on Facebook /leonardotimesjournal

LEONARDO TIMES N°3 2016

03

CONTENTS FRONT FEATURES 03 Editorial 07 Leonardo's Desk 08 In the News

22

AERODYNAMICS

Glass Ceiling "It's not women who need to change, it's the work environment that does." Nadya Fouad

10 Mimetic Discretization

SPACE DEPARTMENT 14 New Space: Launching Entrepreneurship

CONTROL & OPERATIONS (C&O) 12 Emirates' A380 Strategy 31 The State of the Industry

NICK'S CORNER 22 Flying Through The Glass Ceiling

SPACE ENGINEERING 17 Reality Check!

48 Trajectory Design: Solar Obersevatory

24 Eco-Runner Eco-Runner: Research, Design and Development of the most fuelefficient Hydrogen powered car, built by the students of the Delft University of Technology

TIME FLIES 28 Six Day War

FLIGHT PERFORMANCE AND PROPULSION (FPP) 34 Vortex in the Propulsor Inflow

INTERNSHIP 32 Asteroid Sample Return Without Landing

WIND ENERGY 40 Ducted Wind Turbines

VISIT 36 Visiting SES Astra in Luxembourg

INTERVIEW 38 CEO Interview: NLR 44 From a Brick to a Comet

AVIATION DEPARTMENT 42 The Airbus A400M

STUDENT PROJECT

Interview Michel Peters

24 Eco-Runner

COLUMN 50 Drone ADVERTISMENTS 02 KLM

Upon his visit to the faculty of aerospace engineering in Delft, Michel Peters sat down with two editors from the Leonardo Times for an interview.

06 Thales 27 EPO 51 NLR 52 Fokker

38 04

N°3 2016 LEONARDO TIMES

Time Flies

WORDS & WAR

COLOPHON

28

In 1967, with an impending threat of war on 3 fronts, Israel averted a potential national catastrophe by opting for pre-emptive airstrikes. How did the IAF realize this triumph?

Year 20, NUMBER 3, JULY 2016 The ‘Leonardo Times’ is issued by the Society for Aerospace Engineering students, the VSV ‘Leonardo da Vinci’ at the Delft University of Technology. The magazine is circulated four times a year with a circulation of around 5000 copies per issue.

EDITOR-IN-CHIEF: Victor Gutgesell FINAL EDITOR: Eleonoor van Beers EDITORIAL STAFF: Mannat Kaur, Martina Stavreva, Nicolas Ruitenbeek, Nithin Kodali Rao, Ramya Menon, Raphael Klein, Rosalie van Casteren and Thijs Gritter.

FINAL WEB EDITOR: Stevan Milošević THE FOLLOWING PEOPLE CONTRIBUTED: Bart Jacobson, Luca Corpaccioh, Vinit Dighe, Matys Voorn, Ralph van Zunten, Raphael Klein, Sushant Gupta, Yannian Yang, Yi Zhang, Zhouxin Ge. DESIGN, LAYOUT: SmallDesign, Delft PRINT: Quantes Grafimedia, Rijswijk

Electric Propulsion

NASA JPL

Articles sent for publishing become property of ‘Leonardo Times’. No part of this publication may be reproduced by any means without written permission of the publisher.

‘Leonardo Times’ disclaims all responsibilities to return articles and pictures. Articles endorsed by name are not necessarily endorsed editorially. By sending in an article and/or photograph, the author is assured of being the owner of the copyright. ‘Leonardo Times’ disclaims all responsibility. The ‘Leonardo Times’ is distributed among all students, alumni and employees of the Aerospace Engineering faculty. The views expressed do not necessarily represent the views of the Leonardo Times or the VSV 'Leonardo da Vinci'.

VSV ‘Leonardo da Vinci’ Kluyverweg 1, 2629HS Delft Phone: 015-278 32 22 Email: VSV@tudelft.nl ISSN (PRINT) : 2352-7021 ISSN (ONLINE): 2352- 703X Visit our website www.leonardotimes.com for more content. Remarks, questions and/ or suggestions can be emailed to the Editor-in-Chief at the following address:

Investigation of low-thrust, multiple gravity assist trajectories to reach high ecliptic inclinations to observe the poles of the Sun.

48

LeoTimes-VSV@student.tudelft.nl

LEONARDO TIMES N°3 2016

05

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LEONARDO'S DESK

SIMPLICITY IS THE ULTIMATE SOPHISTICATION Dear reader, As I am writing this preface for the new Leonardo Times, the days are getting longer and our time as board members is coming to an end. The few months that we had left before the summer break seemed very short, however, they were filled with great activities.

Those include, for example, Airbase, a party of 750 students hosted inside our own faculty, and the Flying Weekend. During the latter, several teams competed with each other by completing puzzles in mid-air. Furthermore, the weektend included a barbecue, a car-rally and a fly-in cinema.

We are very proud that we can organize these activities and that we have so many students who want to participate and use them to enrich their student life. Moreover, the magazine that you have in your hands right now is another asset of our society that deserves admirations. Once again, the Leonardo Times editorial staff has done an amazing job in publishing an issue filled with the latest research topics at the faculty of Aerospace Engineering. Just like in every edition, our two departments, the Space Department and the Aviation Department, have written an article on their own.

A very special event occured on the 10th of June at the Royal Netherlands Air Force Open Days 2016, the first Dutch F-35s made their grand first appearance in the Dutch airspace, over the heads of hundreds of thousands of visitors. The VSV ‘Leonardo

da Vinci’ happily congratulates the Royal Air Force on this step forward in the defence apparatus of the Netherlands. These events are reminiscent of the large air shows that the Royal Dutch Airforce and the VSV ‘Leonardo da Vinci’ have had in the past. Just last August, we went to the VSV Breda Airshow, which welcomed over 15,000 visitors. This has been the third air show that was held at Breda's International Airport. However, the history of VSV air shows goes back much further than that.

The first ‘Flying Party’ was held in 1965 at the airport ‘Zestienhoven’. The special opening was a demonstration of an Alouette helicopter of the Dutch Royal Air Force. The air show continued with over 13,000 spectators, who saw, amongst others, Lightning fighter jets, delta wing V-bombers, an acrobatics team and four supersonic Mirage fighter jets. This marked the beginning of a series of very special air shows that the VSV ‘Leonardo da Vinci’ has organized over time in close cooperation with the Air Force.

A very special edition was also held in 1980, as part of the celebrations of the 7th Lustrum.

In cooperation with some other institutions, including the Air Force, over 100,000 people visited the air show in Rotterdam. They saw, amongst others, Spitfires, the Hurricane, the Flying Fortress of B17s, a Mustang and 100 paratroopers that jumped out of three DC-3 Dakotas. The grand finale was provided by the Red Arrows.

The year will be further enriched by a great event that is to be organized, our Study Tour to Brazil and Chile. In September, 30 aerospace students will depart for Rio de Janeiro, where a four-week journey will take them along established companies, such as Embraer, ITA, Akaer, Enaer and Helibras. These students will meet the South-American aerospace industry by visiting the cities of Rio de Janeiro, Sao Paulo, San Jose dos Campos, Santiago and Antafogasto. The final stop is reserved for the overwhelming telescopes that gaze into the universe in the isolated Atacama Desert.

Finally, we enjoyed two trips in July that took two groups of 18 students into Europe. The Aviation Excursion traveled through England and visited companies like Airbus and Rolls-Royce. At the same time, the Space Department trip included visits to the German-based space division of Airbus and the DLR. Excursions like these have been a part of the VSV for a very long time. It is quite a simple concept, but sometimes those are the best. Like Leonardo da Vinci himself said in the 15th century. Simplicity is the ultimate sophistication.

With winged regards, Matys Voorn President of the 71st board of the VSV ‘Leonardo da Vinci’

LEONARDO TIMES N°3 2016

07

A Floating Wind Farm statoil

ESO

May 2016 With a focus shifting towards global sustainability, more effort is being put into improving the efficiency of renewable energy technologies. Wind energy is a predominant area of interest and now it takes on a new twist. Many pilot projects have been conducted to test which ones were the most effective. Statoil was the first company to make significant strides in the area, and now that they have refined their design, a new project is about to set sail.

The Hywind Park has recently been approved to develop the world’s first, and largest, floating wind farm. The ocean off the coast of Scotland will soon be welcoming five floating six-megawatt turbines, anchored 24-35km from land, in waters over 100m deep.

Although there are numerous advantages to a bunch of bobbing windmills, it certainly

comes with many challenges. To survive the corrosive salt water, special coatings need to be applied. Additionally, all generated energy needs to be connected to the grid, which is not as evident when at sea. However, once everything is in place, the setup is far easier than a fixed offshore wind farm, which requires a far more delicate configuration.

With the general complaint that "wind turbines are obtrusive" now irrelevant, as offshore wind farms are invisible to most people, the size of the turbine can be significantly increased. The floating turbines will have a height of 258m, enabling them to power roughly 20,000 homes when combined.

Although they are around eight times more expensive than land-based wind turbines and still pose a risk to birds, their increased efficiency and flexibility are significant advantages. Having a wind farm at sea could be a promising step in the right direction for renewable wind technologies. N.R.

A race to Sagittarius A* Discovery News

May 26, 2016 At the core of most spiral and elliptical galaxies, like our very own, supermassive black holes exist. In the direction of the constellation Sagittarius, at the center of the Milky Way, there is an astronomical radio source called Sagittarius A*. This is believed to be the site of our galaxy’s central supermassive black hole.

Following in the triumph of LIGO’s direct detection of G-waves earlier this year, scientists worldwide are working to directly observe Milky Way’s central black hole. The Event Horizon Telescope (EHT) and the GRAVITY instrument are two projects with the same goal: to observe Milky Way’s supermassive black hole. While both the projects will make use of the power of interferometry, the EHT will produce radio observations and GRAVITY will look for infrared and optical light changes when doting over Sagittarius A*.

The EHT will operate by creating a very large 08

N°3 2016 LEONARDO TIMES

Shooting for the stars, literally! Breakthrough Starshot May 2016 Interstellar travel is finally seeping into the realms of reality from science fiction.

The Breakthrough Starshot program aims to launch thousands of nanocrafts towards the Alpha Centauri’s system which is over four light-years away. Propelled by lasers shot from the Earth, these nanocrafts will be able to travel at 15-20% the speed of light. It is estimated to take around twenty years to reach Alpha Centauri’s system and an additional four years for Earth to get information from the nanocrafts. M.K.

STATOIL

BREAKTHROUGH STARSHOT PROGRAM

QUARTERLY HIGHLIGHTS

planet-wide virtual telescope by combining information from a global network of linked radio telescopes. This should enable the EHT to have sufficient angular resolution and spatial definition to observe the supermassive black hole’s event horizon. On the other hand, the GRAVITY instrument will combine light from just 8 VLT interferometers to also create a larger virtual telescope measuring the distance between each of the telescopes. GRAVITY should then be able to observe and trace features just outside of the event horizon, like the flaring around black holes caused by an energy flash due to stuff falling into it.

A better detection of these flares will not only help in understanding the workings of a black hole, but will also give key information about the geometry of the fabric of spacetime in it’s region. Furthermore, combined with the radio observations of the event horizon from the EHT, both projects together will be able to provide quite an extensive view of what mysteries surround black holes. M.K.

Could this be on Airbnb?

EMBRAER

Embraer’s New E2 embraer

NASA May 29, 2016, ISS NASA’s 2nd attempt at deploying the BEAM was successful. The ISS astronauts entered this module for the first time on June 6. The next two years will mark the trial and testing of such a space habitat and its feasibility for future manned space missions. M.K.

Mercurcy's Transit optimal speeds. Consequently, the turbofan consumes 15% less fuel, pollutes less, and is 75% quieter. In addition to its propulsion system, the airplane has new wings, a new empennage, enclosed main gear, a digital Fly-By-Wire (FBW) and other improvements over its predecessor now called the E1.

The E190-E2 is scheduled to enter service in the first half of 2018. The larger E195-E2 will follow a year after, and the smaller E175-E2 a year after that. For further reading, head on over to The Leonardo Times website.

N.R.

Life on comets? space.com

phosphorus in the comet’s “atmosphere”, both compounds crucial for life. Furthermore, the detection of organic molecules explains the formation of amino acids and the comet has everything it needs to cook up life. However, the one thing missing is energy, which is the reason why the comet itself cannot harbor life.

May 27, 2016, Rosetta Being a first of its kind, Rosetta has directly detected the presence of simple amino acids and other organic molecules in the cloud of gas and dust enveloping the Comet 67P/Churyumov-Gerasimenko.

This discovery could help in answering the age-old question if comets bought the building blocks to life to Earth.

Rosetta has been orbiting the comet 67P since 2014 and has recently made an unambiguous detection of glycine and elemental

EgyptAir flight MS804 EGYPTAIR

Egyptair

With enough energy and warmth, things could start happening. Hence, there is a very real possibility that comets could have been the deliverers of vital prebiotic chemicals to Earth and could have set the gears in motion for creating life. M.K.

Did you catch Mercury’s transit? On May 9, Mercury could be seen as a minuscule black dot sailing in front of the Sun’s magnificent inferno. Understanding a transit and how it appears from the Earth helps astronomers study distant exoplanets navigating across their stars. This can lead to the discovery of many new exoplanets when a tiny amount of starlight is blocked by the planets’ transit.

For closer planets, such a transit event can also be beneficial in understanding a planet’s exosphere by studying the sunlight that passes through it. N.R.

Glorious creation

ESA, Hubble, NASA May 20, 2016 At least 2280 light-years away, the IRAS 14568-6304, a young star cloaked in golden gas and dust. M.K. ESA, HUBBLE & NASA

May, 24, 2016 Embraer’s E190-E2 recently took to the skies several months ahead of the internal schedule, making it the only new airplane program in recent history to be significantly ahead. The E2 is Embraer’s entry into the next phase of the E-Jet development being powered by Pratt & Whitney's GTF engines. A gearbox located within the shaft of the engine permits the compressor to run at a different regime than the fan. Conventional turbofans have both components attached to each other, thereby running at the same velocity. The GTF engine allows for them to be dissociated and operate at their

May 19, 2016 On May 19, EgyptAir flight MS804 was en route from Paris to Cairo with 66 passengers and crew when it crashed into the Mediterranean. Data from the final moments appear to indicate that the aircraft carried out 90-degree and 360-degree turns before disappearing from radar. Investigators are still trying to determine whether the A320 was brought down by terrorism or a technical fault, as a series of warnings indicating smoke filled the cabin were detected shortly before the plane went missing. Specifically, analysis of the plane’s flight data recorder showed that there was smoke in the lavatory and the avionics bay. Some of the wreckage retrieved from the aircraft’s front section showed signs of high temperature damage. Additionally, audio from the flight data recorder mentions an onboard fire in its final moments. It is however still too early to determine the cause of these incidents or the exact location the fire occurred. N.R. LEONARDO TIMES N°3 2016

09

AERODYNAMICS

MIMETIC DISCRETIZATION Mimetic spectral method for 3D incompressible euler flows Yi Zhang, MSc Student Aerospace Engineering, TU Delft

TUD

The mimetic spectral element method, stemming from differential geometry and algebraic topology, provides a new path to solve physical problems numerically. With it, an effective numerical scheme was proposed for solving three-dimensional periodic incompressible Euler flows, which spatially preserves mass, kinetic energy and helicity.

Figure 1 - Manifolds in 3D space [2]. Zero to three manifolds refer to points, lines, surfaces and volumes. Notice that manifolds can be inner or outer oriented.

V

elocity, one of the fundamental variables in fluid dynamics, is a vector that describes the amount and direction of the motion. Take the potential flow for example. The velocity is equal to the gradient of the potential. This velocity, temporarily denoted as “velocity a”, is physically meaningful when it is integrated over an arbitrary line in the flow field. The line integral essentially gives rise to the potential difference between the starting point and the ending point of the line. If the potential flow is incompressible, the velocity will satisfy the divergence free condition, which means that the divergence of the velocity, temporarily denoted as “velocity b”, is zero everywhere in the flow field. It is not difficult to see that “velocity b” is physically meaningful when it is integrated over an arbitrary surface in the flow field. In fact, this surface integral refers to the flux through the surface. Now the question is: Are “velocity a” and “velocity b” identical? Obviously they are not, because at least they are physically meaningful when integrated over different geometries or if they are related to different geometries. Every physical variable has two aspects: its physical meaning and the geom10

N°3 2016 LEONARDO TIMES

etry related to it. Most conventional numerical schemes do not realize this point or they just omit one of them. However, the mimetic spectral element method involves both aspects and mimics them at the discrete level, which is the so-called structure-preserving scheme. This property provides great advantages to achieve conservations of multiple integral invariants for three-dimensional incompressible Euler flows.

There are many integral invariants for three-dimensional incompressible Euler flows, for instance: mass, kinetic energy, helicity etc. These invariants imply essential properties of the flow. However, no numerical scheme can preserve all these invariants.

There is always a trade-off. When a scheme satisfies some conservation laws, it retains some properties, but loses others. Therefore, once the conservation laws you want to preserve are satisfied, for example the mass conservation and the kinetic energy conservation, satisfying additional conservation laws in your scheme is always good because these additional conservation laws bring more properties of real flows into the

numerical system, meaning you can get more physical solutions. In addition, your scheme normally becomes more stable because of that. Unfortunately, most existing numerical schemes just preserve the mass.

Satisfying more physical conservation laws is usually difficult. However, the structure preserving mimetic spectral element method makes preserving multiple integral invariants doable.

Two main mathematical bases of the mimetic element spectral method are differential geometry and algebraic topology.

Differential geometry, which probably is a novel topic for most readers, handles similar problems as conventional vector calculus.

The major difference between them is that vector calculus discusses the geometric aspects of the physical models, while differential geometry plays with physical ideas in addition to the geometric ones. Geometries in differential geometry are called manifolds, which are topological spaces extending the Euclidean spaces. For each point of an n -dimensional manifold (n-manifold), it has a neighborhood, which is isomorphic to an n-dimensional Euclidean space. Zero to three manifolds, in fact, refers to points, lines, surfaces and volumes, as seen in Figure 1. The variables related to n-manifolds are called n-forms (differential forms). In vector calculus, there are variant operators, which can be used to operate the variables. In differential geometry, they appear in different forms like: wedge product, exterior derivative, hodge star operator, codifferential, etc.

The “velocity a”, which is mentioned above, is a one-form while the “velocity b” is a twoform. Algebraic topology, which has a strong analogy with differential geometry, is another important base of the mimetic spectral element method. By making use of the analogy, the mimetic spectral element method (the mimetic framework) can be naturally constructed.

With the ingredients: differential geometry and algebraic topology, physical variables and differential operators can now be understood in a more physical and a reasonable way. The mimetic spectral element method is set up by introducing projection operators, discrete operators and basis functions. The reduction operator reduces differential forms

to the co-chains associated with the chains.

With basis functions, the reconstruction operator reforms the co-chains and results in discrete forms. The reduction operator and the reconstruction operator constitute the projection operator. Furthermore, by analyzing the performance of the projection operator acting on the differential operators, such as exterior derivative, wedge product, interior product, inner product and hodge star operator, discrete forms of differential operators are derived. Using discrete differential forms and discrete operators, the mimetic framework (the mimetic spectral element method) is finally completed, and with it, complicated equations can be discretized easily.

Figure 3 - How the overall helicity of the field changes as a function of time when gird order is three, computational time is 2s, time interval is 0.0001s.

addition, because of the periodic boundary conditions and the fact that the degrees of freedom strongly depend on the distribution of gird cells, the weak form in wedge product for the inner Euler and the weak form in inner product for the outer Euler are chosen. The mimetic spectral element method is then applied to the weak inner Euler and weak outer Euler. Two semi-discretized systems are obtained.

With only these semi-discretized systems, it is not possible to construct a scheme that preserves mass, kinetic energy and helicity, because, only a part of the properties of Euler equations are kept in either the discrete inner Euler or the discrete outer Euler, and each of the two discrete forms of Euler equations cannot satisfy the conservation laws individually. Thus, interactions between the discrete inner Euler and the discrete outer Euler have to be constructed, which should allow the system to make use of the properties of the two semi-discretized systems simultaneously. With the well-designed interactions, a spatially discretized mass, kinetic energy and helicity preserving scheme is set up.

TUD

The mimetic spectral element method is applied to Euler equations, which are first rewritten with inner oriented forms and outer oriented variables respectively. The conservation laws of Euler equations under these new forms are proven. Based on the expressions of the kinetic energy and helicity in the mimetic framework and the discrete spaces, a staggered grid with the dual grid, identical with the primal grid is employed. In

TUD

TUD

Figure 2 - How the overall kinetic energy of the field changes as a function of time when gird order is three, computational time is 2s, time interval is 0.0001s.

Figure 4 - How well the divergence free condition is satisfied over time when gird order is three, computational time is 2s, time interval is 0.0001s.

Together, with a temporal discretization, a fully discretized system is obtained. The resulting scheme is tested by a periodic flow, the results show that the scheme does satisfy the conservation laws and some other important properties like the divergence free flow condition and the relation that the inner vorticity is the exterior derivative (curl) of the inner velocity.

Some results at grid order N (three) are given in Figures 2, 3 and 4. It is clearly observed that even on such an extremely coarse grid, the scheme still preserves the time derivatives of the integral invariants, which indicates the great influence of the structure preserving ability of the mimetic spectral discretization.

Keep in mind that most conventional numerical schemes probably diverge after just a few of steps on a grid of order three, unless the time interval is extremely short and besides, satisfying conservation laws is an extravagant hope.

References [1] Zhang, Y., “Spatially mass-, kinetic energyand helicity-preserving mimetic discretization of 3D incompressible Euler flows”, Delft University of Technology, 2016.

[2] Kreeft, J., Palha, A., and Gerritsma, M., “Mimetic framework on curvilinear quadrilaterals of arbitrary order”, arXiv preprint arXiv:1111.4304, 2011.

[3] Gerritsma, M., “An introduction to a compatible spectral discretization method”, Mechanics of Advanced Materials and Structures, 19(1-3):48–67, 2012.

[4] Gerritsma, M., Hiemstra, R., Kreeft, J., Palha, A., Rebelo, P., and Toshniwal, D., “The geometric basis of numerical methods”, In Spectral and High Order Methods for Partial Differential Equations-ICOSAHOM 2012, pages 17–35. Springer, 2014.

[5] Liu, J., and Wang, W., “Energy and helicity preserving schemes for hydro-and magnetohydro-dynamics flows with symmetry”, Journal of Computational Physics, 200(1):8– 33, 2004.

LEONARDO TIMES N°3 2016

11

EMIRATES

C&O

EMIRATES’ A380 STRATEGY Market demand for the Superjumbo Ralph van Sunten, BSc Student Aerospace Engineering, TU Delft The demand for the Airbus A380 seems to have come to a standstill. In 2015, only three Superjumbos were sold. Some airlines are cancelling their A380 orders in exchange for smaller aircraft. Despite this trend, Emirates stands firm on its record commitment to the world’s largest passenger aircraft.

T

he rapid rise in airline passengers has taken its toll on the infrastructure of many international airports. Congested runways and a limited number of gates, prohibit an increase in flight frequencies.

To cope with this ever-growing demand for air travel, Airbus saw a market for a high capacity, double-deck aircraft that resulted in the A380. The European manufacturer designed the airplane ‘to serve hub-to-hub connections on the highest-yield routes between rapidly expanding megacities.’ Lower operating costs and innovative cabin interiors made the aircraft attractive to many customers for use on these busy routes. Since its entry into service in late 2007, thirteen airlines have taken delivery of more than 190 aircraft.

Yet nowadays, the demand for the Superjumbo seems to have depleted. New orders are scarce and some existing purchases are cancelled or modified for smaller aircraft. By far, the largest customer of the Airbus A380 is Emirates. The Dubai based carrier has 80 aircraft already in service, and a total of 142 Su12

N°3 2016 LEONARDO TIMES

perjumbos ordered, far more than any other airline. Thereby, has the airline overestimated the demand for the A380 or has it found new potential for its use?

The suitability of the A380 for Emirates is unquestionable. The geographical location of Dubai is ideal for a hub operation; it is located at the intersection of Europe, Africa and Asia.

One third of the world’s population is within four hours of Dubai International Airport, and another third within nine hours. It is no wonder that Emirates is a very strong player in the market between America, Europe, SouthEast Asia and Oceania. The strength of the airline is that it can consolidate traffic from multiple smaller airports in the region and Europe to fill flights to popular destinations all over the world. Emirates operates a surprisingly large number of secondary airports in Europe (for instance Birmingham, Hamburg, Lyon), which are usually ignored for intercontinental flights. These airports are served with ‘small’ wide-body aircraft (Emirates only

uses wide-body aircraft, and is aiming for a fleet consisting of only A380s and the Boeing 777 family), such as the Boeing 777-200.

Passengers from these smaller flights can then transfer to popular destinations like Bangkok and Sydney via larger aircraft in Dubai. From East to West, passengers with destinations such as London, Paris and New York are combined. For these flights, the A380 is the ideal aircraft.

Emirates’ initial A380 aircraft were dispatched to these popular routes. After the airline took delivery of more Superjumbos, more principal destinations were covered and some less obvious airports received scheduled services with an A380. Such cities are for example: Copenhagen, Zürich, Birmingham, Prague, Vienna and Kuwait City.

The latter having a flight time of only 1h45, making it the shortest scheduled flight on this aircraft type. These are not necessarily the hubs and megacities that Airbus had foreseen for the aircraft, yet with 142 aircraft ordered, Emirates is likely to expand its A380 service to even more destinations than the current 40. Utilizing all of these aircraft could pose a problem for Emirates as some destinations may or may not be able to accom-

modate the A380.

Deploying the specific aircraft type to certain countries has regularly met resistance from the authorities. The Indian government has been notorious for blocking A380 services to its cities. There were fears that the increased capacity would take away too much passengers from the state-owned flag carrier, Air India. Emirates’ management has been pushing to allow the additional capacity for years on end. India has, in the meantime, allowed the aircraft upgrade on flights from Dubai to Mumbai, but other cities such as New Delhi, Bangalore and Hyderabad are still out of the picture. Considering the huge market potential in India, this is a real struggle for Emirates.

Canada is another country, which tries to prevent Emirates from entering the market.

While Emirates operates flights from Dubai to Toronto with the A380, further landing rights for destinations such as Vancouver and Calgary have been refused by the Canadian government out of fear for the position of Air Canada. The United Arab Emirates authorities retaliated by charging Canadians exorbitant visa fees for a period of three years.

At the height of the row, the UAE closed its airspace for a Canadian government aircraft carrying the Minister of Defence and forced Canada to withdraw from a UAE airbase, used to transport coalition troops to Afghanistan. Relations between the two countries have improved since, but additional A380 flights are still barred.

Besides political and economic limitations, Emirates cannot fly the A380 to every airport for technical reasons. While 220 airports worldwide are classified as capable of handling the aircraft, in practice special arrangements for ground handling, jetways, object clearance and runway strength have to be made to ensure proper operations. Multiple airports in Africa, South-East Asia and the Indian subcontinent are not suitable for the A380. For these destinations, Emirates will have to continue flying their 777 fleet.

Possible opportunities for expansion lie in China. Compared with some Middle Eastern and European competitors, Emirates lacks a comprehensive network in the Asian country. The carrier presently serves Beijing, Shanghai and Guangzhou, with Yinchuan and Zhengzhou in the pipeline. Adding more destinations, such as Chengdu, Chongqing or Xiamen, to profit from the booming outbound Chinese tourism could possibly fulfill part of the excess fleet capacity. The growing middle class in China is keen to travel and there is significant potential in this demographic.

Another possibility is to enter the market between Europe and North America by means of the so-called ‘fifth-freedom rights’. These entail flights between two countries different from the country the airline is based in.

Emirates currently flies between Milan and New York with the A380, taking advantage of these special traffic rights. If the carrier could

gain fifth-freedoms from more European cities across the Atlantic, it could very well use its A380s.

Both of these opportunities, however, are again prone to political blockage. China, both on state and local level, is very protective of its own airlines and bilateral talks seem to be stagnant. In Italy, the Milan-New York route was already temporarily blocked when Alitalia filed a complaint that the route would violate international aviation law. Some European countries, like Switzerland, Hungary and Greece, are offering Emirates fifth-freedom rights, mostly due to lack of their own national airline with an adequate network.

These routes are not necessarily the popular ones Emirates is looking for.

In conclusion, it may seem that Emirates has overestimated the viability of its A380 mega-fleet. Between the political, financial and technical difficulties, the airline could have a hard time deploying the entire fleet of Superjumbos. In the end, Emirates may end up sending the A380 to markets which do not warrant such a large aircraft from an economic interest. Until now, Emirates has only once downgraded a route from an A380 back to a 777. For the Arab carrier, the utilization of the A380 is a matter of prestige. It will continuously try to find new routes, upgrade current ones, or increase frequencies to existing destinations, backed up by the UAE government, which sees the development of the country’s aviation sector as one of its biggest priorities. Whether the carrier manages to enter the most protective markets remains to be seen. If not, Emirates’ audacious fleet strategy could prove dearly.

References www.airbus.com www.ausbt.com.au www.businesstraveller.com www.centreforaviation.com www.emirates.com www.thenational.ae

EMIRATES

In the Netherlands, there has also been resistance to Emirates’ increasing presence at Schiphol Airport, mainly by the Dutch union for airline pilots (the VNV). At the end of last year, the Dubai carrier expressed their desire to upgrade its second daily flight from a Boeing 777 to an A380. The VNV president demanded the Ministry of Infrastructure to prohibit this expansion, citing allegations of unfair competition by the UAE airline through illegal government subsidies. The Dutch

state secretary for transport, after conducting evaluations, concluded a second A380 flight would not have negative consequences for the hub function of Schiphol Airport, through home carrier KLM, and allowed the aircraft upgrade. The agreement between the Netherlands and the UAE for commercial flights does not limit the number of flights, seats or aircraft type used for flights between the two countries as long as there is no unreasonable impact on the supply and demand for air services.

Line-up of Emirates A380 tails at Dubai International Airport.

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SPACE DEPARTMENT

NEW SPACE: LAUNCHING ENTREPRENEURSHIP VSV's Space Department symposium Zhouxin Ge, BSc Student Aerospace Engineering, TU Delft The 30th Space Department of the VStV ‘Leonardo Da Vinci’ had the honor of organizing the annual VSV symposium. With companies like SpaceX, Virgin Galactic and Blue Origin frequently in the news, this year’s theme became ‘New Space: Launching Entrepreneurship’. On March 1, a new record of 608 engineering students and professionals from the space industry visited the symposium and enjoyed fourteen speakers on different facets of ‘New Space’ and space entrepreneurship.

This shift called ‘New Space’ is characterized by low-cost approaches, focus on consumers in the private sector, and privately funded space companies. There is a wide variety of new companies that are a part of this shift.

The products of these companies range from applications of downstream of satellite data, to lunar missions. During the symposium, two facets of the ‘New Space’ industry were touched upon; namely, transportation and satellite production. The symposium was built up of four blocks: transportation, satellite production, entrepreneurship, and a glance into the future. The chairman of the symposium, Frits von Meijenfeldt, with a bird’s eye view of space companies in the Netherlands, linked all the different topics into a coherent story. The aim of the symposium was to inspire, stimulate and broaden 14

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the view of people with interest in space and entrepreneurship.

TRANSPORTATION The day started with the first block entitled ‘transportation’, which focused on low-cost transportation to space, re-usability of the transport vehicles and cooperation with ‘New Space’ companies were the main subthemes.

The day was kicked off by Harry van Hulten, Flight Test Director of XCOR. He shared

The next speaker was Christophe Meerts, the Vice President of Engineering at Swiss Space Systems (S3). His company’s main VSV

E

very year, only a handful of people visit space. Billions of people, however, use space-related technology on a daily basis. Just like the access to airspace in the past, the access to space is undergoing a major shift. At first it was only accessible for government, military and scientific purposes.

Nowadays, our airspace is also being used for commercial and public purposes, which is happening for the space territory as well!

This creates exciting opportunities for entrepreneurs, to start new ambitious companies operating in this ‘New Space’ domain.

XCOR’s vision of access to space, being not only limited to privileged astronauts, but also for civilians. XCOR is a company that is focusing on commercialized spaceflight.

They will provide tickets for civilians to experience spaceflight. This is made possible by its spaceplane, the Lynx. The Lynx departs directly from the runway under its own rocket power. Van Hulten took the attendees through the design evolution of the Lynx and the tests that accompanied it. They have already tested their rocket engine in its test bed aircraft to prove the reliability figures, and at the moment they are assembling the actual Lynx. XCOR is not the only company that has an answer to affordable access to space, as discussed below.

Bustle at the registration desk.

VSV

of the ESA/ESTEC establishment. ESA/ESTEC’s role is ‘to provide for and promote for exclusively peaceful purposes, cooperation among European states in space research and technology.’ On completion of qualification of these projects, they are handed to outside entities for production and exploitation. This stimulates the birth of commercial operators. ESA is also creating Space Incubators all across Europe, the ESA Business Incubation Centers. These centers are supporting space-related start-ups to get their business off the ground. To this day, they have supported over 300 start-ups.

ENTREPRENEURSHIP Carina Maas-Olij and Steve Lee.

The last speaker of this block was Arnaud de Jong, CEO of Airbus Defense and Space Netherlands. He gave us insights into facts, trends and challenges for launchers and space systems. He believes that traditional space companies will still prevail, since ‘New Space’ companies like S3 work together with companies such as Airbus Defense and Space. The traditional space companies possess proven technology and years of experience. These companies also focus on a different market, mainly business to business, and business to government. As for ‘New Space’ companies, their primary focus is on business to consumer. De Jong thinks the demand for large satellites and thus heavier launch vehicles will still exist.

solutions, in terms of price level, production capacity and reliability. This can be realized by their concept of affordable panels. An aspect of this concept is that they use interchangeable end-effectors and off-the shelf robots for the automation process, resulting in low capital expenditure and flexibility. This concept of producing affordable composite panels should appeal to project managers of OneWeb, a company that wants to realize a mega constellation of 900 small satellites.

Next-up was Jeroen Rotteveel, CEO of Innovative Solutions In Space (ISIS) and also an alumni of TU Delft. He founded ISIS, a spinoff from a TU Delft student project ‘Delfi-C3’, together with a few other project members in January 2006. In the years following that, the company has developed into a leading player in the field of nanosatellite product development, mission implementation and launch services. He believes that production of low-cost spacecraft with short turnaround time can be realized by nanosatellites and small microsatellites like the Delfi-C3. These satellites are small and light, thus they can fit on an adapter and hitchhike with launches from large satellites.

Closing this block was Franco Ongaro, head

The first entrepreneur was Carina Maas-Olij, founder of S[&]T Corporation. According to her, there is no real guide in becoming a space entrepreneur. She thinks one needs to combine knowledge and fun as an entrepreneur. She also believes that one needs to love what they are doing, because on the way there will be a lot obstacles that one has to overcome. She quoted Richard Branson: “there’s no magic formula for great company culture. The key is just to treat your staff how you would like to be treated.” Her company uses their experience in Earth Observation (EO) sensor data systems to create software solutions based on EO data for civil, defense and industry applications. Using this experience, the company is able to stimulate the use of space by the general public with the so-called shift from dual-use to triple-use.

The second entrepreneur was Steve Lee, founder and CEO of Stevenson Astrosat. To him, space is distant and challenging, but very exciting. He sees space just as infrastructure, which is now open for all humans.

He thought of himself as ‘highly’ unemployable and he knew that space will need VSV

focus is to situate satellites in orbit, with a different approach towards transportation to space. A aircraft carrier is used to carry its spaceplane, called SOAR, to a certain altitude where they will separate. SOAR then goes into suborbital flight where it can deploy a small conventional launcher, which implements small satellites into orbit. This system allows substantial cost savings. It also allows them to fund their own company by using their airship for commercial ZeroG flights. In contrast to XCOR, S3 relies on existing technology and mature industrial partners. At the moment S3 is setting up ZeroG tourism flights and in 2019 they plan to launch satellites up to 250kg.

The angle of this block was to give the audience a feeling of entrepreneurship in ‘New Space’. Founders of two space companies shared their experience in starting a new company.

SATELLITE PRODUCTION The main focus of this block was on producing satellites at low-cost. Automation of the production of satellite components, production of smaller and lighter satellites, and the role of ESA/ESTEC in this domain were discussed throughout this section.

The first speaker of this block was Sandor Woldendorp, the Sales & Business Development manager at Airborne Aerospace and an alumnus of TU Delft. Airborne Aerospace is a company that specializes in producing composite structures for aerospace and marine applications. Woldendorp believes that the ‘New Space’ market requires disruptive

Presentation of Harry van Hulten.

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start-ups. For space to be more innovative, it needs more innovations from Small Medium-sized Enterprises (SMEs). These will eventually help people, governments and business. From this requirement, which is their drive to think of a space solution to any problem, the 'Astrosat Challenge' was born.

Astrosat’s current focus is on Managed Space Solutions and Services, focused on economic resilience at government level, core infrastructure, and renewable energy solutions. As a part of the “Astrosat Challenge”, they recently moved into ISS hardware and payload development.

A GLANCE INTO THE FUTURE At the heart of this block was the idea of giving the audience some aspects to think about and some research to look forward to. The final block was about space law and five researchers from the TU Delft Space Institute.

Deputy Director of the International Institute of Air and Space Law, Tanja Masson-Zwaan, gave us an insight in space law and its importance for space entrepreneurs. The Outer Space Treaty is a treaty that forms the basis of international space law. It states that fundamentally everything in and from space must be used for peaceful purposes and for the benefit of mankind. This was established in order to avoid a weapons race in space.

She points out the legal issues of innovative uses of space by the private sector. For example, companies that provide private human spaceflight lack evident jurisdiction. It is still unknown if they have to obey aviation or space law. According to her, innovation and entrepreneurship are necessary. These not only bring benefits to mankind on social, financial and technological fronts, but also raise legal issues that must be addressed.

Advice: "Be aware of legal issues from the start, not as an afterthought!"

Space Institute. It was introduced by Eberhard Gill, the director of the TU Delft Space Institute. The mission of the institute is to bundle and create expertise on space for local, regional and global impact on research, education and valorization. Their vision is to contribute ground-breaking solutions to the space sector, to serve scientific, economic and societal needs. The five pitches were given by the theme leaders of the institute.

The first pitch was titled ‘Taking Selfies from the Moon’ by Daphne Stam. She supports the idea that in order to identify new habitable planets, we first have to look at Earth from a distance and see how a habitable planet looks and behaves from there.

The next pitch was ‘Space for Earth Sensors’

by Sandra Verhagen. She advocates for more and better Earth Sensors. With the data coming from these sensors, improvements can be made on environmental monitoring; volcano monitoring, landslides, tectonic motion, atmosphere modeling, and ocean remote sensing.

The following pitch was given by Gleb Vdovin on ‘Prospects and Promises of SpaceVSV

And finally, there were pitches of the Delft

A group picture of the speakers together with the Space Department.

Based Adaptive Optics’. He believes that adaptive optics in space have the potential to offer cheaper and lighter optical systems with higher resolution, which in turn lowers the launch costs of optic satellites.

The subsequent pitch was ‘Business Astronomy’ by Chris Verhoeven. According to him, for innovation to thrive, it needs a ‘Big Bang’. To explain this, he used a spin-off of the TU Delft, ISIS, as an example. ISIS was a result of a research that was driven by technology, curiosity, inspiration, obsession and opportunity. These aspects seem to be the working recipe when looking at where ISIS stands today.

The final pitch entitled ‘2018 Going to the Moon’ was given by Jian Guo. He works on the OLFAR radio telescope that will be composed of an antenna array based on nano-satellites orbiting the moon. The frequency band it is operating on will be able to detect signals originating from the Big Bang until around 400 million years after.

On this symposium, students and professionals had an overview of two directions in the ‘New Space’ industry, an impression of entrepreneurship in ‘New Space’, a look at space law and upcoming research. The Space Department hopes that this symposium has inspired and stimulated the visitors, so that one may say: mission control is ready for launching entrepreneurship!

The Space Department The Space Department promotes astronautics among the students and employees of the faculty of Aerospace Engineering at Delft University Technology by organizing lectures and excursions.

At the drinks after the symposium.

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LIGO/NSF/AURORE SIMONNET

SPACE ENGINEERING

REALITY CHECK! From Einstein’s theory of relativity to the remarkable discovery of gravitational waves, a century-long ride Mannat Kaur, Editor Leonardo Times

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PBS.ORG

Visualizing the propagation of G-waves through the fabric of spacetime.

We hear ‘general relativity’ and we think ‘E=mc2’, Albert Einstein’s gift to humanity. Einstein’s general theory of relativity was first published in 1916. A century later, in late 2015, the very first direct detection of the ‘gravitational waves’ as predicted by general relativity has surfaced. Thanks to the brilliant LIGO team & the experiment, we now have the final proof for the ultimate prediction made by Einstein.

To begin with, Einstein stated that the laws of physics are the same everywhere in the universe and so the properties of gravity would be universally identical and light would behave similarly for all observers anywhere.

This universal property of physics implies that every observer in the universe will perceive space and time differently and personally. To put this into perspective, what might

Curved spacetime?

Instead of imagining a universe where events occur in space at certain points in time, try to think of “spacetime” as a dynamic entity. This fabric of spacetime is distorted by mass (or matter) that it contains and this distortion tells the matter how to move and evolve.

The distortion caused in the fabric defines its curvature and the shortest path between two points in this curved spacetime is called a “geodesic”.

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be one second for an observer crossing a black hole’s event horizon will be millions of years for us. Thereby, it’s all relative.

Einstein’s theory of general relativity explains “gravity” in terms of space and time or rather,

It is essential to realize that our current perLIGO/NSF/AURORE SIMONNET

RELATIVITY: A REFRESHER What is the theory of relativity? Subsequently, what is general and special relativity? An attempt to understand these concepts will require one to abandon predetermined notions regarding what gravity is and the concept of time as an absolute unit for all.

the theory describes the motion of objects in accordance with a “curved” spacetime. Additionally, the Newtonian description of gravity is rather incomplete. Trivially described, Einstein’s general theory of relativity states that objects, e.g. Earth, “move” freely under their own inertia through curved spacetime.

Hence, the feeling of “falling down” that we attribute towards gravity is just the shortest path (geodesic) that we follow on a warped spacetime.

The signals received by LIGO in Hanford and Livingston from the merger of two black holes.

ception and understanding of ‘spacetime’ as an entirely separate entity will severely limit our capacity to comprehend how it works.

For example, when I say “move” through spacetime, it does not refer to motion as we know it because it is not the kind of 3D space we imagine in which, motion exists (like we walk down a street as time evolves), but a 4D entity.

Since their publication in 1915, the calculations and predictions laid out by Einstein have proven to hold up, time and time again.

Several classical tests like the gravitational redshift of light, deflection of light by the Sun etc. and modern ones, like gravitational lensing and gravitational time dilation, are existing evidence that Einstein was right. One of the major predictions of his mathematics is the existence of gravitational waves and their formation and propagation through spacetime due to highly energetic cosmic events.

September 2015 was the final milestone as a direct detection of G-waves reinstated that Einstein’s equations make music, and not noise.

FY.CHALMERS.SE

ity says time passes quicker when the observer is away from a massive astronomical body because the fabric of spacetime is less curved (or low gravity) when compared to being at close proximity. As the GPS satellites are away from the Earth, time dilation would cause the atomic clocks on the ground to fall behind the atomic clocks on-board the satellites. Additionally, the satellite atomic clocks would also appear to slow down, since the satellites are at constant relative high speeds. Although opposite, these two effects are not enough to cancel each other out and need to be compensated for, since they are cumulative.

RELATIVITY AND EVERYDAY LIFE

This might have been true before the human species decidedly ventured into space. With large distances and speeds, relativistic effects like time dilation can accumulate progressively and hence, must be accounted for. The GPS navigation system consists of 24 satellites orbiting at an altitude of roughly 20,000 kilometres. These GPS satellites have orbital periods of almost twelve hours and orbital speeds of about 3.9km/s. Therefore, the effects of special and general relativity are noticeable and erroneous for the system.

Special relativity says that time appears to slow down for an observer in motion relative to a stationary one. This effect is known as time dilation. Furthermore, general relativ-

The satellite clocks run ahead by about 38 microseconds per day and for a high precision system like the GPS navigation technology, such an accumulation of noise could throw the system out of whack. With navigational errors of approximately ten kilometres within one day, the global positioning system would be rendered utterly unusable in hours.

SO WHAT ARE G-WAVES? Gravitational waves are ripples manifested in the fabric of spacetime because of large enough disturbances or some cataclysmic events in space, like colliding black holes or binary neutron star systems. The most common analogy (though unrealistic) is the ‘bowling ball on a trampoline’. The depression caused by the weight of the ball on the sheet depicts the distortion in the fabric of spacetime caused by a large enough astronomical body, like the Sun. Now, if you think about two bowling balls circling each

other on a large enough trampoline, they will cause ripples propagating from the centre to the outside. This is essentially how G-waves can be explained. Though unlike ripples travelling on a sheet, G-waves will “stretch and squeeze” the fabric of spacetime as it passes through, since it is a quadrupole wave.

It is really imperative to grasp that the fabric of spacetime will not resemble the rubber sheet even remotely, because the fabric of spacetime has four dimensions, including the three conventional (and easily perceptible) dimensions of space and an additional dimension of time. Furthermore, the planetary bodies are not exactly on the fabric (like the bowling ball on the rubber sheet), but they are a part of the fabric. This goes for any body with mass; stars, planets, you and me. So if you and I spin around each other as fast as possible, would we cause ripples or distortions in the fabric of spacetime? Yes, of course! Could we detect these ripples? If anyone could, it would be LIGO.

ZACHMITCH

All of this makes for a really good read until you begin to question the implications of these theories in everyday life. Is it required to think of the Einsteinian model of gravity when the Newtonian gravity model has been working just fine since centuries?

Since we cannot see or feel the effects of relativity, does it really make any difference?

Special theory of relativity Since all motion is relative and nothing is absolutely at rest but only relatively, there is no absolute frame of reference that exists but rather subjective ones.

Special theory of relativity only describes the relative motion between two inertial (non-accelerating/constant) frames of reference. The general theory goes on to describe the relative motion of any sort.

What does E=mc2 really mean?

Instead of thinking of matter and energy as two different things, Einstein viewed them as one single entity. The principle of mass-energy equivalence emerged from the special theory of relativity and states that energy equals mass times the speed of light squared.

As the speed of light is quite high, this implies that a small amount of mass will contain a very large amount of energy. Additionally, ‘mass’ is just a property exhibited by ‘energy’.

Quadrupole wave: G-wave ripple effect visualized.

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LIGO CALTECH

Configuration of a basic Michelson interferometer

QUICK FACTS - Advanced LIGO

A laser beam is shot through a beam-splitter into two four-kilometre-long vacuum tubes (right-angled to each other) with a mirror at both the ends. The laser beam is bounced 400 times between the mirrors at either end LIGO/SXS

»» LIGO is the world’s largest and most sensitive interferometer. »» LIGO contains one of the largest and purest sustained vacuums (10-9torr) on Earth, second only to the Large Hadron Collider in Switzerland. »» LIGO attempts to measure the smallest measurement ever attempted by Science (1/10,000th the width of a proton. »» Although being a space observatory, LIGO is blind to the electromagnetic spectrum, as G-waves do not fall into this spectrum. »» LIGO has twin facilities in USA (LIGO Livingston and LIGO Hanford), which ensures that any G-wave detection can be precisely confirmed & tallied, ignoring local disturbances.

WHAT IS THE LIGO EXPERIMENT? The Laser Interferometer Gravitational-Wave Observatory (LIGO) is a very large-scale experiment set up to detect gravitational waves. It was first in August 2002 that the initial LIGO (iLIGO) began its quest for the direct detection of gravitational waves and this continued till 2010. However, there wasn’t a single detection made. At this point iLIGO was capable of detecting a change in the order of 1/1000th the width of a proton! Admittedly, it does sound quite impressive but it also happens to be the minimum sensitivity requirement to have any shot at detecting a passing-by G-wave. To accomplish this, the LIGO experiment makes use of lasers.

A simulation depicting the warped fabric around two black holes in a “death spiral” producing ripples of G-waves through the fabric of spacetime. The above screenshot is at T-0.02 seconds to the merger.

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before it is brought back together. If there is no disturbance (G-wave or otherwise), the laser beam will undergo destructive interference when the two beams reunite and no signal is received. However, if a G-wave happens to pass by, it would shrink one of the arms and simultaneously lengthen the other, causing unbalanced interference and a signal will be detected. Moreover, the signal caused by a passing gravitational wave (as opposed to other external disturbances like seismic activity) will have a very unique signature. As the stretch and squeeze of each arm will oscillate with time, the interference pattern will capture this information and will also reveal the wave’s directionality.

With no detection of G-waves until 2010, iLIGO concluded its initial operations. Between 2010 and 2014, iLIGO underwent some astonishing engineering and technological upgrades. In 2014, iLIGO obtained the approval to evolve into “Advanced LIGO” (aLIGO) with a 10x increase in the sensitivity of the instrument. aLIGO was installed and tested and it had by now surpassed the capabilities and sensitivity of iLIGO. With a ten times higher sensitivity, the aLIGO is not only capable of measuring much smaller changes in length, but it can also observe a volume in space which is 1000 times larger than the iLIGO.

SEPTEMBER 14, 2015 A few days before the first official aLIGO search was scheduled to begin, the LIGO team ran an engineering test and, unknowingly, marked September 14 as one of the most iconic days in the history of mankind.

Described as the greatest discovery of the century, the LIGO team successfully, for the first time, directly detected gravitational waves caused by two colliding black holes about 1.3 billion years ago!

SO, IS ISAAC NEWTON WRONG? It is of course puerile to say that Newton was wrong, since it was his equations that en-

First indirect detection As any system generates gravitational waves, it also emits gravitational radiation. This leads to a loss in the orbital energy of the astronomical body as the waves radiate outwards. The orbital frequency of the binary neutron star system (PSR1913+16) has been observed since its discovery in 1974. The loss of orbital energy moves the stars closer, decreasing their orbital period.

The observed decrease of the orbital period over the past 35 years agrees with the energy loss through gravitational radiation predicted by general relativity to better than one percent accuracy. This marked the first indirect detection of G-waves by Russell Hulse and Joseph Taylor, awarded with the Nobel Prize in 1993.

SWINBURN ASTRONOMY

Albert Einstein A pair of spiraling black holes will cause gravitational waves to propagate through the fabric of spacetime. abled humanity to send our own species to the moon. It is perhaps more prudent to say that Newton’s original theories had certain shortcomings which Einstein recognized. He explained gravity and other Newtonian relationships using general relativity, with mathematical predictions and better precision than Newton ever had. Additionally, Newton was of the opinion that gravity was a constant and instantaneous force of nature and any information regarding a sudden change (in gravity) will be communicated with the entire system in an instant. This would imply that gravity travels faster than light, which did not make sense and was something Einstein could not agree with as he saw the speed of light as a ‘cosmic speed limit’.

“

300 years after Newton, Albert Einstein was successfully able to provide a better and a wholesome understanding of gravity.

FUTURE OF GRAVITATIONAL WAVE ASTRONOMY As aLIGO continues its operations, more detections of gravitational waves are expected in the coming months and years from far away cosmic events. Also, gravitational wave astronomy has begun to have an impact on the scientific community globally.

Projects like LIGO-India (IndIGO), the Virgo interferometer in Italy, KAGRA in Japan etc. are working towards G-wave detection as well.

No one must think that Newton’s great creation can be overthrown in any real sense by this [Theory of Relativity] or by any other theory. His clear and wide ideas will for ever retain their significance as the foundation on which our modern conceptions of physics have been built.

- Albert Einstein

Although Newton understood very well how this “force” of gravity worked, he was not sure what it was. When Einstein explained gravity as a purely geometric property of spacetime, his general theory of relativity not only explained everything that Newton, had but also covered a few things that Newton could not; like what was the agent causing gravity? To quote Isaac Newton, “Gravity must be caused by an agent acting constantly according to certain laws. Whether this agent be material or immaterial, I have left to the consideration of my readers.” Almost

”

ESA’s Evolved Laser Interferometer Space Antenna (eLISA) is proposed to launch sometime in mid-2030s and it aims to accurately detect G-waves from a large volume of astronomical sources. eLISA will work just like LIGO but in space with an arm length of one million kilometres and hence, will be quite sensitive and capable of detecting much fainter signals. In addition to this, ESA’s LISA Pathfinder (LPF) was launched in December 2015 and has been sent to space to test the essential technology required to operate eLISA. The LPF is currently operating 1.5 million kilometres from the Earth (to-

wards the Sun) and will acquire information about the geometry of the spacetime fabric by understanding the “path” of a specimen in pure gravitational free-fall. This is already the beginning of major steps in the field of G-wave astronomy.

LAST WORD The direct detection of these G-waves has been called the greatest discovery of the century. Although it is astonishing that Einstein’s predictions have proven to be correct 100 years after he made them, there is much more to the significance of this detection.

Until now, we have been studying the universe through the electromagnetic (visible or invisible radiation) spectrum. However, gravitational waves do not fall into the electromagnetic spectrum at all. Hence, gravitational wave astronomy will provide a completely new way to look at the Universe, especially in terms of the things that we find most mysterious in the cosmos; like black holes, workings of supernovae or Dark energy.

I believe that it is not only about understanding the things that we already know from a better perspective, but about discovering many celestial unknowns. It is an entirely new dimension of knowledge that we can now step into. Furthermore, it calls for a much deeper sense of curiosity and an initial acceptance of our ignorance as people of science (or not) to be ready for surprising discoveries, many scientific “firsts” and, specially, an influx of unexpected knowledge in the field of gravitational wave astronomy.

References [1] LIGO Caltech, www.ligo.caltech.edu [2] LiveScience, www.livescience.com [3] European Space Agency (ESA), www. esa.int [4] Gravitational waves, https://en.wikipedia. org/wiki/Gravitational_wave [5] PBS Spacetime, https://www.youtube. com/channel/UC7_gcs09iThXybpVgjHZ_7g LEONARDO TIMES N°3 2016

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NASA

NICK’S CORNER

FLYING THROUGH THE GLASS CEILING Women in engineering: do they have the right stuff?

Nicolas Ruitenbeek, Editor Leonardo Times

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There continues to be a considerable gender gap across engineering fields.

Discriminatory workplace dynamics persist in discouraging women from pursuing an engineering-related degree and career. Can women overcome these obstacles or will the engineering world continue to dissuade them?

Whenever you find yourself around other engineering students or working in a project group, I urge you to take a step back and observe the gender diversity. It’s quite fair to say that there are, in general, more men than women. Now have a thought as to why it is like that. Are women simply ill-suited for engineering? If your immediate answer isn’t “NO”, then I highly suggest you re-evaluate your internal moral compass. Nevertheless, to what do we owe this gender imbalance?

The lack of a Y chromosome seems to have brought women a great deal of difficulty and misfortune in the engineering field. On December 9th 1989, a gunman entered a classrom at the Ecole Polytechnique de Montréal, separated the men from the women, and proceeded to kill fourteen female students at point-blank range. The perpetrator claimed that women have no place in the field of engineering, and should not attempt to equate themselves with men by pursuing a scientific career. The Polytechnique Massacre spread like wildfire across the globe, scattering fear amongst women who were considering an engineering-oriented profession.

The nightmarish event of 1989 shone a spotlight on the paramount need to eradicate gender barriers in the engineering field.

Three years later in 1992, a groundbreaking report by the Canadian Committee on Women in Engineering, commissioned in the wake of the tragedy, called for concerted efforts to attract more women and shatter the myth that girls don’t have the “right stuff” to become engineers. This was internationally perceived as a chance for women to empower themselves by launching themselves into these male-dominated waters. Although this resulted in an increase in female enrolment in engineering schools across America and Europe, the trend reversed itself in 2001 and has remained unchanged. While the memory of the horrid massacre may have faded, the gender bias still persists.

In 2008, throughout Canada, the US, and Europe, there were roughly four to five times as many men as there were women applying to an undergraduate engineering-related degree. What is even more disconcerting is that close to 40% of women with an engineering degree either leave the profession, or never enter the field after completion of their studies. The American Psychological Association found that most women are put off due to workplace discrimination and a lack of job satisfaction. Women in Engineering (WIE) is the largest international professional organization dedicated to promoting female engineers and scientists. They also aim to pressure engineering companies to improve their workplace dynamics between men

and women. It is estimated that companies are 15% more likely to thrive if they are gender diverse, and enabling women to meet their full potential in their work environment could add as much as $28 trillion to annual GDP in 2025.

Despite the difficulty that women have, those who have the tenacity to tolerate the copious amounts of testosterone, make significant and distinguished contributions. Emily Roebling (1803-1903) was the first woman field engineer and technical leader of the Brooklyn Bridge. Hedy Lamarre (1913-2000) invented a remote-control communication system for the US military during World War II, upon which all modern-day communication structures are built. Amelia Earhart (18971937) was an aviation pioneer and the first woman to fly across the Atlantic. The list goes on and on… Those claiming that women have not had a prominent impact on science and engineering are simply pedaling fiction. In fact, on average, women perform just as well if not better than men across all engineering fields. Our female counterparts

“

underrepresented girls in STEM. It also gives access to high-quality resources for high school counselors who can encourage female students towards following a scientific career, all whilst making them aware of the current hurdles. These types of initiatives, aimed at inspiring girls towards a technical profession, are paramount in balancing the gender distribution in such fields.

To add more fuel to the fire, it might prove interesting to look at the consequences that arise from a lack of women in science.

A drought of women in STEM means that the perspectives of half the world’s population would be absent. This has already led to many issues, notably in the area of health care. It’s currently widely acknowledged that countless women with heart disease have been misdiagnosed in emergency rooms and sent home, possibly to die from heart attacks. This was because it was incorrectly assumed that women exhibit the same symptoms as men for cardiovascular diseases. The male-dominated cardiology field deemed sex an unimportant variable in the medical research of heart diseases. The National Institute of Health corrected this procedural bias in May 2014 by announcing that the medical researchers it funds will have to always consider sex as a variable in the ex-

We need all hands on deck, and that means clearing hurdles for women and girls as they navigate careers in science, technology, engineering, and math.”

- Michelle Obama

are also renowned for their patience and meticulousness; these are extremely valuable qualities in the ever-evolving world of engineering.

So what needs to change? It’s clear as day that the work environment needs to be transformed for the better since almost half of the women with a scientific degree either discontinue or never enter their field due to bad workplace dynamics. Though that doesn’t explain the persisting low enrolment in technical studies. Educational institutions need to acknowledge their responsibility in removing gender barriers and in positively influencing attitudes of young engineers, especially at a high school and university levels.

There are many programs targeted at female high school students to encourage them to pursue Science, Technology, Engineering and Mathematics (STEM) careers. In March 2015, First Lady Michelle Obama launched “Let Girls Learn”, an initiative that aims to help girls have a proper education. It also aspires to remove gender barriers in fields dominated by men. The National Girls Collaborative Project seeks to effectively reach and serve

”

periment design and analysis.

The engineering world is anything but a smooth ride for women. It remains a competitive male-dominated industry. Hopefully the gender distribution will start evening-out in the coming decade as more women decide to fly through the glass ceiling and put men to the test.

References [1] How can a female engineer remain positive despite what seems to be a discriminatory hiring process? Forbes.com [2] 8 Famous female engineers in History. iveyengineering.com [3] Polytechnique shooting 25th anniversary. Cbc.ca [4] Women in Aerospace. Martina Stavreva.

April 2015 edition of The Leonardo Times.

[5] Why engineering, science gender gap persists. Pbs.org [6] Many women leave engineering, blame the work culture. npr.org [7] Let Girls Learn. Letgirlslearn.com [8] Women’s engineering society. Wes.org [9] Why it’s crucial to get more women into science. Nationalgeographic.com LEONARDO TIMES N°3 2016

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STUDENT PROJECT

ECORUNNER

Amalgamation of diverse engineering disciplines in car building Ramya Menon M.R., Editor Leonardo Times

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The Eco-Runner competes in an annual event called the Shell Eco-marathon.

A staggering 3000 students, spread over 200 student teams from all over Europe compete in different classes within the competition. The Eco-Runner is a novel car designed to compete under the category of one of the most futuristic engineering concepts: cars using Hydrogen as its energy source.

F

rom Delft to Moscow, and back, on one liter of hydrogen? What was deemed once impossible is not so anymore.

Team Eco-Runner has been successful in achieving this goal and has remained a consistent performer at the Shell Eco-marathon. This marathon is one of the premium competitions in the world that attracts many engineering students to put their skills and knowledge to test. The task of the event is to construct a car that is as efficient as possible and covers a maximum distance using only one liter of Hydrogen for power.

The Eco-Runner team was formed ten years ago. They first competed at the Shell Eco-marathon on the Rockingham Speedway in the UK in July 2006 and have been perfecting their design ever since. They have proven to be unrivalled champions so far. Last year, they won the Shell Eco-marathon in Rotterdam with a result of 3653 km/L (energy in hydrogen converted to energy in liter gasoline). This dream project was first realized by three aerospace engineering students. It was a project undertaken by them as a part of their graduate studies and thus, the first Eco-Runner was created. It was later given the status of a dream team among the many at TU Delft. This year, the 10th team is working on the sixth vehicle. A new team is formed each year and the recruitment begins in the early weeks of September. The team consists of students (both undergraduate and graduate) from varying engineering disciplines such as aerospace engineering, mechanical engineering, electrical engineering etc. This new team designs, simulates, develops and tests their new vehicle each year.

The Eco-Runner year is roughly divided into three phases. The first phase consists of the design of the new vehicle. The design is altered each year, starting with a better performing aerodynamic shape, a new suspension and a custom made fuel cell.

Aerodynamics and body design play a vital role in this phase. The second phase is the actual production of the car. Some parts are produced by specialized companies and the other parts are produced by the team members themselves. Most parts of this project are produced at the D: Dreamhall.

The D: Dreamhall, located on the campus of TU Delft , provides the team with multiple milling machines, lathes and other machining and finishing equipment needed for the production phase of the car. During this period, a large part of the team spends their time behind production equipment. The last part

of the Eco-Runner year consists of the race, which will take place in London this year.

The team consists of different departments, each responsible for a different aspect of the project. The departments are assigned their own managers, who are in turn responsible for the task completion of their team members. The different departments are cover body design department, suspension department, fuel cell and powertrain department, finance, PR and sponsoring department. Given below are the tasks carried out by each department as described by the respective managers.

SUSPENSION The work done by this department is further subdivided into the front and rear suspension system, the wheels, the braking system and the steering system. Their main goal is to optimize the vehicle for minimum rolling resistance and produce a lightweight design since the components involved in the suspension of the vehicle are the major contributors to the total weight of the car. The suspension system performs the task of connecting the wheel to the body of the car, and its design is optimized using FEM software.

The front suspension is made of aluminum.

The rear wheel is enclosed in an aluminum cage, which is then attached to the body of the vehicle with carbon tubing.

The wheels are made of carbon fiber and are produced by the team at the Dream Hall workshop. The production for each wheel lasts up to three weeks. The tires are de-

signed with the specific intention of attaining minimum rolling resistance with a coefficient of only 0.00081, thus obtaining higher fuel efficiency. Further enhancements in wheel performance are achieved by setting an optimum Toe-in angle.

The steering system is used to navigate and change the attitude of the vehicle. They are designed following the principles of an Ackermann-mechanism so that the wheels always have an optimal position when cornering. The braking system of the vehicle makes use of disk brakes, which are easily adjustable and lightweight. They can maintain the vehicle in a stationary position even on a 20% inclination.

POWERTRAIN The powertrain department comprises of four divisions: fuel cell, motor, the boost-caps and electronics. These divisions are managed by the manager of powertrain, who is also the fuel cell engineer in the current team.

Within the fuel cell division, the focus this year is to develop and design a control system for a new fuel cell stack the team has obtained.

In previous years, the control system came with the stack, but a system that is designed in-house allows for more optimization, which is beneficial for car efficiency.

One of this year’s innovations within the team is the implementation of ‘boost-caps’ in the powertrain, which will serve as an energy buffer. Any superfluous energy produced by the fuel cell will be stored in this buffer, and when the motor requires a lot of power, this energy is released to relieve some of the strain on the fuel cell.

Finally, the electronics and motor divisions work on the driver interface and car telemetry. The electronics division installs the vari

The new Eco-Runner VI. LEONARDO TIMES N°3 2016

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ous sensors and data-logging systems in the car, while also working on the driver control system with motor division. This division also ‘connects’ the motor to the rest of the powertrain.

BODY This department is responsible for the aerodynamics and structural integrity of the vehicle. The aerodynamic design is the most important design aspect during the first period and a wind tunnel test is scheduled in December. The Eco Runner design makes use of an optimization script for the top view of the vehicle in order to generate a shape, which accommodates all the subsystems.

Subsequently, three-dimensional shapes are generated to perform a CFD performance simulation of the designs. Upon attaining satisfactory results, the first measurement data of the new vehicle is generated.

This whole process is done in close cooperation with the needs of other departments in order to integrate various sub-component dimensions and safety margins that need to be met.

Following the design of the vehicle’s exterior is the design of the internal structure and the laminate lay-up of the vehicle. This is done using FEM software, Patran. The vehicle and its structure are modeled as shell elements due to the use of thin laminates. This department faces several design optimization challenges while ensuring the demands from other departments are met to satisfaction, making the engineer involved well-versed in CATIA and Patran .

RESEARCH AND INNOVATION After achieving the wonderful result of 3653 km/L in May 2015, a new team was formed to try and achieve an augmented performance and lower fuel consumption. The team’s ultimate goal is to achieve a fuel consumption above 5000 km/L, by using hydrogen as the main power source. To attain this result, performance losses are looked at in three main categories: Rolling resistance, aerodynamic drag and the powertrain.

Eco-Runner VI in preparation for a run.

The rolling resistance depends mainly on the weight, meaning that every year, the vehicle is optimized for lower structural weight. The latest model of the Eco-Runner weighs less than 38kg. However, the largest part of the total weight comes from the driver, which, according to the Eco-marathon regulations, may not be less than 50kg. The drivers usually have to lose a few kilograms to achieve this weight. This year onwards, a special team of dietitians have been added to the team to ensure the drivers lose weight in a responsible and healthy manner. The tires of the vehicle, which are prime contributors to rolling resistance, are custom made Michelin tires, with the lowest measured rolling coefficient for its size.

After optimization of the aerodynamic shape in November 2015, the current team quick-

ly realized that the performance could be further enhanced by adapting a new optimization strategy and by implementing novel research results on flow techniques, such as turbulators, to delay flow separation. Furthermore, the vehicle has been laminated as a whole, thus preventing any corrugations that might arise at the point of intersection of carbon fiber body and windscreens. The effects of this was tested at the Open Jet Facility (OJF) in May 2016.

In the powertrain department, a new hydrogen fuel cell system is being developed, that has the capacity to effectively distribute the energy around the track. This is done by implementing a pulsing system. Research is also done in optimizing the driving strategy.

In combination with the new fuel cell, a new strategy has shown a decrease in fuel consumption by over 10% in comparison to the year before. Theoretically, the team believes that this should be well enough to achieve the goal and win the Shell Eco-marathon.

To test the vehicle as a whole, the team will enter a test phase prior to the competition. This phase will take about 2.5 months during which the design will be verified and checked if it meets the competition requirements.

PROGRESS OF THE TEAM (AS OF MARCH 6, 2016) Planning wise, the departments are in the stage of full production. The aim is to have an assembled car by March 30. This way the team has three months to get acquainted with the new Eco-Runner VI. This team and their project are indeed a force to be reckoned with!

Eco-Runner and team on racetrack.

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N°3 2016 LEONARDO TIMES

Join Europe’s top

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TIME FLIES

SIX DAY WAR Operation Focus (Mivtza Moked)

Sushant Gupta, Editor Leonardo Times

The Six-Day War of June 1967 was fought between Israel and its neighboring states of Egypt, Syria and Jordan. Not only was it a watershed in the history of the Middle East; it was also one of the rare occurrences in recent history of a pre-emptive strike.

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Motti Hod.

Prime Minister Levi Eshko.

Israeli Plane 1967.

POLITICAL BACKGROUND The root cause of the Arab-Israeli conflicts has been the creation of the state of Israel in 1948 [1]. Its neighbors have not recognized Israel since its Declaration of Independence in the same year. However, much later in 1979, Egypt became the first Arab country to officially recognize the existence of their neighbor [2]. By 1956, the Arab-Israeli tensions resulted in two wars in a short span of eight years and conflict had become a behavioral norm. In the period leading up to the Six-Day War in 1967, a series of events flared tensions further in West Asia.

One personality who had a major bearing on the events leading up to the war was unmistakably the President of Egypt, Gamal Abdel Nasser. Nasser was a military man, who had become a charismatic leader in the Arab world. He envisioned a great Pan-Arab nation that was strong, secular and socialist.

In this, he saw Israel as a major obstacle and maintained hostility towards Israel’s existence. Egypt had by far the strongest military in the region, in terms of number of troops, tanks and sophisticated fighter aircraft [3].

In the north of Israel, Syria had constant clashes with its neighbor over land and water. In April 1967, Syria shot a civilian Israeli tractor, ploughing in the De-Militarized Zone.

In response, Israel’s army and air force attacked Syria [4]. Egypt and Syria had a mutual defense treaty [5] and as a result, Egypt started a massive build-up of troops along Israel’s southern border in the Sinai desert.

The parade-like build up through Cairo was broadcast on Egyptian TV, with hundreds of thousands of Egyptians on the street cheer-

ing their army and calling for the eradication of Israel [6]. A series of anti-Semitic cartoons popped up showing the extermination of the Israelis. The small state of Israel, with a population a little over 2.5 million, didn’t have any broadcasting service at the time [7]. Israelis watched the visuals in consternation on Egyptian TV in Arabic. In the very first days, 40,000 Egyptian soldiers, 300 Soviet manufactured state-of-the art tanks and various types of heavy artillery crossed into the Sinai Peninsula [8]. All over the Middle East, there was hysteria and excitement of expectation that Israel was to be leveled in a matter of days. This mounted tremendous political pressure on Nasser and in this situation, he could not back out of the war even if he may have wanted to threaten Israel and merely put up a display of strength [9].

Israel, in response, summoned almost every able bodied man into service [6]. Over a few weeks, the armed forces were swiftly and discretely mobilized to key positions. Offices and factories all over Israel were shut down, due to lack of manpower [6]. A narrow buffer

of UN peacekeeping troops from India, Canada, Brazil and Scandinavia separated the two armies along the border in Sinai. On May 16, 1967, Nasser ordered to UN peacekeeping commander to evacuate within 48 hours [10]. Subsequently, on May 22, Nasser visited Sinai with his army’s commanders and announced the closure of Straits of Tiran, blocking the access of Israeli port of Eilat to the Gulf of Aqaba and the Red Sea [11]. On May 30, Jordan’s King Hussein, dumped old apprehensions and visited Nasser in Egypt and signed over control of his army to the Egyptian military under United Arab Command [12] [13] [14].

Israel saw the naval blockade as an act of war and tried to persuade the US, its greatest friend, to open the Straits of Tiran. President Johnson, occupied with Vietnam, was sympathetic but unwilling to act with the emergency that Israel required [6]. The ratio of forces and state of preparedness would have guaranteed the Arab military victory.

Being surrounded by enemies, the inevitability of war was obvious. Israel lacked depth on all fronts with its neighbors and was faced with a grave geopolitical existential threat. It had two main options: allow the Arab states to strike first or take action. It chose the latter and opted for pre-emptive airstrikes followed by a ground offensive against its hostile neighbors.

AIRSTRIKES: JUNE 5, 1967 Israel chose to concentrate on one enemy at a time and understood that Egypt was the biggest threat and if it capitulated, the others would be rendered incapacitated in no time.

In order to do this, Israel would need to gain air superiority. Once that was achieved, its ground forces could take the enemies one by one.

At 0745 Israel time, Israeli Air Force (IAF) launched Operation Focus (Mivtza Moked) deploying almost all of its 196 combat aircraft in the first wave of air strikes on eleven Egyptian airfields [15]. The strikes had the vital element of surprise and caught much of Egyptian Air Force on the ground off guard.

Egypt suffered aircraft and pilot losses even before they could be airborne. The first wave was a brilliant success with 189 Egyptian planes, nearly half of Egyptian air force, burning on the ground [16]. The IAF jets returned

Sud Ouest Vatour.

LEONARDO TIMES N°3 2016

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pletely removed before the sinkhole can be repaired rather than a normal bomb crater which is simply filled in and patched. Once the runways were disabled, entire air bases were effectively grounded and fell victim to subsequent attacks, resulting in near-total Israeli air supremacy [19].

References

Six day war aircraft.

Dassault Mirage 3C.

Egyptian Aircraft Damaged on Runway.

to Israel, where they quickly refueled and rearmed in just 7min 30seconds [17]. During the second wave, Israeli jets pulverized 14 more Egyptian airbases damaging 107 planes and returned with minor losses [17].

As the subsequently planned third wave of attacks was going on, Syria, Jordan and Iraq started attacking Israeli targets in retaliation; many IAF planes en route for Egypt were diverted and were pressed in support of Israeli ground forces against Syria and Jordan. H-3 airbase in Iraq was also attacked [17].

[6]. The aircraft flew at a low altitude, just below 100ft; well below the lowest point at which Egypt’s surface to air missiles could bring down an aircraft [20]. The low flight at speeds of 500miles/hour also prevented detection by Egyptian radar and ensured surprise [6]. The aircraft flew over the Mediterranean Sea and turned back towards Egyptian targets.

By the end of the day, Operation Focus had proved a resounding operational success.

In the span of three hours, Israeli jets numbering less than 200, had destroyed 391 enemy combat aircraft on the ground and 60 in dogfights [18]. Israel had achieved complete air superiority over Golan Heights in the north, the West Bank in the east and the entire Sinai desert in the south-west [19]. IAF jets could now be put in support of Israeli Defense Forces (IDF) on the ground while they pressed on their fronts. In five more days, the IDF defeated the armies of their neighbors and captured large swathes of enemy territory. On June 10, the war came to an end [20].

OPERATIONAL SUCCESS Israeli Air Force mostly deployed the French made Dassault Mirage III and Super Mystère 30

N°3 2016 LEONARDO TIMES

Israeli jets had a very low turnaround time, which meant that IAF could maximize the use of its small number of jets on multiple fronts. With just 12 Israeli jets left to patrol Israeli skies, it was a big risk to go for an all-out attack. Fortunately for IAF, their strategy paid off. The IAF jets managed to fly 3,300 sorties in the six days of war with just 200 odd aircraft available [18].

The operational success was achieved by focusing on initial destruction of the runways with a rocket-assisted anti-runway warhead.

The newly developed prototype used a rocket breaking over the target to point the warhead directly towards the targeted runway. At set altitude, a second accelerator rocket ignites and drives the warhead through the pavement of the runway before it detonates. The explosion creates a small crater over a large new sinkhole, meaning the damaged runway section must be com-

[1] Israel Ministry of Foreign Affairs: Declaration of Establishment of State of Israel: 14 May 1948 [2] "Camp David Accords", 17 Sep 1978 [3] Tucker, Spencer (2004). Tanks: An Illustrated History of Their Impact, p. 176 [4] Gluska, Ami (2007). The Israeli Military and the Origins of the 1967 War., op. cit., p.

100-101 [5] Gawrych, George W. (2000). The Albatross of Decisive Victory: War and Policy Between Egypt and Israel in the 1967 and 1973 Arab-Israeli Wars., p. 5 [6] Ilan Ziv (Director). 2007. Six Days in June [Documentary] [7] Yuval Elizer, Israeli Television and the National Agenda. Retrieved from http://www.jewishvirtuallibrary.org/jsource/ Society_&_Culture/tv.html [8] Michael B. Oren (2002). Six Days of War: June 1967 and the Making of the Modern Middle East, p. 64 [9] Segev, Tom (2007). 1967: Israel, the War, and the Year that Transformed the Middle East op. cit., p. 275 [10] U Thant, The United Nations Secretary-General (26 June 1967). "Report of the Secretary-General on the withdrawal of the United Nations Emergency Force, General Assembly A/6730 & Add.1-3 & A/6730/ Add.3/Corr.1" [11] 'Egypt Closes Gulf Of Aqaba To Israel Ships: Defiant move by Nasser raises Middle East tension', The Times, Tuesday, May 23, 1967; pg. 1; Issue 56948; col A. [12] Quandt, William B. (2005). Peace Process: American Diplomacy and the Arab-Israeli Conflict Since 1967, p. 37 [13] Mutawi, Samir (2002). Jordan in the 1967 War, p. 16 [14] BBC On this Day, Egypt and Jordan unite against Israel. Retrieved from http:// news.bbc.co.uk/onthisday/hi/dates/stories/ may/30/newsid_2493000/2493177.stm [15] Oren 2002, p.172 [16] Bowen 2003, p. 99 (author interview with Moredechai Hod, May 7, 2002) [17] Eshel, Stanley M. Ulanoff, David (1985).

The fighting Israeli Air Force.

[18] Israel Air Force: In the Six-Day War. Retrieved from http://www.jewishvirtuallibrary.org/jsource/ Society_&_Culture/67iaf.html [19] Oren 2002, Chapter 3 [20] Bowen 2003, pp. 114–115 (author interview with General Salahadeen Hadidi who presided over the first court martial of the heads of the air force and the air defense system after the war)

C&O

JUJUG SPOTTING/DANIEL GORUN/EMBRAER/ROUTESONLINE

THE STATE OF THE INDUSTRY Where are our aircraft design jobs?

Raphael Klein, MSc Graduate Aerospace Engineering, TU Delft The main aircraft design programs have come to an end. The boom of the last five years is gradually decreasing and it is now time for aircraft manufacturers to deliver bigger numbers within the next fifteen years. What does this mean for the aircraft designers and engineers in the sector?

2

016 marks the first flight of several aircraft. The first Boeing 737 MAX had its first flight in January, followed by the first A321neo only a month later. In May the Embraer E190-E2 performed its first flight in Brazil. Moreover, the Airbus A350-1000 is planned to take its first flight in September followed by the Boeing 787-10, whose first flight is scheduled for the beginning of 2017.

At the same time, several aircraft programs are in full production mode. This is the case for the largest part of the A320neo series that has started, despite a long string of engine difficulties. Bombardier is slowly but surely ramping up production on its CSERIES with the first delivery of the CS100 to Swiss planned for July 2016. Its CS300 is undergoing an aggressive testing phase and is slated for delivery in 2017. The ramp up there has also begun. Boeing is continuing to test its new B737 MAX with plans to fully transition its production line from the NG to the MAX. On the wide body side, the design phase for most aircraft programs is also coming to an end. Boeing is successfully ramping up the production of its Boeing 787-8 and 787-9.

It recently reached the 400th aircraft delivered as well as the 100th delivered 787-9.

Airbus is going through a similar process. It is increasing the production of its A350-900.

Although Airbus has had problems with delivery due to aircraft cabin issues, it still aims to deliver fifty aircraft by the end of the year.

This picture of program completion is partly affected by the three major programs: The Boeing 787-10, the A330neo and the Airbus A350-1000, which are all in similar stages.

The A350-1000 is undergoing final assembly and was rolled out in April 2016 while parts of the B787-10 are being stocked at Boeing’s Everett plant in preparation for final assembly. The A330neo parts have started production and the aircraft will enter final assembly within a few months. The Boeing 777X program is the last program that is not yet completed and which is in its final design phase.

Overall, this is terrific for aircraft manufacturers. This means that years of labor designing these aircraft are coming to an end, and they can finally collect the fruits of their effort.

Thousands of orders considering all aircraft programs, excluding the A380, seems to ensure that there will not be any shortage of new ones. Airbus, Boeing, Bombardier and Embraer are therefore focusing all their resources on the production and delivery side of the business. At Airbus factories for example, recruitment of mechanics and other production related jobs are constantly ongoing.

This, however, could be a problem for engineers looking for jobs in the sector. Design engineers are not as needed as they used to be five years ago. The Big 2 are now looking for different types of engineers that will design maintenance manuals and focus on the production and operational side of an aircraft’s life. These are engineers that will hunt for small inefficiencies and will aim to produce aircraft upgrades, which reduce fuel consumption by a tenth of a percent.

This also means that a lower number of engineers are needed for each program. Gone are the days where thousands of engineers where employed on the same program at the height of the design of certain wide bodies.

On the other hand, aerospace industry is a cyclic industry. What goes up must come down and also what goes down usually goes back up again. The next generation of airliner is now being considered by Airbus and Boeing as well as Embraer and Bombardier. This generation is scheduled to fly in around the 2030s. All there is to do now is wait.

References [1] reuters.com [2] leehamnews.com [3] nyc787.blogspot.nl [4] boeing,com [5] airbus.com [6] bombardier.com [7] embraer.com

LEONARDO TIMES N°3 2016

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INTERNSHIP

ASTEROID SAMPLE RETURN WITHOUT LANDING Internship at the Colorado Center for Astrodynamics Research Michael Van den Broeck, MSc Student Aerospace Engineering, TU Delft Lofted Regolith Sampling (LoRS) is a new method to collect surface material from an asteroid using an impactor, instead of non-reliable, complex landers.

An orbiting spacecraft can collect the lofted particles caused by the impact.

During the internship, the feasibility of LoRS was evaluated for a mission to the asteroid Bennu.

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One of the current projects at CCAR under the supervision of Dr. Jay McMahon involves a preliminary study for an alternative to NASA's OSIRIS-REx mission. The goal of the latter is to bring back samples from Ben-

CCAR

T

he Colorado Center for Astrodynamics Research (CCAR) is part of the branch of the University of Colorado, situated in Boulder (CU Boulder). CU Boulder was established in 1876 and it is the flagship campus of the University of Colorado. It provides education to approximately 32,000 students of which more than 2,600 are internationals. Besides students, there are 7,800 faculty and staff members (CU Boulder, 2016). The university has a big impact on the economy of the state of Colorado, with an annual contribution of over two billion dollars. The aerospace engineering department is located in the Engineering Center, which is home to the College of Engineering. It is well known and is highly ranked: 10th place in the US for both graduate and undergraduate programs (CU Boulder, 2016). Twenty NASA astronauts are alumni of CU Boulder.

CCAR was founded in 1985 and is located in the Engineering Center. It is dedicated to the study of astrodynamics and the application of satellites to science, navigation and remote sensing of the Earth and other planets.

The institute currently has a staff of twenty and accommodates 59 graduate research assistants (CCAR, 2016).

nu, which is a 500m-diameter asteroid that makes relatively close passes with the Earth every six years. Bennu’s irregular shape (see Figure 1) and mass distribution are the cause of its perturbed non-central gravitational field. The OSIRIS-REx mission is planned to launch in September 2016 and when it succeeds, it will be the first US mission to return samples from an asteroid. Like many other sampling missions, this mission will perform a touch and go landing. Landing on an as-

Figure 1 - Due to the irregular shape of the Bennu asteroid, its gravitational field is highly perturbed.

teroid is always tricky, since the surface texture at the landing area is difficult to predict.

In fact, the surface texture of an asteroid can be so specific that it has a large impact on the design of the lander. As a consequence, either the lander cannot be used for other asteroids (which prevents mission control from changing the asteroid that will be visited), or the engineers have to equip the lander with very costly and challenging mechanisms so that it becomes more universal and can handle multiple types of terrain (like the Philae lander of the Rosetta mission, which nevertheless failed to make a successful landing).

Therefore, there is a need for a more robust asteroid sampling mission, i.e. one that is less dependent on the characteristics of an asteroid. During the internship, the feasibility of performing Lofted Regolith Sampling (LoRS) with the use of low-thrust electric propulsion was investigated. LoRS consists of the following phases. First, a spacecraft orbiting an asteroid will use its instruments to map the asteroid's gravitational field. Second, the surface material will be ejected into space by an impact of a projectile released by the spacecraft. Due to the solar radiation pressure, which has a large effect on orbits around asteroids, the surface particles will be deflected in their orbit according to their illuminated surface area to mass ratio. In this way, the particles will be differentiated into several trajectories according to their size.

This allows scientists to collect particles of a certain size by maneuvering the spacecraft into the stream of the desired particles. The spacecraft is then able to collect the particles due to its low relative velocity. The low magnitude of the gravitational field causes the orbital velocity of the spacecraft to be very small. The gravitational acceleration at Bennu’s surface is around 6.9•10-5m/s2 at the equator, which is roughly 142,000 times smaller than that at the Earth's surface. At an altitude of 1km, the circular orbital velocity is approximately 6.5cm/s.

The advantage of the LoRS approach to collect samples of Bennu is that there is no need for a lander, which greatly simplifies the design of the spacecraft. The downside of LoRS is that detailed simulations of the trajectories of the liberated particles are needed as well as a method to maneuver the spacecraft to the location where it can collect the desired particles. Previous missions, like ESA’s famous Rosetta mission to 67P/ Churyumov-Gerasimenko, have already carried out such detailed maneuvering around small solar system bodies. However this has never been done before with low-thrust electric propulsion. The only mission that used low-thrust electric propulsion around asteroids is NASA's Dawn mission. The Dawn spacecraft recently visited Vesta and Ceres, but these are not small asteroids, in fact they are categorized by the International Astronomical Union as a minor planet and a dwarf planet, respectively.

The task at hand during my internship was to find out if it would be possible to maneuver a spacecraft around a small asteroid by means of low-thrust electric propulsion as a method to collect lofted particles from the asteroid’s surface, and how efficient it would be in terms of required propellant mass and ΔV. Throughout the internship, a Matlab program was written that accurately simulated the trajectory of a spacecraft around Bennu, while taking into account several natural perturbations such as Bennu’s irregular gravitational field, its rotation, solar radiation pressure (SRP) and the influence of the Sun’s gravitational field. From the results of the simulation, it was found that it is indeed possible to maneuver a spacecraft around a small asteroid using low-thrust electric propulsion.

The required amounts of ΔV to change the spacecraft’s trajectory are so low that lowthrust maneuvers can be achieved, which look similar to high-thrust maneuvers around the Earth. Imagine a 2,000kg spacecraft arriving at Bennu with 100kg of propellant mass.

Assuming a maximum thrust level of 90mN, the spacecraft would be able to execute a LoRS trajectory like the one shown in Figure 2 more than 2,400 times. The results also revealed that the required amount of ΔV for a maneuver strongly depends on the direction of the Sun with respect to the spacecraft, since SRP and the Sun’s gravitational force are relatively large compared to Bennu’s gravitational field. Furthermore, each examined trajectory consists of three parts. First, an impactor is deployed from the spacecraft.

Second, the spacecraft removes itself to a safe distance and, third it approaches Bennu again to collect lofted regolith particles.

The work performed during the internship demonstrated that such trajectories are feasible with existing technologies. Future research on LoRS will hopefully lead to an actual mission.

Looking back on my internship, I’m happy to say that it has been a complete success.

It was a very enriching experience in every respect. The hospitality of my guest family and the openness of the Americans were heart-warming. Although the application procedure was a long process, it was worth the effort. The fact that Boulder is located at the foothills of the Rocky Mountains and the presence of numerous student organizations made me enjoy my free time. I encourage future students to take the step I took so that their internship may be the same academic and personal enrichment as it has been for me.

If you are interested in an internship at CCAR or for any other questions, you can contact me at michaelvdbroeck@gmail.com.

References [1] CU Boulder, “About Boulder’’, www.colorado.edu/about, 2016 [2] CCAR, “Colorado Center for Astrodynamics Research”, www.ccar.colorado.edu, 2016

Figure 2 - Example trajectory of a LoRS maneuver. The spacecraft releases the impactor at perigee, distances itself from the asteroid for safety and then closes in on the asteroid again to reach the location of the particles at the right time. The total ΔV is only 0.622m/s.

LEONARDO TIMES N°3 2016

33

YANG

FPP

VORTEX IN THE PROPULSOR INFLOW The aerodynamic interaction between a propeller and a vortex Yannian Yang, PhD candidate, Aerospace Engineering, TU Delft One challenge for the propeller/aircraft integration is the non-uniform inflow on the propeller, which is due to the interference from other airframes. This research focuses on one type of non-uniform inflow: the vortical flow entering the propeller, which is generated from ground vortices or convected from upstream control surfaces. field has an effect of stretching the vortex upstream of the propeller, which results in an increase of the maximum tangential velocity and a decrease of the core radius as the thrust coefficient increases. The circulation in the vortex core undergoes redistribution and the circulation in the inner region of the vortex increases, but the total circulation remains unchanged. The vortex meandering effect upstream the propeller is also inde-

After the vortex goes through the propeller, the flow field containing the vortex is measured at the plane 0.13 R (R is the propeller radius) downstream the trailing edge of the blade root, and one example flow field is shown in Figure 2. The vortex meandering downstream of the propeller becomes larger compared to that of the upstream, because of the cutting process on the blade which has different chordwise and spanwise velocities on the suction and pressure sides of the blade. For the vortex with approximate axisymmetric shape at some specific phase YANG

T

he aerodynamic operating conditions of a propeller can include complex situations where vorticity from sources upstream can enter the propeller plane.

Generally, when the vorticity enters in a concentrated form of a vortex, the interaction between the vortex and blade is referred to as blade-vortex interaction or BVI. For an aircraft propeller, one or more vortices can arise from the ground and impinge on the blades during ground operation [1]. For some specific configurations, the vortex induced by the upstream lifting surfaces impinging on the propeller can be seen in Figure 2. This interaction may affect the propeller performance, cause structural fatigue damage, and generate aeroacoustic noise.

pendent of the propeller advance-ratios at the accuracy of the measurements.

PROPELLER IMPACT ON THE VORTEX By applying a truncated wing in the upstream of the propeller, a well-defined vortex is generated to impinge on the propeller.

The velocities and positions of the vortex upstream of the propeller are quantified by PIV (Particle Image Velocimetry) measurements.

By investigating the vortex properties, i.e. meandering, maximum tangential velocity, core radius, and circulation, the impact of the propeller on the vortex can be analysed. The results show that the propeller induced flow 34

N°3 2016 LEONARDO TIMES

Figure 1 - Result of PIV measurement showing the flow topology downstream the propeller.

angles (phase angle Ψ is defined as zero at the vortex impinging circumferential position, and the positive direction is the same as the propeller rotation direction) of the blade, the properties of the vortex as analysed upstream of the propeller are performed as well.

The vortex downstream of the propeller is still characterized by the stretching effect due to the propeller thrust. The circulation has an increase in the inner region of the vortex due to the stretching effect; the circulation in the outer region of the vortex decreases because of the blade wake with an opposite sign of vorticity.

Figure 3 - Thrust coefficients on one blade in one revolution due to different signs of impinging vortices. a displacement between the suction and pressure sides of the blade; the vortex is chopped into sections, which are located between the blade-wakes downstream of the propeller. The downstream vortex sections still have considerable strength when compared with the upstream vortex, which has the potential to influence the airframes further downstream, e.g. the second row of the rotor of a contra-rotating propeller.

VORTEX IMPACT ON THE PROPELLER Due to the induced flow of the impinging vortex, the propeller inflow has an additional tangential velocity. This additional tangential velocity upstream of the propeller has a non-axisymmetric distribution for a non-coaxial impinging vortex, resulting in a dynamic loading on the blade. The thrust on one blade in one revolution, which represents the variation of the blade loading, is shown in Figure 3. For the co-rotating and counter-rotating vortices, the fluctuations of the blade loadings are compared in terms of the thrust coefficient of one blade, as shown by the black and purple curves in Figure 3. The reference data without impinging vortex is also plotted by the green line in Figure 4. With a thrust coefficient increment for a co-rotating vortex at the phase angles, the blade thrust coefficient has a decrement for a contra-rotating vortex, and vice versa. For the co-rotating vortex case, the blade loading has its maximum value at the phase angle of Ψ=358°, which is near the positon for a contra-rotating vortex with its minimum blade YANG

In addition, the impinging vortex implemented by a Lamb-Oseen vortex model at the velocity inlet is applied in the CFD simulation. By comparing the vortex upstream and downstream of the propeller, the tangential velocity profile and the vortex topology of the CFD results match with those from the experimental results. This means the methodology in the CFD simulation intended to simulate the wing tip vortex is valid to study the propeller-vortex interaction. Based on this, the three-dimensional flow topology of the impinging vortex is further analysed by using CFD, which is shown in Figure 2.

During the cutting process, the vortex has

YANG

YANG

Figure 2 - The three-dimensional flow topology of the vortex impinging on the propeller. The iso-surface shows the vorticity magnitude of |ω|*D/U∞=25.0. Left: global view; right top: detail of the cutting process shows the vortex displacement in the chordwise direction; right bottom: detail of the cutting process shows the vortex displacement in the spanwise direction.

loading (Ψ=10°); and it has its minimum value at phase angle of Ψ=225°, which is near the positon for a contra-rotating vortex with its maximum blade loading (Ψ=232°).

The integral effect of this dynamic blade loading on the propeller performance is investigated by the time-averaged thrust coefficient and the efficiency, as shown in the left and right side figures of Figure 4, respectively. The increment of the thrust coefficient dominates the effect of the vortex on the propeller for a contra-rotating vortex. The same mechanism governs the co-rotating vortex but the loading variation is switched with respect to the contra-rotating vortex case. The torque coefficient follows the same trend as the thrust coefficient. Therefore, the efficiency of the propeller is independent of the impinging vortex. As the magnitude of the vortex strength increases, its effect on the thrust and torque coefficients also increases.

The impact of the vortex on the time averaged loading of the propeller is relatively small, e.g. there is a 5% increase of thrust coefficient with the impinging vortex strength of CVP/(U∞∙D)=-0.1724 and imping radial position of 0.75 R compared with the uniform inflow case. However, the dynamic loading on the blade has a strong fluctuation, e.g. the maximum thrust coefficient on the blade is 16% higher than that of the minimum loading for the above case; this cyclic loading has the potential to cause structural damage and it should be taken into account during the blade design.

If you have further ideas or want to contribute to this research as a graduate student, contact the author for further information by email G.Eitelberg@tudelft.nl References

Figure 4 - Propeller performances versus vortex strength. Left: thrust coefficient; right: efficiency. r_imp/R=0.75, J=1.1.

[1] Yang, Y., Sciacchitano, A., Veldhuis, L., and Eitelberg, G., “Experimental investigation of propeller induced ground vortex under headwind condition,” AIAA Aviation, Atlanta, 2014, AIAA 2014-2308.

[2] Stuermer, A. and J., Y. DLR-AS CROR & Propeller noise. in 14 CEAS-ASC Workshop.

2010. Warsaw, Poland.

LEONARDO TIMES N°3 2016

35

VISIT

VISITING SES ASTRA IN LUXEMBOURG A tour of the largest satellite media broadcasting company on the globe Eleonoor van Beers, Editor Leonardo Times

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N°3 2016 LEONARDO TIMES

With a fleet of over fifty satellites that reach one billion people worldwide, SES Astra has made an impressive name for itself. A team of four Leonardo Times editors were invited for a tour of the headquarters, located in Luxembourg.

The SES Astra SA headquarters in Betzdorf, Luxembourg, are well hidden from view. Located in Château de Betzdorf, a palace that previously housed the Grand Duke’s family until 1964, you have to take windy routes through fields and woods until the sharp turn left up a seemingly dead-end road leads to the security-heavy iron gates. Coming up over the hills, it gives way to a view of SES’s satellite dish field- rows upon rows of dishes ranging up to fifteen meters in diameter.

The headquarters are equally impressive.

The château itself is not the sole building; SES Astra has expanded hugely and the surrounding newer buildings make up the various offices and control rooms, one of which used to house their own means of generating electricity in the unlikely case of a main grid power cut, something that could be catastrophic if not fixed in time. The campus and satellite dish field are enclosed by fields and forests, contrasting the modern buildings with nature and giving it a peaceful atmosphere.

a ground station, it appears as though there is only one satellite. This not only does reduces the number of orbital positions required for the same number of satellites, but it also allows the operator to vary the throughput of each satellite as required, whilst maintaining high reliability (if one satellite fails, there are others to back it up). By using onboard ADCS systems, SES Astra ensures that satellites are always within their allocated 150km ‘box’, and typically a distance of 5km is maintained between two in the same orbital position to avoid collisions.

The presentations were followed up by a tour of the facilities. Walking past the satellite dish field was impressive, but due to the ra-

dle East. They focus on emerging markets where the population has limited access to internet and connectivity, reaching an estimated three billion people (which is where the name stems from: the Other3Billion).

Their lower orbit means that latency is reduced compared to geostationary satellites, allowing for fast connection.

Each satellite transmits ten focused Ka-band beams, 700km in diameter, onto Earth, allowing for specified coverage. However, due to their MEO orbit, the satellites travel faster than Earth spins. This means that the satellites need to ‘hand over’ their regions with coverage to each other as they orbit, requiring careful and precise handling. These beams allow for remote places to have connectivity, or even be tracked, such as cruise ships.

SES Astra also offers internships. Speaking

SES was founded in 1985 as the first private satellite operator in Europe and by 1990 they were already broadcasting to fourteen million viewers. In 2011 they merged with American satellite operator Americom and The Hague-based New Skies to form SES Astra, and are now one of the leading satellite operators in the world. Specializing in high-throughput broadband, the SES satellites transmit over 7200 channels around the globe (2200 of them HD), reaching 317 million homes.

After a presentation introducing the company, their background and their general operation, a short technical presentation was held explaining how the satellites are managed and controlled. The fleet of 53 geostationary satellites covers 99% of the globe, with shares in satellite operators from a great range of counties. Six more satellite launches are planned in the coming two years. Their latest one, the SES-9, launched successfully from Cape Canaveral with SpaceX’s Falcon 9 on the day we arrived.

The satellites themselves are not designed

by SES Astra, but they are ordered from various space companies such as Boeing, Airbus, Orbital and Lockheed. Although SES has 22 offices worldwide, they are controlled from eleven, with a couple located on each continent excluding Antarctica.

To give us a little more insight into the technical aspects of controlling satellites, they explained how SES pioneered satellite co-location. Satellites occupy orbital positions on the geostationary ring, however, at co-location places two satellites are within such close proximity of each other that, seen from

Control room at SES Astra. diation, entering the area was forbidden. The satellite control room was also visible behind a one-way mirror, where thousands of TV channels were being broad-casted at that moment on hundreds of screens. At least five controllers are needed per 30 satellites at a time, day and night.

SES Astra’s main service is video and TV, however, they also offer services in three other areas: enterprise, mobility and government. The enterprise and mobility sectors also use the MEO (medium earth orbit) satellites through its investment with O3b.

O3b is a pioneering company that owns twelve satellites at 8062km altitude at 0° inclination, that work together to provide communication services for North and South Americas, Asia Pacific, Africa and Mid-

to an intern who had graduated from the TU Delft, he explained that his year was divided into three parts, each dedicated to a different area of the company, and that soon he would move to the SES office in Washington DC. “It’s a great opportunity to experience each part of a working company, giving me insight into what I enjoy.”

Special thanks go to Sybren de Vries, Marie-Pierre Quinet, Marc Friederes for making this wonderful visit possible.

References [1] "SES – Global Satellite Services Provider SES.com." <http://www.ses.com >.

[2] "O3bNetworks – The Reach of Satellite with the Speed of Fiber" O3b Networks. N.p., <http://www.o3bnetworks.com/service-coverage/>.

LEONARDO TIMES N°3 2016

37

INTERVIEW

CEO INTERVIEW: NLR Michel Peters’ talk with the Leonardo Times Victor Gutgesell, Editor-In-Chief Leonardo Times Martina Stavreva, Editor Leonardo Times Upon his visit to the faculty of aerospace engineering in Delft, Michel Peters’ sat down with two editors of the Leonardo Times to have a CEO Interview.

As general director of NLR, what does your average day look like?

I think the best answer to that question is that I don’t have an average day. Which is good news I would say since if I had an average day, I would get bored. I am in so many panels, next week for instance, I will be in London for two days, meeting my global colleagues. Wednesday I will have a farewell dinner for Paul Riemens who will no longer lead the LVNL, and Thursday I will fly to Warsaw to meet my European colleagues and so on. That is just normal for me, but it’s not like one’s average everyday life. Most of my colleagues at NLR have a similar network and that makes it a very nice place to work.

from TU Delft in 1987, however only started working at NLR in 2004, what did you do before you worked at NLR? I graduated from TU Delft in 1987, that is true.

However, I started working at NLR in ‘87/88 and stayed there until ‘94. I then shifted to Martinair and worked there for a couple of years. At the time I was head of the maintenance department. After a couple of years, I was responsible for the complete Martinair and KLM city fleet, because Martinair did their maintenance too. I then switched back to NLR, because my predecessor, Fred Abbink who was a technical director at the time asked me if I would like to lead one of the divisions at NLR and I said yes.

Isn’t this a little tiring from time to time?

Tiring, that has to do with your personal outlook and with the activities you do. If you do boring activities then you get tired, but for me that happens quite rarely.

How did you become interested in aerospace?

That is an interesting story. I was always interested in aviation and if I did not have glasses I would be a fighter pilot now. Being in the air force is kind of a boy story. Every boy wants to be a fighter pilot, but that’s not possible.

According to the internet, you graduated 38

N°3 2016 LEONARDO TIMES

BIO

MICHEL PETERS

Michel Peters is currently the CEO of Nationaal Lucht- en Ruimtevaartlaboratorium (NLR, in English: National Aerospace Laboratory).

He is 56 years old and originally from Rotterdam. In the early 1980s, he studied electrical engineering in Twente. Following that, he switched to TU Delft for his master study in avionics, graduating in 1987. Just after his graduation he started working at NLR, followed by a quick period at Martinair in the maintenance department. In 1994, he went back to NLR and went through the ranks of a department leader, division leader and finally general director. Today, Michel Peters is an honorary member of the VSV ‘Leonardo da Vinci’ and maintains good contact with the study association. Henceforth, on May 13, 2016 he came to Delft for a public interview and on the same visit he agreed to be interviewed by the Leonardo Times.

NLR is successor to the Government Service for Aeronautical Studies (RSL), which was founded in 1919 and aimed to increase air safety for military aviation. Later on, due to the rapid growth of civil aviation, RSL put focus on that sector as well. Turning into a foundation in 1937 called for the organization to be renamed to NLL and subsequently to NLR. The main mission of the organization is “to increase the sustainability, safety and efficiency of air transport”. This is done by identifying, developing and applying advanced technological knowledge in the aerospace sector.

Special guests of the VSV 'Leonardo da Vinci' sign the window of opportunity, an aircraft window, framed and hung up in the aerospace faculty at TU Delft..

Anyhow, the interest was there and I started my academic career at the University of

Twente, where I did two years, until I found out that there was an avionics specialization in Delft, which is a combination of electrical engineering and aerospace engineering. So after two years in Twente, I shifted to Delft where I finished my education as an electrical engineer with a specialization in avionics.

Why did you not go for aerospace engineering right away?

Well, I love electronics as well. Thus, electronics in combination with aerospace was really my thing. To this day, I find it fascinating that a relatively small box, a computer, an electronic circuit, filled with some software flies an aircraft. I still find it intriguing how a big 747 flies and lands. For this you need to have an understanding of the flight characteristics of the aircraft as well as the required control loops and how they are implemented by the on-board computer.

You have to understand what the flight characteristics of the aircraft are, but you also have to understand how a computer works, in order to apply a control loop. And of course for this you need an understanding of control loops and so on.

Do you sometimes feel you should have

remained in research instead of becoming CEO? NLR is an applied research institute, so all the activities we do have a technical content. Of course I have to mainly manage and take decisions, for example on what we should focus on next and why we should invest money in the research of composites instead of the newest metals. But that is always a technical question too, and that’s what makes it interesting. I would not like to be the general manager of a bank, because that’s not in my expertise and does not make me tick. Pure management is not for me, but as long as I have to deal with some technical questions, I do not regret my decision.

What did you find most challenging during your career at NLR? That is not an easy question. I mean, there are many technical challenges of course, and certainly in my current job I am responsible for that in the end. But hands down, those challenges are probably the easiest ones.

My colleagues and I went to university to deal with such tasks; we are trained to overcome them. Of course there are technical problems, but that is our everyday business.

Sometimes it is difficult to persuade people to invest in innovation that is in the broader sense, not only in Aerospace. The Netherlands is quite a competitive economy, and that has everything to do with the amount of innovation that is taking place here. Nonetheless, this innovation has to pay off and nobody likes to invest in something with an uncertain outcome. In order to develop innovative products, you need educated people. If you compare to that, and I don’t want to sound as though I am complaining, but if you look at how Germany handles this, they really have a heritage of putting a lot of money into fundamental research and applied research.

What do you think will be the biggest challenge in the aerospace field in the next few decades?

The transition from fuel engines to electrical propulsion. This is an on-going progress now and will of course continue. Already now, we can see the first steps. The E-fan by Airbus is one, and I do think that there is a future, a large future, in electric motors because they are far more efficient than jet engines. The big challenge though, is still: how do you store the electric energy? This is a problem of many fields but also of aerospace. To find a solution will take a lot of time, but eventually I believe it will happen because the environmental impact of aviation is becoming greater and greater and people don’t want emissions or noise around their houses and I do think that at the end of the day, the only solution will be electrical propulsion.

References [1]Interview with Michel Peters on May 13, 2016 in Delft LEONARDO TIMES N°3 2016

39

DONQI URBAN WINDMILL

WIND ENERGY

DUCTED WIND TURBINES A potential energy shaper Vinit Dighe, PhD candidate Aerospace Engineering, TU Delft In order to harvest wind resources more efficiently and to the greatest extent possible, unconventional wind turbine designs have been proposed, but never gained any acceptance in the marketplace. A team of researchers from TU Delft plans to revisit the concept of ducted wind turbines, which have been around for decades, and provide some clarity on its potential.

Over the past several years, the concept of ducted wind turbines has managed to create some curiosity. This concept, claims to 40

N°3 2016 LEONARDO TIMES

augment the power production by roughly two times more than any conventional turbine design (Van Bussel, 2007). The technology for ducted wind turbines was first tested by a US company, Grumman Aerospace in

DUCT4U

A

lthough we are always inclined to get 100% of everything, it is seldom possible. Sometimes nature has its reasons of confining mankind from achieving its goal. One of the most important inventions was made, way back in 1919 by a German physicist Albert Betz, who demonstrated that we can only extract 59% energy from wind turbines (Burton, 2001). It is quite interesting that a calculation made almost 100 years ago holds true even today and nobody yet has been able to prove otherwise, but many continue to claim that it's false. Intelligent thinkers and engineers have tried almost every possible approach to boost the wind energy captured, with some unique and innovative designs, but never managed to shake the iconic three-bladed horizontal axis wind turbine off its footing. These designs are a testament to the countless brainstorming sessions and ingenuity of todayâ&#x20AC;&#x2122;s engineers, which may leave you asking: How exactly is this supposed to work?

the 1970s as a part of a US Energy Department-funded project (Oman, 1978). The full potential of this research was not realized because of the problems in securing the construction material and therefore redirecting the R&D focus. In 1997, the world's first commercial ducted wind turbine was installed by the developer Vortec Energy Ltd. in New Zealand (Phillips, 1999); its performance was evaluated by researchers from The University of Auckland and from the Crown Re-

Figure 1 - Schematic of the ducted wind turbine with multi-element duct and trailing edge vortex generator.

search Institute Industrial Research Ltd. The theory and the wind-tunnel investigations behind this concept have delivered some hopeful results, but failed when tested in real outdoor conditions.

duct surrounding the rotor blades.”

It’s an interesting concept that attempts to enclose the turbine blades in a cylindrical shaped casing, as shown in Figure 1; the duct, shroud or diffuser as its denoted, sometimes is designed to accelerate the moving airflow before passing through the blades.

Theoretically, the power produced by the wind turbine is directly proportional to the cube of the wind speed. Thus, any increase in the wind speed could result in significant power augmentation. Martin Hansen, in his book on Aerodynamics of Wind Turbines, says quite explicitly: “It is possible to exceed the Betz limit.” In the studies dealing with ducted wind turbines, he explains that: “If the cross-section of the diffuser is shaped like an airfoil, a lift force will be generated by the flow through the diffuser. . .” The point here is that the duct geometry creates a low pressure region behind the blades and thus, more air is being drawn by the turbine. Moreover, in the case of a ducted wind turbine, the drag on the duct/diffuser does not contribute to the turbine power. The commenters and few wind energy experts believe the odds are long that this turbine can come even close to delivering the theoretical limits and outweigh performance of the conventional turbine design.

A team of researchers is investigating the idea, further forming a part of a research consortium: Duct4U, which is funded by the STW grant. The consortium consists of the Faculty of Aerospace Engineering - Wind Energy Research Group and the Faculty of Mechanical/Maritime/ Materials Engineering; TU Delft. The consortium will be complemented by industrial partners NPSP BV, Femtogrid Energy Solutions BV and Windchallenge Holland BV. The project aims towards improvement of the aerodynamics and energy performance of the ducted system for urban applications. The experiments will be conducted partly at the TU Delft Open Jet Facility (OJF) and partly at an outdoor testing site: The Energy Wall. The Energy Wall is a large scale conceptual framework along the entering road to TU Delft. The idea is to combine solar panels, small urban wind turbines, a smart grid (DC operated), fine dust mitigation devices and LED lighting. Twenty five or more small urban wind turbines are planned to be integrated into the Energy Wall. This would prove an excellent test-bed, where the ducted turbines could be tested in real outdoor conditions. In parallel, studies based on combined use of theoretical aerodynamics and computational simulations, mainly CFD, would be carried out. This combination between research and tests would allow a good comprehensive validation of theory and models.

Despite the questions and skepticism, Prof.

Gerard van Bussel, a wind energy expert at TU Delft, strongly believes in the idea and says: “One of the most promising concepts for urban wind energy harvesting is the ducted wind turbine.” In the past, ducted wind turbines were only considered for large power and ground applications, due to the heavy cost and weight of the duct and of the tower, which posed difficulty in proposing an economically appealing product. For small size and urban wind turbines, the shortcomings associated with the high cost of the duct and of the tower have a minor impact on the overall cost. Prof. van Bussel adds:, “Ducted wind turbines are a good candidate: They are aerodynamically more efficient than bare wind turbines, inherently safer, produce less noise and have less visual impact due to the

A second aerodynamic phenomenon related to ducted wind turbine that has only been partially explored is based upon the extraction of energy from the air flowing outside the duct. If the reduced wind speed behind the rotor is enhanced, more energy per processed volume of air can be extracted by the turbine blades. Some solutions, mainly based on blowing and swirling of boundary layer flows, have been proposed, but with moderate success. This project will investigate the potential of triangular vortex generators and multi-element ducts to re-energize the reduced wind speed behind the rotor.

The combined effect of irregular protrusions (vortex generator) and multi-element ducts would result in a large scale flow separation outside the duct, where a very low and unsteady pressure zone appears. As a result,

CFD simulation using the simplified 2D duct profile showing velocity contours (left) and static pressure contours (right).

Experimental test conducted on the `DonQI Urban Windmill 1.5’ model in the Open Jet Facility, TU Delft. an increased mass flow is swallowed by the rotor and greater power output seems obtainable. Furthermore, the aerodynamics and the integration of ducted wind turbines with the infrastructural elements will be investigated, which may further enhance the performance and cut down the installation costs. In the system optimization process, noise mitigation and enhanced control systems will be taken into consideration.

The current wind turbine technology is already upscaling, and the fact that researchers across the world are exploring different ways to harness this clean energy source should be an encouraging sign to renewable energy’s bright future. The ducted turbine research is in active development, and if successful, the product design could offer an improved and efficient energy solution for urban environment.

If you have further ideas or want to contribute to this research as a graduate student, contact the author for further information by email V.V.Dighe@tudelft.nl References [1] Burton, T., Sharpe, D., Jenkins, N., & Bossanyi, E. (2001). Wind energy handbook.

John Wiley & Sons.

[2] Van Bussel, G. J. (2007). The science of making more torque from wind: Diffuser experiments and theory revisited. In Journal of Physics: Conference Series (Vol. 75, No. 1, p.

012010). IOP Publishing.

[3] Oman, R. A., & Foreman, K. M. (1978). U.S. Patent No. 4,075,500. Washington, DC: U.S. Patent and Trademark Office.

[4] Phillips, D. G., Flay, R. G. J., & Nash, T. A. (1999). Aerodynamic analysis and monitoring of the Vortec 7 diffuser-augmented wind turbine. Transactions of the Institution of Professional Engineers New Zealand: Electrical/ Mechanical/Chemical Engineering Section, 26(1), 13.

LEONARDO TIMES N°3 2016

41

AIRBUS

AVIATION DEPARTMENT

THE AIRBUS A400M The road to the most advanced strategic and tactical airlifter in the world.

Bart Jacobson, BSc Student Aerospace Engineering, TU Delft The Airbus A400M was launched in May 2003 to provide a solution to the needs of seven European nations grouped within OCCAR. The A400M is one of the most advanced combined strategic and tactical military airlifters in the world, but it did not come without some very expensive setbacks.

The A400M was required to have a cruise speed of Mach 0.72. Since no existing turboprop engine was able to deliver enough power to reach that speed, a new engine had to be designed. Three different engines were deemed suitable: the SNECMA 42

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M138 turboprop, the Pratt & Whitney Canada PW180 and the Europrop International TP400-D6 engines, after Airbus Military issued a request for proposal in April 2002. Eu-

PRODUCTION AND DELIVERY The first problems started to come to light in 2009, when it was announced that the first deliveries would be postponed until at least AIRBUS

ORIGINS AND DEVELOPMENT The project for the development of the Airbus A400M began in 1982, as a cooperative effort between Aréospatiale, British Aerospace (BAe), Lockheed and Messerschmitt-Bölkow-Blohm (MBB) to replace the C-130 Hercules and the Transall C-160.

The project group was called the Future International Military Airlifter (FIMA) group.

Due to international politics and varying requirements, the evolution of the project was sluggish. Lockheed stopped their involvement in FIMA in 1989 and started on the development of an upgrade to the Hercules: the C-130J Super Hercules. This opened up a spot in the production team for the Italian company Alenia and the Spanish company CASA. FIMA, thereby, changed the name of the group to “Euroflag”.

roprop was selected to produce the engines for the A400M, as the SNECMA engine did not meet the requirements and the PW180 was rejected due to political interference.

Airbus A400M taxiing.

AIRBUS

A400M with flares.

2012, due to ‘certain technical characteristics’ that were to be renegotiated. Shortly after this announcement, Financial Times Deutschland reported that the A400M aircraft was 12 tons too heavy and that it would be unable to achieve the critical performance requirement of being able to lift at least 32 tons. It would therefore be unable to carry certain military equipment it was initially designed for. In February 2009, the A400M was already €5 billion over budget and three to four years behind schedule. In November 2010, Belgium, Britain, France, Germany, Luxembourg, Spain and Turkey agreed to lend Airbus Military €1.5 billion for the project. In spite of this, the cooperating countries started to revise their orders. The UK reduced its order from 25 to 22 aircraft and Germany from 60 to 53. Britain’s former Minister of Defense Procurement, John Gilbert, stated in the British House of Lords "The A400M is a complete, absolute disaster, and we should be ashamed of ourselves. I have never seen such a waste of public funds in the defense field since I have been involved in it these past 40 years."

DESIGN PHILOSOPHY With the A400M, Airbus was trying to bridge the gap between the previous generation tactical airlifters and the current strategic airlifters. The previous generation tactical airlifters, like the C-130 Hercules, had good performance on unpaved runways and in

challenging and dangerous terrain, but were too small to carry the outsize military and humanitarian relief loads. The current strategic airlifters, like the C-5 Galaxy, are very good at carrying outsize loads over long distances, but they cannot land on difficult terrain and they are very expensive. The A400M aimed to close this gap by having good tactical abilities in difficult environments and being able to carry outsize loads over long distances at high speed.

TECHNOLOGY One of the key new features in the design of the Airbus A400M was the newly designed turboprop engine. The eight-bladed, 11 000 shaft horsepower engine was developed

by EuroProp international, which is a consortium of Rolls Royce, Snecma, MTU and ITP. The new turboprop engine is the most powerful single-rotation turboprop in the world. It was this new engine that allowed the A400M to have such a large flight envelope. It can cruise at 37,000ft at speeds up to Mach 0.72. At the other extreme of the envelope, it can fly at 150ft at 110kts for airdropping operations. The two engines per wing are counter-rotating, which has led to a structural weight reduction in the wings.

Due to the symmetry of the aircraft when the four engines are running, the adverse yaw in case of an engine failure was reduced thereby decreasing the size of the tail fin by 17%.

Another benefit has been that the lift at low

speeds has been increased by 4%, thus reducing the size of the horizontal stabilizer by 8% and simplifying the slats.

SPECS With a maximum payload of up to 37 tons (81,600 lb) and a volume of 340m3 (12,000 ft3), the A400M can carry numerous pieces of outsize cargo. This may include large vehicles and even helicopters such as the NH-90 or a CH-47 Chinook. It can also carry heavy infantry fighting vehicles, trucks, boats and excavators or mobile cranes to assist in disaster relief operations. The large cargo hold can accommodate 116 fully equipped troops or paratroops, seated in four longitudinal rows.

CONCLUSION Even though the Airbus A400M has had many setbacks during the development stages, it looks as though Airbus has come out on the top, to design and build an extremely modern transport aircraft that is ready to face the challenges ahead.

References [1] http://www.raf.mod.uk/equipment/atlas. cfm [2] http://militaryaircraft-airbusds.com/Aircraft/A400M/A400MAbout.aspx [3] http://militaryaircraft-airbusds.com/Missions/MissionsMilitary/Transport/Outsize. aspx The Aviation Department

Capacity: 37,000kg

Crew: 3 or 4

Cargo compartment: 4 x 3.85 x 17.71m

Engines: 4x Europrop TP400-D6 turboprop 8,200kW (11,000hp)

Length: 45.1m

Cruising speed: 781km/h (at 9.450m alt.)

Wingspan: 42.4m

Range: 3,300km (at max payload)

Height: 14.7m

Ferry range: 8,700km

Wing surface area: 225.1m2

Service ceiling: 12,200m

Empty Weight: 76,500kg

Takeoff distance: 980m

Max takeoff weight: 123,000kg

Landing distance: 770m

The aviation department of the Society of Aerospace Engineering Students ‘Leonardo da Vinci’ fulfills the needs of aviation enthusiasts by organising activities like lectures and excursions in the Netherlands and abroad.

Table 1 - General specifications LEONARDO TIMES N°3 2016

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POLYTECNIC MUSEUM, MOSCOW

INTERVIEW

FROM A BRICK TO A COMET An interview with Matt Taylor, a project scientist for ESA’s Rosetta mission Thijs Gritter, Editor Leonardo Times Mannat Kaur, Editor Leonardo Times

What first sparked your interest in space?

To be honest, my story is not a typical one. I know some people who saw Sputnik in the 1950s, or the Moon landing, which inspired them to forge an entire career just to go to space. For me, this was not the case. I come from a working class family, my father was a bricklayer and had no desire for me to become one as well. He therefore encouraged me to pursue further education, beyond high school. I went to the University of Liverpool, where I became particularly interested in becoming a professional scientist and realized before long that I wanted to carry on past an undergraduate degree. At that time, particle physics had piqued my interest more than anything else. I followed one Astronomy course and was captivated by it. I went on to apply for PhDs in astronomy, which asked for very high grades, but it was the interview with the people from the Imperial College London that ultimately drove me to do Space Plasma Physics research - I got a good feel during the interview. After that, I started to look for a postdoctoral placement and found myself at the Cluster mission at 44

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Mullard Space Science Laboratory in Surrey.

The Cluster mission aims to investigate the physics of how the Sun’s upper atmosphere interacts with our magnetic field. From there, ESA/ROSETTA/NAVCAM

Matt Taylor’s terrific reputation precedes him. Despite this, prior to the interview you aren’t really sure what to expect. This marvelous astrophysicist with a charming personality fosters a deep-rooted passion for science, leading to a very interesting and genuinely inspiring interview.

67P/Churyumov–Gerasimenko comet, as captured by the Rosetta orbiter.

ESO

BIO

MATT TALYOR Matt Taylor did an undergraduate Physics degree at the University of Liverpool, after which he received a PhD in space plasma physics from the Imperial College London.

After completion of his PhD, Matt started working at the Mullard Space Science Laboratory as a research fellow for the four spacecraft ESA Cluster mission, which studied the interaction of the Sun’s solar wind with the Earth’s magnetic field. In 2005, he got a post at ESA where he worked as the project scientist for Cluster. His work on the cluster mission lead to 70 first of co-authored papers. In 2013, Matt Taylor was appointed as the project scientist for the Rosetta mission, which succeeded in landing the Philae lander on comet 67P/Churyumov-Gerasimenko.

The Lagoon Nebula partly consists of space plasma.

ESA

I got a feel on how to interact with different people and work in teams. After doing a couple of other postdoctoral placements, I realized that I was not suited for being a professor; I preferred conducting and helping others with their research. When I found out that there was a permanent position on the Cluster mission at ESA, I applied and got it! That’s where I have been working for the past eleven years.

You did your thesis on 3D space plasmas.

What are space plasmas and what triggered your interest in this field?

Plasma is the fourth state of matter. You have solid, liquid, gas and when you put enough energy in a gas, it splits into its charged constituents. This is a plasma, and it is what most of the universe is made of. Stars for instance are made up of plasma. Concerning my interest in the field, I wanted to do a PhD related to space, and space plasmas happened to be what the Space and Atmospheric group were doing at that time, as well as interpreting data from Galileo and Ulysses.

As opposed to other astrophysical entities, which are so far away that even light from that location would take years to reach us, plasmas are locally available. By detecting and analyzing the physics behind this phenomenon, one can relate the findings to other areas and fields. Even though you cannot get your hands on it, since it cannot be seen, you can send a spacecraft and attempt to detect it in situ. A familiar example are the Aurora Borealis; they are evidence of such plasmas on Earth.

Would you say that space plasmas are similar to dark matter ?

Not really, they are somewhat different. Dark matter, or dark energy, is a hypothetical form of matter that serves to balance all quantities and elements in the universe when summed up.

Artist impression of Rosetta orbiting the comet while Philae lands.

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We know what plasmas are like and how they behave, but dark matter and dark energy remain unknown elements that we do not yet understand.

You have a lot of experience working at ESA, what is the trickiest situation you have ever encountered there?

The trickiest situation I have ever been in was when I started to work on Rosetta, because I joined the mission in full flight. Effectively, the project had already been underway for ten years. It was an opportunity to work on something that was, in my opinion, the biggest undertaking we have had for a long time. The hardest part was meeting the team for the first time. Most of the scientists had been working on this mission for years, some even their whole career. Then there I was, coming out of nowhere to supposedly guide and help them. It was all very intimidating. It remained difficult, because the mission is such high profile and everyone wanted to do their own work, but of course not everything can be done at the same time. We do not have the capability to get all the data that everyone wants. Furthermore, there is always a discussion or things running in the background. It has been a challenge for me since 2013, to come into a mission at a very late stage, when everyone was used to do things in a certain way and I had to adapt to that and work with these people to achieve our common goal.

There is a theory that life on Earth could have been seeded by a comet. Could you tell us how the Rosetta mission could validate or oppose this theory?

This is a very particular theory, which I would say is not widely accepted. The key aspect of this notion for me is that some of these CSIRO

The Rosetta mission is truly one of a kind.

What would you say was the most surprising thing you learnt over the duration of

the project?

I was actually surprised about the number of people that were interested in, what is essentially a big lump of dust, dirt and ice, and that it had such an impact, to the point that everyone was excited about it and a lot of people got involved. This interview reflects this as well, if I were still working with the Cluster mission, I would not be here. The manner in which it has captured peopleâ&#x20AC;&#x2122;s imagination was what surprised me the most. There are many things that I am in awe of, like the way Cometary science relates to all those paramount questions regarding where we come from and how the solar system was formed. The fact that we are detecting phenomena from a comet that can alter the way we think about the temperature of the cloud from which the solar system was formed is astounding. Perhaps, it is because of this that so many people are interested in the Rosetta mission.

celestial bodies actually carried life on them. The problem that my colleagues and myself have with this is that a comet is such a desolate place that it couldnâ&#x20AC;&#x2122;t possibly support life. There is simply not enough energy on them. One of the key questions that the Rosetta mission was hoping to resolve was looking at the origin of the solar system. We are viewing comets as the suppliers of the key building blocks of life; therefore, they have the primordial materials that were present at the beginning of the solar system.

Such materials can be found in smaller celestial bodies, such as comets, within which we are looking to postulate how the solar system was formed, and there are all kinds of constituents there. Carbon-based materials that are found on comets could be the building blocks to life, but they are incapable of supporting it.

However, the question still remains whether the comets brought these key materials to the Earth One of the things that we are doing is comparing the different abundances of various materials on the comet to materials on Earth and other planets in our solar system.

We discovered that the water found on this comet is different to that found on our planet.

This shows that comets are unlikely to have brought all of the water to Earth, as they are not a predominant mechanism of delivery.

This is in line with some of the results we had with other comets. However, it does not rule it out completely, it only says that they might have contributed a little bit, but the majority of the water more likely came from asteroid impacts. From the measurements, we see that, even if comets had only a minor impact, only a few of them would have been needed to deposit the corresponding amount of material on Earth. The fact that this substance exists and is deep-frozen means that it was there from the beginning and that it could have brought organic material to the Earth.

Putting that together with the water that came from the asteroids and some sunlight just might have set things in motion.

What do you think will be the next step(s) regarding comets in terms of science or

A simulation of two merging black holes and the resulting gravitational waves.

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ESA/NASA

exploration?

This has been recently discussed during a few meetings I set up with my colleagues.

It was about the Giotto mission, which went past the comet Halley in the 80s. We looked at how we got from Giotto to Rosetta and what we could project. In fact, Rosetta was proposed to be a sample-return mission, but because that proved to be too difficult, we tweaked the mission parameters instead.

You could make an incremental step from Rosetta, because the biggest challenge is conducting all the experiments at the same time. What you probably want to do is have a couple of spacecraft, each investigating different elements at the same place. However, for me, it is the actual sample-return which would be the next step, and that’s a massive challenge. To actually grab a piece of a comet, and then bring it back. It is not just about deploying the mechanism correctly.

The key part is to actually keep that material restrained and uncompromised. You have to keep it at temperatures hundreds of degrees below zero centigrade, bring it back intact at that same temperature, and get it to a lab without opening the bottle. However, I am not sure whether we will do this in the near future, because it is such an elaborate and expensive mission.

The recent detection of gravitational waves is phenomenal; could you give us an insight into gravitational wave astronomy?

Well, it is not my field as I am a plasma physicist, but certainly you can’t help but pick up on the waves. I have two colleagues down the corridor from myself, Paul McNamara, who is the project scientist of LISA Pathfinder and Olivier Jennrich, who are both working on the gravitational waves and are massively excited about the discovery. A newly realized mechanism that opens up another universe is absolutely fascinating and stimulating. However, what to do next is the not so obvious. One makes an observation, but how do you build on that to make it a robust

and a useable mechanism? You have what is called “multi-wavelength universe” in astronomy, wherein you use different wavelengths in telescopes to observe various phenomena in the universe, and now gravitational waves add a new dimension. This will be built up into ESA missions, based on LISA Pathfinder, which is a technology demonstration mission, and will lead to bigger missions within the next twenty years. Frankly, confirming that such a hypothesis is actually correct is an amazing aspect of science and was great to see.

Are there certain questions you hope will be answered by gravitational waves, or are you just hoping to see the discovery of new things?

For me, it is more about broadening the scope for what we can look at. You end up with more questions than answers, so you have to change your perception of what you are doing, depending on the situation and the context. I would imagine that the detection and utilization of gravitational waves will likely change our approach on how we will do things at ESA and that we evolve given the new findings.

How does the discovery of gravitational waves influence future ESA-missions and in particular the eLISA mission which is planned to be launched in 2034?

First, let me make clear that in our science program we have small, medium and large class missions. We will have calls for the next large class missions, but we took kind of a consolidated approach to look at a pathway for said undertakings. The community was saying that x-rays and gravitational waves are the way of the future, which locks out the big money program until 2030. This means

that for the next 20 years at least, after the Juice mission to Jupiter, it is unlikely that ESA will do planetary missions as extravagant as the Rosetta mission alone. So, unless we are able to work together with other agencies, we will not do a sample return mission for example. Due to the discovery of gravitational waves, we have not changed what we are going to do. However, the technology that is needed to achieve what we want to attain, which is a space placed interferometer, is the reason that the eLISA mission is planned so far in the future. We knew that at least we had to realize certain technologies, like the LISA pathfinder, in order for the interferometer to come about. eLISA was a mission for the near future, but it is now pushed further downstream. Regarding the large and medium class missions, there is a cadence to them. Every few years, we will have a call for a medium class mission, which costs around five to six hundred million euro, against closer to one billion for large class missions. These billion euro class missions, like the x-ray and gravitational wave missions, will probably have to wait for the 2030s, whereas this year there will be a call for medium class ones.

What are your goals for the future and what missions would you like to work for?

At the moment, I just want to make it until October, because my short-term goal is to complete the Rosetta mission. My work at the moment is to end the mission as we have planned. We put the spacecraft on the comet, which means that we have limited time to conduct all the calculations and necessary projections. There is in fact, a list which is actually getting bigger and bigger, with things to do until the end. This can be quite stressful, because “let’s do it next year” is not a possibility. There is no next year, as the data rate and the power are draining since the spacecraft is getting further away from the Sun. So, there are numerous factors that are compounding the situation, which is why we will eventually break the orbiter. When everything is done and Rosetta crashes on the comet, I will be busy focusing on making sure that the data taken from the comet is put into valuable format so that observations can be made. That will be my task for the coming years.

If you wanted to land on a comet or another astronomical body, which one would it be?

I would not want to go there myself, because I do not have the stomach for it. Astronauts are a particular breed that can do it for that very reason. Though I would really like to work on a comet sample-return, or a mission that would go to one of the icy moons such as Enceladus, land there, drill and go subsurface below the ice, to see if you can actually find liquid water. It is quite boring, but it’s something that has not yet been done, which is always interesting.

References [1] http://rosetta.jpl.nasa.gov/ LEONARDO TIMES N°3 2016

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ESA

SPACE ENGINEERING

TRAJECTORY DESIGN: SOLAR OBSERVATORY High ecliptic inclinations with low thrust solutions Luca Corpaccioli, MSc Graduate Aerospace Engineering, TU Delft er (SolO) mission, set to launch in 2018; the probe will reach an optimal heliocentric orbit by making use of a complex series of Earth and Venus gravity assists – its orbit will have a maximum inclination of 26 degrees [2].

LOOKING AT THE SUN

EXISTING RESEARCH AND TOOLS

The motivation for this research stems from the need of our modern society to understand the Sun's impact on life on Earth. Our star’s behavior is dynamic, extremely complex, and has a strong impact on dozens of fields. These range from predicting tomorrow’s hurricane movements to modeling climate change for the next 100 years. Understanding the Sun’s behavior is crucial, and this, in return, depends on accurate observations of our star.

Over the years, several studies have been done to investigate trajectories that reach high ecliptic inclinations. Those are mostly divided into two broad sets depending on the adopted solution strategy. The first strategy is using the inner planets of the solar system in a sequence of multiple gravity assists (MGAs). Such missions would gradually reach the required inclination whilst still maintaining sufficiently short orbital periods.

This is in fact the basis of ESA’s Solar Orbit-

The second set of studies involves the use of low-thrust propulsion, and in particular solar electric propulsion (SEP). The idea here is to replace the usual spacecraft rocket engines with ion engines, which propel a spacecraft by accelerating ionized Xenon gas with an electric field. As such, the exhaust gas velocity is extremely high (roughly ten times higher than regular rocket engines), and is thus extremely efficient. The downside is that the thrust levels are very low (<1N) and thereby need to stay active for many days at a time

To this end, throughout the years, mankind has launched several space based solar observatories. However, almost all of them present the same flaw: their orbits lie on the ecliptic plane, and as such, they cannot observe the solar poles. To completely map the star one would require a heliocentric orbit with a sufficiently high ecliptic inclination.

Unfortunately, due to Earth’s relatively high orbital velocity around the Sun, increasing inclination requires extremely high amounts of energy. This implies the need for complex trajectories and mission design efforts. NASA’s Ulysses mission was the only satellite to observe the solar poles, fly to Jupiter and perform a gravity assist – this in turn left it with a very long orbital period (6.2 years) and limited payload [1].

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NASA

Solar observatories are crucial for the understanding of our star’s behavior.

While many such observatories have been launched throughout the years, the poles of the Sun have seldom been imaged. The research presented here studies the possibility of using novel electric propulsion technologies combined with gravity assists to reach the high inclinations needed to observe solar poles.

Figure 1 - NASA's 2.3 kW NSTAR ion thruster for the Deep Space 1 spacecraft during a hot fire test at JPL.

to gradually change the spacecraft’s velocity. An example of an ion engine is shown in Figure 1.

Modeling SEP trajectories is rather complex, and requires its own modeling methods and tools. The mission presented here will use both SEP and MGAs to get the best of both worlds.

This research was performed at the University of Colorado, within the Colorado Center for Astrodynamics Research (CCAR), where a SEP modelling tool was already made available to the author. The latter is the Boulder Optimization of Low Thrust Trajectories (BOLTT) [3]. It approximates the trajectory by breaking up the effect of the constant low thrust propulsion into a series of discrete impulsive burns, and then using an optimizer to determine the optimal trajectory parameters and impulsive burn vectors. While being a very advanced tool, BOLTT still requires good initial conditions as inputs to be able to construct meaningful trajectories within the imposed constraints, particularly when considering long MGA sequences.

TRAJECTORY FORMULATION The problem still remains on how to construct a SEP MGA strategy, which achieves high ecliptic inclinations that in return will drive the inputs for BOLTT. For this, the SolO mission is considered once more. Its MGA sequence was an EVEEV-VVVV (note that E=Earth and V=Venus). There are two phases: the EVEEV approach, and the VVVV resonance. These two phases have two distinct goals: during the approach phase the spacecraft moves between the Earth and Venus multiple times, with the final obMission

CORPACCIOLI

CORPACCIOLI

Figure 2 - EV approach phase trajectory.

Earth and Venus orbits are shown in blue and pink, impulsive SEP burns are shown as grey arrows

Figure 3 - VVV resonance phase trajectory. Spacecraft performs multiple resonant hits of Venus, each time increasing its inclination. jective to maximize the relative velocity with the arrival planet, in this case, Venus. This is because relative velocity with a planet sets a maximum ceiling to the best achievable inclination from gravity assists. In the next phase, the spacecraft performs resonant gravity assists of Venus, where with each pass, the planet cranks inclination a little bit further. Note that relative velocity cannot increase during resonant assists, thus justifying the need for the approach phase. This basic strategy will also be used for this mission.

ber of resonant assists is not variable, and depends on the achieved relative velocity during the approach phase (for instance, since EVEEV reaches high relative velocities, it requires more resonances to reach the higher inclinations). The chosen simulation assumes a spacecraft with a launch mass of 2000kg, power system providing 4000W and engine Isp of 2000s, launched with Atlas V – 401. Table 1 shows the results for bestachieved inclination compared to total time of flight.

Given this two-phase strategy, the initial conditions for BOLTT were formulated using two initial conditions tools. Each tool provides inputs for each phase. For the approach phase, the tool is a modified version of the Gravity Assist Space Pruning (GASP) algorithm [4]. The idea here is to take a sample MGA sequence, and analyze it, one leg at a time, pruning away infeasible transfers, which in return reduces the search space for the next leg. This algorithm ultimately gives relatively narrow bounds, inside which feasible transfers can exist. From these bounds, it is easy to extract the initial conditions needed for BOLTT. For the second phase, the resonant transfers are analyzed using a three-dimensional sphere to represent the relative velocity vectors and parametric circles on the sphere to represent fly-by rotations and resonant locations. Using a discrete dynamic programming algorithm, it is possible to derive the optimal resonant gravity assists and use them as initial conditions for BOLTT.

The EV-VVV strategy was ultimately selected, due to its excellent compromise between the achieved inclination and time of flight.

RESULTS Ultimately, four different MGA strategies were tested: EV-VVV, EVE-EEEE, EVEV-VVVV and EVEEV-VVVVVVVVV. Note that the num-

Time of Flight [years]

Inclination [°]

EV-VVV 2.0 36.6 EVE-EEEE 4.8 46.8 EVEV-VVVV 4.2 39.9 EVEEV-VVVVVVVVV 9.2 58.0 Table 1 - Results for varying mission scenarios, comparing time of flight and achieved inclination.

Figure 2 shows the approach EV portion.

One can observe a portion of the Earth’s and Venus’s orbit, with the spacecraft’s transfer appearing in black. The grey arrows represent the discretized SEP impulses.

Figure 3 shows the resonant portion. Here, only Venus’s orbit is shown, and the resonant point is clearly visible. The three resonant transfers can be seen, wherein with every pass the inclination increases further.

References [1] K-P Wenzel, RG Marsden, DE Page, and EJ Smith. Ulysses: The first high-latitude heliospheric mission. Advances in Space Research, 9(4):25–29, 1989.

[2] Solar orbiter: Exploring the Sun-heliosphere connection. Technical report, ESA, 2011. Definition Study.

[3] S. De Smet. Preliminary Design of a Crewed Mars Flyby Solar Electric Propulsion Mission. Master’s thesis, Delft University of Technology, December 2014. http://repository.tudelft.nl/view/ir/uuid [4] Dario Izzo, Victor M Becerra, DR Myatt, Slawomir J Nasuto, and J Mark Bishop.

Search space pruning and global optimisation of multiple gravity assist spacecraft trajectories. Journal of Global Optimization, 38(2):283–296, 2007.

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C&O

DRONE (noun) [drohn] a remote-controlled pilotless aircraft or missile Stevan Milošević, Editor Leonardo Times With a growing commercial market and affordable prices, what could the future of unmanned aviation bring?

W

hat was initiated as military technology developed some fifty years ago has started trickling down into the consumer market. The unmanned aircraft has seen an ever-increasing exposure and appreciation, in the defense industry as much as in the commercial sector.

times askew from the truth. News agencies love nothing more than a good story, and nowadays drones make a great one. While mass-targeted news media being factually inconclusive is not exactly news, an important dilemma has risen: What shall society do with all these pesky flying objects?

The technological evolution is alike the one of the Global Positioning System (GPS) - it started as a military initiative out of necessity for a superior technology, which later reached primarily the general population - adopting commercial users who found ways of utilizing it, and finally ended up in everyone’s pockets in the form of a smartphone.

The commercial drone industry is still in the early-adopter phase, amongst the customers buying them one can find professional photographers, inspection, surveillance and security companies, as well as ‘amateur’ hobbyist who spend their weekends racing their toys for big boys around the park. Unlike with GPS though, the widespread use of drones could bring potential safety hazards, as the airspace around the world is already crowded enough on its own.

The regulations that could be put in place are rather worrying, FAA last year proposed a plan which would mandate all drones (above a certain weight threshold) to register in a centralized system, so that the government could have a general overview of who is flying what and where. The AIRR (Aviation Innovation, Reform and Reauthorization) Act [3] introduced this year aims to require any drone weighing above 4.4lbs to be registered. While seeming logical, these restrictions will limit the growth of the industry and increase ownership costs. These restrictions are almost irrelevant to amateur drone operators, as they are mainly focused on the commercial sector. At the same time, it might actually be a beneficial change for the industry, which is currently struggling with licensing drones for commercial purposes. Amazon has been developing a quick-delivery system using UAV’s for quite some time, and so has Google (Alphabet) with their Project Wing. While Amazon is trying to combat the law in the US, Project Wing has seen an ongoing development in Australia, where the laws concerning unmanned systems are practically non-existent.

Following the current trends, the whole unmanned aircraft market is about to reach the point of exponential growth. While the advancements are quite welcome, be it for entertainment purposes or for capital gain through the use of newly available tools, concerns and questions arise. The legislature is lacking, and the all-very-typical privacy concerns arise as well. No-drone zones have already started sprouting up worldwide, due to the nuisance a flying object can introduce in certain places. The whole city of Washington DC is a no-drone zone, for example, due to the potential security threats that comes with a remotely piloted aircraft. National reserves as well as historically important institutions were quick to outlaw the flying frenzies.

Taking a laidback approach to the upcoming rise of people hectically flying their personal drones around public spaces might work, but a better solution is having foresight of this next evolution of aviation.

Whilst the governments around the globe are whizzing around trying to come up with a proper bill of law, legislating what is legal and what not in the world of drones, a whole new industry has emerged alongside the drone industry: the anti-drone market. Numerous innovations are being designed in order to protect information, resource, or otherwise sensitive locations. Laser-gun systems and shooting nets, aiming to capture intruding drones from entering restricted areas, have already reached the market. The Dutch and British police forces went as far as to train eagles to remove drones, while the Tokyo police operates so-called anti-drone drones, which use nets to entangle unwanted drones and put them down from the sky. While the precautionary measures might seem inane, reports keep emerging of drones unwantedly interfering with other businesses. An amateur photographer crashed his drone into a British Airways’ A320 during takeoff at Heathrow not long ago (April 2016) [1]. On the other side of the globe, efforts to diminish the forest fires in California were cut short [2] on numerous occasions due to an unmanned drone interfering with the aerial firefighting crew’s operations (which later turned out to be one of the US government agencies playing around with their big boy toys).

In defense of hobbyist drone enthusiasts, the news reports are some50

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The manufacturers have also identified the problem of irresponsible use of their products, and started developing the latest generation of drones accordingly. DJI’s newest Phantom uses its onboard GPS to determine whether the drone is flying in a no-drone zone, or if it has reached the allowed altitude ceiling (400m in the US). In case the operator is going beyond the allowable areas, the drone will descend back to the ground. While these measures will ensure an average drone enthusiast does not commit any crimes or do any damage, if someone’s intention is to commit an illegal act, these software limitations do not make for a reliable deterrent. Hence, while being a step forward, these new features do not address the whole issue.

The coming years are going to be nothing but interesting for the UAV industry. The technology will, without a doubt, live on in the defense industry just as in the commercial world, but the challenges that the manufacturers and operators will face might slow the progress and growth of the market down. While the fear mongering recently pushed around by media did not have a grand effect, the regulations that are going to be introduced in the near future might create a bureaucratic bottleneck, and make it difficult for the average Joes to fly their drones around the park.

References [1] 'Drone' hits British Airways plane approaching Heathrow Airport BBC, http://www.bbc.com/news/uk-36067591 [2] Drones impede air battle against California wildfires. ‘If you fly we can’t,’ pleads firefighter - Washington Post, https://www.washingtonpost.com/news/morning-mix/wp/2015/07/31/if-you-fly-we-cantpleads-california-firefighter-as-drones-impede-spreading-wildfirebattle/ [3] AIRR ACT - US House of Representativesl, http://transportation. house.gov/airr-act/

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