NIAC 8th Annual Meeting: 2006
Photon Tether Formation Flight (PTFF)
Young K. Bae, Ph.D. Bae Institute Tustin, California, USA www.baeinstitute.com
NIAC 8th Annual Meeting: 2006
Participants z
Joseph Carroll, Tether Applications Inc. -- General Tether Aspects and Hardware
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Claude Phipps, Ph.D., Photonics Associates -- Nano-Newton Thruster Stand
z
Eugene Levin, Ph.D., STARS, Inc. -- Dynamics of Tethers and Formation Flying
z
Bob Scaringe, AVG Communications -- Business Development
NIAC 8th Annual Meeting: 2006
Examples of Revolutionary/Disruptive Technologies Key Enabling Factor: Orders of Magnitude Enhancement in Critical Parameters z z z z
Subatomic Dimension -- Particle Accelerators Critical Parameter: Particle Energy Atomic Dimension – STM/AFM Critical Parameter: Scanning Ability/Noise Reduction Molecular to Daily Life Dimension -- Lasers Critical Parameter: Coherence of Photons Astronomical Dimension – Precision Formation Flying (?) Critical Parameter: Control Accuracy (?)
NIAC 8th Annual Meeting: 2006
Examples of Precision Formation Flying Concepts
TPF
LISA SPECS
MAXIM
SI Mission
NIAC 8th Annual Meeting: 2006
Selected Formation Flying Missions GRACE >1 km SNAP 1 Tsinghua
Control Accuracy
1m
TechSat 21 GEMINI
DARWIN 1 mm
XEUS
ESA Proba-3
Control Limitation with Conventional Thrusters?
1 Âľm
SPECS MAXIM
1 nm 1m
10 m
LISA
FTXR
PTFF 100 m
1 km
10 km
100 km
Baseline Distance
>1,000 km
NIAC 8th Annual Meeting: 2006
Nano-Meter Precision Spacecraft Formation Flying: -- is able to cover most of critical missions planned -- enables many other new missions
• Thus, it is Potentially a Revolutionary/Disruptive Technology of the 21st Century in Astronomical Dimension. • So far, its Enabling Technology has been illusive. • We believe that PTFF could be the Enabling Technology, if successfully demonstrated. • The Primary Goal of this NIAC Phase II is to demonstrate a sub-scale prototype PTFF engine.
NIAC 8th Annual Meeting: 2006
Photon Tether Formation Flight (PTFF) z
Force Structure: Counter Balance of Two Forces: Contracting Force: Tether Tension Extending Force: Photon Thrust - Intracavity Arrangement - Thrust Multiplied by Tens of Thousand Times by Bouncing Photons between Spacecraft
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Geometrical Structure: Crystalline Structure
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Interspacecraft Distance Accuracy: better than nm
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Maximum Operation Range: Tens of kms (Limited by Laser Mirror Size)
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Can be Used for both Static and Dynamic Applications
NIAC 8th Annual Meeting: 2006
Major Advantages of PTFF z
Ultra-High Baseline and Pointing Accuracy -- Baseline Accuracy: better than 1 Nano-Meter -- Pointing Accuracy: better than 0.1 micro-arcsec for 1 km baseline system – Enabling Wide Ranges of Imaging Missions
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Propellantless -- System Mass Savings, Contamination Free, Long Mission Lifetime
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Low Power Consumption
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Low Construction Cost
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Dual Usage of Photon Thruster Laser for Interferometric Ranging System -- Simplified System Architecture and Control, Low System Weight
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Readily Downscalable to Nano- and Pico- Satellites Usage -- Ideal for Sophisticated Fractionated Spacecraft or Space Structures
NIAC 8th Annual Meeting: 2006
PTFF System Architecture Nano-Precision Formation Flying System Architecture Satellite II
Satellite I Lens
Photon Thruster System
Intracavity Laser Beam
Interferometric Ranging System
Diode Pump Laser
Ultrahigh Precision CW Photon Thrust
Precision Laser Power Meter
Partial Mirror
Pump Laser Beam
Laser Gain Media
Partial Mirror
HR Mirror
HR Mirror
HR Mirror
Photodetector HR Mirror
Partial Mirror
Tether
Tether System
Tether Reel
Tension Clamp
Piezo-Translator
Stepper Motor
NIAC 8th Annual Meeting: 2006
Photon Thruster System: TRL 3
Satellite II
Satellite I
Laser Gain Media
Lens
Intracavity Laser Beam Ultrahigh Precision CW Photon Thrust
Precision Laser Power Meter z
z
HR Mirror
HR Mirror
Laser System -- Diode Pumped Intracavity Laser -- Lifetime of Diodes 1 Year for Continuous Operation Pump Diode Carousel Design – Tens of Years
Pump Laser Beam Diode Pump Laser
NIAC 8th Annual Meeting: 2006
Intracavity Photon Thrust as a Function of the Mirror Reflectance (R) 10 W System 10000
Photon Thrust (ÂľN)
1000
100
10
Off-the-Shelf Super Mirror
1 Predicted Capability of the Proposed System
0.1 10
100
1000
1 1 - R
10000
100000
NIAC 8th Annual Meeting: 2006 Specific thrusts as functions of Isp of various conventional and photon thrusters.
Intracavity Multiplication Factors
0
10
X 20,000 X 10,000
-1
Specific Thrust (mN/W)
10
-2
10
Photon Thrusters
Electric Thrusters
-3
X 1,000
10
X 100
-4
10
-5
10
-6
10
-7
10
10
2
10
3
10
4
10
5
Isp (sec)
10
6
10
7
10
8
NIAC 8th Annual Meeting: 2006
Mirror Diamter (cm)
Photon Thruster System: Mirror Diameter vs. Operation Distance
10
1 0.01
0.1
1
Intersatellite Distance (km)
10
100
NIAC 8th Annual Meeting: 2006
Interferometric Ranging System: TRL 5
Satellite II
Satellite I Precision Laser Power Meter
Lens
Pump Laser Beam
Laser Gain Media
Parti al Mirror
Intracavity Laser Beam Ultrahigh Precision CW Photon Thrust HR Mirror
HR Mirror
HR Mirror
Partial Mirror Photodetector
Partial Mirror z
HR Mirror
Dual Usage of Photon Thruster Laser for Interferometric Ranging System Source Laser -- System Architecture Simplification -- System Mass Reduction
Diode Pump Laser
NIAC 8th Annual Meeting: 2006 Heterodyne Interferometric Ranging System Integrated with Photon Thruster System
Satellite II
Satellite I Lens
Laser Gain Media
Parti al Mirror
Intracavity Laser Beam Ultrahigh Precision CW Photon Thrust
Precision Laser Power Meter
HR Mirror
HR Mirror
Beam Splitter
AOM
AOM
Mirror
Retroreflector Measurement Detector
ODL
Reference Detector
Pump Laser Beam Diode Pump Laser
NIAC 8th Annual Meeting: 2006
Tether System: TRL 5 Satellite I
Electromechnical Damper
Satellite II
Tether Tether Reel
Clamp
Inchworm Piezo-Translator
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Coarse Control: Reel System-- mm Accuracy
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Fine Control: Inchworm or Stepper Motor-- Âľm Accuracy
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Ultrafine Control: Piezo-Translator (off-the-shelf) -- 0.1 nm Accuracy
NIAC 8th Annual Meeting: 2006
Method of Tether Vibration Suppression • Major Tether Vibrations will Result from Reorientation of the Whole Formation Structure, and other Sudden Environmental Perturbations, such as Meteoroid Impacts. • Longitudinal Tether Wave Damping Tether Material Friction/ Modulation of Photon Thruster Power • Transverse Tether Wave Damping Electromechanical Damper with Impedance Matching Damping Applied
Electromechanical Damping Simulation by Lorenzini et al. For 1 km Baseline System
NIAC 8th Annual Meeting: 2006
Example I: 10 km 1-D PTFF at L2
NIAC 8th Annual Meeting: 2006
Example II: 1 km PTFF Telescope at L2
NIAC 8th Annual Meeting: 2006
1 km PTFF Telescope: Enables New World Imager Freeway Mission By Prof. W. Cash – 2005 NIAC Fellow Meeting -- Searching for Advanced Civilization in Exo-Planets
• 300 m resolution at 10 parsecs = 0.02 nano-arcseconds • 500,000 km based line distance between Collectors • Huge collecting area – one square kilometer
NIAC 8th Annual Meeting: 2006
More Advanced PTFF Telescope
Image Processing With Real-Time Holographic Aberration Correction (NIAC)
James Webb Space Telescope
Stretched Membrane Mirror (NIAC)
NIAC 8th Annual Meeting: 2006
Technology Readiness Assessment Summary z
Photon Thrusters: TRL 3
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Interferometric Ranging System: TRL 5
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Tether System: TRL 5
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System Integration and Control: TRL 2
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R&D3: II - III (moderate -high) (Degree of Difficulty) -- Requires to optimize photon thrust design based on the current laboratory system and system integration, and to develop control system.
NIAC 8th Annual Meeting: 2006
Phase II Work Started Since Sept. 1st 2006 z
Proof-of-Concept Demonstration of Photon Thruster z Construction of a Thrust Stand with nN Accuracy
z
Overall System Stability and Control z Tether Vibration Dynamics z Environment Perturbation z 3-D Simulation
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Design of Prototype Interferometric Ranging System
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Design of Prototype Tether System
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Detailed Study of Specific Applications z In-Depth Revisits of Existing Concepts -- SPECS and MAXIM z Ultralarge Membrane Space Telescopes z Ultralarge Sparse Aperture Space Telescopes z Others
NIAC 8th Annual Meeting: 2006
Prototype Sub-scale PTFF Engine Demonstration Counter Weight
Interference Pattern Corner Cube
Optical Fiber Torsion Fiber
Photo Detector for Fringe Monitoring
Low Power Laser
Concave HR Mirror
Windows Laser Media
HR Mirror
Pump Laser Diode
Intracavity Laser Beam
Tether Laser Power Meter
Vacuum Chamber
Computer
Piezo-Translator
Feedback Electronics
NIAC 8th Annual Meeting: 2006
Conclusions I z
If successful, PTFF technology will be revolutionary/disruptive technology of 21st Century in Astronomical Dimension.
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If successful, PTFF technology will open new innovative (revolutionary) ways to implementing new and existing mission concepts at very affordable costs. -- Many applications can be implemented at fractional costs of HST.
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Preliminary Studies concluded that PTFF system can be implemented with off-the-shelf technologies – This will be tried to be proved during this study.
NIAC 8th Annual Meeting: 2006
Conclusions II • Mission Specific Applications • PTFF Simplifies the Architecture and Reduces the Weight in Space Interferometery Missions -- TPF, DARWIN, MAXIM, SPECS, FTXR etc. • Ultra-large PTFF Space Telescopes -- For New World Imager (300 m Resolution – Freeway Mission with km Mirror) -- Earth imaging/Monitoring/Surveillance (10 cm Resolution Monitoring at GEO with 200 m Mirror)
NIAC 8th Annual Meeting: 2006
The Support by NIAC and NASA for this project is greatly appreciated.
“I believe in intuitions and inspirations. I sometimes feel that I am right. I do not know that I am.� by Albert Einstein