The Lunar Space Elevator
Jerome Pearson, Eugene Levin, John Oldson, and Harry Wykes NIAC Phase I Fellows Meeting Atlanta, GA, 16 Mar 2005
The Earth Space Elevator
An L2 Lunar Space Elevator
Types of Lunar Space Elevators
NIAC Study Phase I Goals •Develop LSE System Architecture •Coordinate with NASA Moon-Mars Initiative •Conceptual Design of all Components •Substantiate Revolutionary Impacts
System Architecture •A Revolutionary Cis-Lunar Transportation System •Low-Cost Transportation of Lunar Materials and Propellants to Earth orbits •Low-Cost Supply of Lunar Bases from LEO •Support for Moon and Mars Missions
Concept of Operations •The Lunar Space Elevator is an EarthMoon-L1“Hi ghway” •LSE Can Carry Traffic Throughout CisLunar Space, with Nodes in Earth Orbit, L1, Lunar Orbit, and the Lunar Surface •Robotic Vehicles Provide Redundancy, Reliability, and Low Cost Transportation
Transportation Architecture Earth
L1 Ballast
Payloads
Moon
Payloads
LSE to Earth Orbit Launches 300
250
Earth orbit radius, km
Apogee 200
150
Perigee 100
Synchronous orbit
50
0 60
90
120
150
180
210
Release height on L1 elevator, km
240
LSE Cis-Lunar Transportation Earth Orbit to Moon: –Ribbon to L1 –Supplies to Lunar Bases Moon to Earth Orbit: –Lunar Materials –Propellant to LEO –SSPS to GEO
System Components
•LSE Ribbon •Robotic Climbers •Catenary to Pole •Surface Robots •Mining Bases
Lunar SE Materials Material
Density ρ, kg/m3 2266
SWCN*
Stress Limit σ, GPa 50
Break Height σ/ρge, km 2200
T1000G†
1810
6.4
361
Zylon§ PBO
1560
5.8
379
970
3.0
316
M5**
1700
5.7
342
M5 Expected
1700
9.5
570
Kevlar††49
1440
3.6
255
Spectra¶ 2000
* Single-wall carbon nanotubes (lab measured) †Tor a yca r bonf i be r § Aramid, Ltd. Polybenzoxazole fiber
¶ Honeywell extended chain polyethylene fiber ** Magellan honeycomb-like 3-D polymer ††DuPontaramid fiber
Meteoroid-Safe Ribbons
Mean Time Between Meteor Cuts: T, yrs = 6 h2.6/L h = width, mm L = length, km
Strands
2
Safety Factor 4
3
4
5
6
3 2.7 2.5 2.4
LSE Ribbon and CW Mass 1.E+07
1.E+06 Mass, kg
ribbon counterweight Total Mass 1.E+05
1.E+04 60
120
180
240
He ight, thousands of k m
300
Spinning Tethers for Lunar Sling Launch (and Catch)
L1
Type
h, km r, km Vtip, km/s
atip,g’ s P, kW Tons/day
Low Orbit
4
118
1.68
2.4
100
3
Escape
4
236
2.38
2.4
100
3
Robotic Climber Design
•500-kg Climbers •100 Climbers on Ribbon •10-20 m/s Speed •340,000 kg/yr
Robotic Climber Design
•Articulated Solar Panels •10 kW at Surface, 100 W at 0.26 L1 •Big, Soft Drive Wheels •Ribbon Tracking Control •Full and Empty c.g. Control
Climber Components
Unloaded Climber Concept of Climber and LSE
c.g.
Polar Ice from Clementine Data
Curved LSE to Approach Poles Maxim um Latitude 90 Curved LSE
80 2
z/rm z/r
m
Latitude, Degrees
70
1
60 50 40 30 20
0
10 0
1
2
x/rm x/rm
3
4
0 0
1
2
3
4
5
6
2 2 ď ¨==vvt2/v02 Eta t /vo
7
8
9
10
“ Pol arExpr ess”Cat enar y
200 km crater, 4 km deep
Regolith Encapsulation
Truncated Octohedron Blocks
Unfilled Filled
Lunarcrete Blocks
Blocks Cast with Tension Wires
Tensegrity Towers 0.36 lb/foot on moon
Stations on the Polar Express
Equatorial: •Regolith mining •Factories •Habitats Catenary stops on the 2700km long Polar Express: •Mineral deposits •Water ice mining •Propellants
Two Man Catenary Crew Cab
Habitat Constructed with Regolith Blocks
Preliminary LSE Cost Analysis •LSE Construction: ~$10 B •(Assumes $5 M per Ton Launched to LEO) •Ion Propelled Payloads: 10-15% of mass, 6 mos. from LEO to Moon or Moon to LEO
Vision and Significance •Revolutionize Cis-Lunar Space •Drastically Reduce Cost of Propellants and Supplies in Earth Orbit •Provide Low Cost Support of Lunar Bases •Directly Support Moon-Mars Initiative
Potential Lunar Schedule
2008-15: 2015-20: 2020-25: 2025-35:
Robotic Missions Manned Missions LSE Construction Lunar Space Elevators Revolutionize Cis-Lunar Transportation
Phase II Objectives •Complete LSE architecture for future NASA missions •Create LSE roadmap with all enabling technologies •Evaluate benefits and cost vs. performance
Conclusions •Lunar space elevators and slings are new, revolutionary ideas with broad applications •The LSE is achievable, and provides a new architecture for lunar development •The lunar space elevator creates a new paradigm for lunar space transportation