The Space Elevator building our future Space Elevator
The Space Elevator … building our future
Space Elevator Basics
The SE in Literature • Artsutanov, Y. 1960. V Kosmos na Elektrovoze, Komsomolskaya Pravda, (contents described in Lvov 1967 Science 158: 946). • Isaacs, J. D. , Vine, A. C. , Bradner, H. , and Bachus, G. E. 1966. Satellite Elongation into a true ‘Sky-Hook’. Science 151: 682. • Pearson, J. 1975. The Orbital tower: a spacecraft launcher using the Earth’s rotational energy. Acta Astronautica 2: 785. • Clarke, A. C. 1979. The Space Elevator: ‘Thought Experiment’, or Key to the Universe. Adv. Earth Oriented Appl. Science Techn. 1: 39.
The Space Elevator in Science Fiction
From Sci. Fi to NASA • Capture an asteroid and bring into Earth orbit • Mine the asteroid for carbon and extrude 10 m diameter cable • Asteroid becomes counterweight • Maglev transport system • Tall tower base • Large system • 300 years to never. . . From Smitherman, 1999
Proposed System: Overview l First elevator: 20 ton capacity (13 ton payload) l Constructed with existing or near-term technology l Cost (US$10 B) and schedule (15 years) l Operating costs of US$250/kg to any Earth orbit, moon, Mars, Venus, Asteroids
Carbon Nanotubes (CNTs) l Carbon nanotubes: measured at 200 GPa (54 x. Kevlar) – Sufficient to build the elevator l Mitsui(Japan): 120 ton/yr CNT production, US$100/kg – Sufficient to build the first elevator l CNT composite fibers: 3 -5% CNTs, 3 GPa, 5 km length – Not strong enough yet but a viable plan is in place to get there (Carbon Designs, Inc. ) 5 km continuous 1% CNT composite fiber
Deployment Overview
Ribbon Design l The final ribbon is onemeter wide and composed of parallel high-strength fibers l Interconnects maintain structure and allow the ribbon to survive small impacts l Initial, low-strength ribbon segments have been built and tested
Initial Spacecraft l Deployment spacecraft built with current technology l Photovoltaic arrays receive power from Earth l An MPD electric propulsion moves the spacecraft up to high Earth orbit l Four 20 -ton components are launched on conventional rockets and assembled
Climbers l Climbers built with current satellite technology l Drive system built with DC electric motors l Photovoltaic array (Ga. As or Si) receives power from Earth l 7 -ton climbers carry 13 ton payloads l Climbers ascend at 200 km/hr l 8 day trip from Earth to geosynchronous altitude
Power Beaming l Power is sent to deployment spacecraft and climbers by laser l Solid-state disk laser produces k. Ws of power and being developed for MWatts l Mirror is the same design as conventional astronomical telescopes (Hobby-Eberly, Keck)
Anchor l Anchor station is a mobile, oceangoing platform identical to ones used in oil drilling l Anchor is located in eastern equatorial pacific, weather and mobility are primary factors
Challenges l Induced Currents: milliwatts and not a problem l Induced oscillations: 7 hour natural frequency couples poorly with moon and sun, active damping with anchor l Radiation: carbon fiber composites good for 1000 years in Earth orbit (LDEF) l Atomic oxygen: <25 micron Nickel coating between 60 and 800 km (LDEF) l Environmental Impact: Ionosphere discharging not an issue l Malfunctioning climbers: up to 3000 km reel in the cable, above 2600 km send up an empty climber to retrieve the first l Lightning, wind, clouds: avoid through proper anchor location selection l Meteors: ribbon design allows for 200 year probabilitybased life l LEOs: active avoidance requires movement every 14 hours on average to avoid debris down to 1 cm l Health hazards: under investigation but initial tests indicate minimal problem l Damaged or severed ribbons: collatoral damage is minimal due to mass and distribution
Technical Budget Component Launch costs to GEO Ribbon production Spacecraft Climbers Power beaming stations Anchor station Tracking facility Other Contingency (30%) TOTAL Cost Estimate (US$) 1. 0 B 400 M 500 M 370 M 1. 5 B 600 M 500 M 430 M 1. 6 B ~6. 9 B Costs are based on operational systems or detailed engineering studies. Additional expenses will be incurred on legal and regulatory issues. Total construction should be around US$10 B. Recommend construction of a second system for redundancy: US$3 B
SE Operating Budget Annual Operating Budget per year in US$M Climbers Tracking system Anchor station Administration Anchor maintenance Laser maintenance Other TOTAL (50 launches) 0. 2 - 2 each 10 10 10 5 20 30 135 This is ~US$250/kg operating costs to any destination.
Advantages l Low operations costs - US$250/kg to LEO, GEO, Moon, Mars, Venus or the asteroid belts l No payload envelope restrictions l No launch vibrations l Safe access to space - no explosive propellants or dangerous launch or re-entry forces l Easily expandable to large systems or multiple systems l Easily implemented at many solar system locations
Applications l Solar power satellites - economical, clean power for use on Earth l Solar System Exploration - colonization and full development of the moon, Mars and Earth orbit l Telecommunications - enables extremely high performance systems
Global Attention l Have briefed Congress, NASA HQ, NASA MSFC, AFRL, NSA, NRO, DARPA, FCC, FAA, and satellite insurance companies. Invited talks at Harvard/Smithsonian Cf. A, APL, GSFC, Berkeley, National Space Society, SPIE, Space and Robotics 2002, ISU, etc. l Held the three Space Elevator Conferences. One session at Space and Robotics 2002, two sessions at the IAC meeting in Oct. , 2004, and Space Exploration 2005 are focusing solely on our work. l ESA, Japan, Canada and Australia have expressed interests in being involved. l Reported positively in New York Times, Washington Post, Discover, Wired, Seattle Times, Space. com, Canadian National Post, Ad Astra, Science News, Maxim, Esquire, etc. l Globally over 1000 media spots including live interviews on CNN, Fox News, and BBC.
Next Steps l Material development efforts are underway by private industry l Space elevator climber competition will demonstrate basic concept l Engineering development centers in the U. S. , Spain and Netherlands are under development l Technical conferences continuing l Greater public awareness l Increased financial support being sought
Summary l The space elevator is a revolutionary Earth-to-space transportation system that will enable space exploration l Design, deployment and operational scenarios for the first space elevator have been put together. Potential challenges have been laid out and solutions developed. l Development of the space elevator requires an investment in materials and engineering but is achievable in the near future with a reasonable investment and development plan.
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