The Space Elevator… 2009 and beyond

Dr. Brad Edwards Markus Klettner

EuroSpaceward A.s.b.l. Luxembourg

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 SciFi to NASA• Capture an asteroid and

bring into Earth orbit

• Mine the asteroid for carbon and extrude 10m diameter cable

• Asteroid becomes counterweight

• Maglev transport system

• Tall tower base

• Large system

• 300 years to never...

From Smitherman, 2000

Comparison

Can we really build the space elevator?

Proposed System: Overview

• First elevator: 20 ton capacity (13 ton payload)

• Constructed with existing or near-term technology

• 15 years and US$10B to construct the first elevator

• Operating costs: US$250/kg to any Earth orbit, moon, Mars, Venus, Asteroids

Ribbon Design

• The final ribbon is one-meter wide and composed of parallel high-strength fibers

• Interconnects maintain structure and allow the ribbon to survive small impacts

• Initial, low-strength ribbon segments have been built and tested

Deployment Overview

Initial Spacecraft• Deployment

spacecraft built with current technology

• Photovoltaic arrays receive power from Earth

• An MPD electric propulsion moves the spacecraft up to high Earth orbit

• Four 20-ton components are launched on conventional rockets and assembled

Climbers

• Climbers built with current satellite technology

• Drive system built with DC electric motors

• Photovoltaic array (GaAs or Si) receives power from Earth

• 7-ton climbers carry 13-ton payloads

• Climbers ascend at 200 km/hr

• 8 day trip from Earth to geosynchronous altitude

Power Beaming

• Power is sent to deployment spacecraft and climbers by laser

• Solid-state disk laser produces kWs of power and being developed for MWatts

• Mirror is the same design as conventional astronomical telescopes (Hobby-Eberly, Keck)

Anchor

• Anchor station is a mobile, ocean-going platform identical to ones used in oil drilling

• Anchor is located in eastern equatorial pacific, weather and mobility are primary factors

Technical BudgetComponent Cost Estimate (US$)Launch costs to GEO 1.0BRibbon production 400MSpacecraft 500M Climbers 370MPower beaming stations 1.5BAnchor station 600MTracking facility 500MOther 430MContingency (30%) 1.6BTOTAL ~6.9B

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$10B.

Recommend construction of a second system for redundancy: US$3B

Once built then what?

Challenges• Induced Currents: milliwatts and not a problem• Induced oscillations: 7 hour natural frequency couples

poorly with moon and sun, active damping with anchor• Radiation: carbon fiber composites good for 1000

years in Earth orbit (LDEF)• Atomic oxygen: <25 micron Nickel coating between 60

and 800 km (LDEF) • Environmental Impact: Ionosphere discharging not an

issue• Malfunctioning climbers: up to 3000 km reel in the

cable, above 2600 km send up an empty climber to retrieve the first

• Lightning, wind, clouds: avoid through proper anchor location selection

• Meteors: ribbon design allows for 200 year probability-based life

• LEOs: active avoidance requires movement every 14 hours on average to avoid debris down to 1 cm

• Health hazards: under investigation but initial tests indicate minimal problem

• Damaged or severed ribbons: collatoral damage is minimal due to mass and distribution

A Future with the Space Elevator• Solar power satellites• Solar system exploration & colonization • Full commercialization of space (R&D,

manufacturing, tourism,…)• Space activities dominated by private,

possibly non-US entities

Where are we now?

CNT Development

• CNT’s are getting longer o 18mm long in bulko Microns needed for

composites, centimeters for spinning

• Different methods for spinning are coming on lineo Some have serious scale-up

issues, others don’t

• Efforts have become business so are now closely held

Space Elevator Games

• Coming up on four years

• $4M in prizes

• This year major sponsors, 1 km height, and high-power lasers (9kW)

• Possibly two CNT tethers

• Nearing the capabilities we need in a real space elevator in terms of speed, payload ratio, etc.

Space Elevator Games 2009

• $900K prize won by Lasermotive: 4m/s over 1km

Europe

• Eurospaceward pushing the space elevator development

• EuroSpaceward conference in Luxenbourg: Dec. 5-6, 2009

• Cambridge University producing spun CNT arrays

• Germany producing ultralight PV arrays that may completely change the climber design

Japan

• 1st Space Elevator climber competition (JSETEC) run in 2009.

• Japan Space Elevator Association established.

• The Ministry of Economy, Trade and Industry of Japan has the SE in their Technology Strategic Map

• "Space Elevator - the Future as Foreseen by Scientists" played at the 2008 G8 Science and Technology Ministers' Meeting in Japan.

Space Elevator Wiki

• Wiki developed to initiate collaborative work on the space elevator

• Includes:o Baseline Elevatoro Major and minor development

issueso Software to assist development

work

• Just finishing set-up and ready for collaborators: www.spaceelevatorwiki.com

International Space Elevator Consortium

• ISEC was formed in August 2008 to coordinate and support space elevator activities around the world.

• ISEC members include:o Eurospacewardo The Japanese Space Elevator Associationo Spaceward foundationo Individuals from five different countries

Space Elevator Technology in

Terrestrial Elevators• As buildings grow taller the high

strength cables, climbing mechanisms or lightweight cars of the space elevator may be required.

• The high strength cables could become safety lines in conventional elevators

• The power beaming techniques - though in optical bundles - may also find a place in new buildings of great height

• The space elevator is a revolutionary Earth-to-space transportation system that will enable space development

• Design, deployment and operational scenarios for the first space elevator have been put together. Potential challenges have been laid out and solutions developed.

• The space elevator is viable in the near future with a reasonable investment and development plan.

Summary