Space elevator economics

Space elevator economics compares the cost of sending a payload into Earth orbit via a space elevator with the cost of doing so with alternatives, like rockets.

Costs of current systems (rockets)

The costs of using a well-tested system to launch payloads are high. Prices range from about $2,350/kg for a Falcon Heavy launch[1][2] to about US$40,000/kg for a Pegasus launch (2004).[3][4] Various systems that have been proposed have offered lower rates, but have failed to get sufficient funding (Roton; Sea Dragon), are still under development like New Glenn or the SpaceX Starship (which promises prices as low as $47/kg[5] and first flight in the 2020s[6]), or more commonly, have financially underperformed (as in the case of the Space Shuttle). The Shtil-3a rocket offers costs approximately $400/kg, but launches are infrequent and have a comparatively small payload, and its costs are partially subsidized by the Russian navy as part of launch exercises.[7]

Rocket costs have changed relatively little since the 1960s, but the market has been very flat.[4]

Cost estimates for a space elevator

For a space elevator, the cost varies according to the design. Bradley C. Edwards received funding from NIAC from 2001 to 2003 to write a paper,[8] describing a space elevator design. In it he stated that: "The first space elevator would reduce lift costs immediately to $100 per pound" ($220/kg).[9][10]

The gravitational potential energy of any object in geosynchronous orbit (GEO), relative to Earth's surface, is about 50 MJ (15 kWh) of energy per kilogram (see geosynchronous orbit for details). Using wholesale electricity prices for 2008 to 2009, and the current 0.5% efficiency of power beaming, a space elevator would require US$220/kg just in electrical costs. Dr. Edwards expects technical advances to increase the efficiency to 2%.[11][12]

However, due to the fact that space elevators would have a limited throughput as only a few payloads could climb the tether at any one time, the launch price may be subject to market forces.

Funding of capital costs

According to a paper presented at the 55th International Astronautical Congress[13] in Vancouver in October 2004, the space elevator can be considered a prestige megaproject whose current estimated cost (US$6.2 billion) is favourable compared to other megaprojects e.g. bridges, pipelines, tunnels, tall towers, high-speed rail links and maglevs. Costs are also favourable compared to that of other aerospace systems and launch vehicles.[14]

Total cost of a privately funded Edwards' Space Elevator

A space elevator built according to the Edwards proposal is estimated to cost $6 billion.[15]

For comparison, in potentially the same time frame as the elevator, the Skylon, a 12,000 kg cargo capacity single-stage-to-orbit spaceplane (not a conventional rocket) is estimated to have an R&D and production cost of about $15 billion.[15] The vehicle has about $3,000/kg price tag. Skylon would be suitable to launch cargo and particularly people to low/medium Earth orbit (targeting maximum 30 people per flight[16]). Early space elevator designs move only cargo but could move people as well to a much wider range of destinations.[17] Another alternative project to get large numbers of people and cargo to orbit inexpensively during this time frame is the BFR rocket which, like Skylon, is not a conventional rocket design as it will be fully reusable. Its cargo capacity will be 150,000 kg (250,000 kg if expendable), is estimated to have an R&D cost of $10 billion,[18] and production cost of about $200-million for a ship, $130-million for a tanker and $230-million for a booster. The system has a less than $140/kg price tag which is possibly as low as $47/kg.[19][20] It will be capable of transporting 100 people comfortably to Mars (therefore significantly more to low/medium earth orbit)[21]

See also


  1. "Capabilities & Services". SpaceX. Retrieved 2014-06-15.
  3. "Pegasus". Encyclopedia Astronautica. Archived from the original on 2008-09-05. Retrieved 2006-03-05.
  4. "The economics of interface transportation". 2003. Retrieved 2006-03-05.
  5. Spacex BFR to be lower cost than Falcon 1 at $7 million per launch. Brian Wang. 17 October 2017.
  6. Jeff Foust (15 October 2017). "Musk offers more technical details on BFR system". SpaceNews. Retrieved 15 October 2017.
  7. Bradley Edwards (1 Mar 2003). "NIAC Phase II study". Eureka Scientific.
  8. "2nd Annual International Space Elevator Conference held in Santa Fe New Mexico". September 24, 2003.
  9. "What is the Space Elevator?". Institute for Scientific Research, Inc. Archived from the original on 2007-10-13. Retrieved 2006-03-05.
  10. Bradley C. Edwards, Eric A. Westling (November 2003). The Space Elevator: A Revolutionary Earth-to-Space Transportation System. ISBN 0-9726045-0-2.
  11. Bradley C. Edwards, Philip Ragan (October 2006). Leaving the Planet by Space Elevator. ISBN 978-1-4303-0006-9.
  12. "55th International Astronautical Congress". Institute for Scientific Research, Inc. Retrieved 2006-03-05.
  13. Raitt, David; Bradley Edwards. "THE SPACE ELEVATOR: ECONOMICS AND APPLICATIONS" (PDF). 55th International Astronautical Congress 2004 - Vancouver, British Columbia, Canada. IAC-04-IAA.3.8.3. Archived from the original (PDF) on 2006-03-16. Retrieved 2006-03-05.
  14. Bradley Edwards (2003). "11: Budget Estimates". The Space Elevator.
  15. J.L. Scott-Scott; M. Harrison & A.D. Woodrow (2003). "Considerations for Passenger Transport by Advanced Spaceplanes" (PDF). Journal of the British Interplanetary Society. 56: 118–126. Archived from the original (PDF) on 2009-03-19.
  16. Bradley Edwards (2003). "7: Destinations". The Space Elevator.
  19. "Falcon 1 Overview". SpaceX. Archived from the original on 2012-01-18. Retrieved 2007-05-05.
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