Space elevator economics

Summary

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. The main cost comes from the components of the launch system that are not intended to be reused, which normally burn up in the atmosphere or are sent to graveyard orbits. Even when reusing components, there is often a high refurbishment cost.[1] For geostationary transfer orbits, prices are as low as about US$11,300/kg for a Falcon Heavy or Falcon 9 launch.[2][3][4] Costs of low earth orbit launches are significantly less, but this is not the intended orbit for a space elevator.

Proposed cost reductions

Various adaptations of the conventional rocket design have been proposed to reduce the cost. Several are currently in development, like the SpaceX Starship. An aspirational price for this fully reusable launch vehicle is $10/kg, significantly cheaper than most proposed space elevators.[5] New Glenn is also currently in development, a partially reusable rocket that promises to reduce price. However, an exact cost per launch has not been specified.[6] Others, like the Sea Dragon and Roton have failed to get sufficient funding. The Space Shuttle promised a large cost reduction, but financially underperformed due to the extensive refurbishment costs needed after every launch.[1]

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,[7] 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).[8][9]

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%.[10][11]

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[12] 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.[13]

Total cost of a privately funded Edwards' Space Elevator

A space elevator built according to the Edwards proposal is estimated to cost $6 billion.[14]

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.[14] 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[15]). Early space elevator designs move only cargo but could move people as well to a much wider range of destinations.[16]
  • Another alternative project to get large numbers of people and cargo to orbit inexpensively during this time frame is the SpaceX Starship which, like Skylon, is not a conventional rocket design as it will be fully reusable. Its cargo capacity will be between 100 and 150 tonnes (220,000 and 330,000 lb), is estimated to have an R&D cost of $10 billion,[17] and production cost of about $200-million for Starship crew, $130-million for Starship tanker and $230-million for Super Heavy. The system has a less than $140/kg price tag which is possibly as low as $47/kg.[18][19] It will be capable of transporting 100 people comfortably to Mars (therefore significantly more to low/medium earth orbit).[20]

See also

References

  1. ^ a b Grush, Loren (24 December 2015). "SpaceX's reusable rockets will make space cheaper – but how much?". The Verge. Retrieved 4 February 2021.
  2. ^ "Capabilities and Services" (PDF). SpaceX.com. SpaceX. Retrieved 4 February 2021. Falcon 9: $62M for 5.5 metric tons. Falcon Heavy: $90M for up to 8 metric tons.
  3. ^ Sheetz, Michael (February 12, 2018). "Elon Musk says the new SpaceX Falcon Heavy rocket crushes its competition on cost". CNBC.
  4. ^ "The economics of interface transportation". 2003. Retrieved 2006-03-05.
  5. ^ Zafar, Ramish (8 May 2020). "SpaceX Could Bring Starship Launch Costs Down To $10/kg Believes Musk". Wccftech. Retrieved 4 January 2021.
  6. ^ "New Glenn". Blue Origin. Retrieved 4 February 2021.
  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. ^ a b 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.
  17. ^ "Five things to know about Elon Musk's space projects". Phys.org. February 6, 2018.
  18. ^ http://www.spacex.com/sites/spacex/files/making_life_multiplanetary-2017.pdf[dead link]
  19. ^ "Falcon 1 Overview". SpaceX. Archived from the original on 2012-01-18. Retrieved 2007-05-05.
  20. ^ Dinkin, Sam (October 9, 2017). "Estimating the cost of BFR". The Space Review.