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Space Launch System

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Space Launch System
SLS concept art from September 2011
FunctionLaunch vehicle
Country of originUnited States
Size
Diameter8.4 m core
Stages2 (plus strap-on boosters)
Capacity
Payload to LEO70,000 kg (150,000 lb) - 129,000 kg (284,000 lb)
Launch history
StatusBeing studied
Launch sitesLC-39, Kennedy Space Center
First flight2017
Boosters - Solid Rocket Boosters
No. boosters2
Engines1 solid
Thrust12.5 MN each, sea level liftoff (2,800,000 lbf)
Specific impulse269 s
Burn time124 s
Propellantsolid

The Space Launch System, or SLS, is a Space Shuttle-derived heavy launch vehicle being designed by NASA, following the cancellation of the Constellation Program, to replace the retired Space Shuttle. The NASA Authorization Act of 2010 envisions the transformation of the Ares I and Ares V vehicle designs into a single launch vehicle usable for both crew and cargo. It is to be upgraded over time with more powerful versions.

Design and development

NASA's Space Launch System (SLS) reference configuration from February 2011

The Space Launch System is to be a Shuttle-Derived heavy launch vehicle. The initial capability of the core elements, without an upper stage, should be for between 70 tons (for the 3-engine, partially fuelled core) and 100 tons (for the preferred 4-engine, fully fuelled core) into low-Earth orbit (LEO) in preparation for transit for missions beyond low-Earth orbit. With the addition of integrated upper Earth Departure Stage and 5th SSME derived core engine, the total lift capability of the Space Launch System should be 130 tons or more.[1][2]

Preliminary designs indicate that the current Space Shuttle Main Engines (RS-25) and Space Shuttle Solid Rocket Boosters would be utilized, and much of the External Tank design would remain the same.[2] This design would require dramatically less development time than the Ares V heavy lift launch vehicle. On May 24, 2011, NASA announced that development of the Orion from the Constellation program will continue under the name Orion Multi-Purpose Crew Vehicle (MPCV).[3]

On June 17, 2011, Aerojet announced a strategic partnership with Teledyne Brown to develop and produce a domestic version of the NK-33 engine, with its thrust increased to 500,000 pounds-force (2.2 MN) at sea level. This booster is to compete against Shuttle-derived solid rocket boosters for the SLS launch vehicle.[4]

On September 14, 2011, NASA announced that it had selected the design of the new Space Launch System. NASA declared that it would take the agency's astronauts farther into space than ever before and provide the cornerstone for future human space exploration efforts by the U.S.[5][6][7] For early flights SLS has an 8.4-meter diameter core with three RS-25D/E engines, 8.4-meter upper stage with a J-2X engine, and two 5-segment solid rocket boosters.[8] Later versions will use five RS-25D/E engines and the boosters will be upgraded as well. Selection of the upgraded boosters will be by competitive bid.[9] The proposed SLS is visually similar to the legacy Saturn V booster and in particular the proposed, two-stage, Saturn INT-20. The initial two stage variant will have a similar lift capability to the Saturn INT-20's 60,000 kg. The proposed final variant will have similar lift capacity and height compared to the original Saturn V.[10]

As of November 2011 NASA has selected five rocket configurations for wind tunnel testing. Said configurations are described in three Low Earth Orbit classes; 70 mt, 95 mt, and 140 mt.[11]

Program costs

During the joint Senate-NASA presentation in September 2011, it was stated that the SLS program has a projected development cost of $18 billion through 2017, with $10B for the SLS rocket, $6B for the Orion Multi-Purpose Crew Vehicle and $2B for upgrades to the launch pad and other facilities at Kennedy Space Center.[12] An unofficial NASA document estimates the cost of the program through 2025 will total at least $41B for four 70 metric ton launches (1 unmanned in 2017, 3 manned starting in 2021). The 130 metric ton version should not be ready earlier than 2030.[13][14] Another NASA unofficial study shows that a propellant depot architecture is cheaper and more flexible than a heavy lift.[15][16]

Opposition

In August and September 2011, US Representative Dana Rohrabacher said NASA should use the SLS budget to plan an orbital Propellant depot instead,[17] and accelerate the Commercial Crew Development (CCDev) program.[18] In October 2011 Rohrabacher added "There's nothing new or innovative in this approach, especially its astronomical price tag, and that's the real tragedy. Unfortunately, after a number of years, perhaps during development or just after a few flights like Saturn, budget pressures will bring this program to an end".[19]

The Space Access Society, Space Frontier Foundation and The Planetary Society called for cancellation arguing that it will consume the funds for other projects and will not reduce the price per pound to launch into orbit.[20][21][22] Others suggest it will cost less to use an existing (Falcon 9, Atlas V, Delta IV), or proposed derivative (Falcon Heavy) American commercial rocket with on-orbit assembly/fueling as needed, than to develop a new launch vehicle for space exploration without competitive bid for the whole design.[23][24][25][26][27]

The Competitive Space Task Force points out that spending billions to try to create a new Government launcher to replicate/replace existing/proven private American boosters directly violates NASA’s charter, the Space Act, and the 1998 Commercial Space Act requirements for NASA to pursue the "fullest possible engagement of commercial providers" and to “seek and encourage, to the maximum extent possible, the fullest commercial use of space” [28] “It is a sad day for our space program. The amazing possibilities offered by engaging commercial space to lower costs and develop a sustainable long term infrastructure to support NASA space exploration, settlement and a new space industry have been trumped by the greed, parochialism, and lack of vision of a few congressional pork barrelers intent once again on building a government super rocket,” said Space Frontier Foundation co-founder Rick Tumlinson. “We’ve been to this party before, it was a bust then, and it will be this time as well.”[29]

The Space Review also criticized the SLS plan. The Space Frontier Foundation and Space Access Society leaders have commented that SLS will be too costly and it will drain resources from NASA's other projects. Rep. Dana Rohrabacher added. “… this plan will suffer the same fate as Constellation: overpromised, under-delivered, and cancelled. Where will we be then?”[30][31][32]

SpacePolitics.com, Congressman Tom McClinton and other groups argue that the Congressional mandates forcing NASA to use Space Shuttle components for SLS amounts to a de-facto non-competitive, single source requirement assuring contracts to existing shuttle suppliers, and calling the Government Accountability Office (GAO) to investigate possible violations of the Competition in Contracting Act (CICA).[33][34]

Schedule

A very preliminary and unofficial schedule based on a worst case budget has outlined some early SLS flights as:[35]

Mission Targeted date Notes
SLS-1 December 2017 Send Orion/MPCV on unmanned trip around the Moon.
SLS-2 August 2019[36] Send Orion/MPCV on a manned trip around the Moon.
SLS-3 August 2022
SLS-4 August 2023
SLS-5 August 2024 First launch of SLS Cargo configuration
SLS-6 August 2025 Manned "Exploration" Mission
SLS-7 August 2026 Cargo launch
SLS-8 August 2027 Manned launch
SLS-9 August 2028 Cargo launch
SLS-10 August 2029 Manned launch
SLS-11 August 2030 New configuration, Cargo launch
SLS-12 August 2031 Manned mission
SLS-13 August 2032 New configuration, Cargo launch

See also

References

  1. ^ "Featured Legislation: The NASA Authorization Act of 2010". United States Senate. July 15, 2010. Retrieved May 26, 2011.
  2. ^ a b Clark, Stephen (March 31, 2011). "NASA to set exploration architecture this summer". spaceflightnow.com. Retrieved May 26, 2011.
  3. ^ [1]. NASA
  4. ^ Morring, Frank. "NASA Will Compete Space Launch System Booster". Aviation Week. Retrieved June 20, 2011.
  5. ^ Release:11-301, NASA (September 14, 2011). "NASA Announces Design For New Deep Space Exploration System". NASA. Retrieved September 14, 2011.{{cite web}}: CS1 maint: numeric names: authors list (link)
  6. ^ VideoLibrary, C-Span (September 14, 2011). "Press Conference on the Future of NASA Space Program". c-span.org. Retrieved September 14, 2011.
  7. ^ "NASA Unveils New Rocket Design". The New York Times. September 14, 2011. Retrieved September 14, 2011.
  8. ^ [2]. nasaspaceflight.com
  9. ^ NASA's New Space Launch System Announced
  10. ^ "Space Launch System: NASA's Giant Rocket Explained". September 16, 2011.
  11. ^ http://www.nasaspaceflight.com/2011/11/sls-nasa-dac-1-configuration-candidates-wind-tunnel-tests/
  12. ^ Smith, Marcia (September 14, 2011). "New NASA Crew Transportation System to Cost $18 Billion Through 2017". spacepolicyonline. Retrieved September 15, 2011.
  13. ^ "ESD Integration, Budget Availability Scenarios" (PDF). spacepolicyonline.com. August 19, 2011. p. 18. Retrieved September 15, 2011.
  14. ^ Smith, Marcia (September 9, 2011). "The NASA Numbers Behind That WSJ Article". spacepolicyonline.com. Retrieved September 15, 2011.
  15. ^ Keith Cowing. "Internal NASA Studies Show Cheaper and Faster Alternatives to The Space Launch System". spaceref.com. Retrieved October 21, 2011.
  16. ^ Doug Mohney. "Did NASA Hide In-space Fuel Depots To Get a Heavy Lift Rocket?". satellite.tmcnet.com. Retrieved October 21, 2011.
  17. ^ Rohrabacher, Dana (September 14, 2011). "Nothing New or Innovative, Including It's Astronomical Price Tag". Retrieved Sept 14, 2011. {{cite web}}: Check date values in: |accessdate= (help)
  18. ^ "Rohrabacher calls for "emergency" funding for CCDev". parabolicarc.com. August 24, 2011. Retrieved September 15, 2011.
  19. ^ "NASA's new plan for massive rocket greeted with enthusiasm, criticism". space-travel.com. October 4, 2011. Retrieved October 20?, 2011. {{cite web}}: Check date values in: |accessdate= (help)
  20. ^ "Impossibly High NASA Development Costs Are Heart Of The Matter". moonandback.com. September 15, 2011.
  21. ^ "Monster Rocket Will Eat America's Space Program". spacefrontier.org. September 15, 2011. Retrieved September 16, 2011.
  22. ^ "Statement by The Planetary Society before the Committee on Science, Space, and Technology U.S. House of Representatives Hearing: A Review of the NASA's Space Launch System" (PDF). The Planetary Society. planetary.org. 12 July 2011.
  23. ^ "Affordable Exploration Architecture" (PDF). United Launch Alliance. 2009.
  24. ^ Grant Bonin (June 6, 2011). "Human spaceflight for less: the case for smaller launch vehicles, revisited". thespacereview.com.
  25. ^ Robert Zubrin (May 14, 2011). "How We Can Fly to Mars in This Decade—And on the Cheap". marssociety.org.
  26. ^ Rick Tumlinson (9/15/11). "The Senate Launch System - Destiny, Decision, and Disaster". huffingtonpost.com. {{cite web}}: Check date values in: |date= (help)
  27. ^ Andrew Gasser (10/24/11). "Propellant depots: the fiscally responsible and feasible alternative to SLS". thespacereview.com. {{cite web}}: Check date values in: |date= (help)
  28. ^ "The Senate Launch System". CompetitiveSpace.org. September 15, 2011.
  29. ^ Ferris Valyn (9/15/11). "Monster Rocket Will Eat America's Space Program". spacefrontier.com. {{cite web}}: Check date values in: |date= (help)
  30. ^ Jeff Foust (9/15/11). "A monster rocket, or just a monster?". theSpaceReview.com. {{cite web}}: Check date values in: |date= (help)
  31. ^ Jeff Foust (1/11/11). "Can NASA develop a heavy-lift rocket?". theSpaceReview.com. {{cite web}}: Check date values in: |date= (help)
  32. ^ "Impossibly High NASA Development Costs Are Heart Of The Matter". moonandback.com. September 15, 2011.
  33. ^ "Congressman, Space Frontier Foundation, And Tea Party In Space Call For NASA SLS Investigation". space-travel.com. October 4, 2011. Retrieved October 20?, 2011. {{cite web}}: Check date values in: |accessdate= (help)
  34. ^ "The Senate Launch System". competitivespace.org. October 4, 2011. Retrieved October 20?, 2011. {{cite web}}: Check date values in: |accessdate= (help)
  35. ^ Bergin, Chris (July 27, 2011). "Preliminary NASA Plan Shows Evolved SLS Vehicle 21 Years Away". nasaspaceflight.com. Retrieved July 28, 2011.
  36. ^ [3] SLS mission schedule improving – Crewed Moon mission moving to 2019