National Launch System

The NLS launch family would have shared a common liquid-fuel engine.
Proposed NLS family of launch vehicles.

The National Launch System (or New Launch System) was a study authorized in 1991 by President George H. W. Bush to outline alternatives to the Space Shuttle for access to Earth Orbit.[1] Shortly thereafter, NASA asked Lockheed Missiles and Space, McDonnell Douglas, and TRW, to perform a ten-month study.[2] A series of launch vehicles was proposed, based around the Space Transportation Main Engine (STME) liquid-fuel rocket engine, a proposed simplified, expendable version of the Space Shuttle Main Engine (SSME).[3][4] The largest of three proposed vehicles was designated NLS-1 and used for its core stage a modified Space Shuttle External Tank which would feed liquid Oxygen and liquid Hydrogen to four STMEs attached to the bottom of the tank. A payload or second stage would fit atop the core stage, and two detachable Shuttle Solid Rocket Boosters would be mounted on the sides of the core stage as on the Shuttle.[3] Period illustrations suggest that much larger rockets than NLS-1 were contemplated, using multiples of the NLS-1 core stage.[5][6]

Program cancellation

A National Launch System engine being test-fired at a NASA centre

The NLS program did not venture beyond the planning stages and did not survive the ascendancy of the Clinton administration in 1993. Perhaps the inevitable was already clear by 1992 with the selection of Daniel S. Goldin to replace Vice Admiral Richard H. Truly as NASA administrator. Goldin championed the motto, "faster, better, cheaper,"[7] which may not have appeared to fit the ambitious NLS vision. A NASA history from 1998 offers that reusable Single-stage-to-orbit (SSTO) rockets and space planes such as the DC-X and X-33 seemed attainable and represented smaller, simpler alternatives to the sprawling Shuttle program.[8] NLS, by contrast, was more of a continuation of the Shuttle legacy. Whether it was ever explicitly stated, by the beginning of the Clinton administration, the expensive Space Shuttle and planned Space Station Freedom programs had enough momentum to continue, and the SSTO projects showed enough promise to fund. There was no budget left for another big program, the National Launch System.

Legacy

Soon after the faster, better, cheaper Evolved Expendable Launch Vehicle (EELV) was proposed by the United States Air Force in 1994, Rocketdyne realized that they would need a powerful, simple engine for the proposed liquid-fueled Common Booster Core (CBC). NLS research on the STME, a simpler SSME, served as a starting point for the greatly simplified RS-68 that powers the current Delta IV EELV rocket.[9] The Delta IV Heavy rocket, composed of three Common Booster Cores, has already launched, and plans exist for rockets with as many as seven CBCs.[10] It could be argued that with its SSME-derived engines and bundled Common Booster Core form, the Delta IV Heavy rocket represents an embodiment of the National Launch System ideal, albeit on a smaller scale.

See also

Notes

  1. ↑ Bush 1991.
  2. ↑ Flight International 1991, p. 12.
  3. 1 2 Lyons 1992, p. 19.
  4. ↑ Federation of American Scientists 1996.
  5. ↑ Lyons 1992, Figure 1.
  6. ↑ Duffy, Lehner & Pannell 1993, Figure 1.
  7. ↑ Thompson & Davis 2009.
  8. ↑ NASA History Division 1998.
  9. ↑ Wood 2002, p. 1.
  10. ↑ Boeing 2005, p. 50.

References

External links

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