Encyclopedia Astronautica
Synthesis Study

Credit: © Mark Wade
American manned Mars expedition. Study 1991. On 11 May 1991 President Bush declared that he would support a Space Exploration Initiative program leading to a Mars Landing by 2014.

To coincide with the announcement, the SEI Synthesis Group issued a report America on the Threshold that foresaw Mars expeditions based once again on nuclear thermal propulsion.

This was seen as a concession to Los Alamos National Laboratory, which was looking for a major project to offset the ending of further development of nuclear weapons in the post-Cold War period. There was no space station in the plan. Four architectures were studied, essentially a cut-price version of the 90 Day Study. There was no interest in the plan. Congress cancelled further funding for Mars studies in FY 1991. NASA's Exploration Office was dissolved. The Case for Mars V conference in 1993 was poorly attended.

Synthesis Study Mission Summary:

  • Summary: Chartered by National Space Council - "major study"; Explore Mars and provide significant science return
  • Propulsion: Nuclear thermal
  • Braking at Mars: propulsive
  • Mission Type: conjunction
  • Split or All-Up: split
  • Launch Year: 2014
  • Crew: 6
  • Outbound time-days: 210
  • Mars Stay Time-days: 460
  • Return Time-days: 230
  • Total Mission Time-days: 900
  • Total Payload Required in Low Earth Orbit-metric tons: 1080
  • Total Propellant Required-metric tons: 600
  • Propellant Fraction: 0.55
  • Mass per crew-metric tons: 180
  • Launch Vehicle Payload to LEO-metric tons: 150
  • Number of Launches Required to Assemble Payload in Low Earth Orbit: 4
  • Launch Vehicle: Shuttle Z

More... - Chronology...

Associated Countries
See also
  • Mars Expeditions Since Wernher von Braun first sketched out his Marsprojekt in 1946, a succession of designs and mission profiles were seriously studied in the United States and the Soviet Union. By the late 1960's Von Braun had come to favour nuclear thermal rocket powered expeditions, while his Soviet counterpart Korolev decided that nuclear electric propulsion was the way to go. All such work stopped in both countries in the 1970's, after the cancellation of the Apollo program in the United States and the N1 booster in the Soviet Union. More...

Associated Manufacturers and Agencies
  • NASA American agency overseeing development of rockets and spacecraft. National Aeronautics and Space Administration, USA, USA. More...

  • Portree, David S. F., Humans to Mars: Fifty Years of Mission Planning, 1950 - 2000, NASA Monographs in Aerospace History Series, Number 21, February 2001.
  • Griffin, Brand; Thomas, Brent; Vaughan, Diane, A Comparison of Transportation Systems for Human Missions to Mars, AIAA 2004-3834, 40th AIAA/ASME/SAE/ASEE Joint Propulsion Conference and Exhibit ,11-14 July 2004.

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