Encyclopedia Astronautica
Mars Semi-Direct 1991

Mars Direct
Credit: NASA
American manned Mars expedition. Study 1991. Mars Semi-Direct was a NASA concept bridge between Zubrin's Mars Direct and NASA's Design Reference Mission 1.0. It was essentially a low-cost version of Boeing's STCAEM.

Mars Semi-Direct Mission Summary:

  • Summary: Concept bridge between Mars Direct and Design Reference Mission 1.0; low cost STCAEM
  • Propulsion: Nuclear thermal
  • Braking at Mars: aerodynamic
  • Mission Type: conjunction
  • Split or All-Up: split
  • Launch Year: 1997
  • Crew: 4
  • Mars Surface payload-metric tons: 40
  • Outbound time-days: 180
  • Mars Stay Time-days: 550
  • Return Time-days: 170
  • Total Mission Time-days: 900
  • Total Payload Required in Low Earth Orbit-metric tons: 220
  • Total Propellant Required-metric tons: 170
  • Propellant Fraction: 0.77
  • Mass per crew-metric tons: 55
  • Launch Vehicle Payload to LEO-metric tons: 105
  • Number of Launches Required to Assemble Payload in Low Earth Orbit: 2
  • Launch Vehicle: Ares Mars Direct

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...

  • 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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