Encyclopedia Astronautica
PH-D Proposal


American manned Mars orbiter. Study 1981. 1981 Mars orbiter expedition design, using Phobos and Deimos as bases, and using solar electric propulsion.

By the time of the first Case for Mars conference in 1981, development of the shuttle was complete and NASA was attempting to obtain funds for a follow-on manned project. S Fred Singer proposed a $10 billion program to send humans to Mars. Deimos would be used as an orbital base; no manned landing would be attempted. Instead the 6 to 8 man crew would guide the surface activities of 10 to 20 Mars surface rovers. The spacecraft would be propelled by solar-electric propulsion on its 700 day mission. The engine would be operated at full thrust throughout the long trip to Mars and back. To prevent the crew from having to endure long months in the acceleration spiral out of earth orbit, much of it in the radiation belts, they would be brought up to rendezvous with the main spacecraft just before it reached escape velocity. These considerations kept the spacecraft mass down to 270 metric tons, A launch in the 1990-1999 period was proposed, with a Venus swing-by to reduce return velocity.

PH-D Proposal Mission Summary:

  • Summary: Proposal for robotic exploration of Mars, with surface rovers and sample return vehicles being operated from a manned base on one of the moons of Mars.
  • Propulsion: Solar electric
  • Braking at Mars: propulsive
  • Mission Type: low acceleration
  • Split or All-Up: all up
  • ISRU: no ISRU
  • Launch Year: 1995
  • Crew: 8
  • Outbound time-days: 400
  • Mars Stay Time-days: 30
  • Return Time-days: 270
  • Total Mission Time-days: 700
  • Total Payload Required in Low Earth Orbit-metric tons: 270
  • Mass per crew-metric tons: 33
  • Launch Vehicle Payload to LEO-metric tons: 30
  • Number of Launches Required to Assemble Payload in Low Earth Orbit: 10
  • Launch Vehicle: Shuttle

Crew Size: 6.

Gross mass: 270,000 kg (590,000 lb).

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Associated Countries
See also
Bibliography
  • Portree, David S. F., Humans to Mars: Fifty Years of Mission Planning, 1950 - 2000, NASA Monographs in Aerospace History Series, Number 21, February 2001.

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