Encyclopedia Astronautica
Planetary Mission Module



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Mars 1969 MM
Credit: NASA
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PMM Quarters
Planetary Mission Module
Credit: NASA
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Station Cutaways
Credit: NASA
American manned Mars orbiter. Study 1969. NASA had the long range goal of sending men to explore the planet Mars.

To assure that the developments undertaken as part of the Space Station program contributed to this long term goal without undue increase in program cost or complexity, an assessment was made to determine where common or near common requirements existed. Two manned Mars missions, a 1981 opposition class mission and a 1986 conjunction class mission, were selected as representative types about which to develop total vehicle and operational concepts. These concepts involved the use of two Nuclear Shuttles for Earth departure and a third Shuttle to accompany the planetary spacecraft for use in braking into Mars orbit, in Mars orbit departure and in braking into a highly elliptic Earth orbit.

Although complete spacecraft concepts with Mars excursion modules and probes were laid out by both Phase B contractors, the principal effort was devoted to the so-called mission module which housed the living quarters, command and control, and laboratories. These were 10 m in diameter, utilized isotope Brayton power generation systems, and had centrally-located radiation shelters. Both contractor design teams concluded that substantial commonality could exist between the postulated planetary mission and the Earth orbital mission, particularly in habitability and long life system approaches.

Non-commonalties of station and planetary mission module (PMM) were based on several unique interplanetary mission characteristics or requirements. The long mission duration, with no practical feasibility of resupply, demands larger storage volumes in the PMM. Maintenance philosophy, in the interest of weight constraints, emphasized repair over throw-away and replacement from spares supply; while at the same time requiring considerable spares storage. The fact that the planetary spacecraft may approach the Sun as closely as 0.5 A.U. requires resized of the environmental control system radiator to operate satisfactorily at 4 times the solar constant near Earth.

Maximum solar distance may be as large as 1.8 AU This rendered solar cell arrays unsuitable, considering a required power level of 25 kW. It also necessitated greater meteoroid protection. The consequences concerning solar flare exposure outside the geomagnetic shield created the need for a radiation shelter arrangement. The use of a two-vehicle buddy system for mutual self-rescue and survive required that each PMM store provisions for a crew of 12 while housing 6 under nominal conditions, thus providing still more ample shielding. The planetary mission plan called for the use of Mars Surface Sample Returners (MSSR) and manned Mars Excursion Modules (MEM). The resulting exposure to Mars material required special provisions to avoid possible backward contamination.

Characteristics

Crew Size: 6. Habitable Volume: 930.00 m3. Electric System: 25.00 average kW.

Gross mass: 100,000 kg (220,000 lb).
Height: 33.50 m (109.90 ft).
Diameter: 6.70 m (21.90 ft).
Span: 10.00 m (32.00 ft).

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Associated Countries
Associated Spacecraft
  • Von Braun Mars Expedition - 1969 American manned Mars expedition. Study 1969. Von Braun's final vision for a manned expedition to Mars was a robust plan that eliminated much of the risk of other scenarios. Two ships would fly in convoy from earth orbit to Mars and back. More...

See also
  • US Space Stations Wernher von Braun brought Noordung's rotating station design with him from Europe. This he popularized in the early 1950's in selling manned space flight to the American public. By the late 1950's von Braun's team favoured the spent-stage concept - which eventually flew as Skylab. By the mid-1960's, NASA was concentrating on modular, purpose-built, zero-G stations. These eventually flew as the International Space Station. More...

Associated Manufacturers and Agencies
  • NASA American agency overseeing development of rockets and spacecraft. National Aeronautics and Space Administration, USA, USA. More...
  • North American American manufacturer of rockets, spacecraft, and rocket engines. North American, Palmdale, El Segundo. Downey, CA, USA More...
  • McDonnell American manufacturer of spacecraft. McDonnell, St Louis, USA. More...

Bibliography
  • Larmore, L and Gervais, R L, Editors, Space Stations - Volume 27 - Advances in the Astronautical Sciences, AAS Publications Office, Tarzana, 1971.

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