This page no longer updated from 31 October 2001. Latest version can be found at Mars Expeditions

Spacecraft: Mars USA. Mars landing studies in the USA from 1963 to 1969 focussed on use of NERVA nuclear rocket stages to take a manned expedition to the red planet.

Spacecraft: MORL Mars Flyby.

Spacecraft: Project Deimos.

Project Deimos was a Mars expedition proposed by Philip Bono in the late 1960's. It would use the huge Rombus single-stage-to-orbit booster, refuelled in earth orbit, as the propulsion system to Mars and back. Separate Mars landers would bring crews to explore the Martian surface.

Spacecraft: Planetary Mission Module.

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.

Spacecraft: Mars Direct.

In 1991 Martin Marietta and NASA Ames ()ubrin, Baker, and Gwynne) proposed 'Mars Direct' - a Mars expedition faster, cheaper, and better than the standard NASA plan. Key features included:

  • Direct flight to and from the Martian surface. Artificial gravity provided en route. No earth orbit or lunar orbit rendezvous; no zero-G assembly operations or crewed monitoring of spacecraft in Mars orbit.

  • Fuelling of the Earth Return Vehicle using propellant generated on Mars from the atmosphere.

  • Extended operations on the Martian surface (555 days) as opposed to the 20 days for NASA 'fast' missions.

Mars Direct would be completed in two launches of the proposed Ares heavy lift booster. The first launch would deliver an unfuelled and unmanned Earth Return Vehicle (ERV) to the Martian surface. After landing an on-board production plant would generate methane/oxygen propellants. A second launch would deliver the four-person crew. Following eighteen months of extensive exploration of the surface, they would enter the ERV and return directly to Earth. The same launch vehicles and spacecraft developed for Mars Direct could also support a lunar base.

Spacecraft: ERTA.

In the 1990's Energia studied use of nuclear electric propulsion for the scientific development project 'Mars - Nuclear electric propulsion Stage' under contract to the Russian Space Agency and the project 'Star - Soarer' under contract to the Ministry of Atomic Industry. These studies looked at designs for the 2005 period. At the beginning of the 1990's a new type of nuclear generator was studied, that would have a capacity of 150 kW in the transport role and provide 10-40 kW to power spacecraft systems while coasting. This was designated ERTA (Elecktro-Raketniy Transportniy Apparat). Technologies and concepts for this engine were studied by FEI and other organisations. A modular concept was adopted. In 1994 ERTA was studied for launch by Titan, Ariane 5, or Energia-M launch vehicles. The reactor weight was 7,500 kg and it could provide up to 10 years of electrical power traded off against 1.5 years of powered flight.

Aside from this work on the 150 kW design, there was also an examination at the same time of the use of nuclear electric propulsion for Mars expeditions. Single and multiple launch approaches were considered. For a single-launch complex of 150 tonnes a nuclear electric propulsion unit of 5 to 10 MW with enough fuel for 1.5 years would be required. For the multiple launch design, a power of 1 to 1.5 MW and fuel for three years would be required.

Spacecraft: Mars Together.

In 1994-95, RKK Energia, and NASA's Jet Propulsion Laboratory analysed the project 'Mars Together'. This studied the use of spacecraft using solar arrays or nuclear reactors of up to 30 to 40 kW for insertion into Martian orbit and operation of a side-looking radar to digitally map the surface. As a preliminary step a demonstration launch was proposed of a spacecraft with a mass of 120 to 150 kg, a solar panel area of 30 square meters and engines with a thrust of 3 kW. Objectives of the experiment would be understanding of the changing of the orbital altitude with continuous work of the ion engine for several hundred hours.

Spacecraft: Athena.

In 1996 Robert Zubrin proposed a new version of a manned Mars flyby mission, dubbed Athena. Unlike previous fly-by concepts, Athena would remain in the vicinity of Mars for a year while the crew remotely operated probes of the Martian surface and atmosphere. This would eliminate the round-trip radio time lag of ten to forty minutes in trying to operate such probes from the earth.

Athena would follow a low-energy earth-Mars trajectory. At Mars encounter the planet's gravity would be used to change the spacecraft's orbit to one similar to but inclined 9.5 degrees from that of Mars. The spacecraft would spend a year 'shadowing' the planet and operating four remote-controlled rovers delivered separately to the surface. At the end of that period Athena's orbit would again bring it to Mars. The flyby would send it on a slow nine month trajectory back towards earth. On approach to earth the crew would an ISS ACRV-derived re-entry vehicle to renter the earth's atmosphere. The 2.5 year mission would finish with splashdown in the ocean for recovery by the US Navy.

Athena would have a crew of two. The spacecraft and its trans-Mars injection stage would be assembled in low earth orbit using two shuttle launches and four Proton launches. The Mars probes (four rovers) would be launched separately by Delta 7925 or Molniya launch vehicles. Other possible probes would include subsonic remotely piloted drones or controlled balloons equipped with imaging systems and deployable/recoverable rovers.

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Last update 28 March 2001.
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© Mark Wade, 2001 .