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Ride Report

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Ride Report Credit: NASA

Status: Study 1987.

The Ride Report was issued in August 1987, and proposed a Mars Exploration Plan that took an evolutionary approach leading to the first Mars landing in 2005.

The Mars missions described were one-year, round-trip sprints, with astronauts exploring the Martian surface for two weeks before returning to Earth. The chosen scenario significantly reduced the amount of mass that had to be launched into low-Earth orbit, and by doing so brought a one-year round trip into the realm of feasibility. This was accomplished by splitting the mission into two separate parts-a cargo vehicle and a personnel transport-and judiciously choosing the launch date for each. SAIC was again subcontracted to design the Mars mission, but the first missions used a split/sprint mission profile developed by the University of Texas and Texas A&M students.

The Mars cargo vehicle minimized its propellant requirements by taking a slow, low-energy trip to Mars. The vehicle would be assembled in low-Earth orbit and launched for Mars well ahead of the personnel transport, and would carry everything to be delivered to the surface of Mars plus the fuel required for the crew's trip back to Earth. Seven heavy lift launch vehicle launches would be required to assemble the cargo vehicle. The first would orbit the cargo vehicle and its aeroshell; the second the reusable trans-Mars injection stage and its aeroshell; and the remainder would deliver propellant for the injection stage.

The cargo vehicle would be joined to the injection stage at an existing orbiting space station, followed by fuelling of the injection stage. On 9 June 2003 the stage would put the cargo vehicle on a trajectory for Mars, and separate. The injection stage would maneuver back towards earth, aerobrake back into a low earth orbit, and rendezvous with the space station for refueling and reuse. The vehicle sent on trans-Mars injection would be 30.5 m long with a fuelled mass of 58.8 metric tons. 23.4 metric tons of this would be the Cargo Vehicle, with propellant for the Earth Return Vehicle and the Mars lander. The cargo vehicle would aerobrake into Mars orbit on 29 December 2003.

The personnel transport would be assembled and fueled in low-Earth orbit, and would leave for Mars only after the cargo vehicle had arrived in Mars orbit. It would carry a crew of six astronauts, crew support equipment, and propellant for the outbound portion of the trip. Eight launches of the heavy lift vehicle would be required - one with the passenger transport, one with an injection stage, and the remainder with propellant. However this time both the injection stage previously used for the cargo vehicle and the new injection stage would be joined in series with the passenger vehicle. After both stages were fuelled, the two stages would fire in sequence to thrust the passenger vehicles on its faster trajectory toward Mars on 21 November 2004.

Both stages would then separate, return to earth, aerobrake, and rendezvous with the space station for refueling and reuse. Enough propellant would be available for a six month trip to Mars, but the study favored an eight month voyage with the possibility of a free return to earth in case of a major propulsion failure, failure of the Cargo vehicle to reach Mars orbit, or other problem occurred. The spacecraft would reach Mars on 3 July 2005.

The personnel transport would be 47.5 m long and have a mass of 73.9 metric tons and a 24.4 m diameter aeroshell for aerobraking at Mars. 19.4 metric tons of the total would be the sprint vehicle. The personnel transport would also include four living modules housing six crew; and a conical Earth Return Vehicle, that would also serve as a radiation shelter.

Once the personnel transport had aerobraked into Mars orbit, it would rendezvous with the cargo vehicle, refuel, and prepare for descent of the Mars Lander to the surface. The landing party would spend 10 to 20 days on the Martian surface, and then re-rendezvous with the Sprint Vehicle for the trip back to Earth orbit. This would leave Mars orbit on 2 August 2005 on a fast five-month return trajectory to earth. Recovery would involve aerobraking into an elliptical earth orbit. An OTV would dock with the ERV and maneuver it to a docking with a Space Station rehabilitation facility. The round-trip time for this scenario was approximately one year. All of the hardware elements except for the Mars lander, and cargo vehicle structure and aeroshell, would be available at the space station for refueling and reuse in further sprint missions.

The initiative proposed three of these sprint missions, the third around the year 2010. By the second decade of the 21st Century, the U.S. would have the knowledge, the experience, and the technology base to begin developing an outpost on Mars.

Ride Report Mission Summary:

• Summary: First NASA recognition of new elements (ISRU, aerobraking, split missions) developed by private enthusiasts.
• Propulsion: LOX/LH2
• Braking at Mars: aerodynamic
• Mission Type: opposition
• Split or All-Up: split
• ISRU: no ISRU
• Launch Year: 2004
• Crew: 6
• Outbound time-days: 240
• Mars Stay Time-days: 20
• Return Time-days: 150
• Total Mission Time-days: 410
• Launch Vehicle Payload to LEO-metric tons: 30
• Number of Launches Required to Assemble Payload in Low Earth Orbit: 7
• Launch Vehicle: Shuttle C