arry at the center of its 28-meter-diameter bowl-shaped Mars Orbit Insertion (MOI) aerobrake heat shield the mission’s two-stage, 60-metric-ton Mars Lander. Spherical tanks surrounding the Lander would hold the 82.5 tons of cryogenic liquid hydrogen and liquid oxygen propellants the piloted sprint spacecraft would need for return to Earth. The cargo spacecraft would also carry 4.2 metric tons of propellants for correcting its course during flight from Earth to Mars and 16.4 metric tons of propellants for circularizing its orbit after it aerobraked in Mars’s atmosphere. A 9.1-metric-ton cooling system would prevent the propellants from boiling and escaping.
On 9 June 2003, the 30.5-meter-long cargo spacecraft/OTV stack would move away from the Space Station. The OTV would then ignite its engines to push the cargo spacecraft out of LEO. After sending the cargo spacecraft on its way, the OTV would separate, fire its engines to slow itself, aerobrake in Earth’s upper atmosphere, and return to the Station for refurbishment, refueling, and reuse.
The cargo spacecraft would intersect Mars on 29 December 2003. It would aerobrake in Mars’s upper atmosphere to slow itself so that the planet’s gravity could capture it. The cargo spacecraft would rise to its apoapsis (orbit high point), then fire its rocket engines to raise its periapsis (orbit low point) out of the atmosphere and circularize its orbit. Flight controllers would then begin careful checkout and monitoring of the cargo spacecraft and its cargo, paying special attention to the propellants the piloted sprint spacecraft would need for return to Earth.
SAIC offered a piloted spacecraft design with Station-derived pressurized crew modules connected in “race track” formation; that is, in a square with each module linked by short tunnels to the modules on either side of it. A pair of 4.4-meter-diameter, 12.2-meter-long habitat modules, each with a mass of 15.5 metric tons, would form two sides of the square; a 4.4-meter-diameter, 12.2-meter-long, 10.8-metric-ton logistics module would form the third side; and an 8.5-metric ton command module and a 3.2-metric-ton airlock module would together make up the fourth.
A pressurized “bridge” tunnel would cross the inside of the square, linking directly the two habitat modules. Another tunnel would pierce the center of the bridge vertically. Its forward end would link with the top of the drum-shaped, 11.9-metric-ton Earth Recovery Vehicle (ERV), while its aft end would carry a docking unit. The ERV, situated deep within the spacecraft’s structure, would double as the crew’s solar flare “storm” shelter. Four spherical tanks holding a total of 91.9 metric tons of cryogenic liquid hydrogen/liquid oxygen propellants and two rocket engines with a combined mass of 4.6 metric tons would be mounted atop the crew modules.
The ERV/storm shelter would be mounted at the center of an 11.4-meter-diameter, one-metric-ton flattened conical aerobrake heat shield. ERV, ERV aerobrake, crew modules, tunnels, propellant tanks, and engines would nestle within a bowl-shaped, 25-meter-diameter, 16.1-metric-ton MOI aerobrake. Except during propulsive maneuvers and aerobraking, four solar arrays capable of generating a total of 35 kilowatts of electricity at the piloted spacecraft’s maximum distance from the Sun (that is, in Mars orbit) would extend beyond the edge of the MOI aerobrake. During maneuvers and aerobraking, the arrays would be folded out of harm’s way atop the crew modules, Fully assembled and loaded with propellants, the piloted spacecraft’s mass would total 193.7 metric tons.
The assembly crew based at the Space Station would link a newly assembled smaller (197.4-metric-ton) OTV to the piloted spacecraft, then would attach the larger OTV used to launch the cargo spacecraft to the new OTV. This would create a 48-meter-long, 738.7-metric-ton stack.
The stack would move away from the Space Station on 21 November 2004. Shortly thereafter, the first OTV would ignite its engines to start the second OTV and the piloted sprint spacecraft on their way. I