The mission profile involved a single Saturn V launch with an Apollo Command Service Module, the flyby spacecraft, and an MS-IVB stage. The MS-IVB was a modification of the basic S-IVB, with stretched tanks and more internal foam insulation, allowing the stage to remain for sixty hours in low earth orbit before firing. The CSM, with four crew, would undock from the stack, transpose, and dock with the flyby spacecraft.
The flyby spacecraft itself consisted, from fore to aft, of a Mid-Course Propulsion Module with four engines; an Earth Entry Module (a modified Apollo CM, which would also serve as a radiation shelter); and a two-level Mission Module, 4.27 m in diameter, providing living quarters on level 1, and a control console and wardroom on level 2. Exterior to the MM would be a manipulator arm; a biology lab; a 1-m diameter telescope; an airlock for spacewalks equipped with a the CSM docking unit; and a 5.8 m diameter antenna. 185 square meters of solar panels would produce 22 kW at earth and 8.5 kW at Mars and 4.5 kW in the asteroid belt.
The mission scenario involved four Saturn V launches. Launch 1 would orbit the crew and the spacecraft, and launches 2 to 4 would place three MS-IVB's into earth orbit. In order to make this many launches in the short 60 hour storage life of the MS-IVB's, a third Saturn V launch pad, LC-39C, would have to built at the Kennedy Space Center. The Apollo CSM would power the spacecraft to a series of rendezvous and docking maneuvers. After all three MS-IVB stages had been docked in tandem, the Apollo CSM would undock and redock with the side airlock port. Following checkout and testing, the temporary forward docking structure and the Apollo CSM would be jettisoned.
The three stages would be fired in sequence to send the spacecraft toward Mars. This would all have to occur in a launch window extending from 5 September to October 1975. The coast to Mars would take 130 days, with flyby occurring between 23 January and 4 February 1976.
Three 45 kg impact probes, a 4500 kg orbiter, a 567 kg lander, and a 5450 kg Mars Surface Sample Returner would be released toward Mars. The MSSR would return a 1 kg sample to the spacecraft, where it would be studied during the coast back to earth.
The MSSR would be an unmanned versions of the FLEM Mars flyby lander. MSSR would be released weeks before the flyby, land, but then rocket off the Martian surface with the sample 5 minutes after closest approach of the flyby spacecraft. 17 minutes later it would be in solar orbit, a few kilometers ahead of the flyby spacecraft. The flyby would rendezvous with it and snare it with a boom-mounted docking ring, which would then move it to the lateral docking port. The return coast would take the crew out into the asteroid belt, allowing studies to be made there, before returning to earth on 18 July 1977.