The Mars micromission (MM) spacecraft (MMSC) is a multi-purpose platform capable of orbiting Mars for communications/navigation and science payloads or for precision Mars flybys to drop up to six probes. An MMSC is launched as a secondary payload on an Ariane 5 rocket from Kourou, French Guiana, to GTO using the Ariane 5 structure for auxiliary payloads (ASAP5). The maximum launch wet mass is 222kg and can include up to 45kg of payload depending on ΔV needs. The on-board propulsion system is used for maneuvering in the Earth–Moon system and injecting the spacecraft into Mars transfer orbit and, if needed, Mars orbit. The first MMSC to be launched in early 2003 will be a Communications/Navigation (Comm/Nav) Orbiter. JPL is responsible for the Comm/Nav payload. Ball Aerospace, working with JPL, provides the multi-purpose spacecraft bus, system integration and test, and assists in operations over the 3 year mission duration. This paper summarizes the baseline spacecraft concept for the first Mars Com/Nav mission as defined at the start of the program in February 2000 and describes the spacecraft bus implementation in more detail.

The Ball Micromission Spacecraft (MSC) is a multi-purpose platform capable of supporting science missions at distances from the Sun ranging from 0.7 to 1.7 AU. In the baseline scenario, MSC is launched as a secondary payload on an Ariane 5 rocket from Kourou, French Guiana, to GTO using the Ariane 5 structure for auxiliary payloads (ASAP5). The maximum launch wet mass is 242 Kg and can include up to 45 Kg of payload depending on AV needs. The on-board propulsion system is used for maneuvering in the Earth-Moon system and injecting the spacecraft into its final orbit or trajectory. For Mars missions, MSC enables orbiting Mars for science payloads and/or communications and navigation assets, or for precision Mars fly-bys to drop up to six probes. The micromissions spacecraft bus can be used for science targets other than Mars, including the Moon, Earth, Venus, Earth-Sun Lagrange points, or other small bodies. This paper summarizes the current spacecraft concept and describes the multimission spacecraft bus implementation in more detail.