Mars Pathfinder Microrover Flight Experiment — A paradigm for very low-cost spacecraft

Abstract

The Mars Pathfinder Microrover Flight Experiment (MFEX) will be carried by the Mars Pathfinder mission to the surface of Mars, where it will perform technology, science and Mars mission engineering experiments in July 1997. The total cost of MFEX, including H/W and SAW development, mission design, operations and inflation is $25M, but it will perform many of the functions of large rovers estimated to cost over $1B.The Mars Pathfinder microrover packs full planetary spacecraft functionality into a very small package (<12 kg, <0.1 cubic meter, <$25M cost). It is self contained (solar powered, with primary batteries for night operations and emergencies); it takes pictures (with 3 cameras); carries and supports a science instrument (an Alpha-Proton-X-Ray spectrometer); performs technology experiments (e.g. for soil mechanics and small vehicle mobility in an unknown terrain); is commanded; collects, stores, packetizes and downlinks data; monitors and controls its attitude and autonomously navigates; actively manages its power and its thermal control; and telecommunicates. In addition it functions on the Martian surface, a much harsher environment than most spacecraft must face. On top of that, the microrover must interact with and respond to its environment in an “intelligent” fashion to carry out its mission and avoid hazards in an uncertain terrain, rather than merely exercising preprogrammed sequences as an ordinary spacecraft does.The factors which allow this include: 1) use of a new onboard autonomous “behavior control” technique (first developed at MIT) combined with “Computer Aided Remote Driving” (developed at JPL); 2) the world-wide miniaturization of electronic and mechanical components; 3) the development at JPL of the a 6-wheeled, very mobile “rocker bogie” mobility system; 4) functional support by the Mars Pathfinder mission (the rover is delivered by, and communicates with earth through, the Mars lander, requiring a rover-lander communication range of less than a kilometer — a large rover power and mass savings); 5) relatively modest mission requirements (the rover carries only one instrument and must survive only for a few months in space and from a week to a month on the Martian surface); and 6) innovative management techniques