The surface of Mars has long been thought to consist of a mixture of rock, soil and icy material. However, the exact composition of these materials was largely unknown. Odyssey has been collecting images that are used to identify the minerals present in the soils and rocks on the surface and to study small-scale geologic processes and landing site characteristics. By measuring the amount of hydrogen in the upper meter of soil across the whole planet, the spacecraft helps us understand how much water may be available for future exploration, as well as give us clues about the planet's climate history. The orbiter also collects data on the radiation environment to help assess potential risks to any future human explorers, and acts as a communications relay for Mars landers such as Phoenix.
Mass: 758 kilograms (1,671 pounds), fueled
Science instruments: Thermal emission imaging system, gamma ray spectrometer, Mars radiation environment experiment
Launch: April 7, 2001
Arrival at Mars: October 24, 2001