2001 Mars Odyssey

Mission Profile

2001 Mars Odyssey is the longest-lived spacecraft currently operating at Mars, launched on 7 April 2001 aboard a Delta II 7925-9.5 and arriving at Mars in October 2001. The orbiter carries three instruments — THEMIS, GRS, and MARIE — to map the mineral and chemical composition of the Martian surface, measure radiation levels, and study the global distribution of water ice. Mars Odyssey made the landmark discovery that large quantities of hydrogen (indicative of subsurface water ice) exist in the Martian polar regions, revolutionizing understanding of Mars's water history. The spacecraft has also served as a crucial communications relay satellite for subsequent Mars surface missions including Spirit, Opportunity, and Curiosity, collectively relaying hundreds of gigabits of data over more than two decades.