Phoenix Mars Lander
Launched on Aug. 4, 2007, Phoenix landed on May 25, 2008, farther north than any previous spacecraft sent to Mars. The lander dug, scooped, baked, sniffed and tasted the Red Planet's soil. Among early results, it verified the presence of water-ice in the Martian subsurface, which NASA's Mars Odyssey orbiter first detected remotely in 2002. Phoenix's cameras also returned more than 25,000 pictures from sweeping vistas to near the atomic level with the first atomic force microscope ever used outside Earth.
During its mission, Phoenix confirmed and examined patches of the widespread deposits of underground water ice detected by Odyssey and identified a mineral called calcium carbonate that suggested occasional presence of thawed water. The lander also found soil chemistry with significant implications for life and observed falling snow. The mission's biggest surprise was the discovery of perchlorate, a chemical on Earth that is food for some microbes and potentially toxic for others.
"Phoenix not only met the tremendous challenge of landing safely, it accomplished scientific investigations on 149 of its 152 Martian days as a result of dedicated work by a talented team," said Phoenix project manager Barry Goldstein at NASA's Jet Propulsion Laboratory in Pasadena, Calif.
Additional findings included documenting a mildly alkaline soil environment unlike any found by earlier Mars missions; finding small concentrations of salts that could be nutrients for life; and discovering perchlorate salt, which has implications for ice and soil properties.
Phoenix's findings also added to the history of water on Mars. These findings included excavating soil above the ice table, revealing at least two distinct types of ice deposits; observing snow descending from clouds; providing a mission-long weather record, with data on temperature, pressure, humidity and wind; observations of haze, clouds, frost and whirlwinds; and coordinating with NASA's Mars Reconnaissance Orbiter to perform simultaneous ground and orbital observations of Martian weather.
Viking Mission Overview
Mars Exploration Rovers
Mars Reconnaissance Orbiter