Mars Exploration Rovers
Mars Exploration RoversTwo NASA robotic roving landers named Spirit and Opportunity, launched to Mars in summer 2003 from Cape Canaveral, Florida, by Delta 2 rockets. Spirit was launched on June 10, followed by Opportunity on July 7. The two landers made planetfall on Mars in Jan. 2004, using parachutes and giant airbags to cushion their landings. Spirit touched down in Gusev crater, just south of the Martian equator, on Jan. 3. Three weeks later, on Jan. 24, Opportunity landed in Meridiani Planum, an extensive plain just north of the equator but on the other side of the planet. Both rovers were equipped with a battery of cameras, spectrometers, microscopes and digging and sampling tools. Spirit's chief task was to explore Gusev, a large impact crater about 145 km wide, and investigate the possibility that it might have been a lake in Mars' remote past. Opportunity's landing site in Meridianum Planum was an area covered by an ancient layer of hematite, an oxide of iron that on Earth is usually found in watery environments with small amounts of the mineral goethite. Opportunity was to investigate this hematite layer in the hope of finding goethite and once again uncovering evidence that water once flowed on Mars. A software problem threatened to cut short Spirit's science-gathering program early on, but engineers found a way of working around the difficulty. Project scientists estimated that the rovers would function for no more than three months, but by the beginning of 2005 both were still transmitting back valuable scientific data, much of which seemed to confirm Mars' watery past.
Collins Dictionary of Astronomy © Market House Books Ltd, 2006