An artist's depiction of what one of the MER rovers may look like on the surface of Mars.
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Image courtesy NASA/JPL

An Overview of the Mars Exploration Rover (MER) Mission

NASA's Mars Exploration Rover (MER) mission has sent two robotic rovers to the surface of Mars. The two separate spacecraft are exploring sites named Gusev Crater and Meridiani Planum that are on opposite sides of Mars. The rovers are designed primarily as geological surveyors, with a special focus on finding signs of past or current deposits of water on or near the Martian surface. Many types of rocks that form in the presence of water contain clues that reveal that water was around when they formed. The rovers are looking for such rock types, such as sedimentary deposits formed in lakes or seas and the mineral gray hematite.

The twin MER missions were launched in June and July of 2003. The spacecraft landed on Mars in January 2004. The rovers are expected to have an operational lifetime of about 90 days on the surface of the Red Planet. The rovers have been given names: "Spirit" and "Opportunity".

Last modified February 7, 2004 by Randy Russell.

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