Mars Exploration Rover — Spirit
<i>Spirit</i>'s West Valley Panorama (False Color)
Mars Exploration Rover — Spirit

Mars Exploration Rover — Spirit

Courtesy of NASA

Spirit was the first of two robotic, solar-powered, six-wheel exploration rovers to arrive on Mars. Its twin, Opportunity, arrived about three weeks later and landed on the opposite side of Mars. NASA hoped that each rover would explore for about 90 days and drive over about 1 kilometer of the Martian surface. The rovers traveled separately to Mars, each inside a protective landing shell, but once the antennas deployed, cameras and scientific instruments calibrated, the rovers went on independent of their protective shells. Through several cameras “eyes” that send images back to engineers on Earth, scientists are able to command the rovers to navigate and perform science investigations, using the onboard instruments, which include a panoramic camera (Pancam), navigational camera, microscopic imager to obtain close-up images of rocks and soils, and instruments to analyze the minerals. A diamond-coated Rock Abrasion Tool exposed fresh material in Martian rocks.

To test the rover idea prior to sending them to Mars, a prototype rover called FIDO was sent to several desert areas in the United States where scientists practiced navigating and performing experiments.

Spirit outlasted longevity expectations by more than twenty times and traveled almost ten times farther than originally planned. Unfortunately, Spirit got stuck in 2009 in soft soil and engineers were unable to get it unstuck. It continued to return scientific data from its stuck spot, but finally became unresponsive in 2010. 

June 10, 2003

January 4, 2004

End of Mission
(last communication) March 22, 2010; May 24, 2011


Study rocks and soils that may hold clues to past water activity on Mars, study geologic processes near the landing site, verify the accuracy of data obtained by Mars Reconnaissance Orbiter, and determine if environmental conditions were ever conducive to life on Mars.

Spirit endured far beyond its original expectation of 90 days to last 2,269 days in the Martian environment. It survived dust storms that blocked sunlight needed to maintain a power supply, wheels that stopped working, and stresses far beyond anything that was expected. Spirit landed in Gusev Crater, a 170 km diameter crater that formed three to four billion years ago. A channel system drains into the crater that likely, at some point in Mar’s history, carried liquid water or a combination of water and ice. The crater appears to be an old lake bed filled with sediments. It was hoped that sedimentary material from this early era could be studied. At first the region proved disappointing because there was no exposed bedrock on the flat lava plains of the crater. Spirit eventually made its way to the Columbia Hills, a small group of low-lying hills about 3 km from the landing site. Rocks examined there do show evidence of interaction with small amounts of briny (salty) water.