A Broken Spirit

After the success of the Pathfinder mission, NASA decided to send further rover missions to explore Mars. This time, scientists would send two rovers to work at the same time as the Mars Exploration Rovers mission. These twin robot geologists were designed to study Martian rocks and soil to determine what kinds of minerals there were and possibly how the developed. An especially important goal was to research whether any rocks or soil had been affected by liquid water in the past because the discovery of water on Mars could indicate that life could have developed on Mars.

Artist's rendition of Spirit on Mars. Source.

The first of these twin rovers, MER-A, was named Spirit by one of 10,000 entries from a student essay contest. It launched on June 10, 2003 from Cape Canaveral and landed on January 4, 2004 in Gusev Crater, a large impact crater and possible dry lake bed.

Panorama of the Gusev Crater landing site. Source.

Upon landing (using the airbag system developed for Pathfinder) Spirit set to work with its 7 scientific instruments examining the Martian surface, analyzing the chemical makeup of rocks and soil, and taking high-resolution photographs of the terrain and microscopic images of the soil. The Rock Abrasion Tool (RAT) allowed the two rovers to look at the insides of Martian rocks for the first time.

Spirit examining the "Adirondack" rock formation. Source.

Though Spirit far outlived its original 90-day mission length by an astounding 7 years, 2 months, Spirit's time eventually came to an end. On April 23, 2009, Spirit drove over a weak part of the crust at a site named Troy and sank into a sand trap. Because one of its six wheels stopped working in 2006, scientists were not able to guide it out. To make matters worse, they only had until winter to free Spirit; otherwise its solar panels would not be able to get enough sunlight to keep it powered.

A scientist examines a model of Spirit in the hopes of setting it free. Source.

After months of unsuccessful maneuvering, Spirit entered its power-saving hibernation mode on March 22, 2010. Though scientists hoped that it would reawaken once it had recharged enough power, Spirit never sent another signal. NASA officially ended Spirit's mission on May 25, 2011.

During its more than 7 years of work, Spirit made many important discoveries. In the Columbia Hills area, it discovered that the terrain was formed by impacts from asteroids, explosive volcanoes, and water under the surface. It also found very bright patches of salty soil that is believed to have been effected by past water. Even while stuck in the sand trap at Troy, Spirit continued collecting data and taking photographs. Though the Spirit rescue mission failed, it still gave scientists valuable information about how to look at Martian terrain and how to drive on Mars.

Thus, Spirit's long life can easily be considered a success. However, even Spirit's discoveries pale in comparison to that of its twin, MER-B, also known as Opportunity.

For more on the MER mission, see the MER website and NASA's MER Fact Sheet.
To read about the Spirit rescue mission, read the following articles about the attempts to rescue it, its winter shut down, and the mission's end.