The NASA Mars Exploration Rover (MER) Mission began in 2003, when Spirit (designated MER-A and MER-2) was launched on June 10 and Opportunity (MER-B and MER-1) was launched on July 7—each one onboard a U.S. Delta 2 rocket. Spirit landed in the Martian Gusev crater on January 4, 2004, and Opportunity landed on January 25, 2004, in the Meridiani Planum, a hermatite (a mineral type of iron oxide) plain near the Martian equator and on the other side of the planet from Spirit.

Since then the two robotic explorers have far exceeded the expectations of scientists and mission managers at NASA’s Jet Propulsion Laboratory with regards to the amount of scientific data returned to the Earth. The mission of Spirit and Opportunity was to (generally) search for and identify a wide range of soils and rocks and to (specifically) search for previous water activity on Mars.

Four computer software upgrades were beamed to the rovers in September 2006 and installed within their computer memory. One upgrade allows the rovers to decide the best targets to explore. (In the past, the rovers would first send back pictures for mission managers to look over before proceeding to the next location.) The “auto-place” upgrade will speed up the process by which the rovers explore the planet.

The second upgrade is called “visual target tracking” because it allows the rovers to recognize and lock onto a target as they approach even when the target change in appearance due to the rover’s forward motion or ascending/descending motion.

The combined use of “auto-place” and “visual target tracking” will eventually allow mission managers on the Earth to select a target and the rovers will automatically drive to it and place instruments on it—in a process called “go and touch”.

Dust devils and clouds have been causing troubles for the rovers because they are often identified as solid objects. A third upgrade called “watch” will give the rovers the ability to distinguish these mirages from real physical objects, which will dramatically reduce wasted efforts.

The fourth upgrade is called “D*”. It helps the rovers to pre-plan maneuvers in order to avoid obstacles.

Since September 2006, mission managers have tested the four new computer upgrades to make sure they work properly. Besides helping to improve the efficiency of this mission, the ability to install computer upgrades on-the-run will dramatically help to customize future missions and allow for much more ability in unmanned robotic machines.

Spirit and Opportunity, as of January 24, 2007, have been on the surface of Mars for more than three years. This three-year extended mission for Spirit and Opportunity is even more amazing when one considers that the initial mission goal was to have the two rovers explore the Martian surface for a maximum of three months.

Spirit and Opportunity were given these names based on a student essay contest in which 10,000 students entered. Nine-year-old Sofi Collis, who was born in Siberia but currently lives in Scottsdale, Arizona, submitted the winning entry:

I used to live in an Orphanage. It was dark and cold and lonely. At night, I looked up at the sparkly sky and felt better. I dreamed I could fly there. In America, I can make all my dreams come true.... Thank-you for the "Spirit" and the "Opportunity".

At the time the third-grade student won the competition, NASA Administrator Sean O'Keefe said of Sofi, “One of NASA's goals is to inspire the next generation of explorers. Sofi is a wonderful example of how that next generation also inspires us.”

The NASA press release informing the public about Sofi Collis’ winning (and inspiring) entry is found at: http://mars.jpl.nasa.gov/mer/newsroom/pressreleases/20030608a.html.

Information about Spirit and Opportunity is available at http://mars.jpl.nasa.gov/mer.

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