NASA’s Opportunity rover begins its tenth year on Mars this week. On January 25, 2004 at 05:05 GMT, the unmanned craft landed in Eagle Crater (1.95°S 354.47°E) in the Meridiani Planum region of the Red Planet. Though scheduled for only a 93 day mission, it continues to explore the Martian surface almost a decade later.

Instead of driving the planned total of 2,000 feet (600 m), Opportunity, also known as MER-B (Mars Exploration Rover B), has traveled 22.03 miles (35.46 km) since it landed. Three weeks before it arrived on Mars, its twin rover Spirit landed on the other side of the planet. Thanks to very good engineering and some very good luck, the two rovers lasted years beyond their projected three month lives with Spirit continuing to operate until 2010.

Opportunity’s mission is to study past water activities and geological processes, analyze the mineral composition of rock outcroppings, calibrate findings of the Mars Reconnaissance Orbiter and seek environments conducive to life. Solar powered, it relies on radioisotope heaters protect it from the freezing Martian nights and its tools include mast cameras and a robotic arm with spectrometers, microscopic imagers and rock abrasion tools.

"Matijevic Hill" panorama for Opportunity's ninth anniversary (Image: NASA/JPL-Caltech/Cornell/Arizona State Univ.)

In the first months of its mission, Opportunity uncovered evidence of water having once been relatively abundant in the area. As the mission was extended, it was sent to larger and larger craters in search of deeper, older geological layers for study.

"What's most important is not how long it has lasted or even how far it has driven, but how much exploration and scientific discovery Opportunity has accomplished," said the Jet Propulsion Laboratory's John Callas, manager of NASA's Mars Exploration Rover Project.

Opportunity is currently studying outcroppings on the rim of the 14 mile (22 km) wide Endeavour Crater at an area called "Matijevic Hill" where there may be signs of an older, wet environment that may be less acidic than areas previously investigated.

Source: NASA