One of the most successful interplanetary exploratory missions, that of NASA’s Opportunity rover, came to an end after almost 15 years roaming the surface of Mars. NASA lost communication with the rover last June when a planetwide dust storm apparently put it out of commission. Some scientists believe dust from the storm covered its solar arrays, causing it to run out of power.
Designed to last just 90 Martian days and travel 1,100 yards (1,000 meters), Opportunity went above and beyond the call of duty in its endurance, scientific value, and longevity. In addition to exceeding its life expectancy by a factor of 60, the rover traveled more than 28 miles (45 kilometers) by the time it reached its most appropriate final resting spot on Mars, Perseverance Valley.
The final transmission from Earth was sent using the 230-ft Mars Station antenna at NASA’s Goldstone Deep Space Complex in California. It was the last command send at part of an eight-month recovery effort to get the rover to talk back.
The rover landed on Mars on Jan. 24, 2004, seven months after being launched from Cape Canaveral Air Force Station in Florida. Its twin rover, Spirit, which was also planned for a 90-day mission, landed 20 days earlier on the other side of Mars. Spirit operated for seven years and logged almost 5 miles (8 kilometers) before its mission ended when it became stuck in sand. It was stuck at an angle that prevented its solar panels from recharging its batteries. Its last communication with Earth was in March 2010.
During its life, Opportunity set several milestones:
- Setting a one-day Mars driving record (March 20, 2005) of 721 ft (220 m);
- Returning more than 217,000 images of Mars, including 15 360-deg color panoramas;
- Exposing the surfaces of 52 rocks to reveal fresh mineral surfaces for analysis, while clearing 72 additional targets with a brush to prepare them for inspection with spectrometers and a microscopic imager;
- Finding hematite, a mineral that forms in water; and
- Discovering strong geological indications at Endeavour Crater of the remnants of an ancient body of water.
All those accomplishments were not without the occasional extraterrestrial accident. In 2005, for example, Opportunity lost steering to one of its front wheels; a heater got electrically stuck in the “on” position, which threatened to limit the rover’s available power; and a sand ripple almost trapped it for good. Two years later, the rover had to withstand a two-month dust storm. In 2015, Opportunity lost use of its 256-megabyte flash memory and, in 2017, it lost steering to its other front wheel.
Mars exploration continues. NASA’s InSight lander, which touched down on Nov. 26, is just beginning its seismic investigations. The Curiosity rover has been exploring Gale Crater for more than six years. Looking ahead, NASA’s Mars 2020 rover and the European Space Agency’s ExoMars rover will launch in July 2020, becoming the first rover missions designed to seek signs of past microbial life on the Red Planet.