After an almost 15-year run, Mars rover Opportunity finally wrapped up its historic leg of exploration a day before Valentine’s.
“No response has been received from Opportunity since Sol 5111 (June 10, 2018), amid a planet-encircling dust storm on Mars,” NASA said in its log.
Sol, which is short for Solar day, is the measurement NASA used to tell the time it takes Mars to revolve once around its own axis.
Eight months later, on February 13, the Mars Exploration Rover (MER) team at NASA’s Jet Propulsion Laboratory (JPL) at Pasadena, California declared Opportunity’s mission “complete,” after the golf-cart-sized rover failed to answer the final call of scientists.
Opportunity arrived on the Red Planet in January 2004, a couple of weeks after its twin rover Spirit landed on the other side of Mars.
These two Mars Exploration Rovers were originally programmed for 90-day missions for them to image, explore, and investigate the Martian surface.
But as luck would have it, the Martian weather helped in extending their missions. According to Space.com, “strong winds came along and blasted both robots’ arrays clean before the robots had to face down their first Martian winter.”
The rovers also had “the finest batteries in the solar system,” MER project manager John Callas said.
Opportunity and Spirit—the twin rover that went dead in 2010—have contributed numerous, invaluable information about the Red Planet, especially those that provided “signs of life” on the Mars.
Among them are enumerated in a 2014 article of Space.com by rover deputy principal investigator Ray Arvidson, of Washington University in St. Louis.
To begin with, Opportunity has found several meteorites on Mars dispersed across Meridiani plains.
Opportunity has also found evidence that ancient Mars may have been habitable for millions of years. “At the rim of Endeavour Crater, Cape York, the rover discovered ferric and aluminous smectite clays in finely layered Matijevic formation rocks that pre-exist the Endeavour impact event,” Arvidson explained.
Spirit, on the other hand, treaded through Home Plate, Gusev Crater to find Opaline silica formed in volcanic fumaroles and/or hydrothermal vents, which showed how water was interacting with magma.
Spirit also spotted “complex coatings on olivine basalts; Gusev Crater plains showing modern water on Mars, or possibly frost, has altered rock surfaces.”