NASA formally extended its ongoing mission to Mars, giving a pair of rovers another five months to search for evidence the planet once was a wetter place hospitable to life, agency officials said Thursday.
The $15 million extension means Spirit and Opportunity could operate on Mars through September, said Firouz Naderi, manager of the Mars exploration program at NASA's Jet Propulsion Laboratory.
The move is expected to nearly triple the planned mission of the rovers, although dust, cold and mechanical wear-and-tear could curtail the lifetime of either or both robots, Naderi added.
Opportunity builds on evidence of water
For Opportunity, the move should allow it to build on the evidence it already has found that water once bathed its landing site on Mars, by allowing it to visit at least four outcrops of rock, said Ray Arvidson of Washington University in St. Louis, the mission's deputy main scientist.
The first outcrop Opportunity analyzed, within the small crater it landed in Jan. 24, revealed that standing water, perhaps a salty sea or swamp, once covered Meridiani Planum. Scientists hope to learn how broad that body of water might have been, as well as how deep and long-lived, by studying more locations where similar rocks appear.
Opportunity already has reached its second such spot, a linear trough that fractures the rock underlying the largely flat and smooth region, Arvidson said.
Opportunity should then visit a third rocky location before traveling to a large depression, called Endurance Crater, that lies about 2,300 feet (690 meters) away. A stack of rocks tens of yards high appears to rim a portion of the crater.
"That's why there is a compelling reason to get on with the driving," Arvidson said of Opportunity, which recently traveled 330 feet (99 meters) in a day to set a one-day distance record for the double mission.
Spirit is still willing
For Spirit, working in Gusev Crater on the other side of planet since Jan. 3, similar evidence of abundant past water activity has been elusive.
It continues to press on with its quest. The extended mission should give the rover time to reach a cluster of hills, roughly 1.5 miles (2.5 kilometers) away, that may contain layered deposits laid down if and when Gusev contained a sloshing lake of water, as scientists believe.
The hills also could have formed in the impact that punched out Gusev, or through volcanic processes.
Mission members expect Spirit to take one to two months to reach the so-called Columbia Hills.
NASA will lose touch with the rovers on Sept. 13, when Mars passes behind the sun. The blackout should leave Earth out of contact with the two rovers for a week to 10 days, Naderi said.
If NASA can re-establish contact with the rovers once Mars pops back into view, the agency could further extend operations on either one or both robots, Naderi added.
The mission's original tab was $820 million, including $645 million for development of the spacecraft and instruments, $100 million in launch costs and $75 million for mission operations and processing of science data.