The US space agency's robotic Mars explorer Opportunity has completed 90 days on the Red Planet, bringing its primary mission to an end.
The rovers will spend 150 days longer on Mars than expected
But Opportunity is not finished yet: the rover will carry on investigating the Red Planet for at least another 240 sols, or Martian days.
The rover has uncovered evidence that its landing site was once the shoreline of a salty lake or sea.
Its "twin", Spirit, passed the 90 sol landmark earlier this month.
Opportunity is exploring Meridiani Planum, a flat plain rich in the mineral grey haematite - which usually forms in water.
"We have full mission success on the project," said mission manager Matt Wallace. "It's a remarkable milestone."
The rover has now driven nearly 812m (about half a mile) since it landed on Mars and has downlinked 12,429 images to Earth.
It is now investigating two soil targets on Meridiani Planum which have been dubbed "nougat" and "Fred Ripple".
The robot explorer will complete a drive on Wednesday that will put it 75m away from Endurance Crater, the large depression it is en route to explore.
But the rover is now close enough that it has been able to send back relatively detailed images of the crater's rim.
"Some of us have seen what we think are bedding like features; some of us have seen what we think are erosion-like feature," said mission scientist Scott McLennan.
"There's some very interesting science [at Endurance Crater], but we won't know what we want to do until we get closer, hopefully in the next day or so."