The Mars rovers continue to send back intriguing new photos and scientific data from the Red Planet, but they are showing signs of "aches and pains" as they pass their two hundred day mark, more than twice their expected life expectancy.
The twin rovers Spirit and Opportunity are facing the arrival of the Martian winter.
Its shorter days will cause hardship for the solar powered rovers, and mission specialists are trying to steer the vehicles toward brighter areas and out of shadows.
Opportunity Mission Manager Chris Salvo said that the rovers are showing their age, but continue to work well on their mission, which was only scheduled to last three months.
He said that Opportunity has run into a problem with one of its test probes, the so-called "RAT" or rapid abrasion tool.
The specialised drill appears to have a rock jamming up its gears.
Opportunity is currently traversing open ground, though, and the team hopes to free up the drill over the coming days.