NASA is working to resolve an increasingly frustrating problem with the Curiosity Rover's drill, which has stalled, leaving the Martian explorer out of action on the slopes of Mount Sharp for more than two weeks.
On December 1st, scientists at the Jet Propulsion Laboratory learned that the Curiosity Rover failed to execute its latest drilling commands. The rover was scheduled to drill its seventh hole of the year and its sixteenth rock since arriving on Mars in August of 2012. Since glitching out, Curiosity has stayed put while engineers attempt to diagnose and fix the problem.
Curiosity's drill bores into rocks using a combination of hammering motion and a rotating drill bit. Since early in the mission, an electrical malfunction has caused problems with the hammering mechanism, but drilling has proceeded in spite of that. About a year ago, Curiosity encountered another issue, when the motor that opens a sample processing chamber stalled out.
A December 2nd view from the Curiosity Rover's navigation camera, the day after its drill glitched out. Image: NASA/JPL-Caltech
"That problem was intermittent but has recently gone away," Curiosity's project scientist Ashwin Vasavada told reporters at a press conference at the American Geophysical Union meeting last week.
The new problem, Vasavada said, appears to be related to Curiosity's drill feed, a mechanism that moves the drill up and down. Specifically, it looks like a brake on the drill feed failed to disengage fully on December 1st. "We were able to determine it was the brake that's most likely the issue," Vasavada said. "And we were able to get some partial success in moving the drill feed and un-stalling it, if you will."
While that sounds encouraging, it isn't yet clear that Curiosity is on the road to recovery. "Just in the last few days, we've determined that the problem is recurring," Vasavada continued. "So we're in the process of still figuring out how to recover the operation of that drill feed."
The Curiosity Rover is slowly climbing Mount Sharp, the central peak in Gale Crater, an impact basin that is believed to have harbored a saltwater lake billions of years ago. At regularly-spaced intervals, Curiosity is drilling boreholes to measure mineralogy and organic materials. The rover is currently parked in the Murray formation, a diverse band of mudstones which are proving to change dramatically with elevation, yielding insights into Mars' past environments and habitability.
Cartoon of the different geologic formations along Mount Sharp, including the Curiosity Rover's present location (not to scale). Image: NASA/JPL-Caltech
"A sedimentary basin such as this is a chemical reactor," John Grotzinger, another member of Curiosity's science team, said in a statement. "Elements get rearranged. New minerals form and old ones dissolve. Electrons get redistributed. On Earth, these reactions support life."
It would be a shame if Curiosity's latest investigation was cut short due to something as minor as a hyperactive drill brake. But when you're operating machines beyond their expected lifespans and tens of millions of miles from the nearest mechanic, minor glitches can mean the world.
"Although the rover doesn't want to be a stick in the mud, it sort of is," Curiosity deputy project scientist Joy Crisp said.