NASA engineers have suspended the Mars rover Curiosity's work for a few days while they try to fix an electrical short circuit.
Technicians are running tests to find the cause of what they're calling a change in voltage that happened on Sunday. The electrical problem seems to be between the rover's chassis and the 32-volt power bus that distributes electricity to systems throughout the machine.
Curiosity has been running at about 11 volts since landing in August 2012. Now, however, it's at about 4 volts.
The robotic rover was designed with a floating bus, which enables it to operate anywhere within that range.
"The vehicle is safe and stable, fully capable of operating in its present condition, but we are taking the precaution of investigating what may be a soft short," said Mars Science Laboratory Project Manager Jim Erickson, in a statement.
NASA describes a soft short as a leak through something that's partially conductive, as opposed to a hard short where electrical wires touch. Soft shorts can impair the rover's ability to tolerate any future shorts and could indicate that there's trouble with the component involved.
Over the next few days, engineers will send up instructions for Curiosity designed to check out the potential root causes of the problem.
So far, scientists have found that the short happened three times, intermittently, in the hours before the voltage changed for good.
Following a software update earlier this month, a glitch caused Curiosity to switch into safe mode. Engineers fixed that problem and it does not seem to be related to this electrical issue, NASA noted.
The rover suffered one other soft short.
According to the space agency, the first problem, caused by explosive release devices used during landing, happened the day the rover landed on Mars. It's not thought to have affected Curiosity's operations.
Curiosity is in the second year of a mission to explore the Martian surface, looking for clues as to whether the Red Planet has, or ever had, supported life, even in microbial form.
However, the rover has not been able to detect any methane, which generally is produced by living organisms, in the Martian atmosphere.
Sharon Gaudin covers the Internet and Web 2.0, emerging technologies, and desktop and laptop chips for Computerworld. Follow Sharon on Twitter at @sgaudin, on Google+ or subscribe to Sharon's RSS feed . Her email address is firstname.lastname@example.org.