If you’ve had to spend hours on the phone with a technical support center to solve a problem with a computer or other electronics products–and who hasn’t, these days–then you can sympathize with the engineers at JPL who had to deal with the faulty computer problem on the Mars rover Spirit a few weeks ago. As this Associated Press article points out, the engineers dealing with Spirit’s computer glitch had the additional issues of remotely diagnosing a problem with a computer that was, along with the nearest human tech support, nearly 200 million kilometers away. They were aided by the fact that the operating system the rover’s computer was using, VxWorks, was not only flight tested on previous missions, it was in widespread commercial use here on Earth in everything from aircraft to pacemakers. The problem with Spirit’s computer–too many files on the rover’s flash memory taking up space in RAM when the computer tried to boot up–was eventually diagnosed and solved. It was something engineers admit they overlooked on the ground in testing before launch, but given tight schedules they didn’t have the time to perform all the tests they wanted. Fortunately for the rover it had a good tech support hotline to call.