Mars Camera's Worsening Eye Problems

Mr_Foo writes "According to a Nature article, the Mars Reconnaissance Orbiter's HiRISE imager is suffering from a loss of peripheral vision. The problem surfaced less than a month after the orbiter reached Mars. One the camera's four color detectors has completely stopped working, and it is feared that the problems are spreading. Currently seven of the fourteen HiRISE's detectors are sending back corrupted data and although the issue is only creating a 2% loss of signal at this time it is expected to worsen. The lead investigator for the mission is quoted as saying the problem is systemic: 'In the broken detectors, extra peaks and troughs are somehow being introduced, causing... a "ringing" in the signal. "We don't know where the ringing is coming from," [the investigator] says.' Warming the electronics before taking images seems to help the problem. This effect might be one reason why the detectors on the cold periphery of the array were the first to pack up."

Comments

Re:Slowly degenerate?

[starman97]

I read that as ringing in the electrical signal. Possible caused by a ground on a coax cable working loose
or maybe a component failing due to thermal cycling or cold stress.

The boards are built at room temperature, it's pretty cold in space if the sun isnt shining on something.
Parts contract and if whatever they're attached to doesnt contract at the same rate, if can loosen things
or even crack them over time. Qualifying parts for that sort of thermal stress is what makes things cost so
much for Space Grade parts. It's also where they try to save money, only test 10 parts instead of 100 or
only test for 10 day/night thermal cycles instead of 1000. It's always easy to say after the fact that
they should use better, more expensive parts, but sometimes if you do, the mission goes over budget and
doesnt get done at all.