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

A Damn Shame

[fsh]

Although the rovers are certainly the superstars of Mars research, the MRO has provided more usable data than any other Mars mission so far. I certainly hope they can fix this problem, or at least work around it; the MRO should have many years of good science left in its system. I believe that the primary mission is scheduled to run through 2008 and then extended missions will be tacked on after that.

Incidentally, this is the camera that could pick out the rovers from orbit. Losing definition on this camera would certainly impact one of the missions objectives, which is to look for good landing spots for future missions (robotic and human).

Camera problems common of late?

[Tablizer]

I've read about a fair number of camera problems on fairly recent missions. Cassinni had unexpected fogging problems that appeared to be reduced by heating. The comet collider companion craft (forgot name) also had blurred vision of some kind. Perhaps they are pushing the limits of camera technology and feeling the effects.

The second best camera around Mars

[YA_Python_dev]

I completely agree with you: the problem with space missions is that even a very small problem can be unsolvable if the hardware is more than 100 million km away!

But even if we completely lose the camera, it will be a big problem but not a disaster for science: there are currently 3 operational spacecrafts orbiting Mars (2 American + 1 European) and High Resolution Stereo Camera on ESA Mars Express, the second best camera after HiRISE with a resolution of up to 2 metre/pixel, is still working and sending back beautiful images.

Re:Next time...

[Aerovoid]

Well the thing is, most (if not all) interplanetary probes do not get launched into Earth orbit first. The MRO, for example, was launched into a Hohmann transfer orbit. Even if they were to have tested it in Earth orbit first and found something was wrong, then what? It's not like the shuttle could just go up and get it either.

Re:No pictures

[fsh]

In this case, the problem isn't the optics involved (like when they showed before and after pictures of the Hubble problem), but in the circuitry to transmit the images from the CCD to the antenna. Check out this schematic. If you look at the top picture, all the way on the right, you'll see 14 stylized circuit boards; that's where the problem is.

Because it's a circuitry/transmission problem, they can essentially recover the image from a particular detector or not. For the 'ringing' problem they've mentioned, if it's a small enough effect they can subtract it from the data.

Also in that picture, they show the 'focal plane assembly'; this is essentially a separate CCD for each color filter used (except the red color which goes all the way across). The problem is very bad in one of the IR chips; bad enough that they can't use the data at all.

In other words, it's a problem with the digital transmission. Just like for digital phone, radio, or TV; you either get a usable signal (perhaps with some drops) or no signal at all.

Re:Ringing? Duh!

[Alioth]

While your post is obviously a joke (I note that when there's a story with elements many Slashdotters don't understand, they make corny jokes about it), it's probably worth mentioning what ringing in this context actually is.

"Ringing", in electronics, is small unwanted oscillations in the signal. It is usually caused by stray capacitances and inductances in the circuit. Stray capacitances and inductances are caused not by components in the circuit, but just the innate capacitances etc. of things like tracks on the printed circuit board (two PCB tracks close together naturally form a very small capacitor). A great deal of thought is needed in laying out some printed circuit boards to minimize stray capacitances and inductances.