MER 2003/Athena Update Week Ending January 4, 2003

For weeks now, we’ve been chasing a nasty problem with our Moessbauer
Spectrometer. There may finally be a light at the end of the tunnel.

The problem’s not the instrument… the instrument works just fine
when we test it by itself. But the Moessbauer Spectrometer comes in
two parts. One part is the “sensor head”, which is out at the end of
the rover’s arm, and the other is the electronics, deep inside the
rover body. The two parts are connected by a long and complicated
cable, and it’s the cable that’s been the problem.

The thing you’d want to do is simply replace the cable with one that
works better, but that turns out not to be so simple. Half of the
cable — the part of it that’s inside the rover — is fairly easy to
replace, and we’ve done that already. It helps, but it doesn’t solve
the problem. The other half of the cable, which runs up the arm, is
very, very difficult to replace. We’d essentially have to take the
whole arm apart to do it, and nobody wants to do that to a piece of
flight hardware that’s been assembled and tested, and that works
beautifully.

So what to do? A team of very talented electrical engineers, both in
Germany and at JPL, has been working on that problem for a couple of
months now. The solution appears to be to add a tiny little
electronics board to the outside of the sensor head. This board
improves the signal that runs up the arm enough that the cable can
handle it. We tested it this week at JPL with one of our two flight
instruments, and it worked. We still have to confirm that it works
with the other one, and we also have to make sure that it works at
martian temperatures. But the solution to one of our toughest
problems now may be in sight.