MER Status Report Week Ending October 12, 2002
The MER rovers are fiendishly complicated machines, and literally
thousands of things are going to have to go right for this mission to
work. All of them have to be tested, and it’s pretty common for
things not to work right on the first try. This past week, we’ve been
troubleshooting our “step and settle” problem.
The Mini-TES instrument sits at the bottom of a big piece of hardware
called the Pancam Mast Assembly, or PMA. (See a recent picture of the
PMA mounted on the rover deck.) Mini-TES looks up the inside of the
PMA tube, using it like a periscope to view the scene around the
rover. There are mirrors at the top of the PMA, just like in a
periscope, and one of them is supposed to move very quickly as the
Mini-TES shifts its gaze from one spot to the next. The time this
mirror has to “step and settle” — to move and then settle down so
that it’s motionless — is just two tenths of a second. And right now
it’s taking a good deal longer than that. If the mirror is still
moving when Mini-TES is trying to look out at the world, we get a
blurry view and bad data.
The problem seems to be that we’re not giving the motor that moves
the mirror enough juice, so we’re going to change that and try it
again. We’ll see how it goes. But it’s just one of thousands of
things we’ve got to get right before we can take these things to the
launch pad.