Spirit Sol 1068

Happy New Year, everybody! It's January 3, which means that tonight at 8:35PM Pacific Time is the 3-year anniversary of Spirit's landing.

We always take care in sequencing, but never more than when we have an anniversary like this one. You don't want the story of your three-year anniversary to be that you hurt the rover -- not that you'd want that any other day, of course.

So we're particularly careful about planning the drive to Troll. Troll is an outcrop just a few meters from our Winter Haven. Currently, it's under our left solar panel, but we think we can get there -- although, with the high tau we've been experiencing lately, we're concerned that the obvious approach to Troll leaves us with an unfavorable tilt.

At least we'll be able to gather lots of data about the drive -- Spirit's got only 10.3Mbits of data on the file system, perhaps an historic low!

Except that we won't be able to do the drive after all. Not today, anyway. It turns out tau is even higher than we thought, which means we have less energy to play with than we thought. So the drive will have to wait for another day.

Instead, we're going to repeat the third step of the IDD autoplace checkout -- just another capability added in R9.2 of the rover's FSW that aims to make us rover drivers damn near obsolete.[1]

While Chris Leger -- who wrote the code for that new capability -- works on that, Ashley and Terry and I go ahead and work on the drive anyway. So what if we can't send it up? That's no reason to deprive ourselves of the fun of planning it!

The drive to Troll will be challenging for our little five-wheeled bot. We'll face a decline in our northerly tilt, from about 7.5 degrees to about 5, and that can be a lot of change for a power-starved vehicle. Moreover, as we climb the outcrop, our westerly tilt increases, which means the solar-array wakeup would happen later in the day. Furthermore, we may simply be unable to climb the slope: it's about 12 degrees, and that seems to be around the limit of what we can do now.

But Jake Matijevic OKs the power issues, so our plan will be to do what we always do: try our damndest, and find a way to make it work if humans -- and plucky robots exploring other planets -- can.


[1] IDD autoplace enabled the rover to safely unstow the arm and place tools on targets that were outside the IDD's reach at the start of the drive. That is, you could drive to a target and use the IDD on it, all in one planning cycle. It was slow, but it worked. Just like us, the rovers got smarter as they got older -- but I'm pretty sure they didn't lose their glasses all the time. Damn glasses. Where did I put them?

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