The West Valley Route Options

[mhoward]

"Kit Carson" - Pancam L257 false color, Spirit sol 1864

(I know the Pancam doesn't match up perfectly with the Navcam background; this is just a quick MMB screen grab)

[fredk]

From the latest Planetary Society update:

Last weekend, Spirit spent some time “looking off to the northwest for possible contingency locations,” said Arvidson, “just in case we can't continue in West Valley or can't get to the south.” ... If by chance Spirit cannot make it through West Valley, what then? “We'll bop back out and look at alternate exploration sites,” Arvidson said. “There may be more silica ridges to the northwest.”

I had wondered about that sequence of pancam images looking to the NW, for example:
http://marsrovers.jpl.nasa.gov/gallery/all...LTP2355L2M1.JPG

On another topic, I love this little hill off to the west:
http://marsrovers.jpl.nasa.gov/gallery/all...LTP2561L5M1.JPG
I'm sure the more geologically-minded can correct me, but perhaps the odd rocks at the very peak are remnants of a harder material that originally capped the hill von Braun-style, and has almost completely eroded away now?

[Tesheiner]

On another topic, I love this little hill off to the west:
http://marsrovers.jpl.nasa.gov/gallery/all...LTP2561L5M1.JPG

"Pioneer Mound", it's named.

[climber]

This is the big rock avoidance manoeuvre (see Paolo post) which also put us on much firm soil as opposed to the "sandy" area closer to HP.
This assume that we're going to rotate ~90° around the RF: http://nasa.exploratorium.edu/mars/spirit/...OZP0703L0M1.JPG and then strait for a few meters.
Back seat driver guess...
Edited: I'm in a Ustrax's mood so, here is my real guess

[mhoward]

132x82 degree anaglyph cylindrical projection, Spirit sol 1866, looking due south.

[RoverDriver]

[quote name='climber' post='138729' date='Apr 3 2009, 02:24 PM']

...
Back seat driver guess...
Edited: I'm in a Ustrax's mood so, here is my real guess
...
That's a pretty good guess! As a hint, unless we really have to, we try to have drive segments that are as straight as possible. The reason is that whenever you have a turn, not only you need to make sure you turn the correct amount, but also that the rover is in the correct position to turn. We have means to check these things of course, but they are expensive, they require the use of Visual Odometry which runs pretty slow.

Paolo

[mhoward]

Paolo, I always wondered, is it difficult to keep her driving straight on this kind of terrain, especially minus one working wheel? Does she tend to veer off? I mean obviously the last few drives looked very good, but now it looks like we might be getting back to some seriously challenging terrain again.

[eoincampbell]

Would Spirit be able to peek over and image much of Tartarus and tracks, or what's left of them?

[RoverDriver]

Paolo, I always wondered, is it difficult to keep her driving straight on this kind of terrain, especially minus one working wheel? Does she tend to veer off? I mean obviously the last few drives looked very good, but now it looks like we might be getting back to some seriously challenging terrain again.

It is not really difficult, now that we have a sequence already built that keeps the rover on track. The RF wheel makes the rover drift to the right. The exact amount of the drift depends on the terrain we are driving. There an instrument on board the rover, called IMU (Inertial Measurement Unit) that keeps track of the rover attitude (roll, pitch and heading). While the rover moves the IMU measures the change in heading. After a step the rover compares its own heading vs the desired direction and applies a heading correction for the next step. This driving technique works even without VO and while the sequence is not very easy to understand, it works quite fast for Martian standards, theoretically about 80m/h.

From time to time we adjust the heading correction values depending on the terrain, but pretty much the sequence stays the same.

Paolo

[RoverDriver]

Would Spirit be able to peek over and image much of Tartarus and tracks, or what's left of them?

I'm not so sure *I* would like to see Tartarus again !!

Paolo

[mhoward]

Thanks, Paolo; that makes sense. With respect to Tartarus, I think it's above Spirit's eye level now, but I could be wrong. Looking forward with some trepidation to see what happens in West Valley...

[fredk]

Long-baseline stereo view looking at Pioneer Mound and the plains beyond, sols 1859 and 1861:

As usual, movement is not exactly orthogonal to the line of sight, so there are distortions that are difficult to correct. Eyestrain/headaches may result!

[climber]

May be this illustrate Paolo explanations:

[Ant103]

The view of Pioneer Mound on Sol 1865, in normal and stereo

[mhoward]

It was hard not to post this in the route map thread, but it looks like Spirit's sol 1868 went very well! I'm happy, because considering it was a bit uphill, plus it seems like just the other day she was wallowing in sand - well, I wasn't expecting this one to go nearly so well. Here's a little celebratory screen grab based on the tracking data - I'm not sure how exact this is yet, the Navcams will help.



BTW, love the color anaglyph, Ant.

P.S. I'm raising a glass to the MER team right now. Nice drive!