[X] My Assistant

[fredk]

We may have the same scenery for quite a while. From the latest release:

The rover team... has suspended driving Spirit temporarily while studying the ground around the rover and planning simulation tests of driving options with a test rover... "Spirit is in a very difficult situation," JPL's John Callas... said Monday. "We are proceeding methodically and cautiously. It may be weeks before we try moving Spirit again."

In the past week, the digging-in of Spirit's wheels has raised concerns that the rover's belly pan could now be low enough to contact rocks underneath the chassis, which would make getting out of the situation more difficult.

[fredk]

I really liked the low sun angle shadow idea, but I see how HP blocks the morning sun. But the sun should set in the WSW as we're near the solstice. (Azimuth around 245 degrees if I'm correct.) So sunset would be in this navcam frame:
http://marsrovers.jpl.nasa.gov/gallery/all...C6P1961R0M1.JPG
The bellypan is about 1.25 metres below navcam. The top of Tsiolkovsky, the ridge in that navcam view, is about 20 metres away. That means the ridge would appear only about 3.5 degrees higher from the bellypan than from navcam. So the Sun should appear only about three degrees high when it sets behind the ridge from the point of view of the bellypan.

So even with the 10-12 degree roll angle of the rover in the wrong direction, sunlight can enter the gap under the bellypan at an angle of only 13-15 degrees relative to the plane of the bellypan. In addition, the sunlight would enter the gap not directly west-east, but at an azimuth of about 25 degrees relative to west-east. So the sunlight can enter the left side of the gap and emerge at the front (or enter the back and exit the right side). That means it has less distance to travel under the pan than the full gap width, so is more likely to emerge and give us information with shadows.

So could it be that we might still get some useful images of sunset shadows? Admittedly it depends on what exactly the height and shape of the ground is below the rover. But that's what we want to determine. So mightn't a null result (no sunlight passing through the gap) still give us important info? Ie with a null result we could say something like "the ground under the rover must be at least x cm high"?