Stroupe's Slide Options

[helvick]

We're into SH Autumn now with the Winter Solstice arriving on June 25
The previous high atmospheric dust periods have shown that Tau rises very fast and then tends to follow a gradual exponential decay as the dust settles out. The previous less significant localised dust storms cleared out (for the most part) over the course of a couple of weeks to months. One complication is that as the air clears the rate of deposition of dust on the panels is noticably higher for a similar period. By now I would expect that most of the atmospheric dust blocking the incident sunlight would have settled out and I would be surprised if the current rate of dust deposition was dramatically different than it was at similar times during Spirit's two previous Autumn seasons but the amount of dust that is already on the panels is far higher than it has ever been before. If the Rover team were to publish some recent data on the amount of power the panels are actually generating vs the current tau and the orientation of the rover we could work out fairly easily just how much power was "lost" due to dust on the panels on that date (and other gradual systemic degradations, but I beleive the vast majority would be due to dust) and with that predict what the situation is likely to be at mid winter and at the date of lowest insolation which trails mid winter by a couple of Sols.

[slinted]

Another El Dorado monitoring set was taken on sol 1448, showing 3 new streaks (all vertical / N-S, as opposed to the other recent ones which crossed E-W).
Here are the 3 sets taken so far this year:
El Dorado, sols 1416, 1435, and 1448

[Tesheiner]

Another "bump" happened on sol 1459 and the tilt increased to 28 degrees (based on this image).
Check the latest fhazcam picture; don't you think the wheels have reached the slope?

[fredk]

Yeah, I'd say the right front wheel is at the edge now. Hard to tell for sure with the left, but judging from older imagery from above it's very close.

Being at the edge doesn't necessarily mean we're at our maximum tilt. It depends on what's happening to the slope lower down, where the rear wheels are sitting, ie is that lower slope still increasing. It also depends on how steep the uppermost slope is, where the front wheels would sit.

This has got me thinking, though: 30-ish degrees is pretty darned steep, and I hope the rocks are firmly embedded in the slope and we don't suddenly slide down on loosened rocks and end up with a bad tilt...

[Floyd]

Looking at the front and rear HazCam images that came down at the Exploratorium today, I thought Spirit had inched back up the slope. However, they have an earlier time stamp and must be pre move.

fredk-it does look like the dead right wheel has snaged some rocks and is dislodging them a bit. Hopefully no rock slides

[djellison]

Yeah - that depends on the criticality of the imagery. The 'end' imagery would be considered most important, so would be higher up the list to download than the rest.

Doug

[Tesheiner]

Sol 1463: Yet another bump, increasing the tilt to 29deg.

[Floyd]

Another bump today and more tilt.
-Floyd

[Ant103]

Little rocks on Sol 1457

[Doc]

increasing the tilt to 29deg.

29deg, are u sure i thought the highest achievable tilt is 28.

[Tesheiner]

Check for yourself. Here's the navcam picture I used as reference: http://nasa.exploratorium.edu/mars/spirit/...25P1809R0M1.JPG

In any case those are "old" news. There was another bump after that one, noted by fredk, increasing the tilt to 30 deg. Here's the latest navcam image: http://nasa.exploratorium.edu/mars/spirit/...00P1809L0M1.JPG. Given that a "new site" (AY00) was set after this bump I have the impression that Spirit won't be moving again for a looooooooooong time.

[ElkGroveDan]

I'd sure love to see a power chart now with indicators where each new tilt occurred.

[Aussie]

EGD, most true. I thought that the official approach was that they would only bump when the power fell below a set limit. If they stuck by that and are on maximum tilt at this early time I feel that a certain level of concern is justified. They seem to be keeping the power curves close to the chest and this does not instill a great deal of confidence.

[djellison]

The angle wasn't a 'we're running out, tilt more' - it was to get the most power possible at any one time. However, we all know concern is justified. We know we'll enter this winter with a very dirty rover, for a long, cold winter that will be far more taxing on the rover than the last. The only upside is that we have an excellent tilt, and the experience of the dust storm. In what do you lack confidence? The team?

Doug

[Aussie]

Not for a second Doug. Given what they have done in keeping these rovers operational one can only feel a sense of awe. But I do lack a certain confidence in NASA's PR spins and the dearth of power information does not bode particularly well. I would be delighted to be proved wrong.