Extricating Spirit, Digging out from Troy Options

[vjkane]

the science returns from Spirit as a stationary object can tell us a great deal about seismic activity

How will Spirit measure seismic activity without a seismometer? Even if it had one, with all those panels and the mast, it would vibrate with every wind gust, making seismic studies hard. Or have I missed something obvious?

[Tesheiner]

Agree : I think they will announce a choice between 3 possibilities :
1. a few more moves to position to make her face north and then keep her as a stationary rover -forever (VL1 was a great mission as stationary lander...) ;
2. they were encouraging moves to extricate her, BUT winter comes in : more extricating tries to come BUT after winter (i.e. spending winter here and move after) ;
3. really encouraging moves to extricate her : extrication to occur just on time before winter, BUT then no more moves and spending winter on "dry" ground a few meters away from current position... and then more moves after winter

Given the current power levels, I believe we are in option 2, except that we MAY see some more driving but only intended to improve the tilt.

[Guest_Oersted_*]

How will Spirit measure seismic activity without a seismometer? Even if it had one, with all those panels and the mast, it would vibrate with every wind gust, making seismic studies hard. Or have I missed something obvious?

An atmospheric density 1% of that on Earth.

[djellison]

The rover has been seen to move because of wind. Atop Husband hill, there were Navcam sequences (DD movies) where the camera moved a pixel or two. Of course, the camera didn't move - the whole rover just moved slightly in the wind. It's got quite a lot of surface area for quite a light vehicle.

[ustrax]

Hmmm...all the big guys in town in the update?...but no video?
I'm here balancing between the dark and bright side...and, has I told already Stu I have this strange feeling that makes me rewind to the days where we've met back at the Mars Forum...some stupid nostalgia settling...
Big, not good, but not the end, that's my take, now...make this nail biting worthy...

[climber]

Same feeling here, Big= no good... at least for "short" term (winter). Because of recent progress, I think they'll never give up on extracting... after winter. Let see this in another 4 hours.

[vjkane]

An atmospheric density 1% of that on Earth.

I've read a number of studies for Mars seismic network missions, and one of the big concerns has always been to shield the instrument from the wind (get it off the lander and preferably buried) and diurnal temperature changes. Most seismic events involve tiny soil movements.

[fredk]

Sol 2156 drive pics down. Looks like another decent drive:
http://qt.exploratorium.edu/mars/spirit/fo...T5P1214R0M1.JPG
Apparently the LF RF wheel has moved the rock to its rear along a bit. Also, it looks like the horizon has risen a bit in the front images and dropped in the rear hazcams, which would mean the northward tilt has improved.

Edit: that image is quite evocative of the coming winter, with the Sun now low enough in the north sky to start to peak into the hazcam view.

[mhoward]

From the images, it looks like it was a pretty good drive on sol 2156. The rear left wheel came up quite a bit.

Of course, she's not out. I have no idea what the tone of this press conference is going to be.

Edit: Beat me to it, fredk

[Hungry4info]

Interesting how the ground that just came into view looks smoothe, as if it were in contact with the rover bottom. And where's that rock that we all were worried about?

[Tesheiner]

Speaking about tilt, here are some numbers. Let's hope I'm doing my math correctly because there was a really important improvement in this last drive.
Yaw is the rotation CW/CCW (negative value is CCW), pitch is the S/N tilt (negative value means N) and roll is the E/W tilt (negative values means W).

+ Site/drive B200 (beginning of extrication attempts)

Yaw -16º
Pitch 0,06º
Roll -16º

+ Site/drive B2GX (sol 2147)

Yaw -25º
Pitch -0,5º
Roll -19º

+ Site/drive B2PG (sol 2154)

Yaw -43º
Pitch -2,8º
Roll -18º

+ Site/drive B2T5 (thisol)

Yaw -49º
Pitch -6,4º
Roll -16º

[Hungry4info]

Nice measurements! It's great to see the N/S tilt with respect to the apparent rising of the left-rear wheel.

[alan]

Yeah, Spirit. Crush that potato.

[fredk]

How will Spirit measure seismic activity without a seismometer?

This has been discussed before. I agree that wind would make this very challenging.

[Hungry4info]

Yeah, Spirit. Crush that potato.

I ask again. What is the potato?