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Wheel Trouble, ...down to 5 good wheels?
mars_armer
post Mar 14 2006, 12:29 AM
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I hate to be the bearer of bad news, but I just heard that there is a serious problem with Spirit's right front drive actuator after yestersol's drive. (This is the actuator that had high currents in the past and led to the backward-driving strategy.) It will take awhile to evaluate the situation, but early speculation is grim.

In a worst-case scenario, they can still drag the bum wheel along, but don't expect another summit view.

Best-case scenario would be a rock or debris jammed in the wheel.

This is a heads-up, sorry I can't really give more info at this time. I still thought you all would like to know.
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marsman
post Mar 18 2006, 01:39 AM
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In today's press release below, there are a few additional tidbits of information about SPIRIT's wheel problem and current driving expectations.


Guy Webster (818) 354-6278
Jet Propulsion Laboratory, Pasadena, Calif.

Dwayne Brown/Erica Hupp (202) 358-1726/1237

NASA Headquarters, Washington


News Release: 2006-039 March 17, 2006

Mars Rovers Get New Manager During Challenging Period

NASA's long-lived Mars rovers demand lots of care as they age and the Martian winter approaches.

Dr. John Callas, newly named project manager for NASA's Mars Exploration Rover mission, is coordinating the work to meet these challenges. He is a scientist at NASA's Jet Propulsion Laboratory in Pasadena, Calif. He was named project manager after earlier roles as science manager and deputy project manager for the Spirit and Opportunity rovers.

"It continues to be an exciting adventure with each day like a whole new mission," Callas said. "Even though the rovers are well past their original design life, they still have plenty of capability to conduct outstanding science on Mars. The JPL operations team and the remote science team working on the project are the best in the solar system at what they do. It is a pleasure and a privilege to lead such an outstanding team and great mission."

One of Spirit's six wheels has stopped working. Dragging that wheel, the solar-powered rover must reach a slope where it can catch enough sunshine to continue operating during the Martian winter. The period of minimum sunshine is more than 100 days away, but Spirit gets only enough power for about one hour per day of driving on flat ground. And the supply is dropping fast.

Spirit's right-front wheel became a concern once before, when it began drawing unusually high current five months after the January 2004 landing on Mars. Driving Spirit backwards redistributed lubricant and returned the wheel to normal operation. This week, during the 779th Martian day of what was originally planned as a 90-Martian-day mission, the motor that rotates that wheel stopped working.

"It is not drawing any current at all," said JPL's Jacob Matijevic, rover engineering team chief. One possibility engineers are considering is that the motor's brushes, contacts that deliver power to the rotating part of the motor, have lost contact. The motors that rotate Spirit's wheels have revolved more than 13 million times, far more than called for in the rovers’ design.

Spirit's solar panels have been generating about 350 watt-hours of electricity daily for the past week. That is down about 15 percent since February and less than one-half of their output during the Martian summer.

The best spot for Spirit is the north-facing side of "McCool Hill," where it could spend the southern-hemisphere winter tilted toward the sun. Spirit finished studying a bright feature called "Home Plate" last week and is driving from there toward the hill. It has approximately 120 meters (about 390 feet) to go. Driving backwards with the right-front wheel dragging, the rover needs to stop and check frequently that the problem wheel has not snagged on anything and caused other wheels to slip excessively. Expected progress is around 12 meters (40 feet) per day under current conditions.

Opportunity is closer to the equator, so does not need to winter on a slope like Spirit. Opportunity spent most of the past four months at "Erebus Crater." It examined layered outcrops, while the rover team determined and tested a strategy for dealing with degraded performance by a motor in the shoulder of its robotic arm. Opportunity left Erebus this week and is on a 2 kilometer (1.2 mile) journey to a giant crater called "Victoria."

Callas has worked on the Mars rovers' mission since 2000 and five other Mars missions since joining JPL in 1987. He succeeds Jim Erickson, who switched to a leadership role with NASA's Mars Reconnaissance Orbiter. Callas grew up near Boston and graduated from Tufts University, Medford, Mass. He earned his doctorate in physics from Brown University, Providence, R.I.

JPL, a division of the California Institute of Technology, Pasadena, manages the Mars Exploration Rover and Mars Reconnaissance Orbiter projects for NASA's Science Mission Directorate.
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odave
post Mar 18 2006, 02:42 AM
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QUOTE (marsman @ Mar 17 2006, 08:39 PM) *
News Release: 2006-039
<snip>
The period of minimum sunshine is more than 100 days away
<snip>
It has approximately 120 meters (about 390 feet) to go. [...] Expected progress is around 12 meters (40 feet) per day under current conditions.


Those numbers make me feel better, though I know anything can happen at any time. I assume the 120 meter figure is to the nearest possible "good" slope. Here's hoping Spirit can make it to a windy spot too!

wheel.gif wheel.gif wheel.gif


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--O'Dave
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Posts in this topic
- mars_armer   Wheel Trouble   Mar 14 2006, 12:29 AM
- - Myran   Thank you for the heads up mars_armer. With winter...   Mar 14 2006, 12:44 AM
- - DFinfrock   QUOTE (mars_armer @ Mar 14 2006, 12:29 AM...   Mar 14 2006, 01:20 AM
- - Sunspot   You mean the wheel will no longer turn at all anym...   Mar 14 2006, 01:27 AM
|- - mars_armer   QUOTE (Sunspot @ Mar 13 2006, 05:27 PM) Y...   Mar 14 2006, 01:44 AM
- - Shaka   QUOTE (mars_armer @ Mar 13 2006, 02:29 PM...   Mar 14 2006, 01:31 AM
- - Jeff7   Yeah, let's really just hope that it's jus...   Mar 14 2006, 03:28 AM
- - BruceMoomaw   Do you mean that the wheel won't turn even if ...   Mar 14 2006, 04:13 AM
|- - Shaka   QUOTE (BruceMoomaw @ Mar 13 2006, 06:13 P...   Mar 14 2006, 05:15 AM
|- - mars_armer   QUOTE (Shaka @ Mar 13 2006, 09:15 PM) Do ...   Mar 14 2006, 04:37 PM
|- - RNeuhaus   QUOTE (mars_armer @ Mar 14 2006, 11:37 AM...   Mar 15 2006, 12:49 AM
- - BruceMoomaw   Under ordinary circumstances that is possible. In...   Mar 14 2006, 05:17 AM
- - CosmicRocker   Oh, no. So that is one reason why Spirit has move...   Mar 14 2006, 07:08 AM
|- - djellison   QUOTE (CosmicRocker @ Mar 14 2006, 07:08 ...   Mar 14 2006, 08:25 AM
- - Bill Harris   Oh well, stuff happens. We're all a lot creak...   Mar 14 2006, 08:34 AM
- - edstrick   I note that both from Husband hill and from the dr...   Mar 14 2006, 10:37 AM
|- - Marz   Poor Spirit, just as she regains the lead in milag...   Mar 14 2006, 03:43 PM
- - tty   Design lesson for future rovers: there should be s...   Mar 14 2006, 05:53 PM
|- - Bob Shaw   QUOTE (tty @ Mar 14 2006, 05:53 PM) Desig...   Mar 14 2006, 11:06 PM
|- - RNeuhaus   QUOTE (tty @ Mar 14 2006, 12:53 PM) Desig...   Mar 15 2006, 01:06 AM
|- - monty python   QUOTE (tty @ Mar 14 2006, 11:53 AM) Desig...   Mar 15 2006, 09:49 AM
|- - Ames   QUOTE (monty python @ Mar 15 2006, 09:49 ...   Mar 15 2006, 10:47 AM
||- - odave   QUOTE (Ames @ Mar 15 2006, 05:47 AM) But ...   Mar 15 2006, 02:16 PM
|- - lyford   QUOTE (monty python @ Mar 15 2006, 01:49 ...   Mar 15 2006, 07:35 PM
|- - imipak   QUOTE (monty python @ Mar 15 2006, 09:49 ...   Mar 15 2006, 08:37 PM
- - Bill Harris   QUOTE there should be some simple and reliable mec...   Mar 14 2006, 06:09 PM
- - alan   Something in there?   Mar 14 2006, 07:49 PM
|- - Toma B   That's good news...if it got in, it can posibl...   Mar 14 2006, 08:23 PM
|- - helvick   [quote name='alan' post='45573' date='Mar 14 2006,...   Mar 14 2006, 08:32 PM
|- - mars_armer   QUOTE (alan @ Mar 14 2006, 11:49 AM) Some...   Mar 14 2006, 09:34 PM
|- - helvick   QUOTE (mars_armer @ Mar 14 2006, 09:34 PM...   Mar 14 2006, 09:46 PM
||- - helvick   QUOTE (helvick @ Mar 14 2006, 09:46 PM) A...   Mar 14 2006, 10:05 PM
||- - Shaka   QUOTE (helvick @ Mar 14 2006, 12:05 PM) A...   Mar 14 2006, 10:34 PM
|||- - helvick   QUOTE (Shaka @ Mar 14 2006, 10:34 PM) ......   Mar 14 2006, 10:37 PM
||- - Daba   QUOTE (helvick @ Mar 14 2006, 11:05 PM) A...   Mar 14 2006, 11:28 PM
|- - Shaka   QUOTE (mars_armer @ Mar 14 2006, 11:34 AM...   Mar 14 2006, 09:46 PM
- - Sunspot   I thought it might have been a rock at first... bu...   Mar 14 2006, 10:55 PM
- - djellison   At a first look - it just looks like dust to me - ...   Mar 14 2006, 11:05 PM
- - slinted   There was a tiny bit of motion between sol 779 and...   Mar 14 2006, 11:39 PM
|- - ElkGroveDan   QUOTE (slinted @ Mar 14 2006, 11:39 PM) T...   Mar 15 2006, 01:24 AM
- - djellison   That's a very odd motion - at first I thought ...   Mar 15 2006, 12:11 AM
- - Bill Harris   Not at all good. Slinted's animated-GIF shows...   Mar 15 2006, 04:01 AM
- - mars_armer   Looks like a drive will be attempted on Sol 781 (d...   Mar 15 2006, 04:33 AM
- - edstrick   quote: "I've got a little list..... I...   Mar 15 2006, 10:49 AM
- - Burmese   Yeah, wheel bearing looks likely to me, or some ot...   Mar 15 2006, 01:57 PM
|- - MahFL   Strange co-incidence......today the front left whe...   Mar 15 2006, 06:10 PM
- - djellison   I gave a talk to some 16-18 y.o. school students t...   Mar 15 2006, 06:48 PM
- - Sunspot   Still limping along: http://qt.exploratorium.edu/...   Mar 15 2006, 07:54 PM
|- - general   QUOTE (Sunspot @ Mar 15 2006, 08:54 PM) S...   Mar 15 2006, 08:13 PM
|- - Marcel   QUOTE (Sunspot @ Mar 15 2006, 08:54 PM) S...   Mar 15 2006, 08:16 PM
|- - Sunspot   QUOTE (Marcel @ Mar 15 2006, 08:16 PM) Oh...   Mar 15 2006, 08:50 PM
- - Burmese   Good, they aren't going to sit still and spend...   Mar 15 2006, 08:05 PM
- - elakdawalla   Squyres did not mention the wheel trouble in his t...   Mar 15 2006, 08:24 PM
|- - Shaka   QUOTE (elakdawalla @ Mar 15 2006, 10:24 A...   Mar 15 2006, 09:07 PM
|- - AlexBlackwell   QUOTE (Shaka @ Mar 15 2006, 09:07 PM) P.S...   Mar 15 2006, 09:10 PM
|- - Shaka   QUOTE (AlexBlackwell @ Mar 15 2006, 11:10...   Mar 15 2006, 09:49 PM
||- - djellison   QUOTE (Shaka @ Mar 15 2006, 09:49 PM) I s...   Mar 15 2006, 10:18 PM
||- - odave   QUOTE (Shaka @ Mar 15 2006, 04:49 PM) I s...   Mar 15 2006, 10:20 PM
||- - Shaka   QUOTE (odave @ Mar 15 2006, 12:20 PM) See...   Mar 15 2006, 11:00 PM
||- - ToSeek   QUOTE (odave @ Mar 15 2006, 10:20 PM) See...   Mar 16 2006, 05:48 PM
||- - AlexBlackwell   QUOTE (ToSeek @ Mar 16 2006, 05:48 PM) Sh...   Mar 16 2006, 05:50 PM
|- - helvick   QUOTE (AlexBlackwell @ Mar 15 2006, 09:10...   Mar 15 2006, 09:54 PM
- - centsworth_II   "Looks like she's returning to Home Plate...   Mar 15 2006, 09:01 PM
- - Bill Harris   >Looks like she's returning to Home Plate ...   Mar 15 2006, 10:23 PM
- - djellison   I think they moved to the nearest patch that offer...   Mar 15 2006, 10:31 PM
- - alan   First impression: the right front wheel looks like...   Mar 15 2006, 10:34 PM
- - Shaka   http://static.flickr.com/41/113051772_e40da86735_o...   Mar 15 2006, 11:57 PM
- - CosmicRocker   QUOTE (elakdawalla @ Mar 15 2006, 02:24 P...   Mar 16 2006, 04:10 AM
- - mars_armer   The wheel is definitely looking dead (open circuit...   Mar 16 2006, 04:44 PM
|- - Sunspot   QUOTE (mars_armer @ Mar 16 2006, 04:44 PM...   Mar 16 2006, 05:28 PM
|- - ToSeek   QUOTE (Sunspot @ Mar 16 2006, 05:28 PM) O...   Mar 16 2006, 05:50 PM
|- - mars_armer   > Well, until next summer, at least. And don...   Mar 16 2006, 06:13 PM
- - odave   I'm sure the MER engineers will be able to squ...   Mar 16 2006, 06:17 PM
|- - helvick   QUOTE (odave @ Mar 16 2006, 06:17 PM) I...   Mar 16 2006, 06:46 PM
|- - Bob Shaw   QUOTE (helvick @ Mar 16 2006, 06:46 PM) O...   Mar 16 2006, 08:46 PM
- - odave   Yeah, I know that Ma'adim Vallis is not a real...   Mar 16 2006, 06:55 PM
|- - Marz   QUOTE (odave @ Mar 16 2006, 12:55 PM) Yea...   Mar 16 2006, 09:14 PM
|- - Shaka   QUOTE (Marz @ Mar 16 2006, 11:14 AM) lol ...   Mar 16 2006, 10:57 PM
- - djellison   The day time temps might be getting to -60 instead...   Mar 16 2006, 10:02 PM
- - Jeff7   Can't they just use the routines they develope...   Mar 16 2006, 10:46 PM
- - djellison   Spirits wheel wasnt stuck back in the 150-350 sol ...   Mar 16 2006, 10:50 PM
- - GregM   .   Mar 17 2006, 03:22 AM
|- - Shaka   QUOTE (GregM @ Mar 16 2006, 05:22 PM) My ...   Mar 17 2006, 04:32 AM
|- - RNeuhaus   QUOTE (Shaka @ Mar 16 2006, 11:32 PM) As ...   Mar 17 2006, 06:11 AM
|- - MahFL   "We're now in a drive or die situation,...   Mar 17 2006, 03:17 PM
|- - helvick   QUOTE (MahFL @ Mar 17 2006, 03:17 PM) ...   Mar 17 2006, 04:08 PM
|- - ToSeek   QUOTE (helvick @ Mar 17 2006, 04:08 PM) P...   Mar 17 2006, 06:23 PM
- - ddeerrff   QUOTE (Shaka @ Mar 16 2006, 04:57 PM) Mar...   Mar 17 2006, 04:29 AM
- - djellison   <360 Whr's per sol and decreasing quite rap...   Mar 17 2006, 04:09 PM
- - mars_armer   How sure are we of the 280 Whr "death" n...   Mar 17 2006, 06:37 PM
|- - helvick   QUOTE (mars_armer @ Mar 17 2006, 06:37 PM...   Mar 17 2006, 07:21 PM
|- - Bob Shaw   QUOTE (mars_armer @ Mar 17 2006, 06:37 PM...   Mar 17 2006, 11:44 PM
- - Sunspot   Was Spirit supposed to drive today? http://qt.e...   Mar 17 2006, 07:08 PM
|- - djellison   QUOTE (Sunspot @ Mar 17 2006, 07:08 PM) W...   Mar 17 2006, 08:29 PM
|- - akuo   QUOTE (Sunspot @ Mar 17 2006, 07:08 PM) W...   Mar 17 2006, 08:40 PM
- - Oersted   I think we're all happy that the team was pret...   Mar 18 2006, 12:00 AM
- - nprev   On the weakly positive side, I hope that the wheel...   Mar 18 2006, 12:28 AM
- - marsman   In today's press release below, there are a fe...   Mar 18 2006, 01:39 AM
- - odave   QUOTE (marsman @ Mar 17 2006, 08:39 PM) N...   Mar 18 2006, 02:42 AM
- - Steve   QUOTE (marsman @ Mar 17 2006, 08:39 PM) N...   Mar 18 2006, 02:59 AM
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