MGS in Trouble, Formerly: MGS in safe mode Options

[odave]

That's the cracked yoke I was wondering about. Here's an excerpt from the 1997 JPL press release:

"The investigation of the unexpected motion of the unlatched panel led us to identify a secondary source of damage in the yoke, a piece of structure that connects the solar panel to the spacecraft," Cunningham said. "This secondary source of damage was a result of the failure of the damper arm that jammed in the panel's hinge joint shortly after launch when the solar panels were initially deployed."

Mechanical stress analysis tests suggest that the yoke -- a triangular, aluminum honeycomb material sandwiched between two sheets of graphite epoxy -- probably fractured on one surface. The analysis further suggests that the fractured surface, with increased pressure on the panel during aerobraking, began to pull away from the aluminum honeycomb beneath it.

MGS made it through the rest of aerobraking just fine. If the yoke did finally break off, what kind of stresses would have made that happen during normal operations?

[Rakhir]

Europe joins hunt for missing Mars probe
http://space.newscientist.com/article/dn10...mars-probe.html

The radio beam from MGS's antennas is about 60° wide, giving only about a 1 in 6 chance of it reaching Opportunity, since MGS's orientation is unknown.

Spirit, will try to detect the beacon, too. But Spirit will not have enough power to spare for this task until a few weeks from now, Thorpe says.

"We've asked the Mars Express people to take an image of MGS with their High Resolution Stereo Camera," Thorpe says, adding that the Mars Express HRSC team had agreed to make the attempt. The earliest opportunity is on 7 December 2006, when the two spacecraft should come within 400 kilometres of each other.

MRO is too busy to continue hunting for MGS. But if MEX can locate MGS, a case could be made for a second imaging attempt with MRO.

NASA is beaming commands to MGS from Earth every day in the hope of reviving it.

The two points of light in MRO images were in two very different orbits, so it's pretty unlikely that both could have come from the spacecraft.

[elakdawalla]

I thought I'd point out that Thorpe gave me an update yesterday...

http://www.planetary.org/blog/article/00000778/

Also, he told me earlier that the problem panel is indeed the same one that caused the lengthy aerobraking period. However, he said it was a different part of the panel that was reporting problems this time.

--Emily

[Guest_AlexBlackwell_*]

Ten posts dealing with tomorrow's scheduled press conference were moved to a new thread in the same (MGS) forum.

This post has been edited by AlexBlackwell: Dec 5 2006, 08:07 PM

[Guest_AlexBlackwell_*]

Mars Global Surveyor: Still Silent, Yet Hope Remains
Leonard David
LiveScience.com Blog
December 12, 2006

[Guest_Zvezdichko_*]

Any news regarding the images of HRSC?

[tuvas]

I just found out that the MRO star tracker successfully imaged Odyssey, so there's still a chance that it could image MGS. If it manages to successfully image MGS, then HiRISE will follow suit.

[ustrax]

However, he said it was a different part of the panel that was reporting problems this time.

What will be the problems tormenting Anahita generation about space exploration?!...
How IO would love to be around toeb concerned...

[jaredGalen]

Anyone have more details on this?? MGS possibly seen, perhaps tumbling?

http://www.livescience.com/blogs/author/leonarddavid

[tuvas]

Anyone have more details on this?? MGS possibly seen, perhaps tumbling?

http://www.livescience.com/blogs/author/leonarddavid

Haven't heard a thing, if it is tumbling though, I imagine it might be a good thing... That's just a guess, that's all folks, I don't know anything about spacecraft flight...

[elakdawalla]

A tumbling spacecraft is an out-of-control spacecraft.

--Emily

[djellison]

Well - tumbling would suggest ACS failure - and ACS failure (for whatever reason) would almost certainly mean a spacecraft that was not power positive - and MC's words on that were that unless it was power positive, it was good-night Mr Bond.

But - conversely - SOHO was found to be tumbling back when it played truent for 6 months - and was saved ( even from a point when all its fuel had frozen solid ).

However - I think MGS is probably lost - I just hope that HiRISE can get a picture of MGS...even if it's a hard sequence to get right, and a bandwidth whore ( black should compress really well ) - I think it's an image we would all want to see (and one that would make it into the main stream press as well )

Doug

[tuvas]

A tumbling spacecraft is an out-of-control spacecraft.

--Emily

Well, I guess I've learned a thing or two... I thought tumbling would lead to a power-positive system, at least half power, which would do something. Hmmm. Would be quite interesting to see with HiRISE, to see if it moves during the picture...

[djellison]

Problem is - you could have tumbling in an axis that had zero power - or full power...but more likely somewhere inbetween. Call it an average of Half Power. But that half power is over half the orbit - so you never have a charged battery going into eclipse, and always come out with it flattened. Then, if you don't get a good enough angle on the arrays next time around - you end up with a cold spacecraft, a flat battery, and that's when you have actual failures of the hardware required to keep things under control.

Depending on what sort of orientation it is in and what that spin is like - it may well be that after a few months - everything rotates around the sun to give the old girl enough power to wake up and perhaps tell us what's wrong...but it would be a long shot.

Doug

[Guest_Zvezdichko_*]

That's pretty strange. We had contact on 5th November which means that the batteries were charged... that probably means that ... we don't have zero power. So we could still have a chance...