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MSL reasons for delay
mcaplinger
post Mar 4 2009, 03:33 PM
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I wanted to make sure that everyone interested sees Adrian Brown's articles at http://www.thespacereview.com/article/1319/1 and http://www.thespacereview.com/article/1318/1 about the technical and budgetary problems with MSL that led to the launch slip. While I can't claim to be privy to the budgetary and political issues at the mission level, the technical discussion seems like a fair summary of the situation as I understand it, at least as good a one as can be gathered from public sources.

People in other forums have complained about errors in these articles, but without giving specific examples or providing any factual basis for their objections. I don't find that very useful. If there are real flaws in this account, I'd be quite interested to know what they are.

p.s. I guess we need to change the name of this subforum. sad.gif


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djellison
post Mar 4 2009, 03:41 PM
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Thanks for linking to these Mike - they're very good, and quite thorough. What has this done to the Mastcam delivery date? I'm going to make the bold assumption that there's not a chance in hell of the zoom being reinstated.

And that's a good point about the sub-forum name sad.gif Phoenix needs to get stuffed into past missions as well.
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ElkGroveDan
post Mar 4 2009, 04:49 PM
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QUOTE (djellison @ Mar 4 2009, 07:41 AM) *
Phoenix needs to get stuffed into past missions as well.


...we should wait for the Spring thaw and see what happens.


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dvandorn
post Mar 4 2009, 06:24 PM
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Yeah -- I've been meaning to ask when Phoenix was going to move to Past Missions, but figured that ever-optimistic Doug was waiting to make sure that Lazarus Mode failed before taking that step... smile.gif

-the other Doug


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tedstryk
post Mar 4 2009, 08:58 PM
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I was thinking (and still think) that it would be a good idea to wait until after LPSC, the first major conference at which properly digested results will be presented. I figure it will receive a flurry of activity. Then move it.


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ugordan
post Mar 4 2009, 09:04 PM
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QUOTE (dvandorn @ Mar 4 2009, 07:24 PM) *
I've been meaning to ask when Phoenix was going to move to Past Missions, but figured that ever-optimistic Doug was waiting to make sure that Lazarus Mode failed before taking that step... smile.gif

I'd rather have it moved only to find out Lazarus mode worked than leave it and find out L-mode failed. smile.gif


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monitorlizard
post Mar 5 2009, 03:58 PM
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I had also seen the Adrian Brown essays. In his references, he links to a series of presentations made about MSL on Jan. 9, 2009. These powerpoints contain the things he mentioned and more, in quite a bit of detail. They are at:

www.lpi.usra.edu/pss/jan92009
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algorimancer
post Mar 5 2009, 08:16 PM
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QUOTE (djellison @ Mar 4 2009, 09:41 AM) *
...there's not a chance in hell of the zoom being reinstated.

I'm a bit confused about the zoom. I had thought that it had been definitively canceled, but I gathered from the Technical article that it may have been complete in December. I have mixed feelings about the zoom capability -- as I've stated before, I don't trust the mechanism not to lock-up once on Mars, though I appreciate the benefit of being able to get both telephoto and wide angle views from the same camera. In retrospect they might simply have placed a dedicated third camera with fixed telephoto capability centered between a pair of stereo wide angle cams on the mast head with rather less trouble and similar capabilities as the dual zoom system.
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mcaplinger
post Mar 5 2009, 09:34 PM
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QUOTE (algorimancer @ Mar 5 2009, 12:16 PM) *
I'm a bit confused about the zoom. I had thought that it had been definitively canceled, but I gathered from the Technical article that it may have been complete in December.

The article could be more clearly stated. It says "A redesign of the MASTCAM zoom system ... was essentially complete and ready to ship." That would be better stated as "A redesign of the Mastcam system without the zoom" -- see http://www.msss.com/msl/mastcam/news/index.html
QUOTE
as I've stated before, I don't trust the mechanism not to lock-up once on Mars...

Did you trust the MER Pancam filter wheel or the MI cover to not lock up? There's little mechanical difference between them and the zoom. (You're basically saying that you don't trust MSSS to build an instrument that works.)


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ElkGroveDan
post Mar 5 2009, 10:36 PM
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QUOTE (mcaplinger @ Mar 5 2009, 01:34 PM) *
(You're basically saying that you don't trust MSSS to build an instrument that works.)



...and them's fightin' words!


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mcaplinger
post Mar 5 2009, 11:20 PM
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Forgive me if I lose patience with armchair engineers.

At any rate, the fixed-focal-length but adjustable focus Mastcams, like MAHLI, are mechanically very similar to the original zoom design, they just have one fewer motor and one fewer cam. From http://www.msss.com/press_releases/mahli_d...ery/index.html:

"MAHLI focus is controlled by a precision mechanism developed by Alliance Spacesystems. This mechanism uses a stepper motor to position the internal focus group by means of a cam."

We're very confident that these mechanisms are not going to "lock up".


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stevesliva
post Mar 6 2009, 12:06 AM
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You're forgiven. It is armchair-knee-jerk reflexive, but everybody gets the heebie-jeebies with anything mechanical after Galileo. Umbrellas and tape drives oh my.

The thing that gives me the greatest heebie-jeebies is Cassini's main engine cover, which has worked flawlessly. And not to comment on MSSS, but isn't there an outgas-contaminated camera with a locked up filter wheel wizzing towards a comet somewhere? Or am I combining two issues in my mind?
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djellison
post Mar 6 2009, 12:18 AM
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You're thinking of the Stardust Navcam. That was a major spares-cupboard raid effort ( Voyager optics and shutter ) - and I don't believe MSSS had anything to do with it.

Doug
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stevesliva
post Mar 6 2009, 12:35 AM
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To be clear, I did not mean to imply MSSS had something to do with it. More of a crap-happens sentiment. And we could all list crap that happens with solid state stuff, too.
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lyford
post Mar 6 2009, 01:53 AM
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"Less moving parts!?!?!" The whole rover is a moving part! smile.gif


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