[X] My Assistant

[mcaplinger]

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.

[djellison]

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 Phoenix needs to get stuffed into past missions as well.

[algorimancer]

...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.

[mcaplinger]

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

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.)

[ElkGroveDan]

(You're basically saying that you don't trust MSSS to build an instrument that works.)

...and them's fightin' words!

[mcaplinger]

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".