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MSL development & assembly, Until it's shipped to the Cape
punkboi
post Jul 25 2010, 07:55 AM
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QUOTE (Mirek @ Jul 24 2010, 11:38 PM) *
Funny video of one of the engineers doing Robot Dance in front of MSL:

Link to YouTube

P.S. It was me who asked him to do that. laugh.gif


Funny video. Hopefully all of you JPL folks will have a much bigger reason to do the Robot Dance in November '11 and then August of '12 smile.gif


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Stu
post Jul 25 2010, 09:40 AM
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QUOTE (Mirek @ Jul 25 2010, 08:38 AM) *
P.S. It was me who asked him to do that. laugh.gif


Haha! I remember, I was with you in the "audience" in the Ustream chat room, watching. (Which was a GREAT event, BTW; anyone who missed it should try to make the next one. Thanks to JPL for letting us watch, much appreciated!)

Those techs really joined in with the spirit of things, didn't they? (maybe it was just a way of coping with the nerves!) I was still hoping they'd all gather around the rover and put on a performance of "Greased Lightning", but maybe next time... laugh.gif


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Drkskywxlt
post Jul 28 2010, 06:26 PM
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Just attended a talk by Sylvestre Maurice, deputy PI for ChemCam. Some interesting facts:

- ChemCam is planning to zap 7-20 targets per day for the entire 2 Earth-year mission (!!!!)
- ChemCam sees alkali metals extremely well and the transitional metals and other metals reasonably well
-- It has a harder time (but doable) with H, C, O, N, P, S, Si ...those elements need .5-10% by weight fractions of the zapped rock to be identified. He said they need 3-5% for C, in particular, depending on range.
-- They can't get any of the noble gases (but who cares?) or F and unfortunately, they can't get Cl at all. APXS will have to look for Cl
- They're operational range is 1.5-7m
-- It would take double the power to extend it to 9m, which was their initial goal
- They added a cooler to their body unit, because the heat from the RTGs would have been too much for it to handle. They were in an awkward spot for awhile where the mast-mounted laser wasn't going to work well when it was too cold, while the body unit was going to be too hot! He feels confident the electric cooler resolves this.
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Stu
post Jul 28 2010, 08:57 PM
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Some memories of a fun evening watching Ustream with fellow rover-huggers! smile.gif

http://astropoetry.wordpress.com/2010/07/28/first-drive


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MahFL
post Jul 29 2010, 02:08 PM
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QUOTE (Drkskywxlt @ Jul 28 2010, 07:26 PM) *
Just attended a talk by Sylvestre Maurice, deputy PI for ChemCam. Some interesting facts:

- ChemCam is planning to zap 7-20 targets per day for the entire 2 Earth-year mission (!!!!)


Frankly that does not sound posssible.
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Drkskywxlt
post Jul 29 2010, 02:53 PM
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Yeah, that kind of blew me away as well. I looked into detail on ChemCam's documentation available online, and it corroborates his statement saying "~15 targets" per day.

It seems that such frequent use of a complicated system in a harsh near-vacuum environment would eventually degrade it to uselessness.
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ugordan
post Jul 29 2010, 03:08 PM
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QUOTE (Drkskywxlt @ Jul 29 2010, 04:53 PM) *
It seems that such frequent use of a complicated system in a harsh near-vacuum environment would eventually degrade it to uselessness.

As opposed to any other system that is somehow immune to degradation?


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djellison
post Jul 29 2010, 04:18 PM
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QUOTE (Drkskywxlt @ Jul 29 2010, 07:53 AM) *
It seems that such frequent use of a complicated system in a harsh near-vacuum environment would eventually degrade it to uselessness.


How, exactly?
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Drkskywxlt
post Jul 29 2010, 04:27 PM
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No doubt the other systems are complex too...just seems that an operating laser might even be beyond what's already flown. It is the first LIBS instrument to ever fly. He already said that severe cold might limit/halt operations to the mast-mounted unit.
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ugordan
post Jul 29 2010, 04:32 PM
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So how does severe cold play into the usage frequency, or alternatively, why would one want to spare an instrument of frequent usage if it's more prone to failure in the first place? I say use it while you can to the fullest extent possible. Extended missions are gravy, but shouldn't be primary mission decision drivers.


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Drkskywxlt
post Jul 29 2010, 04:39 PM
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He didn't go into specifics. He said the cold limits the mobility of the mast and would narrow/eliminate their targeting thusly. I'm speculating with what affect it will have long-term. The primary mission is 2 Earth years long! So, that works out to 2555-7300 targets, each of which will include ~20-50 laser pulses. That's a lot of operation!
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djellison
post Jul 29 2010, 09:09 PM
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So you think they're using it too quickly? Where is your MTBF number to suggest that's the case? 500,000 pulses is 'a lot of operation' ?

MOLA fired 390,000,000+ times in its primary mission.

What is it that makes you think the ChemCam team are going to do more with the laser than it is designed to do, or that they have designed it to do less than is required?

In short - what are you going on about?
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Drkskywxlt
post Jul 29 2010, 11:17 PM
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I admire their confidence. I hope it's warranted. I have no technical expertise to cast doubt on it.

If I were in their shoes, I'd have to be supremely confident to set my mission baseline at sampling so many targets. I'd rather aim lower, particularly with a never-flown before instrument and then have it overperform. Same way the MERs were only baselined for 600m and 3 months. Steve Squyres himself said in his book he thought they'd be able to go longer, but didn't want to oversell.

MOLA is not in the same class as ChemCam. MOLA had a much higher TRL when it flew with a long heritage. Although LIBS technology is well established, it has never flown in space before.
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ugordan
post Jul 29 2010, 11:42 PM
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QUOTE (Drkskywxlt @ Jul 30 2010, 01:17 AM) *
I'd rather aim lower, particularly with a never-flown before instrument and then have it overperform.

The point is, what makes you think they aren't being conservative in their estimates?

QUOTE
I have no technical expertise to cast doubt on it.

So why do it in the first place, then?


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Drkskywxlt
post Jul 30 2010, 12:21 AM
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QUOTE (ugordan @ Jul 29 2010, 06:42 PM) *
The point is, what makes you think they aren't being conservative in their estimates?

Maybe they are. Each target obviously takes time to identify, prepare the system, fire, analyze the results, possibly fire again (the first firing might be to remove dust), analyze again, and then move in closer for APXS or other instrument analysis. Some targeting apparently will be autonomous. Only so many hours in a day though.


QUOTE
So why do it in the first place, then?

To make conversation. I want to see if someone knows better. If no one does, we can have the conversation.
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