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MSL EDL Hardware, Its state & fate
DeanM
post Sep 7 2012, 07:26 AM
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This is a mildly off-topic post (although relevant to MSL hardware), but something that I haven't been able to resolve by searches here & elsewhere.

After backshell separation, the descent stage employs all 8 MLEs until closer to the surface when only 4 are needed.

Were the flight/control software + harware designed to handle failure or non-ignition of one (or more) MLE when all 8 were initially needed?

Or would that have resulted in too much assymmetric thrust?

Cheers!

Dean
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markril
post Sep 7 2012, 03:09 PM
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Just one more, this is a close up of the sky crane impact site. You can make out quite a large chunk that ends up in the upper left corner:

Attached Image


Also, I posted a 3D stereo pair of this in a thread I started on tips for viewing them.

Mark
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nilstycho
post Sep 7 2012, 09:09 PM
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A crude approximation of what the debris field would look like had the Descent Stage impacted at the minimum safe distance of 150 meters from the Rover. ("Flight of the Mars Sky Crane", Cockrell School of Engineering, The University of Texas at Austin. Singh et al. give 200 meters.)

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djellison
post Sep 7 2012, 09:59 PM
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QUOTE (DeanM @ Sep 7 2012, 12:26 AM) *
Were the flight/control software + harware designed to handle failure or non-ignition of one (or more) MLE when all 8 were initially needed?

Or would that have resulted in too much assymmetric thrust?


It would have resulted in failure. They needed that thrust.
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EdTruthan
post Sep 15 2012, 11:26 PM
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In response to "MarsInMyLifetime's" post here, yes I took note of that when stitching together the Sol 36 mosaic. Combined with the better positioning and the resolution of MC100 this is the best view we've gotten thus far of the potential heat shield location (pic below), but as for whether it's visible or not, I'm hesitant on that. It looks from HiRISE as if it's well down inside a small crater. Still, the darkish material we're seeing up along the rim of the crater could very well be impact residue. And I'm pretty sure, as I previously illustrated in this post that that's the location of the heat shield. It's probably not on the itinerary, but if Curiosity were to amble over there and peer into the crater it'd sure be interesting to see the condition of the HS wouldn't it?

Attached Image


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MarsInMyLifetime
post Sep 16 2012, 01:42 AM
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QUOTE (EdTruthan @ Sep 15 2012, 05:26 PM) *
It's probably not on the itinerary, but if Curiosity were to amble over there and peer into the crater it'd sure be interesting to see the condition of the HS wouldn't it?

I'm so used to the relative smoothness of Meridiani Planum, this surface looks pretty rough to get through, so I'll pass! If I were an engineer, though, I'd be more interested in the backshell and parachute site since these kinds of EDL artifacts have not been visited before.

Edited to add to your analysis. This excellent 3D enlargement by marswiggle makes clear that the article is indeed in a depression, and that the smudge is from residue that we are seeing on the far side of that crater. I'm pretty certain now that this is the best we'll see of that hardware.
http://www.unmannedspaceflight.com/index.p...st&p=190716


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Ken90000
post Dec 6 2012, 12:23 AM
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I had no idea finding the cruise stage was an option... http://www.nasa.gov/mission_pages/MRO/mult...a/pia16456.html
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Explorer1
post Dec 6 2012, 01:45 AM
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Kudos to the Hirise team for a successful search!

And before anyone asks, the cruise stage and the weights are all way off to the west, even more out of Curiosity's way than the later dropped weights, which hit the slopes Mt. Sharp downrange. Even they would require going around that dune field to reach for a closer look.

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mcaplinger
post Dec 6 2012, 01:49 AM
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QUOTE (Explorer1 @ Dec 5 2012, 06:45 PM) *
Kudos to the Hirise team for a successful search!

Read it again, CTX found the targets; HiRISE just got higher-res views of them.


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Disclaimer: This post is based on public information only. Any opinions are my own.
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Explorer1
post Dec 6 2012, 02:17 AM
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Yes, I misread it; credit to the whole MRO team is what I meant. Considering the browser-breaking size of images from either camera, the manual search must have taken up many hours nevertheless.
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Phil Stooke
post Dec 6 2012, 03:01 PM
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Here is the location of the cruise stage impacts, NW of Gale crater.

Phil

Attached Image


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... because the Solar System ain't gonna map itself.
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Eyesonmars
post Dec 6 2012, 03:59 PM
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Since another more or less identical EDL sequence might fly in 2018-2020 would a visit to some of the closer artifacts be justified? I don't remember either MER visiting a backshell or parachute for instance. We might learn something.
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RoverDriver
post Dec 6 2012, 04:42 PM
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Maybe I was asleep at the wheel, but I thought Oppy did. http://marsrovers.jpl.nasa.gov/gallery/pre...L257-B367R1.jpg Some of teh crud on her FHAZ was collected there? Uh, maybe we used the MI as well? http://marsrovers.jpl.nasa.gov/gallery/all...unity_m358.html But I don't know, I could be mistaken. laugh.gif

Paolo


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Explorer1
post Dec 6 2012, 05:04 PM
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Eyesonmars said backshell and parachute; there has been no close visits by either of the MERs. A combination of being too out of the way and the danger of entanglement were the reasons, I recall... Probably the same for MSL.
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djellison
post Dec 6 2012, 05:37 PM
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QUOTE (Eyesonmars @ Dec 6 2012, 07:59 AM) *
Since another more or less identical EDL sequence might fly in 2018-2020 would a visit to some of the closer artifacts be justified?


The heatshield? No. Phenolic Impregnated CARBON Ablator. Moreover, it was very well instrumented using the MEDLI suite so it's performance can be measured and understood already.

Backshell? It did it's job - that's enough. parachute? We saw how well it did thanks to HiRISE, and, moreover, the deceleration performance that will have been recorded via IMU's

Skycrane? Well - there's not much point as it's just a football field sized debris zone - and lots of Hyrdazine lying around.
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