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The Descent into Victoria, Possible and Actual Strategies
djellison
post Jun 29 2007, 12:19 PM
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My intepretation is this
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MarsIsImportant
post Jun 29 2007, 02:22 PM
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Green marks the entry path. That's my understanding too.
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Tesheiner
post Jun 29 2007, 02:26 PM
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So that's more or less the same site as of sol 952.
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djellison
post Jun 29 2007, 02:29 PM
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Just 'left' of it, if that makes any sense.
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MarsIsImportant
post Jun 29 2007, 03:17 PM
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What I don't understand is that they picked an ingress spot further away from the current rover position than they had too. In fact, the spot they picked requires going over the lip of a dune. Again, that doesn't seem necessary if they had chosen this area marked in red.

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Again, green arrow points the area of entry as understood through the conference yesterday.
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djellison
post Jun 29 2007, 03:51 PM
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Slope too steep there perhaps - too close to the cliff edge w.r.t. shadowing solar and comms.

Doug
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MarsIsImportant
post Jun 29 2007, 04:10 PM
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Well, the slope is not too steep. As for being too close to the cliffs, that would only be true if they were going straight down. I think the reason might be simply because that a straight line is not necessarily the the fastest way to the target. If they went down the area I marked in red, then they would have to traverse the slope for much longer of a distance to get to the intended target. That means a very slow pace on the slope.

The way the MER team intend to go maybe longer in over all distance, but they will have only to go half the distance to the target on a slope. Much of the travel will be quick on flat surface. That is the only reasonable argument for ingress placement that I can think of. Plus, doing the toe dip in and out at that particular place might make it easier for rover to get out again through compression of the soil at that spot. I guess that I'm answering my own questions.
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dvandorn
post Jun 29 2007, 05:14 PM
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I think you have the right idea, MII. I know that during the telecon yesterday, SS made several statements about how they were planning a very specific route that addresses rover safety above all. He said that they would *not* deviate from this route in order to go after interesting-looking targets, but that they may stop *along* this route to look at interesting targets of opportunity.

Whatever the rationale, this route has been selected to maximize the safety of the rover and to get it to the bright-band exposure that is the top scientific priority of entering the crater. Any deviation from this pre-selected route will come only from rover safety concerns, methinks...

-the other Doug


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Tom Tamlyn
post Jun 29 2007, 06:21 PM
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For those who missed the press conference, a telephone replay is available until July 2.

http://www.nasa.gov/home/hqnews/2007/jun/H...ria_Crater.html

Most of the information has been well summarized in this thread, but it's always a pleasure to admire how clearly SS speaks about rover operations and science, and how well he communicates the enthusiasm of the team. I can't think of anyone else in his league.

TTT
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Tman
post Jun 29 2007, 07:24 PM
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Surprisingly on the SPACE-MULTIMEDIA site, that usually has provided only manned spaceflight topic, is it now available - for good I guess. As well the last NASA audio teleconference for the Dawn mission. smile.gif


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BrianL
post Jun 30 2007, 03:55 PM
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One thing is not clear to me in what was announced. Do they feel that the bright band is as deep as they can go into the crater to keep the rover safe? That would be very disappointing if they were not able to continue further downslope to get to older layers of exposed rock.

Brian
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djellison
post Jun 30 2007, 04:13 PM
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It's a case of 'see how we go'. The white band is the only target so far - they have no specific goals beyond that simply because they can't really tell what the terrain is like after that until they get closer to it.

It's probable that there may be a few tens of metres further exposed rock that is easily navigable beyond the white layer. However, if beyond that it's just sand, then they're not going to try 12 degree sand slopes, they're a death trap (see the trouble they had near Wopmay rock in Endurance - many sols of churning and wheels up to the hubs and beyond in sand)

It all depends on what the terrain offers when we get closer. If it's just a tiny bit of sand on top of solid rock, it's doable...otherwise it'll be a case of going as far down as they can, and then coming back out again.

Doug
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ElkGroveDan
post Jun 30 2007, 04:22 PM
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QUOTE (djellison @ Jun 30 2007, 08:13 AM) *
It all depends on what the terrain offers when we get closer. If it's just a tiny bit of sand on top of solid rock, it's doable...otherwise it'll be a case of going as far down as they can, and then coming back out again.

...perhaps doing the same on other "ramps" where different layers may avail themselves - if navigation is difficult here.


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CosmicRocker
post Jul 1 2007, 06:08 AM
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BrianL: That bright band is the safest, pre-impact bedrock they can reach. They will probably be able to go deeper than that, but as others have noted, further safe roving will depend on rover observations.

That Space-Multimedia site was a godsend. I was able to download the audio and listen to all of it. Squyres' performance was as amazing as it always is, but everyone else did just as well. That teleconference was one worth waiting for.

I am really excited that Steve noted that Opportunity would be traversing the first ever, good, vertical slice through an ejecta blanket, and did not want to waste the opportunity. I think this is important.

Sorting out the origin of the bright band, and whether it is due to the past atmosphere working down, or the past groundwater working up sounds like a good idea to me.

As for post-Victoria explorations, I can buy into a journey across the plains, looking at eroded craters for flowing water evidence and exotic cobbles along the way. It sounds like a good plan to me.


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Astro0
post Jul 2 2007, 10:52 PM
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Hi All,

Just before Oppy heads into VC, I thought that I'd share a little SFX image.
The version here includes an inset image from the full-res version which is 6600x2418 and 16.5mb.
The full image is available here for download.

Attached Image

This is just a thumbnail version, see the link above.

I think that the scale is about right.
Thanks to Doug for the MER model used as the base for this image.
Can't wait until we see the real descent next week.

Enjoy
Astro0
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