The Geology of Jezero Crater, Observations & Findings |
The Geology of Jezero Crater, Observations & Findings |
Feb 24 2021, 01:41 AM
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#1
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Merciless Robot Group: Admin Posts: 8784 Joined: 8-December 05 From: Los Angeles Member No.: 602 |
This thread is for those rockhounds among us to discuss the new terrain we'll see as Perseverance scoots around her new home. Let's get dirty & technical!
-------------------- A few will take this knowledge and use this power of a dream realized as a force for change, an impetus for further discovery to make less ancient dreams real.
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Mar 5 2021, 03:45 AM
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Senior Member Group: Members Posts: 2090 Joined: 13-February 10 From: Ontario Member No.: 5221 |
One of the papers I read (can't find it now) implied that speed is not about finishing before the retrieval mission arrives, but placing enough caches down in case something catastrophic happens years down the road, rendering any samples still inside Perseverance irretrievable. The fetch rover's job is difficult enough as is; no need to make it harder.
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Mar 5 2021, 05:28 AM
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#3
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Member Group: Members Posts: 706 Joined: 22-April 05 Member No.: 351 |
One of the papers I read (can't find it now) implied that speed is not about finishing before the retrieval mission arrives, but placing enough caches down in case something catastrophic happens years down the road, rendering any samples still inside Perseverance irretrievable. The fetch rover's job is difficult enough as is; no need to make it harder. The current plan is to double collect in Jezero. Half the collection is left on the rim in case Percy has a catastrophic failure on the way to Midway. Ideally, Percy collects new samples in Midway to supplement those retained from Jezero. There doesn't seem to be a consensus yet on how to deal with samples carried from Jezero or collected in Midway. If they are retained by Percy and it has a catastrophic failure, the fetch rover can't remove them from Percy. If Percy deposits all of them in a cache at Midway and the fetch rover fails, Percy can't pick them up to deliver them to the MAV. -------------------- |
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Mar 5 2021, 07:25 AM
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#4
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Forum Contributor Group: Members Posts: 1372 Joined: 8-February 04 From: North East Florida, USA. Member No.: 11 |
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Mar 5 2021, 10:06 AM
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#5
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Senior Member Group: Members Posts: 2530 Joined: 20-April 05 Member No.: 321 |
One solution to this would be to fill about 3/4 (~24) of the sample tubes on the way up to the rim. At the top of the rim, drop ~16 of them, representing the whole trek up the delta, on the ground, and keep ~8 that also represent the trek up the delta. Then pick up ~8 more on the crater rim, and when that is complete, drop all ~16 in one spot.
That leaves you with ~16 representing the delta in one place and ~16 representing both the delta and the crater rim in another place. The return can choose which group of 16 to retrieve. If there were any failure in the return, there's another group of ~16 for a second try. If Perseverance failed after reaching the crater rim, there would be the first set of ~16 for a first and only retrieval attempt. |
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Mar 5 2021, 02:23 PM
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#6
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Member Group: Members Posts: 706 Joined: 22-April 05 Member No.: 351 |
One solution to this would be to fill about 3/4 (~24) of the sample tubes on the way up to the rim. At the top of the rim, drop ~16 of them, representing the whole trek up the delta, on the ground, and keep ~8 that also represent the trek up the delta. Then pick up ~8 more on the crater rim, and when that is complete, drop all ~16 in one spot. That leaves you with ~16 representing the delta in one place and ~16 representing both the delta and the crater rim in another place. The return can choose which group of 16 to retrieve. If there were any failure in the return, there's another group of ~16 for a second try. If Perseverance failed after reaching the crater rim, there would be the first set of ~16 for a first and only retrieval attempt. Phil Stooke at NASAspaceflight.com posted links to presentations from a recent sampling strategy workshop. Extremely interesting with lots of details on the notional traverses, notional sampling plan, and notional caching strategy Link to Phil's post First set of slides Second set of slides Third set of slides These slides are from those presentations and represent a notional sampling strategy. -------------------- |
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Mar 5 2021, 04:23 PM
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#7
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Senior Member Group: Members Posts: 2530 Joined: 20-April 05 Member No.: 321 |
Thanks for the full background, Van.
It was this pair of adjacent statements from the first set of slides: "Perseverance is likely to create two depots, only one of which will likely be returned. - notionally, one in Jezero Crater and one somewhere on Nili Planum. The Science Team believes that the only way to have the complete collection in a second depot is to 'double sample' critical (all?) samples prior to first depot deployment." …that I was summarizing with my comment in terms of ~16s and ~8s. |
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