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Lost landers from HiRISE, The next step
tuvas
post Jan 3 2007, 08:41 PM
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Okay, we now have definitive pictures of VL1, 2, Spirit, Opportunity, and a Pathfinder coming up soon. So, now, what would the lost landers look like, starting with Beagle, MPL, and Mars 6, which will be the easiest to find of the landers. Just curious to hear your thoughts. Thanks!
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Tesheiner
post Jan 3 2007, 08:57 PM
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> So, now, what would the lost landers look like ...

Mmm, do you already know the answer, tuvas? wink.gif
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tuvas
post Jan 3 2007, 09:15 PM
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QUOTE (Tesheiner @ Jan 3 2007, 01:57 PM) *
> So, now, what would the lost landers look like ...

Mmm, do you already know the answer, tuvas? wink.gif


Nope, I sure don't, yet. Keep in mind even if we did know what to look for, it's a large area, and without having a really good idea, well, it'd be quite near impossible...

As to why, well, let's just say Alfred is getting tired of being asked about one of these landers, and wants to be able to give them a definitive answer sometime relatively soon. Of course, that could be a few weeks, or a few months, but sometime in that time range.
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djellison
post Jan 3 2007, 11:07 PM
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MPL will have to wait until Southern Summer I presume - we should know where it is FAIRLY well from tracking etc. and we know we should be able to find a parachute VERY easily, as well as Backshell and Heatshield. As for the lander itself - slightly smaller than the viking spacecraft if memory serves me right - and likely to be a lot 'shorter' (i.e. crushed landing legs etc ) - and if there were any 'splat' mark from leaked fuel etc - i would have thought that 3 winters would have eliminated much if not all evidence of that.

Beagle 2, well that supposed MOC target would be an interesting starting point. How far B2 got through its landing sequence before failing will dictate how much 'stuff' is on the ground. The Chute - if 'entry' worked - deflated airbags should be visible as well, if it got further than that. The heatshield, backshell and indeed the lander itself - I would say no - going on the sim I managed which seems to be something roughly indicative going on MER experience...
http://www.unmannedspaceflight.com/index.p...ost&id=8409

As for pieces of the historic Russian landers - I would be doubtfull. They were comparatively small, and their Parachutes and indeed any other hardware- if anything like V1 and V2's chutes - will almost certainly be dust-covered and hard to identify.

Doug
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nprev
post Jan 3 2007, 11:47 PM
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Has anybody derived an estimate of the overall dust deposition rate yet based on the MRO VL1 & 2 observations? This might help to identify the 'lost' landers by providing contrast models, etc.

BTW, did all the Soviet landers use chutes (whether they deployed or not)? These seem to be the most detectable artifacts, generally speaking. I seem to recall that Mars 2 was a hard lander, but not sure if that was a cover story myth or not...


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tedstryk
post Jan 4 2007, 12:31 AM
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QUOTE (nprev @ Jan 3 2007, 11:47 PM) *
Has anybody derived an estimate of the overall dust deposition rate yet based on the MRO VL1 & 2 observations? This might help to identify the 'lost' landers by providing contrast models, etc.

BTW, did all the Soviet landers use chutes (whether they deployed or not)? These seem to be the most detectable artifacts, generally speaking. I seem to recall that Mars 2 was a hard lander, but not sure if that was a cover story myth or not...


It was a de facto hard lander. It wasn't supposed to be. It entered the atmosphere at an angle that was too steep, and the parachute never got a chance to deploy before impact.


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Bob Shaw
post Jan 4 2007, 12:52 AM
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I wonder how visible the impact points of the DS2 landers would be?

Obviously, they were pretty small, but they may have kicked off something when they hit.


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dvandorn
post Jan 4 2007, 04:13 AM
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Let's see, a couple of responses, here...

Doug, I'm not sure we have a really good idea of what the MPL remains might look like. The greatest rate of landform change observed on Mars is in the polar regions; an awful lot of material moves around every Martian year when literally trillions of tons of solid CO2 gets laid down and then sublimates off.

Just for starters, I have to wonder what the simple weight of the dry ice built up on and over the crash (and the backshell & heat shield, for that matter) might have done to them. Just how deep does the dry ice layer lay down at MPL's latitude, anyway? Even if it wouldn't cover over MPL entirely, I'd think you would see some serious effects from being buried in dry ice.

Ditto for the 'chute. I don't know what was used to pigment MPL's 'chute, but I know a lot of dyes fade in extreme cold. After three winters, and dust deposition from the winds during sublimation season, I'm thinking that the 'chute may not be recognizable anymore.

And, yes -- the winds. We see that polar latitudes sublimate somewhat unevenly, with "warm" spots (thinner ice layers or rocks which receive more insolation through the dry ice cap and sublimate the frozen CO2 from below) clearing off and blowing dust onto adjacent dry ice surfaces, which creates more preferential sublimation, which creates more clear spots, until the whole surface is clear. The lander and any of its related EDL equipment might have created warm spots and been the sources of early clearing spots -- which means they might have been exposed to pretty stiff winds as pent-up CO2 gas blew through the ice ceiling. Hey, we *know* they blow through energetically enough to spray dust out onto adjacent dry ice-covered surfaces. What would such events do to the 'chute fabric (especially if it's super-cold)? What would they do to the wreck of MPL itself?

I mean, it's even possible that some pieces of MPL have been blown several meters away from the main crach site.

And to Bob, I'm on the fence as to whether the DS2 impact points would be obvious. We know that Spirit's heat shield drew a gouge into Bonneville's rim, which was extremely dark and contrasty with the surrounding materials. It was quite obvious in both MOC imagery and in the ground-level images from the far rim.

However, while MRO's view of Bonneville shows the heat shield, the albedo difference seems to be almost completely gone. I'll grant you, wind smoothing is probably at its peak effect at crater rims, but this would seem to argue against there being much in the way of identifying marks on the craters made by the penetrators. It might well be possible to identify the impact sites in other ways, but (especially after three Martian winters) I'm not all that sanguine that we'll be able to find them.

-the other Doug


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hendric
post Jan 4 2007, 06:37 AM
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QUOTE (dvandorn @ Jan 3 2007, 10:13 PM) *
Let's see, a couple of responses, here...

Just for starters, I have to wonder what the simple weight of the dry ice built up on and over the crash (and the backshell & heat shield, for that matter) might have done to them. Just how deep does the dry ice layer lay down at MPL's latitude, anyway? Even if it wouldn't cover over MPL entirely, I'd think you would see some serious effects from being buried in dry ice.


I will bet, umm...a $5 donation to UMSF that the MPL crash site will be very noticeable, due to the effect it has on the environment around it. Here's my wild scenario:

1. SW failure causes the engine to prematurely shut down.
2. Crash, with a small chance of a catastrophic explosion (although I personally doubt it)
3. Lander embeds itself into the ground, creating a depression and disturbing the dust around it.
4. Winter arrives, with the frost deposition covering the area.
5. Spring arrives, and as the sun starts warming the crash site, several things happen:
* MPL itself will heat up faster than the surroundings because of its albedo, and the pyramidal shape of the lander. Even if it is completely under the CO2, as the ice thins it will be heated below by MPL. My prediction is this will cause a "spider" or "geyser" vent to form at MPL's location, on the north side, while the south side stays mostly ice-locked. If any darker dust was exposed during the impact, this would accelerate and intensify the effect.
* The crash site is its own mini-crater, which will sublime faster on the south wall than the north wall, since the south wall faces the sun more directly. This will make MPL look like it is in an oval crater as the CO2 sublimates. If the crater is small enough, MPL's shadow might prevent this from happening.
* The view of the location would, obviously, change based on when during the thaw it is viewed.

So there you have it, my prediction is that MPL will be the first artificial geyser on Mars!

Of course, if it landed in a boulder field, the boulders could also cause a similar effect, potentially hiding the tree among the forest, so to speak.


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edstrick
post Jan 4 2007, 12:47 PM
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Terminology point: The Soviet Mars landers, as well as the early Luna landers including successful Luna 9 and 13, Pathfinder, and MER landers are all HARD landers. (Also Venera 4 through 8.) None of them were landings you could walk away from, the payloads were "armored", and the vehicles were not attitude controlled after touchdown.

The US Surveyors, the later Soviet Lunokhod carrying and Sample-return-vehicle carrying Luna landers, The later Soviet Venus landers, the US Vikings, Mars Polar Lander, Phoenix, and MSL are all soft landers.

The Deep Space 2 probes were impactor/penetrators, while the US Rangers and Deep Impact probes were impact missions.
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lyford
post Jan 4 2007, 04:58 PM
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The Soviets were true pioneers of lithobraking! smile.gif


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djellison
post Jan 4 2007, 05:21 PM
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http://www.lpl.arizona.edu/tekton/crater_c.html

Could be usefull smile.gif

I've got a segment of the B2 failure report that suggests, if it just splatted in without chute etc - total feature about 5 - 6m across. A crater approx 1.5 metres across, with a rim of about 7cm - think Genesis impact sort of scale.

Doug
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Bob Shaw
post Jan 4 2007, 08:40 PM
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QUOTE (edstrick @ Jan 4 2007, 12:47 PM) *
The Deep Space 2 probes were impactor/penetrators, while the US Rangers and Deep Impact probes were impact missions.


And the Ranger seismic capsules were also rough landers (NASA uses 'rough' in their SP-4210 Lunar Impact: A History of Project Ranger, and to be honest I think 'rough' is a better description than 'hard'!).

NEAR, Hayabusa, Phobos 1&2 and Phobos-Grunt are in a class of their own! 'Featherweight'?


Bob Shaw


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tuvas
post Jan 4 2007, 09:22 PM
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QUOTE (djellison @ Jan 4 2007, 10:21 AM) *


I just found it ironic that you sent a link to a website from the department that I work at. Wow, I didn't know LPL had QUITE so much fun stuff. Still, it shoulld be useful. It will be quite a challenge to find the lost probes, assuming indeed that they are lost, but who knows, we might have a chance somehow. We'll at least give it a shot. Who knows what'll happen.
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djellison
post Jan 4 2007, 09:35 PM
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What we need is an MSL proposed landing at Isidis Planatia - then you could wallpaper the Beagle 2 Ellipse with a proper reason smile.gif

Doug
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