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Mars 3 (Various Topics Merged)
Phil Stooke
post Apr 19 2006, 08:12 PM
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tasp said "can any amount of processing put consistent shadows on the correct sides of all the boulders in your enhancement? Me thinks there is more than a slight chance you've come up with something significant."

I know Ted's perfectly capable of answering this himself - and nobody appreciates his work more than I do - but I want to follow up on this issue.

tasp - don't be misled by the appearance of the image. The bright and dark spots are not boulders and shadows. Ted knows this, I know it, but it's important that everybody knows it. The raw image is a sea of noise. It is just faintly possible that behind the noise is a view of the horizon of Mars, though I don't really think this is true. But the smaller details are just random areas of more or less noise, made to look like landscape features by Ted's careful manipulation. This is a nice image, but it's art. And that's OK.

Phil


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djellison
post Apr 19 2006, 08:41 PM
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My take on it is - it might be a real picture, and if it is - then this might be what it saw - but we don't really know if it was a proper picture or if it actually saw anything.

Doug
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tedstryk
post Apr 19 2006, 10:16 PM
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QUOTE (djellison @ Apr 19 2006, 08:41 PM) *
My take on it is - it might be a real picture, and if it is - then this might be what it saw - but we don't really know if it was a proper picture or if it actually saw anything.

Doug


This is true. That is why I call it a "what if" image. It is the most optimistic processing possible, and then is aesthetically cleaned up. The lower verions on my site are more modest interpretations. Short of finding the original transmission tapes and discovering that modern enhancements can carry the signal out longer, getting more of the image, there will always be mystery around it.

Even if it did see rocks, without a stereo image, some known object for context, or some knowledge of their distance from the lander, it would be impossible to measure their sizes.

QUOTE (BruceMoomaw @ Apr 19 2006, 02:49 PM) *
Oh, yes, Perminov goes into great detail about the lousy microchips (due to a decision made by one lower-level manager to cut costs by manufacturing them using aluminum instead of gold). However, it's doubtful that a "timing error" was the problem, because the ignition moment for the braking rocket on the Soviet landers ings, it could have been a simple wind gust or lower-than-normal upper air density than ruined Mars 6.)


I don't mean that the clock wasn't working. It was a problem that resulted in a timing error. Basically, when the engine needed to fire was based on the exact speekd of the spacecraft as well as altitude, and these things were to be determined based on data from the orbiters on approach. Defaults were programmed in case of a situation like this, based on best guesses. Exact trajectory, entry angle, and atmospheric conditions effect the altitude such firings need to be made at. For example, if the atmospheric density was lower than normal, the engine would have to begin firing longer because the lander would need to slow down more, and thus it would have to fire at a higher altitude. There is no way to be sure, but the lack of ability to adapt to conditions certainly could have caused timiing problems.


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ljk4-1
post Apr 20 2006, 12:22 AM
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As I recall, the famous Mars 3 image was first shown in the West on
the BBC series The Planets in 1999. Perhaps someone who worked
on the series and obtained the image from the Soviet scientists can
help here?

http://www.bbcshop.com/invt/bbcdvd1003

http://www.bbc.co.uk/science/space/solarsystem/index.shtml


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"After having some business dealings with men, I am occasionally chagrined,
and feel as if I had done some wrong, and it is hard to forget the ugly circumstance.
I see that such intercourse long continued would make one thoroughly prosaic, hard,
and coarse. But the longest intercourse with Nature, though in her rudest moods, does
not thus harden and make coarse. A hard, sensible man whom we liken to a rock is
indeed much harder than a rock. From hard, coarse, insensible men with whom I have
no sympathy, I go to commune with the rocks, whose hearts are comparatively soft."

- Henry David Thoreau, November 15, 1853

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Guest_BruceMoomaw_*
post Apr 20 2006, 01:52 AM
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QUOTE (tedstryk @ Apr 19 2006, 10:16 PM) *
I don't mean that the clock wasn't working. It was a problem that resulted in a timing error. Basically, when the engine needed to fire was based on the exact speed of the spacecraft as well as altitude, and these things were to be determined based on data from the orbiters on approach. Defaults were programmed in case of a situation like this, based on best guesses. Exact trajectory, entry angle, and atmospheric conditions effect the altitude such firings need to be made at. For example, if the atmospheric density was lower than normal, the engine would have to begin firing longer because the lander would need to slow down more, and thus it would have to fire at a higher altitude. There is no way to be sure, but the lack of ability to adapt to conditions certainly could have caused timiing problems.


No, the braking engine on all four Soviet Mars landers was (as with our three rough landers) a solid retrorocket fastened to the parachute, triggered by a radar altimeter, and intended to fire for just a few seconds only about 60 meters above the surface -- it had to be riggered entirely by a radar altimeter because (just as with our landers) there was no conceivable way to know in advance exactly what altitude the craft would be at at any given moment.
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tedstryk
post Apr 20 2006, 02:35 AM
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QUOTE (BruceMoomaw @ Apr 20 2006, 01:52 AM) *
No, the braking engine on all four Soviet Mars landers was (as with our three rough landers) a solid retrorocket fastened to the parachute, triggered by a radar altimeter, and intended to fire for just a few seconds only about 60 meters above the surface -- it had to be riggered entirely by a radar altimeter because (just as with our landers) there was no conceivable way to know in advance exactly what altitude the craft would be at at any given moment.


Atmospheric conditions would have a lot to do with that. But I can see where this is going, so I digress...


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Guest_BruceMoomaw_*
post Apr 20 2006, 05:05 AM
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Yeah, atmospheric conditions would have a lot to do with how FAST the lander was dropping at the time the altimeter triggered its retrorocket, and could have killed it that way -- and there are of course plenty of ways the faulty microchips could have killed it. But fouling up the precise firing of its retrorocket with a timer malfunction was not one of them. Still, this is something we'll never know the precise cause of, even if some traveller in that antique land someday stumbles across the remains of the lander.
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The Messenger
post Apr 21 2006, 03:53 PM
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QUOTE (mcaplinger @ Apr 19 2006, 12:20 PM) *
If you're going to make sweeping assertions, it might help to exhibit more cognizance of the process involved. The NAIF FTP site (naif.jpl.nasa.gov) is the standard place where JPL trajectory information is released. The file /pub/naif/MER/kernels/spk/spk_a_c_030610-040104_recon.bsp on that site is, according to its label, "a reconstructed cruise trajectory for MER-A, beginning at TECO and ending at atmospheric entry." There is a similar file for MER-B. If Withers is unaware of those files, you might want to make him aware. If there's something inadequate about the information, I'd be curious as to what.

As previously noted, that state information and the EDL engineering telemetry archive, which has been released and is available on the PDS atmospheric node, are all the information I can think of that would be useful for reconstructing the entries of the MERs.

I'm no apologist for JPL, but carping on this topic would appear to be unjustified.

I appreciate the help, but I am not the only one who is finding it difficult to chase down relevant data:

http://nesc.larc.nasa.gov/admin/documents/...ition_Paper.pdf
QUOTE
3. Finding: The overall EDL reconstruction process is not well documented, making it very difficult for an oversight group such as the Red Team to penetrate and assess.
Recommendation: The EDL technical processes, as well as the processes and schedules for required output products and key decisions, should be well documented in a form that is usable by independent experts.

I'm still trying to figure out how close the actual landing times of both MERs were to the expected atmospheric descent - relative to the time of entry: How fast did these puppies fall?
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mcaplinger
post Apr 21 2006, 04:28 PM
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QUOTE (The Messenger @ Apr 21 2006, 08:53 AM) *
I appreciate the help, but I am not the only one who is finding it difficult to chase down relevant data:

http://nesc.larc.nasa.gov/admin/documents/...ition_Paper.pdf


This is primarily a human factors study, and while it has some interesting tidbits, the notion you seem to be dancing around, that there's some big conspiracy of silence surrounding the MER EDLs, is simply not supported by the evidence.

QUOTE
I'm still trying to figure out how close the actual landing times of both MERs were to the expected atmospheric descent - relative to the time of entry: How fast did these puppies fall?

http://techreports.larc.nasa.gov/ltrs/PDF/...a-2004-5092.pdf -- the "reconstruction" column in tables 3 and 4 seems pretty clear to me. The MER-A RAD firing was 339.4 seconds from entry; the expected 3DOF Monte Carlo range was 317.3-376.2 sec. The MER-B RAD firing was 336.3 seconds from entry; expected 3DOF was 317.1-372.2 seconds.

I'll leave it to Doug to move this discussion to the MER area; it's clearly pretty far off topic here.


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Disclaimer: This post is based on public information only. Any opinions are my own.
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ljk4-1
post May 1 2006, 04:01 PM
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This company (which I have no involvement with) is selling an actual
small model of Mars 3 in orbit around its namesake.

See here:

http://apollomaniacs.web.infoseek.co.jp/ap...rtales2b_05.jpg


--------------------
"After having some business dealings with men, I am occasionally chagrined,
and feel as if I had done some wrong, and it is hard to forget the ugly circumstance.
I see that such intercourse long continued would make one thoroughly prosaic, hard,
and coarse. But the longest intercourse with Nature, though in her rudest moods, does
not thus harden and make coarse. A hard, sensible man whom we liken to a rock is
indeed much harder than a rock. From hard, coarse, insensible men with whom I have
no sympathy, I go to commune with the rocks, whose hearts are comparatively soft."

- Henry David Thoreau, November 15, 1853

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Bob Shaw
post May 1 2006, 05:08 PM
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QUOTE (ljk4-1 @ May 1 2006, 05:01 PM) *
This company (which I have no involvement with) is selling an actual
small model of Mars 3 in orbit around its namesake.


Try searching eBay for StarTales and you'll find *lots* of lovely little Japanese 'Candy' models like this - Viking Lander, Lunokhod, Voyager, Sputnik, Ranger to name but a few!

Bob Shaw


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tedstryk
post May 1 2006, 08:28 PM
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I have one, and am quite fond of it smile.gif


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vikingmars
post May 2 2006, 08:37 AM
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QUOTE (tedstryk @ Dec 30 2004, 12:36 AM) *
.../... but I made it clear on my website it was only a speculative image. I strongly doubt if the raw data even shows Mars at all - it could be all noise.


When I was working on Russian planetary data at Brown University in 1984, Russian scientists told me that (i) the Mars 3 "image" is a strip that should be seen vertically and NOT horizontally, (ii) in the 20 seconds of data, NO contrast was transmitted : it was just a kind of "carrier"...
Sorry, but as Ted said, NO real imaging data there. The Viking landers were the 1st spacecrafts which succeeded in taking images from the surface of Mars...
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tedstryk
post May 2 2006, 09:32 AM
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QUOTE (vikingmars @ May 2 2006, 08:37 AM) *
When I was working on Russian planetary data at Brown University in 1984, Russian scientists told me that (i) the Mars 3 "image" is a strip that should be seen vertically and NOT horizontally, (ii) in the 20 seconds of data, NO contrast was transmitted : it was just a kind of "carrier"...
Sorry, but as Ted said, NO real imaging data there. The Viking landers were the 1st spacecrafts which succeeded in taking images from the surface of Mars...

In my talks with a few Russians, they have contradicted each other on that...some they it is the very beginning of a scan, others do not. The other issue is orientation...Our understanding of the orientation of the "horizon" line, or even where the horizon should be, could be way off, because we don't know the orientation of the craft, given the possibility that the lander didn't fully open up or tipped over, etc.


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djellison
post May 2 2006, 09:59 AM
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Might it be a vertically oriented image, but with a cover or piece of structure blocking the first part thus giving the illusion of a horizon?

Doug
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