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Targets for LRO
PhilHorzempa
post Apr 6 2007, 09:41 PM
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You can imagine this to be a companion thread to the one requesting suggestions
for MRO targets on Mars.

The LRO (Lunar Reconnaissance Orbiter) is set to launch in a little over a year
from now. There was to a be a site selection workshop in May 2007, next month, but
I see now that it has been cancelled. Therefore, it appears that it is up to us, the UMSF
Community to take up the baton and help NASA out. It was done for New Horizons at Jupiter
and was very productive.

So, what are the sites that you would like to see imaged at 0.5 meter resolution by
LROC, LRO's High-Resolution camera?

My first suggestion would be to re-photograph the Surveyor 1 landing site to compare
it with the images obtained by Lunar Orbiter 3.

My second suggestion would be to photograph the Surveyor 6 landing area. This
should image S-6 itself, but even more interesting, it may capture images of
Surveyor 4, which should be only a mile or so away. This would help to
determine whatever happened to S-4, which abruptly stopped transmitting just
short of touchdown.



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nprev
post Apr 6 2007, 10:36 PM
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Scientifically, Aristarchus (sp?) is probably the most interesting area of the Moon since it's been the most frequent site of transient lunar events (TLEs). There might be some accessible volatiles there (probably mostly CO2), and therefore should be closely examined by LRO.


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Phil Stooke
post Apr 6 2007, 11:17 PM
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Other Phil, I have Surveyor 4 and Surveyor 6 about 4 km apart, about 2.5 miles. Bearing in mind we don't really know exactly where Surveyor 4 is, of course. You should also know that sites based on tracking were often off by several km from where the spacecraft was eventually found, which would enlarge the search area.

I would be most interested in the landing sites we do not have exact positions for: all Lunas, Surveyor 5, and the many impact sites not yet identified - such as Apollo 15, 16 and 17 SIVBs, Apollo 12, 15 and 17 LMs, Ranger 4 (long shot), Lunas 7 and 8, and of course SMART-1. To me, Lunokhod 1 is the most interesting of all.

Phil


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As old as Voyage...
post Apr 7 2007, 08:46 PM
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If all the science has been achieved from LRO's initial orbit and the spacecraft's perilune is lowered sufficiently it could well image the scuffed up lunar soil around Apollo 11's descent stage. Perhaps even resolving individual bootprints under the required illumination.

That would certainly be one for the album.

Resolving the the six LM descent stages may also provide some science. The top surface of the descent stages have a fairly large surface area that has been exposed to space for a known period of time and images of sufficient quality could reveal if they have suffered any small impacts. Of course the vast majority of micro-craters would require a microscope to spot but there may be the odd dent a few CM across in one or more of them.

This may help to determine the average impact rate on the lunar surface. Something future Moonwalkers will definately want to know.

The crater left by the impact of Luna 2 is another must see and my money's on Phil Stooke for identifying it in LRO images.


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Phil Stooke
post Apr 7 2007, 11:58 PM
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A little snippet from NASA night at LPSC which I don't recall seeing mentioned anywhere else - and apologies if I get the official names of the various NASA units wrong here, I can't keep up with them all.

Right now, LRO comes under the Exploration Systems Mission Directorate. They will run it for one year. Then it will be handed over to the Planetary Science Division. So, first, it supports operations by looking for landing sites, then it goes into a science-driven extended mission.

LRO will image areas seen in Apollo panoramic camera images (the best Apollo pics for resolution) to try to find new craters, and assess the impact rate that way.

As for Luna 2, its location is quite uncertain. It will be next to impossible to locate. But there was a story in Sky and Telescope in 1959 about its impact being seen, with a location supported by two observers.... who knows?

Phil


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edstrick
post Apr 8 2007, 07:34 AM
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Another crater/debris field that is poorly located is Surveyor 2's.

Surveyor 2 had one vernier engine fail to ignite during midcourse correction after a successful launch and trans-lunar insertion. It was put into a roughly 2 second fast tumble. Repeated engine firings and burpings never got that engine to lite and as it approached the moon on an uncontrolled (disturbed by all the engine burps) trajectory, it was in a 1 second-ish tumble and with dwindling battery power.

To get the most engineering value out of a lost mission that they could, they turned on most or all of the normally used retro-landing electronics, and command fired the main (solid fuel) retro when they were very close to lunar impact. Seconds (?) later, they lost signal from the spacecraft. A careful reading of the Survey 2 Mission Report, JPL TR-32-???? utterly failed to make it clear if they had any clear idea if the LOS was due to depletion of battery power or disintegration of the vehicle under retrofire during it's 1 RPS tumble.

Somewhere, on the moon, in a very poorly known (and by now even more thoroughally forgotten location). is either a discrete crater formed by Surveyor 2 when it impacted, or a main crater with subsidiary (not secondary) craters nearby (which would have formed form pieces falling off the breaking up vehicle)

Note that for all Surveyors (except 2 and maybe 4), there will be 2 subsidiary craters: The Altitude Marking Radar was IN THE NOZZLE of the main retro and was rather violently jettisoned at retro ignition, to impact the moon at essentially full terminal approach velocity. A minute later, following main retro burnout, the vernier engines throttled up momentarily to full thrust and the solid retro case was jettisoned. That would have impacted much closer to the final landing site and at only a few hundred (I think) miles/hr. None, to my knowledge, has ever been spotted from orbit or from the lander (or in Apollo 12 panoramas, etc.), but they should be larger, more intact and much closer to the main spacecraft than the AMR.
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As old as Voyage...
post Apr 8 2007, 09:12 AM
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The Luna 2 impact site will also boast a second crater; that of Luna 2's third stage that hit the Moon some thirty minutes after Luna 2.

I wonder if the impact of the third stage was ever observed?


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antipode
post Apr 8 2007, 12:23 PM
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Is the LRO going to be able to image the terminator? I'm wondering if any of this putative 'electrostatic weather' at sunrise might be resolvable.

Apart from that - yes - any fairly well documented sight for TLPs would be interesting.

Putting on my tinfoil hat for a moment - what about a re-imaging of the infamous 'blair cuspids' rolleyes.gif

P
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Phil Stooke
post Apr 8 2007, 12:29 PM
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The Luna 2 third stage crashed about 30 minutes after the spacecraft. If it followed exactly the same trajectory in space, its impact site would have been displaced by the Moon's orbital motion, which I very roughly estimate to mean it would be somewhere near 30 north, 75 east. But the chance of finding it is very remote.

Those Surveyor retro systems were never observed in images. Even if they could be seen in LRO images it might be difficult to distinguish them from rocks.

Phil


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As old as Voyage...
post Apr 8 2007, 04:38 PM
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QUOTE (antipode @ Apr 8 2007, 01:23 PM) *
Putting on my tinfoil hat for a moment - what about a re-imaging of the infamous 'blair cuspids' rolleyes.gif

P


On this dubious subject, does anyone remember 'The Shard'? That 1.5 mile high pillar seen in Lunar Orbiter 3 image III-84-M? Too bad it was just an image flaw and didn't show up in any other images of the same area.

I think when it comes to possible lunar geological activity, 'Ina' should be very high on the list of potential targets.

http://www.physorg.com/news82217633.html


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dvandorn
post Apr 8 2007, 04:42 PM
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QUOTE (Phil Stooke @ Apr 8 2007, 07:29 AM) *
Those Surveyor retro systems were never observed in images. Even if they could be seen in LRO images it might be difficult to distinguish them from rocks.

That's the real problem, isn't it -- finding things that didn't make obvious craters.

Lunar Orbiter images showed us one landed Surveyor (the first one, out by the Flamsteed Ring) and, as I recall, one of the Ranger impact craters (the last one, in Alphonsus). The Apollo panoramic camera showed us landed LMs, S-IVB impact craters, LM ascent stage impact craters, and even a few of the Ranger impact craters.

But no lunar orbiting camera has ever shown us Luna 9, Luna 13, or either Lunakhod (mostly, I'm sure, due to large uncertainties about their locations). And as you point out, none of the Surveyor retro-rocket systems has ever been imaged.

And the problem with that is we can see the craters formed by man-made objects 'cause they're usually fresh, blocky and rayed. Anything in the field of view in an area we *know* contains an artificial object's final resting (or splatting) place that shows signs of being quite recent becomes identifiable. But a lump, between a third and a half meter across, and thus at the extreme range of single-pixel coverage in a given iimage?

You'd have better luck finding a thoat in MRO images... biggrin.gif

And someone correct me if I'm wrong, but I don't believe that LRO can achieve any greater resolutions from its planned specification by lowering its orbit -- the relative speed of the spacecraft over the lunar surface would cause blurring of the image, no matter what you do. (LRO already uses motion compensation, IIRC, so there's not much further you can do to achieve greater resolutions.) So, don't be expecting imagery of bootprints around landed LMs any time in the near future.

Finally, when it comes to the overall topic, here, we want to be very careful about high-reolution imagery on the Moon. The ubiquitous regolith and massive gardening of the upper crust actually make it *more difficult* to observe lunar geologic processes at high resolutions, not easier. For scientific purposes, LRO's resolution needs to be used for such things as stereo slope mapping and observation of small features that have an intrinsic interest. For example, you might want to take high-res images of the dark-halo vents in Alphonsus, since those might be places where gas is escaping and disturbing surface materials. Beyond that kind of thing, the Moon is better observed, geologically, at lower resolutions. (Read Don Wilhelms' 'To a Rockey Moon' if you don't believe me... smile.gif )

-the other Doug


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Phil Stooke
post Apr 8 2007, 06:28 PM
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I thought the shard was from an Apollo Hasselblad image... they tried to rope me into that.

It was Ranger 8's crater that was imaged by Lunar Orbiter (3, I think, don't have it in front of me). - look in "Exploring Space with a Camera". (you must have that, Doug!) Then nos. 7 and 9 were found by Ewen Whitaker in Apollo 16 images. He also found the Apollo 13 and 14 SIVB craters and Apollo 14's LM ascent stage crater ejecta. I just got hold of before and after scans of the latter site - I'll post them soon. Everything else is up for grabs.

Ina is one of my highest priority sites. It just cries out for a human or a rover mission. Come on, people!

Phil


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Phil Stooke
post Apr 8 2007, 06:51 PM
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I want to clarify something Doug just said, citing Don Wilhelms: "the Moon is better observed, geologically, at lower resolutions."

Don did write that, and nobody would know it better than him. But he was talking about recognizing geologic units - areas of different origin or composition. It doesn't apply to things like block size distributions, small fractures etc. - see the very high resolution panoramic camera images in "Apollo over the Moon", for instance, with very narrow recent fractures in the regolith in Mare Serenitatis. We would also do better with much higher resolution images of Ina! I expect the LRO images will be very useful and probably surprising in many ways.

Phil


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dvandorn
post Apr 8 2007, 07:20 PM
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Oh, of course, Phil -- that's exactly what I meant. It's those relatively few things that you mention (mostly special features and things like block population counts) that lend themselves to the very high resolution offered by LRO.

When you consider that LRO is designed primarily to support future manned lunar operations, it's instructive to remember that while most Apollo landing sites had imagery available at between 1 and 3 meter resolution, some of the later sites (particularly Hadley) had much lower-resolution imagery available pre-flight. I believe the best Hadley imagery prior to Apollo 15 was at 22-meter resolution, and was obtained by LO IV. And that photogeologists, straining to bleed data out of imagery that just didn't contain it, were capable of badly mis-identifying small landforms as volcanic when they were primarily impact-related (as with the 3- to 5-meter resolution images used to plan the Apollo 16 landing at Descartes).

All I'm trying to do is make sure we don't forget lessons learned, here, when it comes to lunar geologic investigations. On a world where erosion and landscape modification is now extremely slow, but which has been almost completely gardened, vertically mixed (and somewhat horizontally mixed) right at the surface, you have to carefully select targets which will actually give you greater insights with very-high-resolution imagery. (Remember, Apollo astronauts had a hard time determining rock types, even when they held the rocks in their hands, because they were usually very dust-covered. John Young on Apollo 16 quipped that one rock was so dust-covered that it "defied description." If you can't tell anything about a rock when you hold it in your hand, how much are you going to be able to tell about it at 50-cm resolution?)

And, just to add my voice to the chorus, yes -- Ina is a definite must for detailed imagery. It's one of those places where the very high resolution might provide some real answers...

-the other Doug


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Phil Stooke
post Apr 8 2007, 07:30 PM
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Early Apollo sites were blanketed by high resolution LO strips, but the Apollo 14 and 15 sites were imaged less intensively - good stereo at medium resolution, but the High Res strips were just samples distributed across the area. At Apollo 14 they landed in one of the high res strips, but at Apollo 15 they landed in an area covered only with the medium resolution stereo - it was LO5, not LO4. The high res strips covered areas initially considered for landing but dropped. By then the Apollo planners were confident that they could land safely without the highest resolution coverage.

Phil


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