[X] My Assistant

[gndonald]

I'd been re-reading one of my space travel books and suddenly it hit me, while the LM ascent stages from Apollo's 5-9 & 11-17 are lost the ascent stage from Apollo 10 was left in a solar orbit when that mission left the moon.

With the increasing sophistication of amateur astronomy has anyone tried to find this historic vehicle? More to the point, have there been any attempts to do so with professional equipment in the past?

[dvandorn]

Snoopy's ascent stage is too small, I think, to be sighted visually or skin-tracked by radar from Earth-based locales. And the gravitational environment in Earth's neighborhood is a little too "bumpy" for our current models to accurately predict where it would be right now.

The people back at Houston had to have had a pretty good initial take on Snoop's trajectory -- they monitored its systems up until it ran out of battery power (which was more of a pacing item than anything else, including its cooling water). And I can well imagine that they continued to track it as long as its transmitter lasted. So, they had a really good idea of the vector and speed of the module as of last contact. But that's just not good enough for the current models to define a present position.

In general, Snoopy ought to be in a solar orbit fairly close to the Earth-Moon system, unless a close pass by Earth or Moon ejected it (either out of plane or into a larger or tighter orbit). It's even possible that it could have been re-captured by Earth for a time -- such a thing seems to have happened to Apollo 12's S-IVB, more than once. The overall energy added to the module wouldn't have been enough, all by itself, to have created a large separation from the Earth-Moon system.

As to your statement that all of the other flown LMs are lost -- well, yes and no. Of course, the descent stages of the landed LMs are still sitting on the lunar surface, and might be re-visited at some time in the future. The RTG fuel element cask from LM-7 (Aquarius) ought to be sitting, intact, on the sea floor in the mid-Pacific. And while I have never heard of any debris being recovered from LM-3 (Spider), I know that at least one of the fuel tanks from LM-1 (Apollo 5) survived re-entry and was recovered from somewhere in Africa. And there *might* be some recognizable pieces in the debris surrounding the LM ascent stage impact craters from the six landings. (Yes, only four of them were sent into controlled impacts, but all six of them did impact the Moon -- and they weren't traveling fast enough to completely vaporize them.) And, don't forget, there is also a single LM descent stage impact site on the Moon, too -- Snoopy's descent stage. It was also not traveling fast enough at impact to be completely vaporized, I don't believe.

As for an intact crew cabin from one of the flown LMs, though -- you're right. Snoopy is the only surviving example. But finding it is going to be about as easy as finding a needle in a haystack the size of Nebraska.

-the other Doug

[gndonald]

Snoopy's ascent stage is too small, I think, to be sighted visually or skin-tracked by radar from Earth-based locales. And the gravitational environment in Earth's neighborhood is a little too "bumpy" for our current models to accurately predict where it would be right now.

I didn't think it would be easy, but aside from the Apollo 12 SIV stage that was spotted a few years ago, one other satellite was picked up (& mistaken for an asteroid) as I recall, so there is the possibilty (however remote) that it could be detected by accident.

As to your statement that all of the other flown LMs are lost

In my OP I actually stated I was concerned with the ascent stages only, there are only three left LM2 (unflown) LM9 (unflown) and LM4 ('Snoopy', flown, currently in a heliocentric orbit.), you are of course right about the descent stages and the ascent stages that were crashed onto the surface of the moon as the final stage of each Apollo mission, one wonders if NASA is planning to re-photograph the sites at high resolution when the next round of lunar probes gets underway?

[dvandorn]

...one wonders if NASA is planning to re-photograph the (LM ascent stage impact) sites at high resolution when the next round of lunar probes gets underway?

That would be nice, and I believe that at least one or two of the impact sites were already photographed by the Apollo J-mission pan cameras.

However, of the six landings, only four ascent stages had controlled impacts. Apollo 11's ascent stage was allowed to slowly decay, with no planned impact, and no one has any idea where it might have impacted. All of the rest of the flights had planned ascent stage impacts, but in the case of Apollo 16, switches were left mis-set and the ground command circuits were not enabled. So, after they separated from their LM, it simply tumbled into the distance. As with Apollo 11, that stage impacted eventually, but no one really knows where.

Several man-made craters have been imaged on the Moon, including some of the S-IVB impact sites and at least one of the Ranger impact sites. However, those craters are so small, about the only thing you could determine from the orbital imagery (mostly taken by Apollo pan cameras) is that the craters exist. Those cameras imaged at about 1-meter resolution, which isn't much worse than what we'll get out of LRO, so I don't know how much better the upcoming probes are going to do in gleaning information from them...

-the other Doug