What Neil saw...

[Ishkabibble]

I am not certain where I heard this story, or what the context of it was, but I think it was one of those "Secret NASA Unexplained Files" things at 2 am...

Neil reported to MC that he had seen some "illumination" over the horizon (I've looked through the transcripts and don't see it) but there was an audio clip played on the tv program where he describes it to MC. They don't say much in response, and I didn't really think much of it until I remembered that Luna 15, I think, impacted the moon while Armstrong and Aldrin were on the surface. I do know that Luna 15 impacted about 550 miles away.

My question is, could it be possible that Neil saw the dust kicked up from the impact being lit by the sun, and this caused the illumination effect?

Or am I misremembering something I heard in the background at 2 am?

Anyone?

[smartcooky]

I am not certain where I heard this story, or what the context of it was, but I think it was one of those "Secret NASA Unexplained Files" things at 2 am...

Neil reported to MC that he had seen some "illumination" over the horizon (I've looked through the transcripts and don't see it) but there was an audio clip played on the tv program where he describes it to MC. They don't say much in response, and I didn't really think much of it until I remembered that Luna 15, I think, impacted the moon while Armstrong and Aldrin were on the surface. I do know that Luna 15 impacted about 550 miles away.

My question is, could it be possible that Neil saw the dust kicked up from the impact being lit by the sun, and this caused the illumination effect?

Or am I misremembering something I heard in the background at 2 am?

Anyone?

I doubt it.

550 miles away is about 1/12th of the circumference, equivalent to about 3,250 miles away on the earth, that is a very long way over the horizon.

Someone else can do the maths for me but my quick sketch on the back of the envelope says that debris would have to be thrown at least in the order of 10% of the moon's diameter (least 220 miles) straight up from the impact point to be visible above the horizon from Tranquillity Base, and I think it would need to be "line-of-sight" to scatter sunlight visible by the astronauts. If Luna 15 was the cause it would have needed to hit with a tremendous velocity, far higher than was likely given its orbital speed.

Also, moon dust kicked up by an explosion or an impact would not linger for very long, the way it does on the earth. The tiniest particles of dust  would fall back as quickly as the largest piece of rock (no atmosphere). 

[Obviousman]

What audio tape? I'm suspect if we have an audio tape but no audio transcript.

[bknight]

What audio tape? I'm suspect if we have an audio tape but no audio transcript.

I agree with that, if it isn't in the transcripts it is likely a voice over

[Ishkabibble]

As I said, it was 2 in the morning, I was at the computer working on something because I couldn't sleep, and I hear what I would have sworn was Neil Armstrong's voice mentioning something about some light on the horizon. The TV was way down so it wouldn't wake my wife up, but I really thought I heard something. By the time I could get up and get a remote, the program ended, and I never did find out what it was.

I'm now pretty much convinced I don't know what to make of it.

Was there, or was there not something that was "luminous" mentioned on 11, from the surface, either during the EVA or shortly after? I've read through the transcript, and I remember a mention of a light near Aristarchus, but that was Collins from Columbia talking about soil or ejecta or some reflection (I haven't memorize the thing, and its been a few days since I skimmed through it.)

At this point, I'm absolutely not sure what I remember hearing. I'd make a lousy eyewitness.

[ka9q]

Maybe it was a remark from orbit about the solar corona? Apollo 11, and at least some other Apollo missions, conducted scientific observations while in lunar orbit, using the moon to eclipse the sun so the fainter corona could be seen.

Several astronauts also observed and sketched a glow around the horizon that may not be the corona, but rather light scattering from very fine dust particles. I don't know if it's generally accepted yet, but there's a hypothesis that electrostatic charging lifts dust around sunrise and sunset.

This could explain the consistently lower than expected returns from the retroreflector experiments. I've chatted with the principal investigator of the ongoing APOLLO project, who sent me his optical link budget for the ranging system. It's the most detailed link budget I've ever seen, but measurements are consistently 10-15 dB below budget predictions. There may be other degradations to the mirrors, but the leading theory is that they've accumulated a very thin layer of dust.

[raven]

Rising dust is at least an admitted hypothesis.

[bknight]

...
This could explain the consistently lower than expected returns from the retroreflector experiments. I've chatted with the principal investigator of the ongoing APOLLO project, who sent me his optical link budget for the ranging system. It's the most detailed link budget I've ever seen, but measurements are consistently 10-15 dB below budget predictions. There may be other degradations to the mirrors, but the leading theory is that they've accumulated a very thin layer of dust.

That is probably correct, if memory serves me the A12 crew saw dust accumulated on the Surveyor camera mirror.  Pete rubbed some with his finger.  I'm unable to open ALSJ currently, but I'll post an image when the web page is available.
http://www.hq.nasa.gov/alsj/a12/AS12-48-7130HR.jpg 
http://www.hq.nasa.gov/alsj/a12/AS12-48-7131HR.jpg
ETA link to two images.

[ka9q]

I think that dust on the Surveyor III camera mirror might have been raised by the LM descent engine.

[bknight]

I think that dust on the Surveyor III camera mirror might have been raised by the LM descent engine.

That may be correct since it "landed" three times likely kicking up dust that the craft past back through each time it settled.

[ka9q]

I doubt it was the Surveyor's own engines for the same reason that little dust lands in an LM's footpads -- the dust leaves in a narrow, ground-hugging sheet. The dust on the camera mirror was probably ejected by Intrepid's descent engine as it passed by not far from Surveyor's location. Surveyor was also inside a crater, putting it below the elevation of that sheet of dust moving away from Intrepid's ground location.

[bknight]

I didn't reference the engines but rather the dust created by the impact of the craft on the moon.  As for dust from the LMs engines, look at
http://www.hq.nasa.gov/alsj/a12/AS12-48-7100HR.jpg
The camera opening is at a minimum of 90 degrees clockwise from the LM, perhaps as much as 120 degrees.

But it could have been deposited as the LM passed overhead.

ETA: Trajectory link

http://www.hq.nasa.gov/alsj/a12/landpath.jpg

[ka9q]

Exactly my point, Intrepid passed within 109 m laterally of Surveyor III as it was approaching the landing spot.

The NASA guidelines on protecting the Apollo sites discusses the dust found on Surveyor III in recommending the minimum distances at which new landings should be made.

[bknight]

However dust was seen much later and further away than the closest approach distance and with the angle of the mirror makes the dust from the LM less likely, but not impossible.  I remember that the hood was impinged by flying regolith from the LM Descent engine, but the hood is more in line with the LM.

[ka9q]

Wouldn't dust on the mirror have shown up in photographs taken by the camera if it had been placed there by Surveyor's own landing?