Unmanned landing sites from LRO, Surveyors, Lunas, Lunakhods and impact craters from hardware impacts Options

[nprev]

I would imagine that someone is preparing to publish a paper on this, hence the delay in release?

[Lightning]

Wow, just can't wait thoses images !
There is so many things to discuss, years later, when additionnal information become available.

[Phil Stooke]

It's unfortunate that we don't yet have the LROC images of Lunas 20, 23 and 24 released... but one little extra bit of news I picked up at LPSC was that it's not absolutely certain which is which of the 23 - 24 pair. The locations wouldn't have been known well enough to tell the difference. I suspect the shapes of the shadows in low-sun images may be able to identify the one with an intact ascent stage.

Phil

[Hungry4info]

How close together did they land?

[Phil Stooke]

The usual sources always said a few hundred meters or something like that. but in reality it could be several km apart - each point would be uncertain by a few km.

Phil

[Hungry4info]

Ah, wow. Was that intentional?

[Paolo]

Also Luna 18 and 20 are said to have landed within a few hundred meters of each other

[Phil Stooke]

Right, Paolo - in each case the first one failed and the second was sent to the same place, knowing it would get close but not exactly at the same point, so it would avoid any local hazard that might have affected the first one.

Luna 20 was imaged... will 18 show up in the same frame? I hope so. I'm very impatient!

Phil

[PDP8E]

Hey Phil,

I have my destriper and blower-upper tools at the ready for some Luna X fun.

~pdp8e

[Phil Stooke]

The LROC site has a place to ask questions. I asked for these images, sneakily hiding my identity by only describing myself as Phil - hmm, I hope they're not reading this...

Phil

[gndonald]

Update. Mark Robinson showed images of three Luna landers, 20, 23 and 24. Luna 20 shows the shadow of its sample delivery arm "as if it's waving at us" according to Mark. Luna 23 is sitting on the very edge of a crater only 2 or 3 m across. No obvious sign of why it couldn't collect a sample.

Pure speculation on my part here, but is it not possible that the drill is pointing into the crater and thus the drill head could not be extended far enough to reach the ground inside the crater to take a sample. It might also explain why the Russians operated the probe for two or three days on the surface after landing, without a camera they would have been unable to see the terrain around the spacecraft and might have tried to diagnose the problem by running the drill at different times of the lunar day.

[Phil Stooke]

They said the drill was damaged - maybe struck a rock as it landed? But that we may not be able to tell from LROC images. I think a GLXP-type rover may have to examine the site to answer that!

Phil

[Phil Stooke]

Now they're teasing us (or just me) - today's release is about 30 km from the Luna 24 position.

Phil

[gndonald]

They said the drill was damaged - maybe struck a rock as it landed? But that we may not be able to tell from LROC images. I think a GLXP-type rover may have to examine the site to answer that!

Phil

For a definitive answer probably, but if the drill head was not making ground contact the following scenarios are likely:

1. Free rotation, which could damage the motors.

2. Someone assumes they've bent the guide rails on the drill.

It would be wonderful to know if they left the drill at full extension or not when they abandoned the probe.

[Geert]

The longer I look at these new images, the more I get a feeling that Luna 23 is standing at some quite extreme angle, not yet completely on its side but certainly tilted a lot (maybe due to the fact that it landed on a crater rim, possibly with one or two legs inside the crater?).

Shadows and reflections just don't seem to match up with what I feel you should see if it was standing upright. Maybe this large tilt was preventing the drill from operating, or the ascent stage from taking off?

I'm searching everywhere in the vicinity of Luna 20 to find any trace of number 18, but as yet nothing. We know it failed at the very final stage of landing, more or less on touch-down, so it should have landed more or less intact although it might be laying on its side..