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

[Shan]

Phil,

Whether this could be Surveyor4's retro rocket impact site? Location: 0.3870, 358.70

The landing target was estimated to be 0.43 N, 1.62 W (or 0.37 N, 1.55 W) for a soft landing and 0.47 N, 1.44 W (or 0.469 N, 1.086 W) for a ballistic crash (From the below link, is it possible it would have crashed 0.3870, 358.70)
https://nssdc.gsfc.nasa.gov/nmc/spacecraft/...on?id=1967-068A

Surveyor4 Impact : Quickmap link

Attached thumbnail(s)

 

[Phil Stooke]

Hi Shan. Give me a few days to consider this. It's certainly possible but there are other dark spots in the area.

Phil

[Phil Stooke]

OK, I have been pondering this. Ponder, ponder - there, I just did it again.

Here is my guess for Surveyor 4:




This shows the Surveyor 4 target as it evolved from before launch to after launch (when they had a better idea of the trajectory and could shrink the landing ellipse) and where tracking suggested it actually went. The failure came at or just before the end of the retro burn, which did most of the job of bringing it to the surface, so it should be fairly close to the tracking location.

The site I zero in on shows two little dark spots. When you start looking at the high sun LROC NAC images there are a surprising number of little dark spots and it is not at all easy to decide which to pick. My rationale is that the retro burn was probably completed and the failure occurred when the small vernier thrusters took over from the retro system. Therefore I assume the retro engine fell to the ground as expected rather than exploding into fragments. So I was looking for a place where there were two dark spots, one for the lander and one for the retro rocket system. The one I found has two spots about 200 m apart, which is roughly what we see for the two where we know we have it right from before/after images (Surveyor 3, Surveyor 6). But other searches might find different candidates.

Shan's point is close to the target but quite a long way from the tracking location. So I still prefer mine for the time being. But I will change my mind if someone finds a better candidate.

Phil