[X] My Assistant

[PhilHorzempa]

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.



Another Phil

[edstrick]

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.

[As old as Voyage...]

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?