After 7 years, a spent Falcon 9 rocket stage is on course to hit the Moon

[smp]

From Ars Technica:
"SpaceX launched its first interplanetary mission nearly seven years ago. ... Now, according to sky observers, the spent second stage's orbit is on course to intersect with the Moon. According to Bill Gray, who writes the widely used Project Pluto software to track Near-Earth Objects, asteroids, minor planets, and comets, such an impact could come in March."

https://arstechnica.com/science/2022/01 ... hin-weeks/

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[helicon]

I wonder if the event will be visible in amateur scopes? You'd have to have the timing and location exactly right.

Edit: Since it will be the "far" side of the moon I am supposing it will not be visible...

[seigell]

Even if it were to impact the lit side, the low speed and moderate mass would likely mean an impact event too small to spot with Amateur Equipment. The resolution isn't sufficient for much less than about a mile in diameter, which is significantly more than the likely impact crater. Maybe one could see the ejecta cloud in profile if it were to hit in one of the central marae when right near the limb edge. (Who knows... But we'll likely need to take SpaceX's word on this one...)

[dcrowson]

I'd just point out that us amateurs can help with this kind of stuff. I provided a handful of observations of the booster that helped refine the orbit. Here's an example:

COD V16
CON Dan Crowson [dcrowson@crowson.com]
OBS D. Crowson
TEL 0.30-m f/8.0 Ritchey-Chretien + CCD
ACK MPCReport file updated 2022.01.17 23:18:07
AC2 dcrowson@crowson.com
NET Gaia DR2
DSCOVR C2022 01 18.12686 00 33 48.57 -05 00 50.4 16.5 G V16
DSCOVR C2022 01 18.13185 00 33 50.42 -04 59 57.5 15.7 G V16
DSCOVR C2022 01 18.13847 00 33 52.91 -04 58 50.0 16.9 G V16
DSCOVR C2022 01 18.14312 00 33 55.05 -04 57 58.0 16.6 G V16
DSCOVR C2022 01 18.14939 00 33 57.92 -04 56 52.3 16.8 G V16
----- end -----

[GCoyote]

Even if it were to impact the lit side, the low speed and moderate mass would likely mean an impact event too small to spot with Amateur Equipment. The resolution isn't sufficient for much less than about a mile in diameter, which is significantly more than the likely impact crater. Maybe one could see the ejecta cloud in profile if it were to hit in one of the central marae when right near the limb edge. (Who knows... But we'll likely need to take SpaceX's word on this one...)

Maybe not.
1. Are there any functioning lunar seismometers still taking data?
2. Will any orbiters be in position to record the impact?

[seigell]

The main Lunar Seismology Experiments were those carried by the Apollo Landers. NASA terminated that Science Program 9/30/1977.
Apollo 17 carried an additional science package - the LSG Lunar Surface Gravimeter - to serve as an augmentation to the 5 working Seismographs of earlier missions.
Due to an unfortunately too familiar Mathematical Error early in the Design Phase that wasn't caught during testing, the LSG was jury-rigged (with duct tape and the few tools on hand) by the Apollo 17 Astronauts in the field (Lunar Surface) to produce partial results.
Lunar Surface Gravimeter as a lunar seismometer

There have been no seismographs delivered on any of the half-dozen post-Apollo Lunar Landers, probably due to a combination of 1) difficulty in successful deployment of such sensitive devices by robotic landers as opposed to human Astronauts; 2) usage of orbital magnetometers and gravitational sensors to investigate the inner lunar layers (replacing one of seismographs' main science purposes); and 3) USA's shift in focus to Mars Landers and Martian Exploration (after Apollo it was "Been there - Done Than" regarding the Moon).

As to whether the various Lunar Orbiters will be in positions to observe the Impact - that will truly be in the hands of Chance given that the Impact Event isn't under Earth Control nor planned for Max Coverage.

[smp]

Here's an article about the impact from Space.com:
"A rogue 3-ton piece rocket debris just collided with the moon"

https://www.space.com/rogue-rocket-stage-hit-moon-today

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