In 1969 Neil Armstrong announced a safe touchdown on the moon with the words 'The Eagle has Landed'. "Eagle" was the name of the Lunar Module, the spacecraft which carried Neil and Buzz to the surface of the moon. After they walked on the surface of the moon they flew the Eagle back into orbit, docked with the Columbia command module and undocked the Eagle, leaving it in orbit while Columbia returned to Earth.
Most spacecraft in lunar orbit suffer from instability in their orbits due to the 'lumpy' nature of the lunar gravity which tends to cause the orbits to eventually get so elliptical that they hit the moon.
However, an amateur space fan wanted to narrow down the possible impact location and used orbit modelling software to propagate the orbit forwards in time until it hit the moon. He was surprised to find that it didn't hit the moon, and remained in a stable orbit for decades, this suggests that the Eagle may still be orbiting the moon over 5 decades after being left there.
Here's the paper:
Long-term Orbit Stability of the Apollo 11 Eagle Lunar Module Ascent Stage
James Meador
https://www.sciencedirect.com/science/article/pii/S0032063321001434
And his github with the scripts for GMAT
https://github.com/RogerTwank/Eagle
And more information in the blog
https://snoopy.rogertwank.net/2020/09/has-eagle-landed.html
NASA's GMAT software:
https://sourceforge.net/projects/gmat/
The thread in Unmannedspaceflight.com showing processing of ingenuity images.
http://www.unmannedspaceflight.com/index.php?showtopic=8610&st=390&start=390
Seán Doran's youtube
https://www.youtube.com/channel/UC28l88GMXXqZYfY0Ru9h50w
7500 Comments