James Meador, an independent researcher at the California Institute of Technology, has found evidence that suggests the Apollo 11 ascent stage may still be orbiting the moon. He has written a paper outlining his research and findings and has posted it on the arXiv preprint server on July 30.
In 1969, NASA astronauts Neil Armstrong and Buzz Aldrin made history when they landed a craft successfully on the moon. After more than 21 hours on the surface, the astronauts blasted off the surface in a part of the Eagle lander called the ascent stage. They soon thereafter rendezvoused with Michael Collins in the command module which carried them back to Earth.
Before departing for Earth, the ascent stage was jettisoned into space—NASA engineers assumed that it would crash back to the moon's surface sometime later. Meador reports that the ascent stage may not have crashed into the moon after all and might, in fact, still be orbiting the moon.
NASA had sent spacecraft into orbit around the moon in 2012 as part of the GRAIL project to map the moon's gravitational field, and the mission eventually drew a detailed map of it.
This made Meador wonder what happened to the Eagle lander after NASA abandoned it, and ask: "Why don't we use this map to see if Eagle had actually faded in the orbit, and to determine where it could crash on the Moon's surface? This could lead observers to the lander's final crashing point."
After adding data from GRAIL, Meador ran the simulation multiple times using different parameters to simulate conditions that likely existed from the time when the ascent was jettisoned on up to the present. He also included data to take into account gravity from the sun and the other planets (except Mercury) and data describing forces due to solar radiation. He found that all of his simulations showed the ascent stage maintaining a steady orbit.
Two years after Apollo 11, NASA launched another mission to that operated a rover on the Moon's surface.