Long-term Orbit Stability of the Apollo 11 Eagle Lunar Module Ascent Stage

TL;DR

This study uses numerical simulations to analyze the long-term orbital stability of the Apollo 11 Eagle Lunar Module ascent stage, suggesting it may still be in lunar orbit today due to stabilizing orbital interactions.

Contribution

It provides the first detailed numerical analysis indicating the potential long-term stability of the Apollo 11 lunar module in lunar orbit.

Findings

Orbit shows periodic eccentricity variation.

Apsidal precession rate correlates with eccentricity.

Orbit may have remained stable over decades.

Abstract

The Apollo 11 Eagle Lunar Module ascent stage was abandoned in lunar orbit after the historic landing in 1969. Its fate is unknown. Numerical analysis described here provides evidence that this object might have remained in lunar orbit to the present day. The simulations show a periodic variation in eccentricity of the orbit, correlated to the selenographic longitude of the apsidal line. The rate of apsidal precession is correlated to eccentricity. These two factors appear to interact to stabilize the orbit over the long term.