WASHINGTON — Earth's so-called "second moon" will make one final pass this week before floating out into space forever.
Astronomers first spotted an unknown object with an incoming trajectory in September 2020 and initially believed it was an asteroid.
On closer inspection, it became clear that the object is a discarded rocket booster from the failed Surveyor 2 mission from 1966.
The lunar lander it was ferrying ended up crashing into the moon.
After ferrying this failed research lander to the moon, the booster floated past the moon, ending up in an orbit very similar to Earth's.
Now, after decades of floating out there, this far-out piece of hardware managed to get itself trapped in Earth's gravitational pull again.
Ironically, it is also this rare entrapment that will finally set the booster free to fall into the gravitational arms of the sun.
This is made possible by the slingshot effect that accelerates small objects and dramatically bend their trajectories when they pass near large bodies and fall into the gravitational fields of these bodies.