As a quick review, 2020 SO is the Centaur upper stage that launched NASA’s Surveyor 2 towards the Moon. It then entered a heliocentric orbit that closely matched the Earth’s. It had flown past the Earth unobserved several times but the September 2020 pass was observed by the PAN-STARRS 1 system in Hawaii and it was quickly realized that it would be captured by the Earth. In December, NASA verified that the object was not an asteroid but the long lost spacecraft.
It has been in Earth orbit since November 2020 when the Moon’s gravity slowed 2020 SO’s speed and Earth loosely captured it. Last night (2 Feb) the spacecraft made a final close pass by the Earth at about half the distance to the Moon. This time the Moon’s gravity added energy to the object and it will break free of Earth’s gravity on the 8th of March.
SO 2020’s Earth orbit.
Image via Phoenix7777/ Wikimedia Commons.
This animation is 120 30-second exposures. I attempted to calibrate the individual exposures but, as mentioned above, the object was very close to the Moon and there was a huge gradient in the images due to scattered light. So the raw images made a better video.