Earth is About to Say Bye-Bye to Its Second Moon

Earth is about to lose its second moon. Now, when you read that statement, you may think that I have gone crazy, but let me rephrase that statement. Earth is about to lose its minimoon. Now you may not know what I am talking about. Well, during September 2020, a small object entered Earth’s orbit and orbited halfway between Earth and our Moon. These small objects are called minimoons. In this case, the minimoon wasn’t a celestial object or space rock. Instead, it was the remains of a 1960s rocket booster that was involved in the American Surveyor moon missions and is being called 2020 SO.

Animation of 2020 SO Around the Sun (Pink Object and Path)

Surveyor 2 Centaur Rocket
Launching in 1966

The Surveyor program was a NASA program that ran from June 1966 to January 1968. During the mission, NASA sent seven robotic spacecraft to the surface of the Moon. The goal of the program was to determine whether soft landings were possible on the moon. The spacecraft in the Surveyor program was the first American spacecraft to make a soft landing on a celestial object. During a typical mission, the spacecraft would have a direct trajectory to the moon, with a three-minute soft landing. As of January 31, 2021, all seven spacecraft are still on the Moon, just maybe revisited during the Artemis program. 2020 SO is predicted to be a Surveyor 2 Centaur rocket booster launched in 1966.

Surveyor Lander

2020 SO made its first and closest approach to Earth on December 1, 2020. However, you will still be able to see 2020 SO, as, on February 2, 2021, it will take another approach by the Earth and will be roughly 140,000 miles (220,000 km) away. 2020 SO will then start to drift away from Earth and eventually leave its orbit in March 2021. 

This isn’t the first time 2020 SO has made an approach near Earth. Back in 1971, 2020 SO made a close approach to the Earth. If you want to see 2020 SO make its final approach towards Earth, The Virtual Telescope Project in Rome is hosting an online observation on February 1, 2021.

Animation of 2020 SO Orbitinig the Earth (Yellow Object and Path)

Sources:

“2020 SO.” Wikipedia, Wikimedia Foundation, 31 Jan. 2021, en.wikipedia.org/wiki/2020_SO. 

Specktor, Brandon. “Earth Is about to Lose Its Second Moon, Forever.” Space.com, Space, 30 Jan. 2021, www.space.com/farewell-minimoon-so-2020. 

“Surveyor Program.” Wikipedia, Wikimedia Foundation, 5 Jan. 2021, en.wikipedia.org/wiki/Surveyor_program.