It looks like Earth has made a new friend – or perhaps just reacquainted with an old buddy. It's thought a new object will soon become a companion of our planet and spend a brief spell in Earth's orbit. While other space-faring objects have unintentionally strayed into orbit around the Earth, known as "mini-moons," this recently discovered object may possibly be a piece of long-lost space junk kicked out from a rocket launch in the 1960s.
The object in question, known as 2020 SO, is expected to be captured by Earth's gravity in October 2020 and temporarily trapped in orbit until May 2021 when it will be flung out back out to space, according to Tony Dunn, Kevin Heider, and a number of other amateur astronomers keep an eye on the situation.
However, it's starting to look like 2020 SO might not be a typical mini-moon. Paul Chodas, director of NASA's Center for Near-Earth Object Studies, told CNN he believes the object is most likely the old booster rocket for Surveyor 2, an uncrewed NASA lunar lander mission that launched on September 20, 1966. That still needs further confirmation, but this would appear to explain the object's distinctive orbit.
“I suspect this newly discovered object 2020 SO to be an old rocket booster because it is following an orbit about the Sun that is extremely similar to Earth's, nearly circular, in the same plane, and only slightly farther away from the Sun at its farthest point,” Chodas told CNN.
“That's precisely the kind of orbit that a rocket stage separated from a lunar mission would follow, once it passes by the Moon and escapes into orbit about the Sun. It's unlikely that an asteroid could have evolved into an orbit like this, but not impossible.”
The launch of Surveyor 2 is particularly of note as a failure led to the spacecraft crashing into the lunar surface near Copernicus crater. The Centaur rocket used to propel the Surveyor lunar lander continued on its original trajectory past the Moon, after which it became untraceable and confirmed lost. Now, after a few decades meandering around our Solar System, it looks like it's been rediscovered again.
Astronomers hope to get a better understanding of 2020 SO with more observations in the coming weeks that will show how the Sun reflects off the object, revealing the material it's made from.
Earth’s gravitational pull regularly catches passing objects and pulls them into orbit around our planet. Back in 2016, astronomers discovered asteroid 2006 RH120 was in Earth orbit from September 2006 to June 2007. Just earlier this year, it was discovered that another asteroid, 2020 CD3, was orbiting Earth until it left its embrace in April 2020.
Since 2020 SO is not a space rock though, most technical definitions would say this is not a mini-moon, but just another large piece of space junk. After all, bits of human-made debris hanging out in Earth's orbit is nothing unusual. From marooned satellites to parts of old spacecraft, Earth's orbit is littered with at least 20,000 pieces of space junk larger than a baseball floating around in space. However, with the rise of private space companies and the increase in objects being launched into space, space debris is becoming an increasing problem.
Just last week, the International Space Station had to make an emergency maneuver to dodge out of the way of a piece of space junk, the third time this year, and the third close-call in two weeks, and NASA Administrator Jim Bridenstine was not happy.
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