• An object is on the way to enter the Earth's orbit soon 
  • A NASA expert says it's possible the object is a rocket booster from a mission in the 1960s
  • If it is the long lost rocket booster, it will be considered space debris and not a mini-moon 

An object is on its way to enter the Earth's orbit to become a temporary "mini-moon" but an expert from NASA believes it may actually just be a piece of space junk from the 1960s.

First observed on Aug. 19, the object dubbed Asteroid 2020 SO has been predicted to enter the Earth's orbit some 27,000 miles away in the coming months and stay there for about six months, with its closest approaches to Earth likely happening in December and in February 2021.

Earlier in 2020, another mini-moon was also spotted by astronomers, although it was confirmed to have left the planet's orbit a month later and was not expected to return anytime soon.

But what's interesting about 2020 SO is that it may not turn out to be a mini-moon when it comes close to Earth's orbit. Experts believe it may not even be an asteroid but a man-made object in orbit.

"What I'm seeing is that it's just moving too slowly, which reflects its initial velocity. That's essentially a big giveaway," space archaeologist Alice Gorman of Flinders University told ScienceAlert.

As Gorman told the outlet, objects from the moon have a lower velocity compared to asteroids but, 2020 SO is even slower. This suggests that the object is not an asteroid but may actually be a piece of space debris.

"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 the Sun at its farthest point," the director of NASA's Center for Near-Earth Object Studies, Dr. Paul 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."

Chodas told CNN that he suspects the object to be a Centaur rocket booster from the 1966 NASA Surveyor 2 mission that intended to make a soft landing on the moon but instead ended up with the spacecraft crashing on the moon's surface. The booster used for this mission reportedly disappeared from sight after this.

With just a short time before the object comes closer to Earth, experts will soon be able to confirm whether 2020 SO is, indeed, a space rock that will serve as a temporary mini-moon or if it is the long lost booster. If it proves to be the latter, it will not be considered a mini-moon but will be part of the thousands of tons of space junk in Earth's orbit.

But unlike the other space debris, 2020 SO will likely not stick around for too long as it is expected to leave the Earth's orbit again in May 2021.

Moon orbiting Earth from 3.9 million miles
Eight days after its encounter with the Earth, the Galileo spacecraft was able to look back and capture this remarkable view of the Moon in orbit about the Earth, taken from a distance of about 6.2 million kilometers (3.9 million miles). NASA/JSC