The near-Earth object is a 1960's-Era Centaur rocket booster, NASA has said.
Scientists at the US space agency NASA have said that the near-Earth object orbiting the planet observed in the month of September is a 1960's-Era Centaur rocket booster.
The object, discovered by astronomers searching for near-Earth asteroids from the NASA-funded Pan-STARRS1 survey telescope, garnered interest in the planetary science community due to its size and unusual orbit and was studied by observatories around the world, according to an official release.
Further analysis of 2020 SO's orbit revealed the object had come close to Earth a few times over the decades, with one approach in 1966 bringing it close enough to suggest it may have originated from Earth.
Comparing the new data with the history of previous NASA missions, Paul Chodas, CNEOS director, concluded 2020 SO could be the Centaur upper stage rocket booster from NASA's ill-fated 1966 Surveyor 2 mission to the Moon.
Later, a team led by Vishnu Reddy, an associate professor and planetary scientist at the Lunar and Planetary Laboratory at the University of Arizona, performed follow-up spectroscopy observations of 2020 SO using NASA's IRTF on Maunakea, Hawai'i.
"Due to extreme faintness of this object following CNEOS prediction it was a challenging object to characterise" said Reddy. "We got colour observations with the Large Binocular Telescope, or LBT, that suggested 2020 SO was not an asteroid."
Through a series of follow-up observations, Mr Reddy and his team analyzed the 2020 SO's composition using NASA's IRTF and compared the spectrum data from the 2020 SO with that of 301 stainless steel, the material Centaur rocket boosters were made of in the 1960's.