In addition to supporting a large number of NASA planetary missions, NASA’s infrared telescope system on Maunakea on the large island of Hawaii is also used to determine the composition of near-Earth objects. Photo credit: University of Hawaii Department of Astronomy / Michael Connelley
Discovered in September by astronomers searching for near-Earth asteroids, the object caught interest in the planetary science community because of its size and unusual orbit.
Use of the data collected at NASAUsing the infrared telescope system (IRTF) and orbit analysis from the Center for Near-Earth Object Studies (CNEOS) at NASA’s Jet Propulsion Laboratory, scientists have confirmed that the Near-Earth Object (NEO) 2020 SO is actually a 1960s SE. Era Centaur rocket booster.
Discovered in September by astronomers searching for near-Earth asteroids using the NASA-funded Pan-STARRS1 survey telescope on Maui, the object attracted interest in planetary science due to its size and unusual orbit, and has been used by observatories all over the world World explored.
Further analysis of the 2020 SO orbit found the object had come close to Earth a few times over the decades, with an approach in 1966 bringing it close enough to suggest that it may have come from Earth. Paul Chodas, CNEOS director, compared this data to the history of previous NASA missions and concluded that 2020 SO could be the Centaur high school rocket booster from NASA’s unfortunate Surveyor 2 mission to the moon in 1966.
This animation shows the 2020 SE temporary orbit around Earth from November to March 2021. The object is believed to be the Centaur’s upper stage booster rocket from the Surveyor 2 mission, which launched in 1966 for the moon . While the Lander Surveyor 2 crashed on the lunar surface, the spent centaur rocket floated past the moon and landed in an unknown solar path. Over 50 years later, the Centaur rocket has apparently returned and entered Earth orbit on November 10, where it will remain until March 2021 before returning to a new solar orbit. This animation was accelerated a million times faster than in real time. Photo credit: NASA / JPL-Caltech
Armed with this knowledge, a team led by Vishnu Reddy, an associate professor and planetary scientist at the University of Arizona Lunar and Planetary Laboratory, performed follow-up spectroscopic observations from 2020 SO with NASA’s IRTF in Maunakea, Hawaii.
“Because of the extreme weakness of this object after the CNEOS prediction, it was a challenging object to characterize,” said Reddy. “We got color observations with the Large Binocular Telescope (LBT) which indicated that 2020 SE wasn’t an asteroid.”
This photo shows a model of the surveyor. Photo credit: NASA / JPL-Caltech
Through a series of follow-up observations, Reddy and his team analyzed the composition of 2020 SO using NASA’s IRTF and compared the spectrum data from 2020 SO to that of 301 stainless steel, the material from which Centaur rocket booster was made in the 1960s were. Reddy and his team, while not an immediate perfect match, insisted that the discrepancy in the spectrum data could be due to analyzing fresh steel in a laboratory against steel that had been exposed to the harsh conditions of space weather for 54 years. This prompted Reddy and his team to conduct additional research.
“We knew that if we were to compare apples to apples, we would have to try to get spectral data from another Centaur rocket booster that had been in Earth orbit for many years and then see if it was better on the 2020 spectrum SO fits, “he told Reddy. “Because of the extreme speed at which Earth-orbiting Centaur boosters move across the sky, we knew it would be extremely difficult to connect to the IRTF long enough to get a solid and reliable data set.”
This 1964 photo shows a Centaur upper stage rocket before it is paired with an Atlas booster. A similar centaur was used in the launch of Surveyor 2 two years later. Photo credit: NASA
However, on the morning of December 1st, Reddy and his team did what they thought was impossible. They observed another Centaur D rocket booster from 1971 when a communications satellite was launched in geostationary transfer orbit long enough to get good spectrum. With this new data, Reddy and his team were able to compare it to 2020 SO and found that the spectra matched one another. Thus 2020 SO was finally classified as a Centaur rocket amplifier.
“That conclusion was the result of tremendous team effort,” said Reddy. “Thanks to the great work of Pan-STARRS, Paul Chodas and the team from CNEOS, LBT, IRTF and observations around the world, we were finally able to solve this puzzle.”
2020 SO was closest to Earth on December 1, 2020 and will remain within Earth’s gravity dominance – a region in space known as the “hilltop” and stretching approximately 1.5 million kilometers from our planet – until it escapes back into a new orbit around the Sun in March 2021. As NASA-funded telescopes scan the sky for asteroids that could pose a threat to Earth, the ability to differentiate between natural and man-made objects is valuable as nations move on explore and become more artificial Objects are in orbit around the sun. Astronomers will continue to observe this relic from the early space age until its disappearance.
