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NEO revealed to be lost rocket booster
near-Earth object (NEO) discovered in September 2020 has been shown to be an 1960s-era
Centaur rocket booster, proving that space debris can sometimes masquerade as a potentially
hazardous Earth-crossing asteroid.
e object, designated 29020 SO, has an orbit that suggests it came close to Earth several times,
including once in 1966 when it seemed like it should have collided with our planet. is prompted
scientists to wonder whether it was actually a spent rocket booster that had launched NASA’s failed
Surveyor 2 lunar mission that year.
Observations with the Large Binocular Telescope in Arizona suggested that 2020 SO had an
unusual colour for an asteroid, so Vishnu Reddy of the Lunar and Planetary Laboratory at the
University of Arizona performed follow-up spectroscopic observations using NASA’s Infrared
Telescope Facility in Hawaii to get a spectrum of the object. Comparing this spectrum with the
spectrum of the stainless steel of a Centaur rocket failed to produce a match. is was because, if
2020 SO was indeed a lost rocket booster, it had undergone 54 years of space weathering.
“We knew that if we wanted to compare apples to apples, we’d need to try to get spectral data from
another Centaur rocket booster that had been in Earth orbit for many years to then see if it better
matched 2020 SO’s spectrum,” says Reddy.
Reddy and his team accomplished this on 1 December when they observed another Centaur rocket
booster that had launched a communications satellite in 1971. e two objects had the same spectra.
2020 SO will now be held by Earth’s gravity until March 2021, when it will escape into a new orbit.
The launch of a Centaur rocket in 1971.
ViewNEO revealed to be lost rocket b...
January 2021
Astronomy Now