Apollo era space junk visits Earth again on Groundhog Day

After a close visit in December, a spent rocket booster that sent a lander to the Moon will make one last pass by Earth on February 2, 2021.

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Centaur D upper-stage rocket
Tony Rice
, NASA Ambassador

The upper stage Centaur D rocket booster which delivered the Surveyor 2 mission to land on the Moon ahead of the Apollo missions, will visit Earth one last time this Groundhog Day, February 2, 2021.

Surveyor 2

The Surveyor 2 lunar lander was launched toward the Moon on Sept. 20, 1966 to study the Moon's surface ahead of the Apollo missions which followed 3 years later. Shortly after lift-off, Surveyor 2 separated from its Centaur upper-stage booster as planned, but control was lost following day when one of the thrusters failed to fire forcing the the spacecraft into a spin.

Surveyor 2 crashed into the Moon just southeast of Copernicus crater on Sept. 23, 1966.

This 1964 photograph shows a the Surveyor 2 before being mated to an Atlas booster.

The spent, 100 foot tall, 10 foot wide Centaur D which sent the spacecraft on its way sailed past the Moon and disappeared into an unknown orbit around the Sun. Until September 2020.

A space rock, or empty space can?

A previously unknown object was discovered by the Pan-STARRS1 survey telescope on Maui in September 2020 and given the name 2020 SO.

Originally thought to be a near Earth asteroid, a 4+ billion year old left over from the formation of the solar system, something didn't seem right about it. As more astronomers observed the object and sufficient data was available to work out it's orbit, several unusual facts emerged.

2020 SO is orbiting on a plane nearly identical to Earth's, highly unusual for a natural object. Changes in the orbit that couldn't be explained by the gravitation pull of the Sun, Moon or Earth offered more clues.

Much like an empty aluminum can is pushed by the wind much more than a small dense stone, the small but continuous pressure exerted by solar radiation acts very differently on dense asteroids than relatively light wight spent rocket bodies.

This 5000 pound empty tube was being blown by the solar wind.

The final clue came when researchers worked the orbit backwards, finding that it should have collided with Earth in 1966.

Close approaches

2020 SO flew within less than 32,000 miles from Earth in the Early hours of December 1, 2020. Additional observations from NASA's Infrared Telescope Facility on the Big Island of Hawaii confirmed that 2020 SO is, in fact, the lost booster that sent the ill-fated Surveyor 2 mission on its way to the Moon.

At 4:39 pm EST, this bit of space junk will pass above Earth (and the Moon) within less than 139,000 miles or a bit more than half the distance to the Moon. Neither passes pose any threat to Earth.

Update: 2020 SO was spotted by Patrick Wiggins of Salt Lake City, Utah with a 14" Schmidt-Cassegrain telescope. Patrick is a retired astronomy educator and was awarded the NASA Distinguished Public Service Medal in 2014.

Other Apollo era relics in orbit

In 2018, an object named 2018 AV2 believed to be the ascent stage from the Apollo 10 lunar module dubbed "Snoopy" by its crew was discovered by Nick Howes, an amateur astronomer and fellow of the Royal Astronomical Society along with a team using telescopes in Australia, Hawaii, and Arizona. 2018 AV2 will make its next close approach to Earth in 2037.


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