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A relic from the early days of spaceflight has likely returned for a brief visit to its home planet, according to months of observations of a near-Earth object dubbed 2020 SO.
2020 SO entered what scientists call Earth’s Hill sphere, where Earth’s gravity governs the behavior of objects, on November 8, according to a NASA statement. Scientists say the object will make two leisurely laps around the Earth before sliding off to resume its path around the sun in March.
But although scientists first spotted it in September during surveys conducted to identify asteroids, the object soon appeared to be something completely different – the upper stage of a rocket from a 1966 NASA robotic moon mission called Surveyor 2. And that would indeed make it quite legendary space junk.
“If it’s the upper stage of the Centaur,” Alice Gorman, an archaeologist focused on the legacy of space flight, told Space.com, “it’s this object itself, it’s this stage of the rocket, but it’s also connected to all of these. other things. “
Related: The strange story of 2020 SO: how an asteroid turned into rocket junk and the NASA scientist who figured it out
This particular piece of metal left Earth on September 20, 1966, perched atop an Atlas D first stage and carrying a spacecraft named Surveyor 2 to its tip. Three days later, that spacecraft inadvertently crashed on the moon. The metal cylinder that had delivered him, meanwhile, passed past our celestial neighbor and settled around the sun more or less in tandem with our home planet.
And apparently, he’s been doing it for 54 years. Throughout these years, the Centaur’s successors have proliferated, launching countless rockets from Earth and on a series of Earth and planetary orbital exploration missions.
A long career for simple design
The Centaur rocket stage, in one form or another, has played a key role in space exploration for essentially the entire history of space flight. It was the result of a partnership between NASA (and its predecessor) and the commercial sector in the late 1950s and first launched in March 1962.
The stage was a vital development in rocketry because it was the first successful project to rely on dangerously temperamental yet light and efficient liquid hydrogen, according to a History published by NASA of the component. Centaur’s success established that liquid hydrogen could be used safely, helping the United States reach the Soviet Union during the space race.
But despite this leading role, the Centaur’s upper stage is deceptively simple. “It’s a really simple rocket,” Gorman said. “It’s just like a big fuel tank with a couple of rocket engines.” And it’s flexible: While over the years it has more commonly flown with the Atlas first stage, it can join a variety of rockets. In the 1980s, it was even adapted for launch inside NASA’s space shuttle to guide satellites to their proper orbits, though it never ended up flying in that configuration.
Only one version of the Centaur tier continues to fly today, integrated into the United Launch Alliance’s Atlas V rockets, but is also designed into the company’s future Vulcan Centaur rocket, due to launch maybe next year.
The long history of the Centaur is a good reminder of the transient and combined nature of each rocket, Gorman said. Launch vehicles spend much more time as components, often spread across large geographic areas, than they do as a single unit.
“In our minds, we have this vision of the rocket, which is the big, pointed thing on the launch pad, but that rocket only exists for a short time,” he said. “It is assembled in the week before launch … it starts and separates and is left in pieces.”
Watch the moon
The particular piece of Centaur that was now temporarily buzzing around Earth was part of a vital series of missions that paved the way for the Apollo program proving it was safe to land on the moon, even if his particular spaceship failed.
Between 1966 and 1968, the United States launched seven dubbed missions Surveyor, each designed to land on the moon. Overall, the program was a success; Surveyor 2 itself was the only exception when it crashed on the lunar surface.
Its predecessor probe, Surveyor 1, made the first American soft landing on the moon.
“Landing on the moon was really exciting; it’s kind of like landing on Mars nowadays,” Paul Chodas, head of NASA’s Center for Near-Earth Object Studies at the Jet Propulsion Laboratory in California, who saw the object detected during asteroid surveys and realized it was probably the Centaur 2 Surveyor, he told Space.com. “It’s especially exciting because I remember these missions. Surveyor 1 was a very exciting moon landing – as a kid, I was looking at the moon through my telescope when it landed.”
And the success of the soft landing also provided vital evidence for the historian Apollo 11 human moon landing three years later, Gorman said.
“There were two kinds of moon dust theories at the time: one was that it was incredibly deep, so if I sent a human mission, they would just sink into the dust, and the other was that the dust wasn’t that deep,” Gorman said. “So one of the things the Surveyors did was show that, at least in the places where the seven missions landed, the dust wasn’t three feet deep, so it would have been safe for a much heavier aircraft to land on the surface. in terms of the whole development of human space flight and lunar science. “
But while Surveyor 2 may not have lived up to its siblings, its Centaur may be well on its way to becoming the first. orbit around the sun 1960s rocket body that scientists rediscovered. Astronomers are planning to observe the object to try to confirm the connection, but for Chodas the trajectory itself is compelling evidence.
“The fact that it can be very strongly linked to the launch of Surveyor 2, which took place 54 years ago, is really amazing,” Chodas said. “This is the first time I’ve managed to create such a strong association with a rocket launch from the 1960s.”
Email Meghan Bartels at [email protected] or follow her on Twitter @meghanbartels. Follow us on Twitter @Spacedotcom and on Facebook.
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