A Chinese space station is going to fall out of the sky in a few weeks, and no one knows where it’ll hit.
The Chinese space program lost contact with — and their ability to steer — the 9.4-ton Tiangong-1 in March of 2016, after it had been spinning around the earth for over four years, according to state media. Now, it’s losing speed in orbit and is expected to fall into the atmosphere sometime around the first week of April. The craft will tumble back into the atmosphere, and perhaps break up, and where it will fall is difficult to predict. Still, it’s pretty unlikely to hit anyone on reentry.
“We can confidently say that this object will reenter somewhere between 43° North and 43° South latitudes,” Aerospace, a federally funded space research center, wrote in a report.
That’s about two-thirds of the world. New York City is just south of the 43rd parallel north, which runs through southern France and parts of Russia; the 43rd south runs south of the entire continents of Africa and Australia, and runs into the southern tips of Chile and Argentina in South America.
The Tiangong was a big-deal launch in 2012 for the Chinese space program. It’s the first space lab, capable of hosting manned missions and conducting space research.
“The reason we can’t predict where accurately is because we can’t predict when. The reason we can’t predict when is because when depends on how much headwind it’s experiencing,” Harvard astrophysicist Jonathan McDowell told VICE News.
The conditions on the sun affect the conditions of the upper atmosphere, and while we can measure the conditions on the sun pretty accurately, they’re hard to predict in advance, according to McDowell.
Adding to the challenge is that Tiangong rotates around the Earth about once every 90 minutes. So predicting where it will land involves predicting when it’ll fall out of orbit with great precision.
Nonetheless, the report’s authors write that “the probability that a specific person (like you) will be struck by Tiangong-1 debris is about one million times smaller than the odds of winning the Powerball jackpot.” The report notes, too, that only one person has ever been hit by any space junk. Lottie Williams was hit by debris from a NASA satellite in 1997, according to Fox News Tech. She wasn’t hurt.
Williams described the piece of debris that hit her as she was walking through a park in Tulsa, Oklahoma, as having the weight of an empty soda can.
Satellites fall out of orbit more often than most people know. There are nearly 19,000 artificial satellites in orbit at right now, according to space-track.org, which is run by the U.S. Air Force’s Joint Space Operation Center. (Check out this visualization, Stuff in Space, of all the satellites currently in orbit.) In January, what is believed to be a Russian rocket fell into Peru, where locals found parts of it, mostly disintegrated on reentry.
The Tiangong-1, too, is expected to mostly disintegrate on reentry. Should any of the debris hit the ground, it’ll likely fall within an area of about 100 kilometers.
Even if there’s a low risk of it posing any threat to people, McDowell told the Guardian, “Tiangong-1 is big and dense, so we need to keep an eye on it.”
The Aerospace report notes, too, that the space ship could be carrying a toxic fuel called hydrazine, used as a propellant in space. “For your safety, do not touch any debris you may find on the ground nor inhale vapors it may emit,” the report says.
Cover image: Scientists look at the screen showing the Shenzhou X manned spacecraft conducting docking with the orbiting Tiangong-1 space module at Beijing Aerospace Control Center on June 13, 2013 in Beijing, China. China's Shenzhou X manned spacecraft successfully completed an automated docking with the orbiting Tiangong-1 space module on Thursday. (Photo by VCG/VCG via Getty Images)