At some point this weekend, a Chinese rocket will hit Earth’s surface. Known as the Long March 5B, the rocket was helping transport the main hub for a Chinese space station currently under construction. The 23-ton, 10-story long rocket is currently traveling at about 18,000 miles per hour and is expected to fall in what’s called “an uncontrolled re-entry.”
Scientists and government agencies, including the Pentagon and U.S. Space Command, are tracking the rocket. But experts aren’t sure where it will crash land.
Chances are the rocket won’t land on someone’s head, says Mike Wall, a senior space writer for Space.com. That’s due to the fact that water makes up 80% of Earth’s surface.
“You could worry about it, but the chances are just so small that your square meter of ground that you're standing on is going to be where a chunk of rocket engine falls. It’ll do more damage worrying about it with the stress than you would by being under it,” Wall tells KCRW. “We do know that it could hit anywhere between about 40 degrees north of the equator to 40 degrees south. So anywhere basically from New York City's latitude down to Sydney in Australia.”
Wall says Earth’s complex atmosphere makes the rocket difficult to navigate. That’s due to the shifting of density and size based on solar activity. Projection modeling is also difficult because an incorrect model could be vastly different than the actual outcome. He says that if a prediction is off by just an hour, the location could be off by thousands of miles.
He points out that typically, rockets are steered into the ocean, which can prevent major damage on the ground. In this case, the Long March 5B rocket reached orbital velocity, and it will continue to zip around Earth until atmospheric drag pulls it down.
Wall notes this scenario isn’t common, but this is the second time in a year that a Chinese rocket has become uncontrollable. He warns that this situation highlights the growing problem that is space junk.
“It's only going to get worse, this problem, if we don't address it, because it's getting cheaper to launch things. ... It's not just the global superpowers who are spacefaring anymore,” he says. “It also just really rams home the fact that we need to have protocols in place about how we prevent these things from becoming space junk and just dead pieces of fast moving metal that are just waiting to slam into another satellite or something up there waiting to fall to Earth.”