Out of Control Space Debris Is About to Plummet to Earth: How to Track

A large section of a Chinese rocket currently in an uncontrolled orbit around the Earth is due to re-enter the atmosphere this weekend—and no one knows exactly when or where.

The rocket is being tracked by U.S. space company The Aerospace Corporation, which as of Friday morning had produced a graph showing the future trajectory of the rocket, as well as a very rough estimated re-entry time of 3:24 p.m. ET on July 30—plus or minus seven hours.

The rocket, a Long March 5B model, also known as CZ-5B, was launched on July 24 on a mission to deliver a new module to China's in-construction Tiangong space station.

The Long March 5B made its first flight in 2016, but unlike some modern rockets such as SpaceX's Falcon 9 or Blue Origin's New Shepard, it isn't reusable.

Long March 5B rocket
A Long March 5B rocket launches from the Wenchang Space Launch Center in China's Hainan province in April 2021. The rocket model is not reusable and parts are sometimes left in uncontrolled orbits. STR/AFP/Getty

This in itself isn't a problem as many other rockets, including NASA's upcoming colossal SLS moon rocket, aren't reusable. However, when the Long March 5B reaches orbit, it sheds its booster stage, which then tumbles around the planet in an uncontrolled manner.

Over a period of days its orbit will decay due to very slight air resistance at high altitude, and eventually the booster re-enters the atmosphere at a time and place that's impossible to accurately predict.

Since the booster stage is over 170 feet long and weighs around 23 metric tons, it's possible that multiple tons of the rocket won't burn up completely in the atmosphere and that it will end up crashing into the ground, The Aerospace Corporation states, potentially posing a risk to life and property.

Newsweek has contacted the China National Space Administration (CNSA) for comment.

Scientists at The Aerospace Corporation's Center for Orbital and Reentry Debris Studies (CORDS) have been tracking the booster for days as more data became available.

The team's most up-to-date predictions are posted to the Aerospace Corporation's Twitter account as well as on the company website here.

The blue and yellow lines show the path the rocket section must take due to its orbit, and cover many populated areas of Earth, including much of the U.S. and China itself.

While it can't be said that there is no risk of damage or injury from this rocket, the chances of a given person being hit are absolutely miniscule.

Marlon Sorge, executive director of CORDS, told Newsweek earlier this week that the risk of an individual being hit by the re-entry debris in a given year is around 1 per 100 billion. "The risk of getting hit by lightning is 80,000 times greater," he said.

Still, Sorge added that this risk is high enough that the world should track the rocket's path.

It's not the first time that debris from a Long March 5B model has caused concern.

In 2020, another uncontrolled re-entry of one of the model's sections was suspected to have been responsible for debris that rained down over Côte d'Ivoire in Africa. There was no solid confirmation that the debris, alleged to include a 12-meter-long object, came from the rocket, but astronomer Jonathan McDowell said at the time it was possible that this was the case.

In addition, in May last year a similar launch left experts concerned after a section of the rocket model was once again left in an uncontrolled orbit. Fortunately, the China Manned Space Engineering Office said the rocket ended up re-entering the atmosphere over the Indian Ocean rather than a populated land area.

While China operated both of those rockets, one of the largest uncontrolled de-orbits ever was that of NASA's 75 Imperial-ton Skylab space station. It de-orbited in 1979 and scattered debris over parts of Western Australia, but luckily, no one was injured.