A Chinese rocket will make an uncontrolled reentry in the coming days

Recently China launched a Long March-5B Y2 rocket into space that carried its first space station module into orbit. While China hailed the launch as completely successful, it turns out something has gone wrong. The 21-ton core stage of the rocket is expected to make an uncontrolled reentry into Earth's atmosphere in the next few days.

An uncontrolled reentry has the potential to cause debris to fall onto populated areas posing a risk to property and lives on the ground. The rocket was supposed to fall into a designated spot in the ocean, which is common for discarded rockets. However, rather than deorbiting as planned, the rocket continues to orbit the planet uncontrolled.

Authorities say the rocket is expected to fall back to the Earth in the next few days. Astronomer Jonathan McDowell, who tracks objects orbiting the Earth, said that it's unacceptable to let an object reenter uncontrolled by current standards. He also pointed out that since 1990 nothing over 10 tons has been deliberately left in orbit in an uncontrolled manner. The Chinese rocket measures 100 feet long and 16 feet wide.

According to McDowell, it could burn up entirely in the Earth's atmosphere when it falls out of orbit. However, there is a chance that large chunks of debris could survive reentry. The bulk of the planet is made of ocean, so it's more likely the rocket would impact water, but it could threaten inhabited areas.

Holger Krag, head of the Space Safety Program Office for the ESA, said that it's hard to assess the amount of surviving mass and the number of fragments that could potentially be created without knowing the rocket's design. However, he said a reasonable rule of thumb is that about 20 to 40 percent of their original dry mass could survive reentry. The rocket has the potential to impact a massive swath of the Earth, with major cities well within the impact zone, including New York, Madrid, and Beijing, among others.