A piece of the Long March 5B gigantic missile may soon enter Earth’s atmosphere uncontrollably, according to the Associated Press. However, it is not known exactly when and where this will happen. Some experts fear that the missile shrapnel could land in areas inhabited by residents. “It’s likely not going to be a good thing,” said Harvard astrophysicist Jonathan McDowell.

According to the Associated Press, space rocket components are typically directed for controlled destruction through friction in the atmosphere once they enter service. However, this did not happen with the Chinese missile clip, the Associated Press writes.

In March, parts of SpaceX’s Falcon 9 missile fell to the ground in Washington state and in the ocean off the coast of Oregon, the agency said.

A Long March 5B rocket launched one of the main units of China’s planned Tiangong space station, the “Celestial Palace” into orbit last Thursday. It then went into temporary orbit on its own and now orbits the Earth once every 90 minutes, flying so fast that space agencies cannot predict where it will enter the atmosphere.

And the US Department of Defense expects that to happen on Saturday. The Pentagon said the location of the re-entry into the atmosphere, however, would be able to be determined only a few hours before this event.

Some experts fear that the missile shrapnel could land in areas inhabited by residents. “It may not be good,” Harvard University astrophysicist Jonathan McDowell was quoted by The Guardian newspaper as saying.

According to The Guardian, since 1990, no object weighing more than 10 tons has been intentionally left in orbit to re-enter the atmosphere in a controlled manner. The main part of the Long March 5B missile weighs more than 20 tons, according to available information.

However, in an interview with CNN, McDowell assessed that the risk to humans is negligible, and that the Pacific Ocean is the most likely location for a potential fall, as it covers the largest area.