China's Tiangong-1 space station will likely fall to Earth between Saturday and Monday morning, but the European Space Agency (ESA) says there is a very small risk to people living in its projected re-entry area. This could be anywhere from 43˚ north to 43˚ south latitude -- a zone that includes a large part of the continental United States.

The agency said the probability of debris hitting someone is 10 million times smaller than the yearly chance of being struck by lightning.

"In the history of spaceflight, no casualties due to falling space debris have ever been confirmed," the agency said in a recent blog post.

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China reportedly lost control of 19,000-pound station nearly two years ago, in June of 2016. The Chinese government later released an estimate that predicted Tiangong-1 would come down at some point in late 2017. The vague guess has led experts to conclude that the country's space agency has lost all ability to direct the crashing station's course or know where it will land.

This map from the European Space Agency shows the potential re-entry areas for China's Tiangong-1 space station. ESA

"Even a couple of days before it re-enters we probably won't know better than six or seven hours, plus or minus, when it's going to come down," Harvard astrophysicist Jonathan McDowell told The Guardian in 2016. "Not knowing when it's going to come down translates as not knowing where its going to come down."

While much of the spacecraft would likely burn up in the atmosphere, ESA experts say portions could survive and reach Earth's surface.

"The date, time and geographic footprint of the reentry can only be predicted with large uncertainties. Even shortly before reentry, only a very large time and geographical window can be estimated," said Holger Krag, head of ESA's Space Debris Office.