China’s small Tiangong-1 space station is expected to make an uncontrolled reentry at the end of this week or the beginning of next. Space objects routinely reenter through the atmosphere and most are destroyed in the fiery process, but there is a small chance that some parts of Tiangong-1 will reach the surface. Predicting when and where is difficult.

China’s official Xinhua news service said yesterday that reentry is anticipated between March 31 and April 4. It expects the space station to be “fully burnt” during the process.

Among the many Western organizations and satellite tracking amateurs closely following the decay of Tiangong-1’s orbit are the U.S. Aerospace Corporation and the European Space Operations Center (ESOC), part of the European Space Agency. The Aerospace Corporation is a federally funded research and development center (FFRDC) that supports the Air Force, including its space tracking operations.

Aerospace and ESOC both issued their most recent predictions yesterday and they largely agree with each other and with China’s offcial estimate. Aerospace predicts reentry on April 1 ± two days, and ESOC predicts March 30-April 2.

If any portion of the 8.5 metric ton (MT) space station survives all the way down to Earth, chances are it will do so over water, which covers 70 percent of the Earth’s surface. Apart from that, it can come down anywhere along its flight path from 42.65 degrees north latitude to 42.65 degrees south latitude.

It is expected to make an uncontrolled reentry, which can be affected by a number of atmospheric factors. Thus the predictions are variable.

The chances that anyone might be hit by a piece of debris are extremely small. The Aerospace Corporation calculates it this way: “the probability that a specific person (i.e. you) will be struck by Tiangong-1 debris is about one million times smaller than the odds of winning the Powerball jackpot.” Its website also had a handy map showing the portions of the globe where debris conceivably might fall. [https://tinyurl.com/y6w75hmu].

Tiangong-1 is China’s first space station. Launched in 2011, it hosted two three-person crews in 2012 (Shenzhou 9) and 2013 (Shenzhou 10). A second space station, Tiangong-2, is currently in orbit and was visited by one crew (Shenzhou 11) in 2016. Additional visits are not expected. China now is focusing on development and launch of a three-module 60 MT space station that would be completed in the early 2020s.