Tiangong 1.

The Chinese space authorities launched their first space station in 2011, used it for just two manned missions, lost control of it in 2016, and it has been in an uncontrolled and descending orbit ever since.

The countdown has now begun for the Tiangong-1’s final plummet back to Earth, which will occur on April 3, plus or minus a week’s time, according to an estimate released today by the Aerospace Corporation.

Most of the 9.3-ton apparatus will burn up on re-entry into the atmosphere – but a small amount of the debris will likely hit the ground, according to physicists.

The geographical range of where it will touch down is still completely uncertain, with the final spot extending from 43 degrees North to 43 degrees South latitude.

The estimates will be better as the final descent begins, especially one day before.

Observers from the Earth may be able to see multiple bright streaks moving across the sky in the same direction.

The likelihood of being hit by some of the Chinese space junk in the descent is statistically around a million times smaller than the odds of winning the Powerball jackpot, according to the Aerospace Corporation. However, one woman walking in an Oklahoma park in 1997 was struck by fragments of a burned-up Delta 2 rocket – though she was not injured.

Over the half-century-plus since space exploration began, thousands of tons of space junk have been estimated to have survived re-entry to land on the Earth’s surface.

The Tiangong-1 is not the largest object to re-enter the atmosphere in an uncontrolled fashion. The Mir Space Station run by the Russian space agency fell back to Earth in March 2001. Its mass was about 120,000 kg – compared to the Chinese satellite, which is 8,500 kg.