The Chinese modular space station Tiangong-1, launched in September 2011, is about to fall to Earth.

It was used to practice space docking and served as a prototype for a future permanent Chinese space station.

While operational, Tiangong-1 was visited by two crews of taikonauts.

Sometime on April 1, give or take a day, the Chinese space station Tiangong-1 will fall into Earth's atmosphere.

Most of the spacecraft will burn up in a fiery blaze as it gets dragged by gravity from the thinner air into the atmosphere itself.

The thicker air of the atmosphere will tear solar panels and antennas loose, melting and disintegrating much of the structure. Some material will stay intact, however — especially densely layered parts like engines. It's possible that compartments and parts of the station could survive re-entry and hit the ground — or more likely, the ocean — on Earth.

China hasn't controlled the Tiangong-1 modular space station for over two years now. Chinese officials confirmed in 2016 that they'd lost control of the spacecraft and that its orbit was deteriorating,

But before that, Tiangong-1 was the first station China launched into space.

Tiangong-1 — the name means "Heavenly Palace" — is a 34-foot, two-room, 9.4-ton vessel that was launched into orbit at the end of September 2011.

Space experts considered its initial launch an important achievement.

One of the main goals was to have a station that could be used to practice docking in space, which is essential for further space exploration, including the use of larger space stations in the future. Tiangong-1 also served as a prototype for a permanent 20-ton space station that China is planning to launch in 2023.

"It conducted six successive rendezvous and dockings with spacecraft Shenzhou-8, Shenzhou-9, and Shenzhou-10 and completed all assigned missions, making important contributions to China's manned space exploration activities," said a memo that China submitted in May 2017 to the United Nations Committee on the Peaceful Uses of Outer Space.

Tiangong was visited by two crews of taikonauts (Chinese astronauts). The first was a three-person crew in June 2012 that included the first Chinese woman in space; the second was another three-person crew in June 2013.

No visitors arrived at Tiangong-1 after that second crew, but the station was still used to gather data and observe Earth's surface, monitoring ocean and forest use, according to Space.com.

In September of 2016, China launched Tiangong-2, a second space station, which was first visited by a crew the next month. Earlier that year (in March), China had lost contact with Tiangong-1.

Since then, the space station's orbit has slowly decayed. As its altitude has decreased, gravity has caused its falling speed to increase. Now we're all just waiting for the fireball and to see where the debris lands.