China’s first space station will fall back to Earth in 2017

China launched its first space station in 2011, and managed to successfully use it intermittently for several years longer than originally planned. Now, the Tiangong-1 module is heading for a crash landing on Earth. However, China doesn’t know exactly when it’s coming down. That has fed speculation that all communication with the module has been lost, meaning it could come down almost anywhere.

The best estimate of reentry China has given is sometime in the second half of 2017. That would indicate a slowly decaying orbit. China announced in March that it had lost telemetry and guidance control of the satellite, but it had not played host to astronauts since 2013, so there was no immediate danger. However, some astronomers worried aloud that Tiangong-1 was completely inoperable and could be dropping out of the sky at any moment.

China’s statement (delivered by the government-backed Xinhua news agency) says that the module is intact and orbiting at an altitude of 230 miles (370 kilometers). This at least implies that it knows exactly where the station is, and will be able to predict its landing closer to the event. When it hits the atmosphere, much of Tiangong-1 will break up into tiny fragments. There may still be some segments as large as 100 kilograms, which could cause real damage if it fell on a populated area. However, the odds of it actually getting close to anyone or anything important are slim. Statistically, it’s likely the debris will just impact the ocean. China says it will monitor reentry for and dangerous objects.

Chinese crew aboard the Tiangong-1.

If China has completely lost contact with the station, at least Tiangong-1 is on the small side. At just just 18,753 pounds, it provided crews 15 cubic meters of space. The International Space Station has over 900 cubic meters of pressurized space, not including the new experimental Bigelow inflatable module. Unlike the ISS, Tiangong-1 didn’t have the facilities for constant habitation. It was originally used to test docking systems in 2011; then crews were able to return to the module for 11 days in 2012 and 14 days in 2013.

China successfully launched the Tiangong-2 station into orbit last week. It’s considerably larger than Tiangong-1, and will host two astronauts next month. They’ll stay on board for a month to do research. The Tiangong-3 station will follow this one in a few years, and will serve as a platform to test the final technologies China needs to perfect before launching a permanent orbital station in the early 2020s.