China's Tiangong-1 due for uncontrolled re-entry, soon
Tiangong-1 potential re-entry area. Map showing the area between 42.8 degrees North and 42.8 degrees South latitude (in green), over which Tiangong-1 could reenter. Image via ESA CC BY-SA IGO 3.0.
Chinaâs first space station â" Tiangong-1 (Heavenly Palace 1) â" was launched in 2011, and, originally, a controlled re-entry was planned. Firing the craftâs engines would have enabled controllers to allow the craft to burn up (mostly) over a large, unpopulated region of the South Pacific ocean. Any surviving pieces would have fallen into the ocean. But, in March 2016, the Tiangong-1 space station ceased functioning. Ground teams lost control of the craft, and it can no longer be commanded to fire its engines. It is, therefore, expected to make an uncontrolled reentry â¦ soon.
The cur rent estimated window for Tiangong-1âs re-entry is approximately March 29 to April 9, 2018. ESA calls these dates âhighly variable.â
Reentry will take place anywhere between 43 degrees North and 43 degrees South (see map below). At no time will a precise time or location prediction for re-entry be possible.
Tiangong 1 re-entry window, as of March 6, 2018, via ESA.
The spacecraftâs main body is approximately 34 feet (10.4 meters) long.
ESA has said that Tiangong-1 will âsubstantially burn upâ in Earthâs atmosphere. Will pieces crash to Earth? Possibly. Will they crash in populated areas? Itâs not possible to say.
As of todayâs date (March 7, 2018), the spacecraft is at about 258 km (155 miles) altitude. Its orbit is clearly decaying; you can follow the spacecraftâs descent here.
Tiangong-1 is not designed to withstand re-entry, as some spacecraft are. It will mostly burn up due to the extreme heat and friction generated by its high-speed passage through Earthâs atmosphere.
Tiangong 1 re-entry, as of March 6, 2018, via ESA.
Tiangong 1âs major goal was to test and master technologies related to orbital rendezvous and docking. One uncrewed and two crewed missions â" executed by the Shenzhou (Divine Craft) spacecraft â" took place during its operational lifetime. ESA explained:
Following launch in 2011, the Tiangong-1 orbit began steadily decaying due to the faint, yet not-zero, atmospheric drag present even at 300 or 400 km altitude. This affects all satellites and spacecraft in low-Earth orbit, like the International Space Station (ISS), for example.
ESA is updating its forecast for Tiangong-1âs re-entry frequently; click here to go to ESAâ s updates.
Bottom line: Chinaâs first space station will undergo an uncontrolled re-entry into Earthâs atmosphere sometime in the March-April timeframe.
Live, real-time tracking of Tiangong-1 here
Deborah Byrd created the EarthSky radio series in 1991 and founded EarthSky.org in 1994. Today, she serves as Editor-in-Chief of this website. She has won a galaxy of awards from the broadcasting and science communities, including having an asteroid named 3 505 Byrd in her honor. A science communicator and educator since 1976, Byrd believes in science as a force for good in the world and a vital tool for the 21st century. "Being an EarthSky editor is like hosting a big global party for cool nature-lovers," she says.