Tiangong-1: Defunct China space lab comes down over South Pacific
China's defunct Tiangong-1 space lab mostly broke up on re-entering the Earth's atmosphere above the South Pacific, Chinese and US reports say.
It re-entered the atmosphere at 08:16 GMT on Monday, astronomer Jonathan McDowell tweeted.
Tiangong-1 was launched in 2011 to carry out docking and orbit experiments.
It was part of the country's efforts to build a manned space station by 2022 but stopped working in March 2016.
The 10m-long Tiangong module should really have been de-orbited in a planned manner.
Traditionally, thrusters are fired on large vehicles to drive them towards a remote zone over the Southern Ocean but this option appeared not to be available, especially after the loss of command links in 2016.
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Thirteen space agencies, under the leadership of the European Space Agency, used radar and optical observations to follow Tiangong's path around the globe.
Tiangong means 'Heavenly Palace'
- The module was launched in 2011 to practise rendezvous and docking
- Two astronaut crews visited in Shenzhou capsules - in 2012 and 2013
- They included China's first female astronauts Liu Yang and Wang Yaping
- China plans a more permanent space station in the next decade
- It has developed a heavy-lift rocket, Long March 5, for the purpose
Tiangong was certainly on the large size for uncontrolled re-entry objects but it was far from being the biggest, historically:
- The US space agency's Skylab was almost 80 tonnes in mass when it came back partially uncontrolled in 1979. Parts struck Western Australia but no-one on the ground was injured
- Nasa's Columbia shuttle would also have to be classed as an uncontrolled re-entry. Its mass was more than 100 tonnes when it made its tragic return from orbit in 2003. Again, no-one on the ground was hit as debris scattered through the US states of Texas and Louisiana
Jonathan McDowell from the Harvard-Smithsonian Center for Astrophysics believes Tiangong is only the 50th most massive object to come back uncontrolled.
China has launched a second lab, Tiangong-2, which continues to be operational. It was visited by a re-fuelling freighter, Tianzhou-1, just last year.
China's future permanent space station is expected to comprise a large core module and two smaller ancillary modules, and will be in service early in the next decade, the Asian nation says.
A new rocket, the Long March 5, was recently introduced to perform the heavy lifting that will be required to get the core module in orbit.