Spain, Israel, Saudi Arabia, Australia and New Zealand sit within the danger zone – though its most likely destination remains the ocean.The Long March 5B blasted off last Thursday as part of China’s mission to build its first permanent space station.
At 30 metres, it is around the length of a basketball court, and is one of the largest launchers to make an uncontrolled re-entry to Earth.
The rocket body, travelling at high speed, has been orbiting the globe roughly every 90 minutes during its return journey.
It is expected to land within the next three hours – with an estimated crash time of between 2am and 3am GMT.
Will Ripley, of CNN, notes that it is “the size of a 10-storey building” and “a fifth as heavy as the Statue of Liberty”.
He said the latest estimate of landing time is 10.04pm Eastern Time, “plus or minus 60 minutes”.
The estimate – 10.04pm EST – is 2.04am GMT.
Mr Ripley notes: “So you have a two-hour window.
“During those two hours, this rocket will orbit the Earth more than once – 1.3 times.
READ MORE: China rocket: Debris expected to reenter between 2am and 4am
Beijing is planning another 10 launches to send up two more modules, four cargo supply shipments and four missions with crews.
Tianhe’s main module will initially be about the size of NASA’s 76-ton Skylab space station of the 1970s.
The station is designed to last for more than 10 years and will be significantly smaller than the International Space Station (ISS).