This, according to ESA, means that the density in the upper part of the atmosphere, through which Tiangong-1 is moving, did not increase as planned, which would pull the uncontrolled space station down faster.
This map by the European Space Agency shows the area in which China's Tiangong-1 space station could fall (shown in green) around April 1, 2018. "Although not declared officially, it is suspected that control of tiangong-1 was lost and will not be regained before re-entry", says The Aerospace Corporation.
South Korea's National Space Situational Awareness Organisation said on Sunday the 10.4-metre-long (34-foot) station is expected to re-enter the atmosphere some time between 5.12am and 1.12pm Seoul time on Monday (8.12pm on Sunday and 4.12am on Monday GMT).
Tiangong-1 is roughly the size of a school bus, weighing in at 8.5 tons.
The space station was the first such devices launched by China in September 2011 and was operated by a test platform as part of the country's space program.
"Small bits definitely will have made it to the surface", he told Reuters, adding that while about 90 percent would have burnt up in the atmosphere and just 10 percent made it to the ground, that fraction still amounted to 700 kg (1,543 lb) to 800 kg (1,764 lb).
Where are the Cadbury Easter Egg Hunts and how to get involved?
Our annual Easter Brunch takes place Sunday, April 1, under the open-air dome of the lovely Rose Hills Foundation Garden Court. The first of several area egg hunts will kick off at 11 a.m. on Friday at Vincennes State Historic Sites, 1 West Harrison St.
The unmanned space station is in orbit above the Earth and is believed to be out of control. But more than five billion people do live beneath its flight path - in vast stretches of North and South America, China, the Middle East, Africa, and Australia.
During the uncontrolled re-entry, atmospheric drag will rip away solar arrays, antennas and other external components at an altitude of around 100 kilometres (60 miles), according to the Chinese space office.
"What I've heard is the possibility of large amounts of debris falling to the ground is very slim". Its last crew departed in 2013 and contact with it was cut in 2016. Since then, it has been orbiting the Earth, gradually coming closer and closer to the planet. On this mission, the crew spent 11 days at the station and completed two dockings - one computer-controlled and one crew-guided.
You can also follow ESA's Twitter account for the latest updates on estimated time and location of the space station's reentry.
The first United States space station, the 74-ton Skylab, fell to Earth in an uncontrolled reentry in 1979.