Debris from a Chinese rocket is expected to crash to Earth in an uncontrolled re-entry this weekend.
The probability of it landing in any populated area is extremely low.
But it has raised questions about how different countries take responsibility for their space junk.
There have previously been calls by Nasa for the Chinese space agency to design their rockets to disintegrate into smaller pieces upon re-entry, as is the international norm.
Recent rockets heading to China’s unfinished space station, known as Tiangong, have lacked the capability for a controlled re-entry.
The latest launch was on Sunday, when a Long March 5 rocket carried a lab module to the Tiangong station. The Chinese government said on Wednesday that the rocket’s re-entry would pose little risk to anyone on the ground because it would most likely land in the sea.
However, there is the possibility for pieces of the rocket to come down over a populated area, as they did in May 2020 when properties in Ivory Coast were damaged.
The empty rocket body is now in an elliptical orbit around Earth where it is being dragged toward an uncontrolled re-entry.
According to The Aerospace Corporation, a non-profit organisation based in California, re-entry will occur around 00:24 GMT on Sunday, plus or minus 16 hours.
It’s too early to know exactly where the 25-tonne chunk of debris will land. The possible area where the debris could fall spans the US, Africa, Australia, Brazil, India and Southeast Asia, according to corporation predictions.
Designing objects to disintegrate upon atmospheric re-entry is becoming a priority for satellite operators. It’s done partly by using materials which have low-melting point temperatures, such as aluminium.
In the case of rockets, this can be expensive, as historically the materials used for housing fuel, such as titanium, require very high temperatures to burn up. The sheer size of such objects is also an issue, especially in the case of the Long March 5, weighing over 25 tonnes.