Fragments from a science satellite are likely to crash to Earth late Sunday or early Monday after the one-ton probe breaks up at the end of its mission, the European Space Agency (ESA) said on Friday.
In a statement, the agency said when and where the pieces would land was still unclear. Experts have previously said the statistical risk to humans is remote.
Several dozen fragments totaling around 200 kilos (440 pounds), or about the weight of car engine, will survive contact with the atmosphere, according to computer models.
The Gravity Ocean Circulation Explorer (GOCE) satellite was placed in orbit in 2009 on a mission to monitor variations in gravity and sea levels. The sleek, finned craft ran out of fuel on October 21, leaving it without power to maintain its altitude in low orbit, where there are still lingering molecules of air.
"Reentry of GOCE into Earth's atmosphere is predicted to occur during the night between Sunday and Monday," ESA said on Friday. "Break-up of the spacecraft will occur at an altitude of approximately 80 km (50 miles). At the moment, the exact time and location of where the fragments will land cannot be foreseen."