A Russian spacecraft delivering supplies to the International Space Station (ISS) is out of control and will fall back to Earth, officials say.
The unmanned cargo ship was launched from Kazakhstan on Tuesday, but contact was lost with it soon afterwards.
Russia's space agency says Progress M-27M is now orbiting in an uncontrolled spin.
It cannot reach the ISS and is likely to break up on re-entering Earth's atmosphere.
The craft carried on to a higher orbit after contact was lost.
Igor Komarov, the head of Russia's space agency, Roscosmos, said: "The craft's continued flight and its docking with the ISS is not possible."
Two astronauts spending a year on the ISS, Scott Kelly and Mikhail Kornienko, told the Associated Press news agency that flight controllers had given up hope of controlling Progress again.
Interfax reports that Progress is likely to re-enter Earth's atmosphere in the coming hours if communication is not restored, but the Russian news agency Interfax said it would re-enter between 7 and 11 May.
Other capsules - including one Progress craft last year - have burned up and disintegrated on re-entering Earth's atmosphere without posing a threat to the planet's population.
Cathleen Lewis, a specialist in Russian space programmes at the Smithsonian Institution's National Air and Space Museum in Washington, said it was not yet known where debris will fall - but that it was highly unlikely to hit urban areas.
"I always remind people that two-thirds of Earth's surface is water," she said.
"The likelihood of it coming down and hitting someone is so remote as to be miniscule."
Progress was to deliver food, water, fuel, oxygen and clothing to the crew of six people on the space station that orbits about 420km (250 miles) above Earth.
Even after Progress' loss, the astronauts have enough supplies to keep them going until the next expected delivery on 19 June.
A Roscosmos spokesman told Reuters that the loss was valued at 2.59 billion roubles ($50.7m).