The unmanned Russian Progress space capsule lost on its way towards the International Space Station last week will burn in the Earth’s atmosphere between Thursday morning and Friday noon. The exact location of the re-entry is still as yet unknown.
The capsule, with 2,722kg of supplies originally destined for the ISS aboard, will most likely burn up completely during the re-entry, with any potential residual fragments falling in to the ocean.
"Only a few small pieces of structural elements could reach the planet's surface," Russia’s space agency Roscosmos said in a statement.
The US Air Force's contractor-operated Space-Track.org web site estimates that the capsule will plunge back in to Earth's atmosphere around 9am GMT on Friday. The European Space Agency (Esa) gives a much wider window for the capsule's return to Earth.
“As of Thursday morning, 7 May, we are forecasting an uncontrolled re-entry by Progress M-27M any time between later in the evening today through to midday tomorrow, 8 May,” Holger Krag, Head of Esa's Space Debris Office, stated in a blog post on the space agency’s web site.
“The current large uncertainty is due to the unpredictability of the drag forces working on the vessel and is a standard feature of such predictions. Any reports claiming precise re-entry times and locations at this stage are speculative.”
Esa’s data indicates that the spacecraft is rotating very fast in its out-of-control flight, with approximately one revolution every 1.8 seconds.
The ill-fated Progress was launched on 28 April from Russia’s cosmodrome in Baikonur, Kazakhstan. Although it reached the orbit and deployed its solar panels as planned, ground controllers failed to establish contact with the spaceship despite repeated attempts.
It was suggested a technical hitch during the capsule’s separation from the launcher caused the spacecraft to spin in a slightly incorrect orbit, unable to perform a set of manoeuvres needed for its rendezvous with the orbital outpost.
The Air Force's Joint Space Operations Center, which tracks satellites and junk orbiting Earth, found 44 pieces of debris near the Progress and its discarded upper-stage booster, a possible indication that an explosion or other problem occurred just before or during spacecraft separation.
The Russian space agency Roscosmos declined to comment. Results of its preliminary investigation are expected on 13 May.
The incident, the latest in a string of mishaps that have afflicted Russia’s space industry in the past years, will cause further delays for the two Progress cargo missions scheduled later this year.
Nasa said the failed re-supply mission does not put the astronauts aboard the $100m space station at any risk, as they have enough supplies for at least four months. During that time SpaceX’s Dragon and Japan’s HTV are expected to perform their regular cargo delivery runs.