The Russian cargo ship Progress has failed to successfully dock with the International Space Station (ISS) during tests designed to facilitate future link-ups, the US and Russian space agencies said Tuesday.
"The re-docking of the Russian ISS Progress 47 resupply spacecraft to the International Space Station has been postponed due to an apparent failure in the new Kurs-NA rendezvous system," NASA said in a statement on its website.
A spokesman for the Russian Mission Control Centre confirmed to AFP that the cargo ship, known as Progress M-15M, had failed to dock, without providing further details.
The docking was to have taken place at 0158 GMT, the Russian Mission Control Centre said.
The vehicle had undocked from the station on Sunday to perform tests to faciliate future dockings of cargo ships to the space station.
The Russian Space Agency said later Tuesday that the cargo ship was currently located 484 kilometers from the ISS and the next docking attempt would take place after the scheduled arrival of the Japanese HTV-3 cargo ship on Friday.
The state RIA-Novosti news agency, citing an unidentified representative of the Russian Mission Control Centre, said the next attempt to dock would take place around 0100 GMT Sunday.
A source in the space industry told RIA-Novosti that if the second attempt at docking fails, the old systems could be used to link the cargo ship to the ISS.
"The ship has the time-tested Kurs system with which the ship was docked to the ISS on April 22.
"If repeated attempts to test the Kurs-NA modernised version do not succeed then Progress M-15M would either be docked using the regular Kurs (rendezvous system) or taken off the orbit and sunk," the source was quoted as saying.
"In any case, the ship has performed its task -- it has delivered goods to the station as planned and has been loaded with waste."
Russian Mission Control officials were not immediately available for comment.
Russia's space programme has been beset by a litany of technical problems which have resulted in the loss of a half dozen satellites and vehicles over the past year, including a Progress cargo vessel bound for the ISS.
There are currently six people on the space station, which orbits 350 kilometres (about 220 miles) above the Earth and is permanently occupied by an international crew.
American Sunita Williams, Japan's Akihiko Hoshide and Yury Malenchenko of Russia joined Russians Gennady Padalka and Sergei Revin and US astronaut Joseph Acaba at the orbiter earlier this month.
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