An unmanned Russian cargo spacecraft has failed to dock with the International Space Station due to a technical failure, officials said.
The spacecraft is due to make another attempt at docking on Sunday, after an unmanned Japanese spacecraft reaches the station and is manually berthed by astronauts later this week.
Russia’s Progress cargo ship separated from the station last Sunday to perform engineering tests and try out a new docking system. The single-use ship had already delivered fuel and other supplies to the six astronauts on the International Space Station. It was due to burn up on re-entry, laden with trash, on July 30, after the next test.
The craft is now orbiting at a safe distance from the outpost while Russian engineers study why the Kurs-NA rendezvous system automatically aborted during the linkup attempt.
"The test was proceeding normally until about the time that the new Kurs-NA rendezvous system was to be engaged," NASA said in a statement on its website.
"As commands were being issued to activate the Kurs system, a failure was announced, triggering a passive abort."
Kurs-NA is an upgrade of the Kurs docking gear used for years on Russia's manned Soyuz and robotic Progress spacecrafts. The system features updated electronics and is designed to improve safety and use less power, according to NASA.