MOSCOW, July 25 (UPI) -- After an initial failure, another attempt to re-dock a Russian space freighter to the International Space Station will be made Sunday, officials said.
The unmanned Progress M-15M space freighter that arrived at the ISS in April undocked from the station Monday to perform a series of engineering tests during a re-docking designed to verify an upgraded automated rendezvous system.
After separation, the freighter moved about 100 miles from the station and held position for 24 hours before attempting a re-docking Tuesday that was unsuccessful due to an apparent failure in the new Kurs-NA rendezvous system, RIA Novosti reported.
The failure of the system triggered a passive abort, a standard procedure that took Progress to a safe distance of about 1.8 miles below the space station.
"Another attempt to dock Progress with the space station is scheduled for 5 a.m. Moscow time (01:00 GMT) on July 29," a spokesman for the Russian Mission Control Center said.
Should another attempt to re-dock the freighter using the modernized Kurs-NA system fail, the ISS crew can revert to using its time-proven predecessor, the Kurs system, a space industry source told RIA Novosti.