An unmanned Russian cargo spacecraft has redocked with the International Space Station after an aborted attempt five days earlier.

The Progress cargo ship had separated from the station a week ago to perform engineering tests and try out a new docking system and had been due to reconnect with the station on Tuesday. But problems developed with the avionics in the docking system.

The second attempt early Sunday was successful. Video streamed from Russian mission control reported no problems.

The Progress already had delivered its cargo, and was being kept at the station to load garbage. When full, it will be released and burn up upon re-entry into the Earth's atmosphere.

The docking system is to be removed from the Progress and sent to Earth for examination and refinement.