A previous attempt five days earlier had to be aborted on Tuesday, July 23, 2012, when the new Kurs-NA rendezvous system on board the Russian vessel failed to work properly.
Further testing of the rendezvous system found that a defective proximity sensor caused the botched docking.
However, after modifying the system's software, the Russians decided to try a second attempt, which turned out to be successful.
The vessel had already docked to the International Space Station after being launched by the Russian. It had been undocked from the ISS for the test about a week ago to perform engineering tests and to test the new system. The vessel was attempting to re-dock when the failure happened.
However, the second attempt early Sunday, at 9:01 Eastern Daylight Time (EDT), was successful and Russian mission controllers reported no problems with the new rendezvous system onboard the Progress spacecraft.
The Progress 47 vessel docked to the ISS's Pirs module, and will remain there until it undocks on Monday, July 30, 2012, for its fiery demise into Earth's atmosphere.
However, the Kurs-NA system will be taken out of the spacecraft before it undocks, and will be returned to Earth for further analysis as to what exactly went wrong.
The YouTube video "ISS Progress 47 Re-docks to Space Station" shows the redocking of the Russian vessel. It's caption states, "The ISS Progress 47 cargo vehicle docks once again to the International Space Station's Pirs docking compartment Saturday, July 28, 2012, at 9:01 p.m. EDT after a successful test of its new automated rendezvous system." (http://www.youtube.com/watch?v=uSpsjodaKw0)