International Space Station commander Oleg Kotov took over manual control of an approaching Progress supply ship Friday after an undisclosed problem and deftly guided the craft in for a smooth docking at the aft end of the Russian Zvezda command module to wrap up a four-day rendezvous.

The aft docking port of the space station's Zvezda service module is visible in a camera view from the approaching Progress resupply craft. Credit: NASA TV

The Progress 53/M-21M spacecraft lifted off from the Baikonur Cosmodrome in Kazakhstan at 3:53:06 p.m. EST (GMT-5) on Nov. 25. Packed away on board were 1,763 pounds of fuel, 48 pounds of oxygen, 57 pounds of air, 925 pounds of water and another 3,119 pounds of spare parts, research equipment and holiday gifts for the station's six-member crew.

Progress cargo ships typically take two days to reach the station, but this time around flight controllers built in extra time for tests of the spacecraft's upgraded KURS rendezvous system, replacing four navigation and positioning antennas with one.

The M-21M spacecraft flew past the station Wednesday, passing within about a mile of the lab complex to give Russian engineers a chance to test the upgraded KURS system. Kotov monitored data from the Progress on a laptop computer as it flew past the outpost and then dropped behind before moving back in for docking Friday.

The final stages of the automated rendezvous appeared to go smoothly but at a distance of about 200 feet, the Progress apparently halted the approach and unexpectedly went into station-keeping mode. Flight controllers told Kotov to take over manual control with the TORU tele-robotic control system in the Zvezda module, using a computer display and a joystick to operate the approaching cargo ship.

Russian cosmonauts are always on standby to take over manual control if the automated system has problems, but there was no immediate explanation as to what prompted the switch to manual control or whether it was related to the KURS upgrades.

In any case, Kotov had no problems lining the Progress up and guiding it in for docking at 5:30 p.m. as the two spacecraft sailed over eastern Asia.