A Russian Progress supply ship loaded with oxygen and critical supplies docked with the international space station today. The final "hard mate" was delayed two orbits or so for troubleshooting to make sure an antenna on the cargo craft had retracted properly.

The Progress M-58 spacecraft was launched from the Baikonur Cosmodrome in Kazakhstan on Monday. It was loaded with 4,812 pounds of equipment and supplies, including 2,784 pounds of spare parts, repair gear, life support and other hardware. The spare parts include equipment to overhaul the Russian Elektron oxygen generator, which was shut down last month after a malfunction.

The Progress also carries 1,918 pounds of propellant that will be added to the station's maneuvering thruster reserves and 110 pounds of oxygen. The astronauts have been tapping into oxygen stored in the U.S. Quest airlock module since the Elektron shut down in late September.

Docking at the aft port of the Zvezda command module occurred at 10:29 a.m. today. But Russian flight controllers told the crew to delay locking the craft securely in place because of concern one of the vehicle's KURS antennas, part of an automated rendezvous and docking system, had not properly retracted.

A fully or partially extended antenna would ram into the station's docking port during the hard-mating procedure when hooks and latches engage to pull the Progress snugly into place. Instead, the M-58 spacecraft was left in a so-called soft-docked mode while Russian engineers discussed the issue.

To avoid jarring the loosely attached Progress, active orientation control was disabled and the station drifted out of optimum alignment for solar power generation. The crew, in turn, was asked to implement power conservation procedures.

About three-and-a-half hours after the initial docking, Russian flight controllers decided to press ahead with hard mating. The Progress was pulled into place with no problems and the station was maneuvered back into its normal sun-tracking orientation.

It was not immediately clear what caused the initial indication the antenna had not retracted, but engineers said it could have been caused by a software glitch.