NASA announced, "The ISS Progress 38 cargo resupply ship successfully docked to the aft end of the International Space Station's Zvezda service module at 12:17 p.m. EDT Sunday," saying the docking maneuver was "executed flawlessly by Progress' Kurs automated rendezvous system."
NASA continued, "The Progress spacecraft carries 1,918 pounds of propellant, 110 pounds of oxygen, 220 pounds of water and 2,667 pounds of experiment equipment, spare parts and other supplies to the station. It launched from the Baikonur Cosmodrome in Kazakhstan on June 30. An attempted docking Friday, July 2, was aborted when telemetry between the Progress and the space station was lost about 25 minutes before its planned docking."
In a report on a previous ISS docking on Jan. 19, 2007, NASA said, "The Progress is similar in appearance and some design elements to the Soyuz spacecraft, which brings crew members to the station, serves as a lifeboat while they are there and returns them to Earth."
In the most recent news release, NASA said, "The most likely cause of Friday's aborted docking was traced to the activation of the TORU [Teleoperated Mode of Control] 'Klest' TV transmitter, which created interference with TORU itself, causing a loss of the TORU command link between Progress and the International Space Station that triggered the abort of the Progress docking."
According to Wikipedia, "The TORU system became known to the public in 1997 when it was used during the manual approach of Progress M-34 to Mir that ended up with a dangerous collision."
NASA noted that TORU was not activated for the second attempted docking. "The TORU TV system is designed to provide a view of Zvezda's docking target to station Commander Alexander Skvorstov, if he had to operate a joystick in the service module to dock Progress manually," NASA explained.
NASA reported earlier the same week that there would be delays of the last two space shuttle missions due to "space traffic." The Discovery's expected liftoff date is now Nov. 1., while the final launch of the Endeavour will now occur on Feb. 26, 2011, NASA said.
The Discovery mission will deliver and install the Permanent Multipurpose Module and the Express Logistics Carrier 4 and provide critical spare components for the ISS, while Endeavour will carry additional spare parts to the ISS.