Three crewmembers of the International Space Station took a short trip aboard their Soyuz lifeboat late Thursday as traffic heats up at the orbital outpost.

Russian cosmonaut Gennady Padalka, the station's commander, and two crewmates moved their Soyuz TMA-14 spacecraft to a new parking spot outside orbiting laboratory to clear a berth for a new cargo ship due to arrive in late July. It was a short trip, lasting just 26 minutes and included half of the station's six-man crew, but is part of a carefully orchestrated series of arrivals and departures at the outpost this month.

"It's just a set up for the traffic patterns in orbit," NASA spokesperson Kelly Humphries told SPACE.com before the brief flight.

The Soyuz trip followed the Tuesday undocking of the unmanned Russian cargo ship Progress 33, which left the space station and is loitering nearby. The automated space freighter will return to the space station on July 12, when it will fly within about 50 feet of a roof-mounted hatch on the station to test new docking equipment installed last month. After the test, the disposable cargo ship will be sent plunging through Earth's atmosphere to be intentionally burned up over the Pacific Ocean.

Also due at the space station this month is NASA's shuttle Endeavour, which is set to launch late July 11 from the Kennedy Space Center in Cape Canaveral, Fla. The shuttle is expected to dock at the station on July 13 - one day after the Progress 33 ship's rendezvous test - carrying the last piece of the outpost's massive Japanese Kibo lab. It will be installed during a marathon 16-day mission, which was delayed by a hydrogen gas leak that has since been resolved.

Endeavour will launch with seven astronauts aboard and temporarily boost the station's crew size to 13 people, its highest number ever and the historical maximum population in space at any given time. Past instances of 13 people in orbit occurred aboard multiple spacecraft.

Another unmanned Russian cargo ship, Progress 34, is also slated to launch this month and dock at the space station on July 27, though its arrival may be delayed up to two days depending on when Endeavour flies, NASA officials said. It is because of the impending arrival of Progress 34 that Padalka and his crewmates moved their Soyuz spacecraft today, they added.

Padalka flew the Soyuz spacecraft from the space station's rear docking port at the aft of its Zvezda service module to a new Earth-facing berth on Pirs, a Russian-built module on the outpost's bottom. Also aboard the Soyuz were astronauts Michael Barratt of NASA and Koichi Wakata from Japan.

The short space hop began at 5:29 p.m. EDT as the space station flew 223 miles above the southern Pacific Ocean. Three other members of the station's Expedition 20 crew, representing Belgium, Russia and Canada, remained inside the outpost during the move. Their spacecraft, Soyuz TMA-15, arrived in late May, boosting the station to its full six-person crew for the first time since construction began on the outpost in 1998.

Padalka, Barratt and Wakata were expected to open the hatches between their Soyuz and station at about 8:45 p.m. EDT to rejoin their three crewmates inside the station, NASA officials said.

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