The ISS Progress 41 cargo craft backs away from the International Space Station after undocking Friday morning. Credit: NASA TV
The departure of an unpiloted Russian cargo craft Friday set the stage for the arrival of the next supply ship and a final visit from space shuttle Endeavour.

The ISS Progress 41 cargo craft, filled with trash and other unneeded items, undocked from the Pirs docking compartment at 7:41 a.m. EDT Friday as the International Space Station flew 220 miles over China. As the Progress slowly backed away from the station, Expedition 27 Commander Dmitry Kondratyev photographed the cargo craft through a window in the Russian segment of the orbiting complex to assess the condition of the rubber seals on its docking interface.

The Russian supply vehicle will remain in orbit a safe distance from the station for engineering tests before being commanded by flight controllers Tuesday to descend to a destructive re-entry into Earth’s atmosphere over the Pacific Ocean.

The departure of Progress 41 clears the way for the next unpiloted supply ship, ISS Progress 42, which is set to launch Wednesday from the Baikonur Cosmodrome in Kazakhstan. The new Progress will arrive at the station on April 29 at 10:29 a.m., just a little more than five hours before Endeavour launches to the station on its final trip into space. The shuttle’s STS-134 crew will deliver the Alpha Magnetic Spectrometer and spare parts including two S-band communications antennas, a high-pressure gas tank and additional spare parts for Dextre.

Flight Engineer Ron Garan spent some time Friday preparing for the arrival of Endeavour as he reviewed the robotics operations involved in removing the Orbiter Boom Sensor System from the shuttle’s payload bay with Canadarm2 and handing it off to the shuttle’s robotic arm.

Meanwhile Flight Engineer Paolo Nespoli performed maintenance on the spacesuits that the STS-134 crew will wear during the four spacewalks planned when Endeavour visits the station. Nespoli performed a water dump and refill of the feedwater tanks and conducted maintenance on the cooling loops of the suits.

Garan and Nespoli joined Flight Engineer Cady Coleman as they continue to unload cargo from the “Johannes Kepler” Automated Transfer Vehicle-2. The European Space Agency supply ship, which delivered seven tons of cargo when it docked to the aft port of the Zvezda service module on Feb. 24, will be reloaded with trash and undocked from the station for disposal in late June.

Cosmonauts Andrey Borisenko and Alexander Samokutyaev, both flight engineers, participated in the Pneumocard experiment, which studies the adaptation of the crew’s cardiovascular system during long-duration spaceflight.

Over the weekend the station’s six residents will enjoy some light-duty time as they attend to some weekly housekeeping chores, perform voluntary science activities and continue their daily two-hour exercise regimen to stave off the physical effects associated with long-duration spaceflight.