International Space Station crew completes successful spacewalk
Venturing outside the International Space Station for the final time during their six month stay at the International Space Station, Expedition 10 Commander and NASA Science Officer Leroy Chiao and Flight Engineer Salizhan Sharipov, clad in Russian Orlan spacesuits, left the Pirs Docking Compartment airlock at 1:25 a.m. EST and quickly set up tools and tethers for their excursion.
During the 4-hour, 30-minute spacewalk, the crewmembers installed communications equipment on the exterior of the Zvezda Service Module and Sharipov activated the Russian Nanosatellite for later deployment. The equipment installation tasks were preparations for the maiden docking of the European Space Agencys cargo carrier, the Automated Transfer Vehicle "Jules Verne," due to launch next year.
Leaving the station unmanned, the systems were either deactivated or put in autonomous operation for the duration of the spacewalk. Hatches were also closed between the U.S. and Russian segments of the complex in the unlikely event the crew would not have been able to return to the outpost.
Despite the recent loss of one of the three functioning Control Moment Gyroscopes because of a circuit breaker failure, the remaining two gyros maintained the Stations attitude without Russian thrusters until just before the end of the spacewalk. The Station drifted slightly without attitude control for less than 20 minutes. When Chiao and Sharipov reported they were a safe distance from Zvezda's thrusters, the jets were reactivated and attitude was quickly regained.
The two spacewalkers entered Pirs and closed the hatch at 5:55 a.m. EST to complete their spacewalk an hour ahead of schedule. After repressurizing Pirs, Chiao and Sharipov were scheduled to return to the Station, remove their spacesuits, reactivate the ISS systems and open the hatches to the U.S. segment.
It was the second spacewalk for Sharipov and Chiao's sixth. The pair logged almost 10 hours of spacewalking time during their two Expedition excursions. Today's spacewalk was the 58th in support of ISS assembly and maintenance, the 33rd staged from the ISS itself and the 15th from Pirs. A total of 348 hours and 15 minutes of spacewalking time has been logged in the Stations lifetime.
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The first task was the installation of three space-to-space communications, or so-called WAL, antennas on the forward conical section of Zvezda. The S-band low gain antennas are part of the Proximity Communications Equipment (PCE) to be used for ATV and Service Module interaction during the future rendezvous and docking operations. The first three antennas were installed on the aft end of Zvezda during Expedition 9.
About 2 hours into the spacewalk, from a ladder attached to Pirs, Sharipov deployed the foot-long, 11-pound Nanosatellite toward the aft end of the Station as Chiao photographed its departure. The experiment contains a transmitter and while it orbits the Earth, is expected to help develop small satellite control techniques, monitor satellite operations and develop new attitude system sensors. Russian experts informed the crew they received a good signal from the satellite two hours after its deployment.
The spacewalkers gathered the tools and equipment for the next task as Russian flight controllers inhibited the Russian thrusters from firing in the crews next worksite area. Once that was complete, the crewmembers were given approval to move toward the aft end of Zvezda. Once in place, they installed a Global Positioning System receiver. The receiver is also part of the ATV communications hardware and will give the approaching vehicle data about its relative position to the Station during rendezvous operations.
Chiao and Sharipov also inspected and photographed the location of an antenna used for communications with the Service Module to confirm its position for Russian technicians. Chiao then photographed a previously installed laser reflector that will also be used for ATV proximity operations. The crewmembers continued to secure cabling on Zvezda as they worked their way back toward Pirs.