Space station crew members released a spacesuit-turned-satellite during the second spacewalk of their mission last night. Called SuitSat, it faintly transmitted recorded voices of schoolchildren to amateur radio operators worldwide for a brief period before it ceased sending signals.
Expedition 12 Commander Bill McArthur and Flight Engineer Valery Tokarev ventured outside for a five-hour, 43-minute spacewalk to release SuitSat, conduct preventative maintenance to a cable-cutting device, retrieve experiments and photograph the station's exterior. Clad in Russian Orlan spacesuits, McArthur and Tokarev opened the hatch to begin the spacewalk at 5:44 p.m. EST. It was the fourth career spacewalk for McArthur and the second for Tokarev.
After setting up tools and equipment, they positioned the unneeded Orlan spacesuit on a ladder by the station's Pirs airlock hatch. The suit reached the end of its operational life for spacewalks in August 2004. It was outfitted by the crew with three batteries, internal sensors and a radio transmitter for this experiment.
The SuitSat provided recorded greetings in six languages to ham radio operators for about two orbits of the Earth before it stopped transmitting, perhaps due to its batteries failing in the cold environment of space, according to amateur radio coordinators affiliated with the station program. The suit will enter the atmosphere and burn up in a few weeks. Tokarev pushed the suit away toward the aft end of the station as the complex flew 225 miles above the south central Pacific Ocean. The suit initially drifted away at a rate of about a half meter per second, slowly floating out of view below the Zvezda Service Module and its attached Progress cargo craft. The suit is now separating from the station at a rate of about six kilometers every 90 minutes.
McArthur and Tokarev then moved from Pirs to the Zarya module where they removed a hubcap-shaped grapple fixture adapter for the Strela crane. They moved the adapter to Pressurized Mating Adapter-3 on the Unity module. The Strela fixture was moved to prepare Zarya for the future temporary stowage of debris shields.
McArthur and Tokarev made their way to the center truss segment of the station, where they tried and failed to securely install a safety bolt in a contingency cutting device for one of two cables that provide power, data and video to the Mobile Transporter rail car. The transporter moves along the truss to correctly position the Canadarm2 robotic arm for assembly work. The Trailing Umbilical System cable on the nadir, or Earth-facing side of the transporter was inadvertently severed by its cutter on Dec. 16.
After several attempts to drive the bolt with a high-tech screwdriver, McArthur wire-tied the cable to a handrail instead. That left the cable out of its cutting mechanism, disabling the Transporter from further movement on the station's rail system for the time being. The Transporter is not needed for assembly work until the STS-115 mission to install additional truss segments.
The severed cable reel mechanism will be replaced during one of the three spacewalks by Discovery crewmembers Piers Sellers and Mike Fossum during the STS-121 shuttle mission later this year.
McArthur and Tokarev moved back to Pirs. Once at the Russian airlock, they retrieved an experiment to study the effect of the space environment on microorganisms.
As their final spacewalk task, the crew photographed the exterior of Zvezda, including Russian sensors that measure micrometeoroid impacts, handrails, propulsion systems and a ham radio antenna. McArthur and Tokarev then returned to the Pirs airlock and closed the hatch at 11:27 p.m. EST. It was the 64th spacewalk in support of station assembly and maintenance, the 36th staged from the station, and the 17th conducted from Pirs. In all, station spacewalkers have accumulated 384 hours and 23 minutes outside the facility since December 1998.
Meanwhile in Russia, final preparations were made this week to ship the next Soyuz spacecraft from Moscow to the Baikonur Cosmodrome launch site in Kazakhstan. The spacecraft is scheduled to depart Monday and will launch the 13th station crew in late March.
During the week, the station was maneuvered through a new procedure using guidance and navigation computers in the Destiny laboratory to request firings of the thrusters on the Zvezda module while maintaining overall attitude control through the Control Moment Gyroscopes.That saves time in handing orientation control of the station between the U.S. and Russian systems.
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