Two members of the Expedition 35 crew wrapped up a 6-hour, 38 minute spacewalk at 3:41 p.m. CDT (2041 GMT) Friday (April 19) to deploy and retrieve several science experiments on the exterior of the International Space Station and install a new navigational aid.
Russian flight engineers Pavel Vinogradov and Roman Romanenko opened the hatch to the Pirs airlock and docking compartment to start the spacewalk at 9:03 a.m. CDT (1403 GMT).
The spacewalkers' first task was to install the Obstanovka experiment on the Zvezda service module. Obstanovka will study plasma waves and the effect of space weather on Earth's ionosphere.
While at the far end of Zvezda, Vinogradov and Romanenko replaced a faulty retro-reflector device, one of a suite of navigational aids that will provide assistance to ESA's "Albert Einstein" Automated Transfer Vehicle 4 cargo ship during its final approach to the station in June.
After deploying a pair of sensor booms for Obstanovka, Vinogradov and Romanenko retrieved the Biorisk experiment from the exterior of Pirs. The experiment studied the effect of microbes on spacecraft structures.
For their final task, the spacewalkers moved to the Poisk module to retrieve one of two Vinoslivost Materials Sample Experiment panels from the Poisk module. As Vinogradov was removing the panel, it slipped out of his grasp and was irretrievable. The trajectory the panel took will move it away from the space station with no chance of the two making contact.
This was the 167th spacewalk in support of space station assembly and maintenance, totaling 1,055 hours, 39 minutes. Vinogradov's seven spacewalks total 38 hours, 25 minutes. Romanenko completed his first spacewalk.
This was the first of as many as six Russian spacewalks planned for this year. Two U.S. spacewalks are scheduled in July.