The 4 hour 58 minute spacewalk by Commander Sergei Krikalev and Flight Engineer John Phillips was the 62nd EVA in support of ISS assembly and maintenance, the 34th conducted from the Station itself, the 16th from the Pirs docking compartment.
The first job once Krikalev and Phillips opened the hatch on Pirs at 2:02 pm CDT was retrieval of one of three canisters from the Biorisk experiment, a biomedical study of the impact of spaceflight on bioorganisms. Biorisk was installed on the Pirs module by Expedition 10 spacewalkers Leroy Chiao and Salizhan Sharipov in January of this year; the other canisters will be retrieved on later EVAs.
Next the spacewalkers moved to the large diameter section of the Zvezda module and prepared two experiment payloads for removal. MPAC, the Micro-Particles Capturer, uses aerogels and foam to collect natural and human-made orbital debris outside ISS; its companion experiment pallet, SEED (Space Environment Exposure Device), exposes samples of possible spacecraft materials like paint, insulation and lubricants, to the environment of low Earth orbit. Matroshka is a biomedical experiment collecting data on radiation absorption by crewmembers on long-duration missions, especially when spacewalking.
From there Krikalev and Phillips moved to the aft of Zvezda to install a backup television camera to assist in docking of the European Space Agency's Automated Transfer Vehicle, a new unmanned supply craft for ISS slated to make its first flight next year. While in the area the spacewalkers photodocumented the condition of an experiment called Kromka, which measures residue from the firing of the nearby jet thrusters, and exchanged sample containers in the materials exposure experiment SKK, the Russian initials for replaceable cassette container.
By the time the spacewalkers gathered together Matroshka, MPAC and SEED and their cluster of tools and transported them all back for stowage inside Pirs, they were about 45 minutes behind the timeline for today's spacewalk. That delay, combined with an estimated two hours it would take to complete the last planned task-relocation of a Strela cargo crane adapter from Zarya to Pressurized Mating Adapter 3 on the Unity node-caused Russian mission managers to decide to forego the last planned task until a later spacewalk. The hatch to Pirs was closed at 7 p.m. for an official spacewalk duration of 4 hours, 58 minutes.
Today's spacewalk was the first in Phillips' career and the eighth for Krikalev, who collected 36 hours and 10 minutes spacewalking experience on seven EVAs during his two missions to the Russian space station Mir.
On Tuesday, at 12:44 a.m. CDT, Krikalev's total time in space surpassed the record of 747 days, 14 hours and 14 minutes set by Cosmonaut Sergei Avdeyev. Krikalev flew two long-duration flights to the Mir space station, two Space Shuttle missions, and was Flight Engineer on the first Expedition to ISS before this flight as Commander of Expedition 11.
The Russian Vozdukh carbon dioxide removal system has been shut down since last Thursday, and Russians specialists are working on a recovery plan. Meanwhile, the Carbon Dioxide Removal Assembly in the U.S. portion of the Station, which has been scrubbing the Station's air since Vozdukh's shut down, failed early this morning due to a stuck check valve, the latest instance of a known and understood problem. It is being managed back to operation by flight controllers in Houston, who reported to the crew that carbon dioxide levels on board ISS are well below the levels that would pose any danger. Plans call for Krikalev to do troubleshooting on Vozdukh starting tomorrow.