Early this week Commander Ken Bowersox, Flight Engineer Nikolai Budarin, and NASA ISS Science Officer Don Pettit completed the first of three rounds of sample collection for a Human Life Sciences experiment looking into the risk of kidney stone formation in astronauts during extended spaceflights. The investigation, developed by Peggy Whitson before her assignment on the Expedition 5 crew, tests whether the use of potassium citrate, which has been used successfully to combat kidney stones in people on Earth, decreases the occurrence of stone formation in astronauts during long periods in a microgravity environment. This week Bowersox, Budarin and Pettit also finished their first monthly session with an apparatus that measures pulmonary function, gathering data on possible adverse impacts from being in zero-g or in the lower-than-normal atmospheric pressure inside a spacesuit during a spacewalk.
On Thursday Pettit completed a scheduled monthly check of the GASMAP equipment in the Human Research Facility rack. The Gas Analyzer System for Metabolic Physiology analyzes gases in a crewmember's breath so flight surgeons can assess aerobic capacity; it also measures cardiac output and lung volume and efficiency.
Flight control teams in Houston and Moscow continue to work on rescheduling the increment's only planned spacewalk, which was postponed this week. The spacewalk by Bowersox and Budarin, which includes tasks to continue outfitting the station's new P1 Truss but is not time-critical, is being considered for late January. The station's Expedition 5 crewmembers—Commander Valery Korzun, NASA ISS Science Officer Peggy Whitson, and Flight Engineer Sergei Treschev—completed their 185-day spaceflight Dec. 7 when the space shuttle Endeavour and its crew, after waiting out three days of poor weather, landed at Kennedy Space Center. Endeavour delivered Expedition 6 and the P1 Truss during its two-week mission. Korzun, Whitson and Treschev returned to the Johnson Space Center in Houston Monday to continue their physical rehabilitation after six months in weightlessness.