International Space Station Status Report #04-14A<br />2 p.m. CST, Friday, March 19, 2004<br />Expedition 8 Crew<br /><br />Heading into the homestretch of their 6½-month mission aboard the<br />International Space Station, Expedition 8 Commander Michael Foale and Flight<br />Engineer Alexander Kaleri spent the week conducting biomedical experiments<br />and performing maintenance on a key Station component.<br /><br />Foale and Kaleri spent two days replacing a liquids unit and a water flow<br />system in the Russian Elektron oxygen-generation device in the Zvezda<br />Service Module after weeks of troubleshooting efforts failed to coax it back<br />into service. The Elektron produces oxygen for the Station atmosphere<br />through electrolysis - the separation of hydrogen and oxygen from water that<br />flows through a series of pumps and valves. The hydrogen is vented<br />overboard.<br /><br />Russian specialists spent several weeks trying to track down the most<br />probable cause for repeated shutdowns of the system after just a few minutes<br />of operation each time. They concluded that particles of potassium hydroxide<br />electrolytes - a by-product of the electrolysis process - that created air<br />bubbles in the liquids unit, resulting in the unit's repeated shutdowns,<br />were the most probable cause of the problem.<br /><br />Since last Saturday, the crew has derived oxygen from solid-fuel oxygen<br />generation (SFOG) canisters activated in Zvezda. The crew has been using an<br />average of two SFOGs each day since available air and oxygen were depleted<br />from tanks in the Russian Progress supply vehicle following the first<br />shutdown of the Elektron.<br /><br />Russian engineers now plan to activate the refurbished Elektron Saturday for<br />a few days of checkouts and diagnosis. If the Elektron repair proves<br />successful, the SFOG canisters will no longer be needed. There is an ample<br />supply of those canisters, as well as oxygen contained in the Quest airlock<br />tanks, that could provide oxygen for the Station for several months.<br /><br />To accommodate the Elektron repair, a few lower-priority tasks were moved to<br />other days, including routine proficiency training for Foale on the<br />Canadarm2 robotic arm.<br /><br />On Friday, Foale did a leak check of the window in the Destiny laboratory.<br />In January, a flex hose that helps to vent air from the inner panes of the<br />window was found to be causing a minor pressure decay from the Station.<br />Although the flex hose is operating normally, today's check revealed a<br />slight leak from one of the inner panes of the window. The leak will not<br />affect the pressure in the Station, but it will require another venting<br />procedure in the next week or so to prevent condensation buildup.<br /><br />Foale and Kaleri took advantage of the recently repaired high-tech treadmill<br />to get in several rounds of intense exercise. A lengthy overhaul last week<br />brought the system back into full operation.<br /><br />Foale spent some time this week conducting experiments with a cellular<br />biotechnology device to test methods for improved cell culture growth and<br />with a device designed to measure the forces imparted on the joints of the<br />lower extremities and the feet in the absence of gravity.<br /><br />Foale and Kaleri also took time out from their schedule to answer questions<br />from a syndicated talk show host from the Premiere Radio Networks and from<br />students at the Howard Bishop Middle School in Gainesville, Fla.<br /><br />Information on the crew's activities aboard the Space Station, future launch<br />dates, as well as Station sighting opportunities from anywhere on the Earth,<br />is available on the Internet at:<br /><br />http://spaceflight.nasa.gov/<br /><br />Details on Station science operations can be found on an Internet site<br />administered by the Payload Operations Center at NASA's Marshall Space<br />Flight Center in Huntsville, Ala., at:<br /><br />http://scipoc.msfc.nasa.gov/<br /><br />The next ISS status report will be issued Friday, March 26, or earlier if<br />events warrant.