Report #12<br />4 p.m. CST, Friday, March 21, 2003<br />Mission Control Center, Houston, Texas<br /><br />Expedition 6 crewmembers on the International Space Station this week<br />continued science investigations and made repairs and upgrades to their<br />orbital home. They also studied plans for the second spacewalk of their<br />mission.<br /><br />Commander Ken Bowersox and NASA ISS Science Officer Don Pettit on Monday<br />installed a new Pump Package Assembly (PPA) in the Moderate Temperature<br />Control Loop (MTL) of the Destiny Laboratory's Thermal Control System, which<br />provides cooling for the station's avionics control boxes. The old pump had<br />failed the previous day. The new pump was started Tuesday but one of its<br />check valves stuck open. Thursday, the crew and flight control team worked<br />together to reseat that check valve, get the PPA running, and verify the MTL<br />for operation. Cooling for the Lab's systems was provided through the TCS's<br />Low Temperature Loop during the interim.<br /><br />While the Americans were installing the new pump Monday, Flight Engineer<br />Nikolai Budarin upgraded the Russian computer system's control software.<br />Wednesday, the crew helped ground controllers respond to a<br />computer-commanded power down of many station systems and science equipment.<br />After the Russian computer system was rebooted, a Russian terminal computer<br />in the Zvezda module was unable to communicate with U.S. Guidance,<br />Navigation and Control (GNC) computer #2, which was in control at the time.<br />When the two computers couldn't talk because of the ongoing software<br />transition, a routine handover of station attitude control to the Russian<br />segment was not possible. This prompted U.S. computers to begin powering<br />down non-critical systems. Flight controllers in Houston restarted all<br />systems within hours, station attitude control was never lost an there was<br />no damage to any station system.<br /><br />The trio also started reviewing a timeline for the second spacewalk of their<br />tour of duty, now scheduled for April 8. Bowersox and Pettit, who conducted<br />the first spacewalk of the mission on Jan. 15, are preparing for another<br />excursion to several sites along the station's Integrated Truss Structure<br />where they'll reconfigure power connections, release a light stanchion on<br />one of the Crew Equipment Translation Aid (CETA) carts, provide a second<br />power source for one of the station's control moment gyroscopes, and secure<br />thermal covers on quick disconnect fittings for the station's thermal<br />control system. This will be the 51st spacewalk in support of station<br />assembly, the 26th to originate from the station itself.<br /><br />After weeks of careful troubleshooting for the cause of a power failure in<br />the Microgravity Science Glovebox, an inquiry board from the European Space<br />Agency has approved a return to normal operation for the experiment facility<br />in the Destiny Laboratory. The apparatus, which provides a controlled<br />environment for microgravity science experiments involving fluid, fumes and<br />flames, has been inoperative since the failure of two power-control boxes in<br />late November. Repaired components were installed in early February, but<br />after being restarted the MSG exhibited signs similar to those seen just<br />prior to its failure late last year. Since then, Pettit has worked with the<br />Payload Operations Center at NASA's Marshall Space Flight Center in<br />Huntsville, Ala., and ESA specialists to complete a detailed series of<br />tests, and they have uncovered no failures or unusual current draws. Next<br />week, MSG will be fully powered and evaluated, and then could be cleared for<br />full operation.<br /><br />Tuesday morning, Bowersox and Pettit talked about the goals of their mission<br />and their progress in achieving them with WISH-TV in Indianapolis (Bowersox<br />is from nearby Bedford, Ind.) and Pettit's hometown newspaper, the Silverton<br />(Ore.) Appeal-Tribune.<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 on Friday, March 28, or sooner if<br />events warrant.<br /><br /><br />###