Russian engineers will spend this weekend analyzing an intermittent problem with the International Space Station (ISS) primary oxygen-generating device. Although the crew is in no danger, engineers want to better understand the situation before taking corrective action.
The oxygen-producing Elektron was restarted today after Expedition 9 Commander Gennady Padalka performed troubleshooting work. It shut down again after operating for approximately one hour. Russian specialists decided to forego additional troubleshooting until Monday. They will have more time to determine why a gas analysis mechanism in the system commanded the Elektron, which is located in the Station’s Zvezda Service Module, to shut down two other times after Padalka cleaned and flushed lines in the device. The Elektron originally shut down on Wednesday, prompting Padalka’s maintenance work.
Despite the intermittent performance of the Elektron, there is plenty of oxygen in the Station’s cabin atmosphere. U.S. flight controllers slightly increased nitrogen levels on board with nitrogen from the Quest airlock tanks. No additional repressurization of the cabin atmosphere is required. The Elektron’s temporary shutdown poses no immediate impact on ISS operations.
After several hours of work on the system this morning, Padalka told Russian flight controllers, the reassembled Elektron had twice run for about five minutes before shutting down. Eventually, Padalka and flight controllers disabled an Elektron gas analyzer sensor system, and the device continued to operate for a little more than an hour before it commanded itself to shut off again. The Elecktron separates water into oxygen for ISS use and hydrogen, which is vented overboard.
Russian flight controllers believe a modification in the
software that regulates commands for the gas analyzer could fix the problem early next week.
Padalka and NASA Flight Engineer/Station Science Officer Mike Fincke completed their 145th day in space today and their 143rd day onboard the orbiting laboratory.
On Wednesday, Padalka used spare parts sent up on a Russian Progress resupply spacecraft last May to bring a spare liquids unit for the Elektron back to operational status. There are no plans to use the backup unit, but it is available, if needed. The Progress docked to the ISS has full oxygen and air tanks. Additional oxygen is available in two high-pressure tanks on Quest, if they are needed. There are 84 Solid Fuel Oxygen Generator canisters, a 42-day supply of oxygen for the crew, available, but there are no plans to use any reserve oxygen supplies.
Earlier in the week, Padalka and Fincke conducted routine housekeeping tasks and a few post-spacewalk tasks, including the stowage of spacewalking tools and the servicing of the Russian Orlan space suits.
Fincke also conducted optional science activities, including some remaining data takes with a Dutch experiment that helps to characterize the performance of a grooved heat pipe in microgravity. European Space Agency astronaut Andre Kuipers brought up the experiment to the Station in April.
Both crewmembers worked with other science and medical experiments this week. Padalka conducted the PLANTS experiment as well as the PROFILAKTIKA experiment. It is designed to study countermeasures to negative physiological effects of lengthy spaceflight.
Fincke also performed proficiency training for the Advanced Diagnostic Ultrasound in Microgravity medical experiment and on Thursday, both crewmembers participated in a bone scanning procedure. That research will not only assist with onboard medical situations but is being developed for possible use in remote areas on Earth.
Padalka and Fincke wrapped up their week with a televised conversation with Native American students at the United Tribes Technical College in Bismarck, N.D. It was the featured event during the 35th Annual United Tribes International Powwow. NASA representatives from the Johnson Space Center and the Langley Research Center attended the powwow and tribal meetings to promote NASA education and Explorer Schools.
Information about crew activities on the ISS, future launch dates and Station sighting opportunities from Earth, is available on the Internet at:
http://spaceflight.nasa.gov/
For details about Station science operations on an Internet site administered by the Payload Operations Center at NASA’s Marshall Space Flight Center, Huntsville, Ala., visit:
http://scipoc.msfc.nasa.gov/