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International Space Station Expedition 11 Science Operations Status Report for the Week Ending May 6, 2005
Steve Roy
Marshall Space Flight Center, Huntsville, Ala.
(Phone: 256.544.0034)
Status Report: 05-068

Expedition 11 NASA Science Officer John Phillips and Commander Sergei Krikalev conducted the first of three sessions with the Renal Stone experiment. The Renal Stone experiment is investigating whether potassium citrate, a proven Earth-based therapy to minimize kidney stone development, can be used as a countermeasure to reduce the risk of kidney stone formation for crewmembers in space. Astronauts are at an increased risk of developing kidney stones because urine calcium levels are typically much higher in space.

The Renal Stone investigation has been designed as a double-blind study. The crewmembers do not know whether they are taking the potassium citrate or a placebo. Further, the Principal Investigator, who will interpret the data, does not know in advance which crewmembers have taken the potassium citrate or which have taken the placebo. The Principal Investigator will study the urine chemistry of the samples to determine each individual's risk of renal stone formation. If the Investigator’s hypothesis is correct, the crewmembers identified as having a lower renal stone formation risk will be those that have taken the potassium citrate pills in-flight.

During this session, Phillips and Krikalev performed a 24 hour urine collection and logged everything they ate and drank for 48 hours. This experiment is crucial to long duration missions since kidney stones can incapacitate a crewmember, and in the worse case, threaten their life if there is no way to get them back to Earth quickly.

NASA’s payload operations team at the Marshall Center coordinates U.S. science activities on Space Station.