Korzun and Whitson worked together for four hours on Monday and another four hours on Tuesday to replace the Desiccant/Sorbent Bed Assembly of the Carbon Dioxide Removal Assembly (CDRA) in the U.S. laboratory Destiny. There are two such beds in CDRA. The one replaced had not functioned properly since its launch in Destiny on Discovery's STS-98 mission in February 2001 because a valve between the desiccant and sorbent sides had stuck in the open position. The second bed continued to function, and a carbon dioxide scrubber in the Russian segment also was available.
Whitson and Korzun overcame or worked around a series of minor difficulties during the removal and replacement. Engineers and flight controllers on the ground are reactivating the Atmosphere Revitalization Rack where the CDRA is situated. The CDRA will be turned on next Tuesday and operated for several days to verify the success of the replacement.
Crewmembers performed an emergency medical operations drill on Wednesday, designed to keep them sharp in emergency medical procedures and to ensure that equipment is optimally stowed and available.
Whitson also worked with a balky spacesuit battery recharger. Her inputs were valuable to engineers on the ground and flight controllers who devised procedures that should fix the problem, the failure of a battery in the device to discharge before receiving a new charge. She also regenerated one of the spacesuit Metox carbon dioxide removal canisters.
Scientific experiments performed by the crew included work with the Microencapsulation Electrostatic Processing experiment, enclosing a drug or drugs in microballoons. Crewmembers also tended the Advanced Astroculture experiment, which grows soybeans in space with an eye to improving their oil, protein or carbohydrate content. The Microgravity Science Glovebox was used in the Solidification Using a Baffle In Sealed Ampoules experiment, designed to understand the motion in melted fluids to improve semiconductors.
All three crewmembers participated on Tuesday in an Educational Outreach project called Toys in Space. They operated toys, among them a boomerang, a jump rope and marbles, to demonstrate scientific principles. The demonstrations were in conjunction with questions from children at the Houston Museum of Natural Science and the American Museum of Natural History in New York City.
Russian officials have decided to perform a reboost of the International Space Station on Aug. 1, to put it at an optimal altitude for arrival of the next Progress unpiloted Russian supply spacecraft, and the next Soyuz crew return vehicle this fall.