Crew Stays Busy with Maintenance, Tests and Exercise<br /><br />Onboard the International Space Station, a Russian oxygen generator was<br />successfully activated Wednesday. A gyroscope that helps control the<br />Station's direction shut down. The crew continues health tests, exercise and<br />preparations for homecoming.<br /><br />A troublesome oxygen generator inside the Zvezda Service Module was<br />reactivated after two restart attempts. Commander Leroy Chiao and Flight<br />Engineer Salizhan Sharipov spent several hours Wednesday troubleshooting the<br />device known as the Elektron. A recently docked Progress cargo vehicle can<br />replenish the oxygen supply if the Elektron shuts down again.<br /><br />A Control Moment Gyroscope shut down early Wednesday after a circuit breaker<br />tripped. The circuit breaker was replaced last year during an Expedition 9<br />spacewalk after it had tripped also. Two other gyroscopes are maintaining<br />the Station's orientation, however. Thrusters on the Russian side of the<br />orbital outpost can provide steering control, but they use up fuel. Another<br />gyroscope that has been broken for three years is due to be replaced when<br />Space Shuttle Discovery visits the ISS in mid-2005.<br /><br />The Expedition 10 crewmembers participated in a hearing test to determine<br />the strength of acoustic countermeasures. Chiao was also scheduled for a<br />30-minute exercise to strengthen his ability to apply advanced cardio life<br />support in an emergency. Sharipov completed a Russian fitness test series to<br />study preventive health maintenance.<br /><br />In preparation for an April homecoming, Chiao and Sharipov performed a fit<br />check of their seats inside the Soyuz descent capsule. During long-term<br />stays in space the body extends in length. As a result, the fit check helps<br />ensure the seats will adequately protect the crew during touchdown.