Foale and Kaleri spent the better part of three days working closely with Mission Control-Houston to take the treadmill out of its well, remove a gyroscope, replace a bearing within that gyro and put all the pieces back together. Thursday the crew began exercising on the treadmill again. The treadmill has operated properly since, but flight controllers are continuing to monitor its performance during initial exercise sessions with the gyroscope both activated and deactivated.
The crew has been able to exercise on the machine without the Vibration Isolation and Stabilization (VIS) system activated, for the last three months. The VIS system keeps the rigorous movement of the crew on the treadmill from affecting delicate microgravity science experiments.
The crew heard noises coming from the treadmill in November, which engineers determined was a failed bearing in the gyroscope that stabilizes movement in the roll direction. A repair kit was sent to the Station in January aboard a Progress resupply spacecraft. After this week's repair work, Foale reported the noises had stopped.
Repair work will continue onboard the Station this weekend as Kaleri works through troubleshooting procedures on the oxygen-generating Elektron system. Friday he began systematically checking its parts to help determine what may need replacing. There is a full complement of spare parts aboard the Station for the Elektron system.
Russian oxygen-generating canisters will be used to supplement the Station's oxygen beginning Saturday. The final repressurization using Progress oxygen tanks was completed this week. The next Progress vehicle is scheduled to arrive in May. The Station has plentiful supplies of oxygen aboard - enough to last more than four months - if needed. However, the Elektron is expected to be fully operational once the current troubleshooting and necessary repairs are completed.
Friday, Foale completed the third of four sessions with the Foot/Ground Reaction Forces During Spaceflight, or FOOT, experiment. By doing so, he gathered additional data about how he uses his legs differently in microgravity, which will help scientists develop countermeasure techniques for future long-duration spaceflights.
Foale also completed a familiarization session with the Advanced Diagnostic Ultrasound in Microgravity, or ADUM, experiment. The training involved working with a computer-based training program that will help him perform an ultrasound examination on Kaleri next week. The ADUM experiment is studying how minimally trained Station crewmembers can perform advanced ultrasound examinations using the computer-based program and guidance from doctors in Mission Control.