The pair will have about an hour of setup time after exiting Space Shuttle Discovery's airlock and positioning themselves at the Station's Z1 truss segment. Mission Control will shut down the failed Control Moment Gyroscope 1 (CMG1) about 4:09 a.m. CDT and then give a go for the spacewalkers to start removing it about 15 minutes later. Mission Specialist Andy Thomas will choreograph the activities from inside and relay information from Mission Control to the spacewalkers.
Noguchi will take the failed CMG to Discovery's cargo bay while riding the Station's robot arm. He will temporarily store it until the new gyro is removed and the old one can be placed in its carrier with Robinson's help. Noguchi will then carry the new gyro at the end of the robot arm to the Z1 truss. Discovery Pilot Jim Kelly and Mission Specialist Wendy Lawrence will operate Canadarm2 for the spacewalk.
After it is installed, Station flight controllers will power up and check out the new gyroscope about 8:14 a.m. CDT and start it up at 8:39 a.m. CDT. With CMG1 replaced, the full complement of four gyroscopes will be available for Station operations. CMG2 has operated well since the spacewalkers restored power to it in the first spacewalk Saturday.
Inside the orbiting complex, Station residents Sergei Krikalev and John Phillips and Discovery Commander Eileen Collins and Mission Specialist Charlie Camarda will continue transferring equipment and supplies between the two vehicles. Collins will focus on collecting byproduct water from Discovery's power generation system for transfer to Station.
Discovery's crew was awakened at 10:09 p.m. CDT by the song "Walk of Life," by Dire Straits for Robinson. The Space Station crew was awakened at 10:39 p.m. CDT by a tone onboard.
The crews of Discovery and the Space Station are scheduled to go to sleep about 2:09 p.m. CDT.