STS-114 Report #12 Sunday, July 31, 2005 – 11:15 p m CDT Mission Control Center, Houston, Texas

Now spacewalk veterans, Astronauts Soichi Noguchi and Steve Robinson will step outside for the second of three planned spacewalks today at 3:14 a m CDT The sole objective of the 6 ½-hour excursion is to replace a failed International Space Station attitude control gyroscope

The pair will have about an hour of setup time after exiting Space Shuttle DiscoveryÂ’s airlock and positioning themselves at the StationÂ’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 DiscoveryÂ’s cargo bay while riding the StationÂ’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 RobinsonÂ’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 DiscoveryÂ’s power generation system for transfer to Station

DiscoveryÂ’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

The next STS-114 mission status report will be issued Monday afternoon, or earlier, if events warrant