NASA EVA: Orbiter Boom Sensor System

The space shuttle's robotic arm released the Orbiter Boom Sensor System at 12:50 a.m., and it was stowed as a permanent part of the space station at 1:42 a.m.

Mike Fincke will connect two grounding connectors, while Greg Chamitoff installs a foot restraint on the station’s robotic arm for use later in the spacewalk.

Currently, a grapple fixture in the middle of the boom is the only one the station arm is able to use, which halves the reach of the boom when on the station’s arm.

To remedy this, the spacewalkers will replace an electrical flight grapple fixture currently on one end of the boom with a power and data grapple fixture the station arm can use.

Once the power and data grapple fixture is added, it will be known as the Enhanced International Space Station Boom Assembly.

Both Mike Fincke and Greg Chamitoff will make their way to the P6 segment of the station’s truss to retrieve the power and data grapple fixture. To retrieve it, Fincke and Chamitoff will work together to release four bolts holding it in place. Chamitoff will then climb onto the station’s robotic arm for a ride back to boom on the starboard side of the station’s truss.

Chamitoff, with assistance from Fincke, will release the six bolts holding the electrical flight grapple fixture to the boom and cut its cable. Then he will install an adapter assembly on the boom, using six bolts and slide the power and data grapple fixture into place on it. Four bolts will hold it in place.