Astronauts Prepare for Spacewalk to Remove Gap Filler

Photographed from ISS while docked with Discovery. Image credit: NASA Click to enlarge
The Space Shuttle Discovery crew begins their ninth day in space with preparations for the third spacewalk of the mission. This extravehicular activity (EVA) was a preplanned activity for the mission, but now includes a new task — repair of two protruding gap fillers between tiles on the bottom the Shuttle.

The crew began the day waking up at 10:09 p.m. CDT to “Where My Heart Will Take Me,” the theme song from Star Trek: Enterprise. The song, composed by Dennis McCarthy, was selected for the crew as a surprise dedication from the Deputy Shuttle Program Manager Wayne Hale. The International Space Station Expedition 11 crew of Sergei Krikalev and John Phillips woke 30 minutes later.

Mission Specialists Steve Robinson and Soichi Noguchi are scheduled to begin their third spacewalk at 3:14 a.m. CDT as they exit out of the Space Shuttle airlock. The two will be assisted by Andy Thomas, serving as the intravehicular officer overseeing the spacewalk from inside, as well as Pilot Jim Kelly and Mission Specialists Wendy Lawrence and Charlie Camarda who will be supporting various robotic arm activities throughout the day.

The spacewalk is scheduled to last about 7 hours. The first task entails Kelly and Lawrence maneuvering the External Stowage Platform-2 (ESP-2), via the Station’s robotic arm, which they pulled from Discovery’s payload bay earlier today, onto the Station. As the ESP-2 reaches its final position, Robinson and Noguchi will guide the structure and secure it into place. With that task complete, Lawrence and Kelly will conduct a “walk off” maneuver of the Station robotic arm, by attaching the “free” end to the Mobile Base System and releasing the other end from the Destiny Laboratory module to where it will be needed as a platform for Robinson later in the EVA.

The two spacewalkers will move on to individual tasks, with Noguchi installing the Materials International Space Station Experiment-5 (MISSE-5), a materials experiment that will study the degradation of solar cell samples in the space environment. He’ll then remove the Rotary Joint Motor Controller from the Space Station truss before proceeding to a support position to assist Robinson in his final tasks.

Meanwhile, Kelly will work with Camarda, using the Orbiter Boom Sensor System to inspect repair demonstration tiles inside the Shuttle’s payload bay. Later, Camarda will also work with Krikalev and Phillips to continue stowing supplies and equipment inside Discovery and the Station. Discovery Commander Eileen Collins will monitor and supervise all the activities.

Robinson, now attached to the Station robotic arm, will attempt to repair two tile gap filler protrusions located on the underside of Discovery. He will first try to gently pull out the protruding material, and if need be, remove by trimming with a hacksaw.

Gap fillers are used in areas to restrict the flow of hot gas into the gaps between Thermal Protection System components. They consist of a layer of coated Nextel fabric and are normally about 0.020-inch thick. These protrusions were identified from photos taken during the rendezvous pitch maneuver conducted on flight day three, as Discovery approached the orbiting Space Station.

The crews are scheduled to go to sleep about 2:09 p.m. CDT.

Original Source: NASA News Release