The crew of space shuttle Discovery awoke Thursday at 8:51 p.m. EDT to “Defying Gravity” by Idina Menzel and Kristen Chenoweth, played for Mission Specialist Dottie Metcalf-Lindenburger.
Spacewalkers Rick Mastracchio and Clay Anderson spent the night in the International Space Station’s Quest Airlock, which was dialed down to a lower cabin pressure than the rest of the complex to rid their bodies of nitrogen and prevent the bends when they start their excursion. Preparations for the spacewalk resume at 9:26 p.m. and the activity is scheduled to begin at 1:41 a.m. Friday. Mastracchio and Anderson will undertake the laborious job of changing out a spent Ammonia Tank Assembly on the station’s exterior, a task that they will continue during the second spacewalk on Sunday and the third on Tuesday. They also will retrieve an experiment from the outside of the Japanese Exposed Facility and replace a failed gyroscope that is part of the station’s navigation system. Lindenburger will choreograph the spacewalk and serve as a link between Mission Control in Houston and the spacewalkers.