In preparation for that Extravehicular Activity (EVA), the crew spent part of the day checking out the suits that will be worn for the planned six and a half hour excursion to install an ammonia servicing unit on the outside of the station. It contains spare ammonia that could be used in the station's cooling system if needed. They also will attach an experiment to the station to expose samples of engineering materials to the space environment. The samples will be returned to Earth for analysis in about a year.
A second space walk currently is planned for Saturday to hook up heater cables for the first of several girder-like truss structures, that will be delivered to the station next year.
Meanwhile, members of the station's Expedition Two crew continued the handover of station operations to their Expedition Three replacements. Throughout the handover, the stowage of equipment and supplies inside the Leonardo Multi-Purpose Logistics Module continued. Some 5,200 pounds of supplies was confirmed on board the station and will be unpacked and stowed by the Expedition Three crew after Discovery departs early next week.
Early in the day, Russian flight controllers completed the reloading of upgraded software into the computers of the Zvezda module in preparation for next month's arrival of a new module to the station, the Russian Docking Compartment, which will serve as a new docking port for visiting Russian vehicles.
The Russian flight control team continues to track preparations of a Soyuz spacecraft set to deliver the next Progress supply vehicle to the station. Launch from the Baikonur Cosmodrome in Kazakhstan remains targeted for Tuesday with docking Aug. 23.
Early Thursday morning, the Expedition Three crew of Frank Culbertson, Vladimir Dezhurov and Mikhail Tyurin plan to televise a commemorative message marking the one-thousandth day in space for the International Space Station. It was Nov. 20, 1998 when the first element - Zarya - was launched atop a Proton rocket initiating the construction of the orbiting outpost.
Discovery and the station are orbiting the Earth every 90 minutes at an average altitude of 246 statute miles with no systems issues being worked by the flight control team.