With temperatures hovering around 28 degrees Fahrenheit, the Proton and the Zarya Control Module were delivered by rail car to its launch pad with everything on track for launch Friday at 11:40 a.m. Baikonur time (1:40 a.m. EST, 12:40 a.m. CST, 6:40 a.m. GMT, 9:40 a.m. Moscow time). The Proton's rollout to the launch pad occurred after Russian and American officials met to give final approval for the launch, following a review of vehicle and booster systems.
The early forecast for Friday at Baikonur called for overcast skies and subfreezing temperatures, no constraint to the launch of an unmanned Russian booster. The Proton's three stages will be fueled with asymmetrical dimethylhydrazine and nitrogen tetroxide about six hours before launch. American flight controllers belonging to the Houston Support Group at the Russian Mission Control Center outside of Moscow have joined a team of flight controllers from the Khrunichev State Research and Production Space Center to keep tabs on final preparations for the start of the multinational project.
Khrunichev built Zarya under contract to prime contractor, Boeing, and will work in concert with American flight controllers to monitor Zarya's systems during launch and its early life on orbit. Another team of U.S. flight controllers will operate out of the International Space Station Flight Control Room at the Johnson Space Center in Houston to provide round-the-clock support for the lifetime of the International Space Station.
The Proton rocket weighs one and a half million pounds fully fueled and generates more than 2 and a half million pounds of thrust from its three stages during the 9 minute, 47 second-ride from launch pad to spacecraft separation.
Within seconds after the Zarya is separated from the Proton's third stage, a pre-programmed sequence of events will occur when the module's computers command the deployment of critical antennas and the Zarya's solar arrays, providing the new module with a wingspan of 80 feet for the generation of electricity.
Zarya's initial orbital altitude will be about 220 by 115 statute miles. The altitude will be circularized next week following a series of maneuvering system engine firings, placing Zarya in the proper orbit for the arrival of the shuttle Endeavour almost three weeks from now, carrying the Unity connecting module, or node. Zarya will be grappled by Endeavour astronaut Nancy Currie through the use of the shuttle's robot arm during the first assembly mission, STS-88, and will be mated to Unity, setting the stage for three spacewalks by Jerry Ross and Jim Newman to connect cables and install equipment for future Station construction flights.