Workers at the Kennedy Space Center in Florida have completed a swap-out of the power drive unit on the orbiter and will spend the next few days completing retests to verify the borrowed unit from Columbia is in good working order. At present there is no anticipated schedule impact to the April 24 launch.
Meanwhile, halfway around the world in Russia and Kazakhstan, work continues in preparation for Zvezda's launch atop a Proton launch vehicle. The Proton that will carry Zvezda into space currently is being assembled at its manufacturing plant at the Krunichev Space Center in Moscow. Its assembly is scheduled to be completed in mid May with delivery to the Baikonur Cosmodrome scheduled about two weeks later.
Awaiting the Proton's arrival at the launch site is the Zvezda service module, which will house life support systems, serve as the living quarters, and provide the ISS with command and control and reboost capability through the early assembly sequence. Zvezda's launch remains targeted to occur between July 8 and 14.
STS-101 will be commanded by Jim Halsell and piloted by Scott Horowitz. Joining them are Mission Specialists Mary Ellen Weber, Jeff Williams, Jim Voss, Susan Helms and Yuri Usachev. The seven-member crew will undergo their final physicals and wrap up training activities at the Johnson Space Center, Houston, this week prior to entering quarantine on Monday. The crew will fly to Florida next Friday, April 21, for the final three days of preparations prior to launch.
The current orbit of the ISS is 231 by 214 miles (372 x 344 kilometers). The average decay of the Station's orbit is about 1-1½ miles per week. While docked, Atlantis' reaction control system thrusters will be used to raise the orbit of the station by as much as 19 miles (about 30 kilometers). The actual orbit raising distance is calculated to 'place' the ISS at an altitude conducive to the rendezvous with Zvezda in late July. As of midday today, the station has circled the Earth more than 7,970 times since November 1998.