Discovery continues its pursuit of the International Space Station, currently trailing the outpost by 3,520 miles and closing that distance at the rate of about 660 miles with every orbit of the Earth. All systems aboard the Space Shuttle Discovery are ready for tonightís docking, scheduled for 11:34 p.m. as the two spacecraft fly just off the east coast of Brazil.
Overnight, the STS-102 astronauts Jim Wetherbee, Jim Kelly, Paul Richards and Andy Thomas, and Expedition 2 crew members Yury Usachev, Jim Voss and Susan Helms installed and checked out a targeting camera, extended the orbiter docking systemís spring-loaded docking ring and unpacked rendezvous tools such as laptop computers and hand-held range-finders. They are scheduled to begin an abbreviated seven-hour sleep period at 9:42 a.m. today. When the crew wakes up at 4:42 p.m. to begin their final rendezvous activities, Discovery will be about 40 miles behind and slightly below the ISS.
About 9:15 p.m., at a distance of about nine miles behind the station, Wetherbee will fire Discovery's engines in a Terminal Initiation (Ti) burn, allowing the shuttle to close in, using its rendezvous radar system to track distance and approach speed. Once Discovery is about half a mile below the station, Wetherbee will take over manual control. Wetherbee will fly Discovery slowly to a point about 600 feet directly below the station, then move up and in front of the orbiting outpost. Closing in and stopping a little more than 300 feet directly in front of the station, Kelly will help control Discovery's approach as Thomas and Richards manage the shuttle's docking mechanism and rendezvous tools. Using a view from a camera mounted in the center of Discovery's docking mechanism, Wetherbee will center the docking ports of the two spacecraft precisely, double-checking the alignment 30 feet out. The final approach will be at a relative velocity of one-tenth of a foot per second.
When Discovery makes contact with Pressurized Mating Adapter 2 on the end of the Destiny module, latches will automatically attach the two spacecraft together. Once relative motion between the spacecraft stops, Thomas will retract the docking ring on Discovery's mechanism, closing latches to firmly secure the shuttle to the station
Early this morning, Wetherbee and Usachev received a congratulatory call from Sergio De Julio, president of the Italian Space Agency responsible for developing the Multi-Purpose Logistics Module, Leonardo, that holds nearly five tons of equipment to be transferred to the station. Leonardo will be temporarily attached to the station during the first of two scheduled space walks on Saturday, to allow the transfer of the equipment and supplies housed inside.
Meanwhile, on board the ISS, Expedition 1 Commander Bill Shepherd, Pilot Yuri Gidzenko and Flight Engineer Sergei Krikalev made last-minute preparations for the arrival of their temporary guests and long-term replacements. The Expedition crews will exchange places on the ISS in a three-step fashion, beginning with Usachev and Gidzenko, who will swap places as Station and Shuttle crew members early Saturday within hours after docking.
The next STS-102/International Space Station mission status report will be issued about 8 p.m. Friday.
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