Endeavour’s crew awoke at 10:36 a.m. CST today to begin the orbital assembly of the International Space Station, uniting the first two station modules, Zarya and Unity. The astronauts were awakened to the sounds of "Somewhere Over the Rainbow," requested by Commander Bob Cabana’s daughter, Sarah.
Endeavour’s crew will begin the final stages of a rendezvous with the Zarya module with an engine firing planned at about 1:30 p.m. CST, when Endeavour is at a point about 55 statute miles behind Zarya. That burn will slow the rate at which the shuttle is closing on the module. The final phase of the rendezvous will begin at about 3:15 p.m. CST, when Endeavour performs a terminal phase initiation engine firing, or TI burn, at a point about 9 statute miles behind Zarya. The TI burn will place Endeavour on a path to arrive about 600 feet directly below Zarya on its next orbit of the Earth. With the three-story-high Unity connecting module latched upright in the shuttle’s payload bay, Cabana will take manual control of the shuttle at about 4:45 p.m. CST as it moves to within about a half-mile of Zarya. Cabana and Pilot Rick Sturckow will execute a sequence of maneuvers that will bring Endeavour from 600 feet below Zarya along a circular path, passing about 350 feet in front of it and finally reaching a point about 250 feet directly above the module.
From there, Cabana will fly Endeavour down toward the Zarya, relying on views from television cameras in the shuttle’s payload bay to align the module, since Unity obstructs the view out of the cockpit windows. Mission Specialist Nancy Currie will operate Endeavour’s outstretched arm for the capture of Zarya. Mission Specialists Jim Newman and Sergei Krikalev will assist with the rendezvous, using a hand-held laser to provide range and closing rate information as Endeavour narrows the gap with Zarya.
When the edge of Endeavour’s payload bay is within 10 feet of Zarya, Currie will use the robotic arm to capture the module, about 5:46 p.m. CST. She then will maneuver it into a position precisely aligned above Unity’s docking mechanism. The 21-ton Zarya will be the most massive object ever moved with the robotic arm, more than three tons heavier than the Compton Gamma Ray Observatory that was released using the arm on Space Shuttle mission STS-37.
Once the Zarya and Unity docking mechanisms are aligned and positioned only inches apart, Currie will put the arm into a "limp" mode while Cabana fires Endeavour’s thrusters to force the mechanisms together, about 7:36 p.m. CST.
Zarya is 41.2 feet long and 13.5 feet wide at its widest point. Once attached to Unity, the new station will tower about 76 feet above Endeavour’s payload bay and have a solar array span of about 78 feet and a combined mass of approximately 80,000 pounds. When fully assembled in 2004, the International Space Station will be larger than a football field and have a mass of more than one million pounds.
Following the mating of Unity with Zarya, Sturckow and Mission Specialist Jerry Ross will begin early preparations for the crew’s entry into the new station, planned for Thursday, and begin setting up equipment for tomorrow’s planned spacewalk by Ross and Newman to connect power and data cables between Unity and Zarya.
The next STS-88 status report will be issued at around 3:30 a.m. Monday. -end-
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