Discovery astronauts Jeff Wisoff and Mike Lopez-Alegria successfully completed the second of STS-92’s four scheduled spacewalks on Monday, attaching an additional docking port to the growing International Space Station. The two spacewalkers also prepared the Z1 truss for the installation of the huge solar arrays to be launched aboard the next shuttle flight.
Wisoff and Lopez-Alegria began their spacewalk at 9:15 a.m. CDT, about 15 minutes ahead of schedule. Their first job was to release the latches that held the docking port, Pressurized Mating Adapter 3, securely in Discovery’s cargo bay. They helped Koichi Wakata, operating the robotic arm, providing eyes for him as he slowly raised the docking port from its support platform.
While Wakata maneuvered PMA-3 to its new location on the Unity module, opposite the Z1 truss installed Saturday, Wisoff and Lopez-Alegria released latches atop the Z1 truss and prepared an attach point for the large solar arrays that will be delivered during the STS-97 mission scheduled for launch next month. Next they worked their way back to Unity, again to act as an extra set of eyes for Wakata as he attached the docking port.
After Discovery astronauts saw a series of “ready to latch” indicators, Pilot Pam Melroy used a laptop computer to command latches and bolts to begin to secure the mating adapter to its new home on the station. She commanded only the first of four stages of the bolting process. The flight crew will do the final commanding Tuesday morning, after flight controllers in Houston confirm that the temperatures of seals on the docking port and Unity’s Common Berthing Mechanism have become more nearly equal.
Monday’s 7 hour, 7 minute spacewalk, which ended at 4:22 p.m., was the 52nd EVA in the Space Shuttle program and the 91st by Americans in the history of the U.S. space program. It brought to eight the total of ISS assembly spacewalks, with a total time of 55 hours, 50 minutes. With the addition of the 18,000-pound Z1 Truss on Saturday and the 3,000-pound mating adapter, the station has gained about 21,000 pounds during STS-92. It now weighs about 80 tons.
As the spacewalk was ending, Discovery Commander Brian Duffy and Pilot Pam Melroy completed the first of three station reboosts scheduled for STS-92. They fired reaction control system jets in 18 pulses of 1.4 seconds each, over a 30-minute period, gently raising the station’s orbit by about 1.7 statute miles.
The next Mission Control Center status report will be issued at 6 a.m. Tuesday, or as events warrant.
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