STS-102, Mission Control Center
Status Report # 21
Sunday, March 18, 2001 – 8 a.m. CST

Carrying nearly one ton of trash and excess equipment, along with personal items belonging to the returning Expedition One crew, the Leonardo cargo carrier was detached from its port on the International Space Station early this morning and gently placed back in Discovery’s payload bay by Mission Specialist Andy Thomas.

After crewmate Paul Richards released the 16 bolts and associated latches holding the Multi-Purpose Logistics Module to its Common Berthing Mechanism port, Thomas received a “go” to begin moving the module with the shuttle’s 50-foot-long robotic arm about 4:40 a.m. CST. About 90 minutes later, at 6:08 a.m., the Italian-built module was securely latched back in its its cargo bay cradle, ready for return to Earth.

Leonardo’s unberthing occurred about four hours later than originally scheduled, due in part to a leaky vacuum access hose used to depressurize the small vestibule between Unity and Leonardo. The hatches between the two modules were closed and the vestibule was depressurized, but after a 15 minute leak check period, ground controllers noted pressure in the vestibule was not at expected levels. Expedition Two flight engineer Jim Voss reported he had found – and tightened – a loose fitting on one of those hoses. The crew was then asked to repeat the depressurization procedure, a process that takes approximately 45 minutes, to verify good seals between the modules. With that action complete, Thomas was given a go to proceed with the unberthing of Leonardo.

Also overnight, Commander Jim Wetherbee and Pilot Jim Kelly verified the performance of Discovery’s general purpose computers. Ground analysis indicated that Saturday morning’s quick power-up of two of those computers would not affect their performance, but flight controllers elected to perform the on-orbit procedure to validate the software load.

Discovery’s crew is scheduled to begin its eight-hour sleep period at 8:42 a.m., waking at 4:42 p.m. The Expedition Two crew will go to sleep one hour later, at 9:42 a.m. and will awaken at 5:42 p.m. The hatches between Discovery and the ISS will be closed for the final time on this mission at 7:37 p.m. today following a final farewell between the STS-102 crew and the two Expedition crews. Discovery is set to undock from the ISS at 10:32 p.m. today, concluding a 136-day stay on board the station for its first resident crew – Commander Bill Shepherd, Soyuz Pilot Yuri Gidzenko and Flight Engineer Sergei Krikalev.

The next mission status report will be issued Sunday evening.

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