At 2:08 p.m. central time, hatches between Endeavour and the station swung open, and the station's Expedition Four crewmembers-Commander Yury Onufrienko and Flight Engineers Dan Bursch and Carl Walz-greeted their visitors-Cockrell, Lockhart, Mission Specialists Franklin Chang-Díaz and Philippe Perrin and oncoming Expedition Five Commander Valery Korzun and Flight Engineers Peggy Whitson and Sergei Treschev.
The 10 astronauts and cosmonauts immediately set to work transferring priority equipment, supplies and experiments between the two vehicles. Items moving to the station included two Extravehicular Activity spacesuits and EVA tools to be used during the mission's three scheduled spacewalks. The Expedition Five crewmembers' custom-made Soyuz return craft seat liners and their Russian entry suits were transferred from Endeavour to the station at 5:55 p.m. central time, marking the official start of the Expedition Five Increment. With that transfer complete, Onufrienko, Bursch and Walz formally concluded their 182-day stay as space station residents. Korzun, Whitson and Treschev now begin their tenure as the fifth resident crew to live and work on board the International Space Station.
Communications checks between the station's Quest Airlock and the EVA suits Perrin and Chang-Díaz will use also were completed today. The spacewalks will see installation of a new platform, the Mobile Remote Servicer Base System, on the station's railcar, the Mobile Transporter, and replacement of the wrist roll joint on the station's arm.
Late in the day, the Flash Evaporator System Primary B controller failed for an as-yet unknown reason. The system has three redundant controllers, Primary A, Primary B and Secondary, and the failure of one controller will have no effect on mission operations.
The Flash Evaporator System sprays excess supply water into the inside of a trash-can shaped vessel that is wrapped by Freon coils. The heat being carried in these coils causes the water to flash into vapor and be vented overboard, disposing of excess heat and excess supply water.