Two American astronauts have connected cooling hoses and avionic cables to power up a new room of the International Space Station during a spacewalk. Robert Behnken and Nicholas Patrick leaving the ISS hooked up plumbing for the Tranquility room during their second excursion in space in three days. Meanwhile, crew members from the U.S. shuttle Endeavour and the space station worked inside the new module to install oxygen generation and water recycling systems. The installation of the new room and its attached observation deck was to be finished during three spacewalks on the shuttle's 13-day mission. The more than 400-million U.S. dollar Tranquility room, made by the European Space Agency, will provide additional space for the crew members and many of the space station's life support and environmental control systems. The Endeavour docked with the 11-year-old ISS early Wednesday after blasting off from Kennedy Space Center in Florida on Monday.