ORBIT: At 2:45 p.m. Thursday afternoon, the four astronauts floating in and around the space shuttle Endeavour will pull out a bag of freeze-dried bubbly and declare the big, expensive, oft-assailed and yet still awe-inspiring International Space Station officially open for business. In a seven-hour space walk completed Wednesday night, the Endeavour crew installed some rudimentary phones, fixed an antenna and removed the hatch covers from the Unity passageway module -– a ceremonial act that means the International Space Station is now more than the sum of its two current parts.

Aside from some trash that was dropped during maneuvers (and which NASA has to track all the way back to Earth’s atmosphere), the crew’s two long space walks have gone smoothly. But they are only two of hundreds that will be needed before the ISS is fully assembled, and the project’s many critics point out that a mishap -– possibly a deadly one -– is only a matter of time. NASA just keeps its fingers crossed; that’s what they said about the Mir’s many dangerous repair missions, and, well, so far so good. The astronauts remain eager; in space, no one can hear you whine.