CAPE CANAVERAL, Fla. -- Space station astronauts opened the world's first inflatable space habitat Monday and floated inside. NASA astronaut Jeffrey Williams swung open the door to the newly expanded chamber and was the first to enter. He said it was pristine but cold inside. The room -- called the Bigelow Activity Activity Module, or BEAM -- arrived at the International Space Station in April, packed in the trunk of a capsule loaded with supplies.