After working for several hours unsuccessfully Thursday morning to inflate an expandable module attached to the International Space Station, NASA astronaut Jeff Williams and a team of engineers in Houston decided to delay operations for a day. Williams summed up the efforts by saying, "That's the space business."

The initial steps of the process to expand Bigelow Aeropace's habitat from a length of 5.7 feet to 13 feet went well. But when Williams opened a valve to add air into the module, pressure inside it began to increase at a greater rate than expected, and the habitat expanded only very slowly. When Williams stopped and then repeated the valve-opening process four more times, the same anomalous pressure rises occurred. After engineers on the ground conferred, they decided to delay the expansion efforts until Friday morning at the earliest.

Teams from NASA, which has paid Bigelow $17.8 million to test the concept, and Bigelow are expected to meet today to study data from the expansion attempts, determine what went wrong, and then make a decision on whether to proceed Friday.

There is considerable interest in the aerospace community, as well as Congress, surrounding Bigelow's project, because NASA is looking at new types of habitation modules for deep space exploration. Lacking a rigid structure, inflatables can be folded inside the limited diameter of a rocket fairing. Once in space they can be expanded to create a massive amount of volume. There are also considerable mass—and potentially cost—savings.

Bigelow already has plans for private space stations and much larger modules, beginning with one that contains 330 cubic meters of volume, but first it must prove to NASA—and the rest of the world—that inflatables can be safely deployed and inhabited. It will get another chance to do so Friday.