During my visit to Building A last July, I got to see the control room, the nerve center where the Genesis I team monitors and controls the orbiting craft. The room, a house-size black enclosure, sits along one interior edge of the massive building, its outer walls painted with murals on interplanetary themes. That day the company let us meet with its top engineers and managers, including Bigelow himself, who seemed elated and eager to talk after years of secrecy.

The swagger of Bigelow and his team was justifiable: they had pulled off a space spectacular in getting Genesis I up and running in orbit on the company’s very first space shot, and they knew it. Genesis I was launched flawlessly this past 12 July, atop a Dnepr booster from a pad in the Orenberg region of Russia. “I’m on cloud nine over this success,” said Bigelow, whose radiant grin was hard to reconcile with the recluse who had dodged the news media for years. But he added, “I don’t want to give the impression we think we’ll have this much success every time.”

His chief engineer, 30-year old Eric Haakonstad, put it bluntly: “The amount of success on the first launch was probably the biggest surprise.” The team went on to explain why they believe their inflatable technology gives them some key advantages over other private ventures in space construction. The first is size. Currently, space station modules are rigid metal cylinders with volumes that are constrained by the dimensions of the booster rockets used to put them into orbit. For example, ISS modules brought up by the shuttle are limited by the size of the shuttle’s cargo bay to about 4.4 meters in diameter and 14 meters long. An inflatable module, on the other hand, can be launched deflated, fitting neatly on top of its booster. Once in space, it can balloon to several times the size of any rigid module that could be brought up on the same booster.

An inflated module also weighs less than a comparably sized rigid module. An inflatable design that NASA studied and that was the direct ancestor of Genesis I, dubbed the TransHab, provided 340 cubic meters of pressurized space with a mass of 13.2 metric tons, a volume-to-mass ratio of 25 to 1. By comparison, the Japanese module mentioned earlier, with its 150 cubic meters of space, has a mass of 15.9 metric tons, a volume-to-mass ratio of just 9 to 1.

Inflatable space modules should also be safer than their rigid counterparts. This may seem counterintuitive at first: shouldn’t solid metal walls offer better protection against temperature extremes, micrometeoroids, and space debris than a skin of fabric? And in the worst-case scenario, in which a hurtling bit of debris does puncture a module wall, wouldn’t a metal module at least offer the guarantee of not collapsing around you while you try to deal with the loss of atmosphere?

It turns out that the surprising answer is no, as NASA itself demonstrated a decade ago in the TransHab project. Before TransHab, “people doubted you could fly humans in a vehicle walled with cloth,” recalls William Schneider, who directed the project for NASA. During TransHab, Schneider knew he’d have to come up with something good to convince other engineers that the skin of an inflatable module could be made tough enough to stand up to the hazards of space, so he set a high bar for the project. “I chose a safety factor of four,” he says—meaning that the flexible fabric and underlying structure had to be able to handle stresses four times greater than the maximum that engineers expected them to be subjected to over their lifetime.

“That’s far stronger than any other material ever used,” adds Schneider, who is now a visiting professor of mechanical engineering at Texas A&M University, in College Station. For comparison, most aerospace systems are designed with safety factors ranging from 1.4 to 2.0.

PHOTO: Bigelow Aerospace

View from Genesis-I shows outer hull, solar panel—and the Earth.

The secret of TransHab’s success is the multilayer skin Schneider’s team developed. Moving from the inside out, the first layer is the scuff layer. It’s made of the fire-resistant material Nomex, and it protects the walls from wear and tear by the module’s occupants. Then come a number of airtight bladder layers made of Combitherm, a nylon-based film used in the food industry as a packaging material. Each bladder layer is separated from the next by a layer of felt to prevent them from sticking together while the module is in its deflated state. Next, come the all-important set of restraint layers, made of Kevlar, that give the skin its structural strength when inflated.

The TransHab team demonstrated just how strong such an arrangement can be by successfully inflating and pressurizing a test module under water. The module reached the equivalent of a pressure difference of four times normal atmospheric pressure between the inside and the outside of the structure.

Protection from orbital debris and micrometeors comes from shielding layers that wrap the restraining Kevlar. Here, a kind of open-cell foam padding—similar to that used in office chairs—is sandwiched between sheets of Nextel, an insulating textile material made from ceramic fibers.

When a piece of space debris strikes any surface at orbital speeds (typically measured in kilometers per second) it gouges a hole, typically breaking up into smaller fragments as it does so. If the surface material isn’t strong enough to absorb the damage from the impact entirely, the fragment will not just punch a hole in the surface, it will spray high-speed particles into whatever is behind that surface—a shotgunlike blast that could cause great damage to occupants and delicate internal systems if a module wall were to be breached. So a multilayer approach is dictated, with an outer layer that breaks up incoming objects, followed by one or more layers designed to block or absorb subsequent fragments.

However, with traditional rigid shell modules, because of launch weight constraints, these shielding layers are only millimeters thick. But on the TransHab, the shielding layer was about 30 centimeters thick, and in testing it easily withstood 1.7-cm-diameter aluminum projectiles being blasted into it at 7 km per second. Finally, a thermal blanket covers the whole module. TransHab’s entire skin was an astounding 41 cm thick and had no fewer than 60 separate layers.

As for fears of occupants getting tangled up in a deflating structure, the lack of external air pressure means the structure would not collapse quickly, and the large internal volume of air would leave ample time for occupants to put on emergency masks and evacuate, if necessary.

Schneider left NASA in mid-2000, but by then the TransHab concept had won enough converts to be actively considered for incorporation into the ISS. In the end, though, the proposal fell victim to the budget ax in 2002. Soon afterward, NASA terminated the TransHab project.

Along came Bigelow. As NASA’s interest had waned, Bigelow’s had waxed. He purchased the patents, signed formal technology-utilization agreements with NASA, and hired Schneider in 2002 as a consultant.

Schneider still can’t contain his glee when recalling his first glimpse of Bigelow’s giant building full of mock-ups. “When I walked in, it was out of my dreams,” he remembers. Bigelow had outfitted the plant with state-of-the-art manufacturing gear, and Schneider jumped right in, helping to fabricate designs for the habitat’s windows.