PHOTO: Bigelow Aerospace

The goal: to rent out a privately funded, inflatable space station.

What happens when a Las Vegas real-estate tycoon who’s made a pile of money building hotels starts thinking big—really big? In the case of Robert T. Bigelow, he starts working out a way to build hotels in outer space. And he just might be smart enough, rich enough, and driven enough to pull it off.

Bigelow made his money in extended-stay hotels, banking, and real estate. In 1999 he founded Bigelow Aerospace, which he personally manages and which now has 125 people in Las Vegas, Houston, and Washington, D.C., to do the nuts-and-bolts engineering required to build the world’s first space hotel. Bigelow’s aim is not to operate his own space tourism business but rather to build habitable structures that others will lease or purchase for their own purposes, including research and manufacturing in addition to providing the ultimate getaway destination.

Bigelow is the latest in a long line of dreamers looking to make money off the nascent human orbital economy. Dozens of aerospace companies with similar notions have come and gone over the years, with little more to show for their existence than a pile of feasibility studies, government grant applications, and whizzy drawings of futuristic hardware. But Bigelow has something none of those predecessors ever had: a functioning prototype of his hardware in orbit, right now. And he also has something else that might prove even more important. It’s a design approach that could dramatically improve the size, cost, and safety features of space habitats, quite different from the technology used to build every other habitat to date—from the old Soviet Salyuts to today’s International Space Station.

Now, with space entrepreneurship developing into something more than a hopeful fantasy, this scrappy Las Vegas operation is emerging as one to watch. It has been 28 months since Elbert Leander (“Burt”) Rutan’s Ansari X–prizewinning, privately funded suborbital flight in SpaceshipOne jolted the field. With popular interest stoked by the first privately funded human space flights to the International Space Station, the entire idea of commercializing some human space flight finally seems here to stay. Even NASA has joined the push, granting development funds to teams trying to set up FedEx-style delivery of cargo and personnel to the ISS.

Amid this futuristic fervor, you’ve got to admire Bigelow’s audacity. While others are hammering out the details of how to launch cargo and wealthy tourists into orbit, Bigelow is already thinking further out, to the day when travelers will want to camp out up there. And he’s focusing on other businesses and organizations that will need orbiting workspace to produce the kind of zero-gravity materials and research that decades of small-scale experiments on space stations have only been able to hint at.

PHOTO: James Oberg

Mockup of the Genesis-I, shown in Bigelow's desert laboratory. The real satellite was successfully launched in June.

I visited Bigelow’s heavily guarded facility this past July with a few other aerospace journalists. Several kilometers north of the fabulously glitzy heart of Las Vegas, it’s located in the scrubby Nevada desert and surrounded by razor-wire fences and armed guards. There, inside the cavernous building known simply as Building A, I saw a looming gray fabric-covered cylinder, 4.4 meters long, that is supposed to represent the wave of the future in habitable space structures.

The fabric of the cylinder represents the crux of Bigelow’s leap, and it’s what separates him from the many who have come before him. Instead of just draping the walls of a solid structure to provide additional thermal insulation (as seen in many spacecraft), the fabric is the wall of the spacecraft. Like a balloon, the habitat is held in shape by the pressure of the air inside.

Of course, the fabric isn’t anything like the materials that the term calls to mind. Rather it’s a technologically advanced, multilayer creation, tens of centimeters thick that simultaneously provides thermal control, structural strength, and an absolutely airtight seal. Bigelow wants to build entire orbiting complexes out of clusters of similar cloth-covered, inflatable structures, with each cylinder enclosing hundreds of cubic meters of habitable space. It’s hard to pin down exact figures, but this inflatable-module concept could cut the cost of building and launching space habitats by a remarkable 25 to 50 percent, compared with traditional rigid-walled modules.

A back-of-the-envelope calculation shows why. The largest single ISS module—the centerpiece of Japan’s contribution to the station—is scheduled to be launched into space in October 2008. The pressurized volume inside this metal-walled module will be about 150 cubic meters, or about half the size of a squash court. In contrast, an inflatable module could easily have an internal pressurized volume well over twice that, requiring less than half as many modules and launches to build a space complex of a given size. Quite apart from the cost of the modules, reducing the number of launches translates directly into major bottom-line savings, because it can cost as much—or more—to launch a module into space as to build it.

Standing in front of the cylinder in Building A, I remember an incident said to have happened in World War I: a British army officer, confronted with a very similar structure, had flicked his fingertip at the surface to see what sound it would make. “Blimp,” he heard—and is supposed to have repeated to himself—thereby naming the unconventional aerial vehicle that would patrol the coasts of wartime England.

I raise my arm, try the same trick, and get a satisfying “blimp” sound, too—because this structure in front of me is also inflated and straining at its airtight envelope. This SUV-sized vertical cylinder is an engineering mock-up of a craft called Genesis I, which is now orbiting Earth 560 kilometers up. Like a blimp, Genesis I maintains its shape thanks to air pressure. Unlike a blimp, which uses helium gas to pressurize the vehicle and whose crew works in a rigid gondola attached to the outside of the inflated structure, Genesis I is testing the idea that breathable air could be used to pressurize the structure, which would allow people to live and work inside it.

At least, that’s the plan. At the moment, Genesis I doesn’t have any astronauts onboard. Rather, it’s a test bed that, at 4.4 meters in length and 2.5 meters in diameter, is about one-third the size of the planned habitable modules that Bigelow hopes to begin launching around 2010, each of which will have an internal volume of over 300 cubic meters.

Fitted with cameras and other sensors, the interior of the orbiting Genesis I has 11.5 cubic meters of internal volume. It is pressurized to a little more than half of sea-level atmospheric pressure as a conservative first step to test the structure’s ability to deploy properly and stay inflated in space.