HOUSTON NASA is still debating whether to build the International Space Station's Habitation Module using a more conservative design or a radical design called the Transhab. But at the Habitation Module Commercialization Conference this week in Houston, both astronauts and NASA officials said they are leaning toward the latter.

During the conference, astronaut Shannon Lucid and Air Force Col. Charlie Precourt touted the inflatable module over the hard shell version dubbed the Common Module Hab.

"The (Astronaut) crew office consensus is that we feel Transhab is going to be a vehicle to make commercialization possible," said Precourt, who is also the Astronaut Office chief.

Transhab is a three-level inflatable module designed as living quarters for up to six astronauts aboard the ISS. It has a volume comparable to a 1,500 square-foot home and offers about 30 percent more room than the aluminum-skinned Common Module.

The additional space provides several benefits, including additional sleeping compartments compared to the Common Module, which sleeps four. Sleeping compartments would be a significant improvement over accommodations aboard the space shuttle or Mir, which are often crammed next to equipment, experiments and work areas, Precourt said.

"You often have to figure out where to put your sleeping bag away from blowing fans and lockers that someone may need to get something out of," he said.

Both Precourt and Lucid agreed that a comfortable, well-rested crew is a productive crew, particularly on long duration flights.

"Habitation has to be improved," Lucid said. "If you dont have a good place to live, you wont have a productive crew and you wont be able to use this wonderful facility to the max."

Lucid said the hard module also has some problems in human factors such as the exercise bicycle placed on top of the table used for eating and working with the bathroom in the same area.

If thats not enough to make someone cringe, she added two words: "sweat floats."

Precourt added that having room for additional crewmembers should make the space station more productive. Astronauts could concentrate on experiments and commercial work, while a dedicated crew maintained the station and performed the routine housekeeping chores.

Lucid also liked the feeling of a home Transhab offered. A table in the first level has enough space for more than a dozen people to gather around to meet or dine.

Two crews might occupy the ISS for a time during a crew changeover. In a similar situation aboard Mir, it was impossible for all to be in the same area.

"We spent two weeks together," she said of an experience on Mir with an extra crew. "At first we tried to eat together and there was no room, so we broke into groups of three."

Lucid said being able to gather everyone in one area is not only a morale booster, but keeps cliques from forming.

Current plans for the International Space Station call for a habitation module to be launched in November 2004. The space agency hopes to forge a deal with private interests to build an improved version over the one financed now with tax dollars. NASA must choose between Transhab and the Common Module Hab, a Boeing-built aluminum structure similar to existing spacecraft designs.

In addition to the astronaut's comments, several other sessions at the conference focused on the versatility and innovations built into the Transhab. For example, the Transhab's multiple layers, which consist of Mylar, Kevlar, Nextel and foam rubber, provide better protection from micrometeorites than a metal shell.

The Transhab team, lead by Donna Fender, has completed vacuum and micrometeorite strike tests on a $1.2 million prototype. Until a decision is made, Fender's team plans to work on risk mitigation factors, she said.