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Space Suit Redux
An old design could yield the suit of the future
By Lisa Scanlon

Dava newman often shows her students films of prototype space suits developed in the 1960s as NASA was preparing to send astronauts to the Moon. One looks like a suit of armor; another is a large transparent bubble. "I show them to students to get them to think really creatively," says Newman, SM '89, PhD '92, a professor of aeronautics and astronautics. Some of these quirky designs were ahead of their time, she says. In fact, one is the inspiration for a lightweight, flexible space suit that Newman and her students are creating for possible long-term human exploration of Mars.

The researchers are revisiting a design for an elastic suit conceived by physiologist Paul Webb in the 1960s. Essentially a very tight leotard, the suit applies pressure to the skin. NASA didn't pursue the concept because the suit proved too difficult to put on and take off; instead, it opted for the now familiar space suit that surrounds the body with a balloon of pressurized oxygen. At 140 kilograms, that suit works fine in low gravity, but it's impractical for NASA's long-term goal of human exploration of Mars. Newman believes that Webb's design is better suited for Mars, and with advances in materials, its time may be nigh.

In a project sponsored by the NASA Institute for Advanced Concepts, Newman and her students made a prototype pant leg that combines the pressurized-gas and tight-fabric techniques. Instead of relying only on pressure created by the fabric, the researchers generate additional pressure by pumping air into foam sandwiched between the suit's layers. The outer layer, made of a less flexible fabric, constrains the foam and forces it to expand inward to produce pressure on the wearer's leg.

Last February, the team tested a pant leg custom made for aero/astro graduate student Kristen Bethke. Bethke wriggled her way into the prototype--with the help of some talcum powder--and put her suited-up leg into a vacuum chamber. Then the team removed some of the air from the chamber and pumped air into the suit to generate the desired amount of pressure. Unfortunately, the sensors on Bethke's leg indicated uneven pressure on her skin, and when she bent her leg, pressure on the joint increased dramatically. "Actually, [the suit] popped," says Bethke. "The pressure increased so much that there's a rip." Previous prototypes tested on immobile parts of the body--like the shin--yielded very good results, but "it looks like for the knee we're going to have to keep working," says Bethke.

Another aero/astro graduate student, Liang Sim, has been working on an alternative suit design that involves wrapping the body with an elastic fabric much like an Ace bandage. Joints based on his design, Sim says, might solve Newman's pressure problem, because the hoops of wound fabric can separate slightly as astronauts bend their limbs.

Newman hopes to build a working prototype of a space-suit leg by the end of the summer. But, the researchers caution, an operational suit is many decades away. "We want to make sure we have all the facts, we've done all the science, we've done the engineering design," says Newman. For now, she says, she and her students are keeping their fingers crossed and enjoying thinking decades into the future.