This suit is made for walking (on Mars)

In 1972, when humans last visited the surface of the moon, the bulky, stiff legs of spacesuits made the "moonwalk" more of a swaying hop. Since then, manned missions to space have stayed in Earth orbit, where astronauts mostly use their arms to get around. But when explorers get back to the moon, or if they ever get to Mars, these old spacesuits aren't going to cut it, scientists say.

Both destinations, in fact, are in NASA's long-range plans. Last month, the agency announced an ambitious plan to return to the moon by 2018 as a launching pad for a mission to Mars. If they pull it off, astronauts will need added mobility and dexterity for the next stage of modern experiments, exploration, and construction.

"We need to design some pretty revolutionary spacesuits if we're really going to realize human exploration of other [planetary] bodies," says Dava Newman, a researcher at Massachusetts Institute of Technology. By combining an old idea with the latest technology, Dr. Newman and her team are trying to build a better spacesuit: the BioSuit, a form-fitting "second skin," designed for lunar and Martian living.

The proposed BioSuit will consist of a skintight body suit, a hard torso and backpack for life-support systems and equipment, and a domed helmet. The conceptual images for the project look like science fiction: sleek, color-coded spacemen and spacewomen climbing Martian windmills, whacking red rocks with hammers, and casually shaking hands.

Much of the technology needed to make the BioSuit practical may be decades away - just like a Mars mission - but the idea behind it was dreamed up decades ago.

A primary function of a spacesuit, and the central thrust of BioSuit research, is to maintain air pressure, or the force exerted on the human body by the weight of the atmosphere, in the airless vacuum of space or the sparse atmosphere of Mars. "The current spacesuits, they tend to be gas bags," says Bob Cassanova, director of the NASA Institute for Advanced Concepts (NIAC), which funded the research. "They're gas-pressurized, very bulky, very heavy, very cumbersome."

In the late 1960s, Paul Webb, a former Air Force physician, tried to create a spacesuit that used mechanical counterpressure - squeezing - instead of gas pressure.

Dr. Webb made a suit of six layers of elastic that physically pressed the body to mimic Earth's air pressure. The design was lighter and less bulky and provided greater range of motion than a "gas bag." Webb tested the suit and its physiological effects and wrote a report in 1971 that said the idea was viable and safe. But NASA didn't bite.

"When the money ran out, NASA said 'thanks a lot,' " says Webb, who still consults on spacesuit development. "Everything went into hibernation."

Thirty years later, Newman, a professor of aeronautics and astronautics, took up the challenge. "I think it was a great idea, just before its time because we didn't have the materials technology," she says.

Newman received a $500,000 grant from NIAC to develop ideas that are 10 to 40 years away from reality - well beyond NASA's usual funding horizon.

Newman's team has made several lower-leg prototypes, including one of nylon-spandex, one of elastic wrapped like bandage, and another of pressurized foam painted with layers of urethane.

Ultimately, the BioSuit must maintain fairly constant pressure over the whole body as it moves. With three-dimensional mapping and scanning, Newman's lab studies how skin stretches and joints move.

"I just marvel at it," says Newman. "Every day, I look at the skin and say, 'How could this be designed so fantastically?' "

Making the BioSuit easy to put on is another challenge. It might feel a bit like squeezing into a wetsuit several sizes too small. It took two helpers 20 minutes to tug on the layered elastic suit Webb developed decades ago.

It still is a problem, which is why Newman and other researchers are looking to "smart" materials, metals and polymers that expand, contract, or change their properties in response to heat or electricity. Most of these technologies exist, but are too weak or power-hungry to use yet. So Newman is making prototypes with available materials and leaving how to put them on until later. "You need prototypes and demonstrations before people will believe you," she says. "Then we wait for some of the materials to come on board."

The NIAC-funded portion of the project ended in August, so the development of smart materials and additional prototypes may have to wait until NASA decides if the BioSuit will receive mainstream funding as part of the new moon mission. "I think NASA ought to be spending more time with those [BioSuit] people and less time flying 40-year-old technology," says Alex Roland, a historian of the space program, professor at Duke University, and critic of the space shuttle. "I think it's more in line with what we want them doing as a science and technology agency."

A skintight BioSuit spacesuit, a space elevator, and a weather control machine. Far-fetched projects, maybe, but all have been supported by the NASA Institute for Advanced Concepts. The dozens of unusual NIAC-supported projects are conceptually possible but rely on materials or technology that do not yet exist. It is up to researchers with NIAC funding to show the projects are feasible within 10 to 40 years and describe the future technologies they will need.

The BioSuit, for example, will need "smart" materials that change their properties when electrically or thermally stimulated. One option is shape metal alloys, such as the nickel-titanium alloy, nitinol, used in cardiac stents. These alloys contract with great force when current is run through them and could, for example, be placed along a seam to pull the suit tight or along a limb to boost strength.

Smart polymers, which can change from rubber-band-like material to stiff plastic in response to heat, could shrink to fit as they are warmed by the body. But researchers need time and funding to make the technologies work: Today's shape metal alloys require too much power and smart polymers aren't very strong. But Bob Cassanova, director of NIAC, thinks the enabling technologies for the BioSuit are closer than we might think. "Something like this could be developed in the next 10 years," he says, just in time for the next planned moon landing.