Dummy Strapped Outside Space Station

Feb. 25, 2004 -- -- "Matroshka" is going where none of his kind has gone before — riding around on the outside of the International Space Station.

It will be a rough journey, but Matroshka is designed to take abuse — and measure it.

Matroshka is a mannequin of a human torso, fashioned from plastic, foam and real human skeleton, that was sent up at the end of January to the space station. Astronauts attached it to the exterior of one of the station's modules during their risky spacewalk today.

It will then remain exposed to the harsh environs of space for an entire year, in research guided by the European Space Agency, along with NASA.

Scientists hope the ordeal will pay off — in data. Matroshka's torso is equipped with dozens of radiation sensors that are placed in strategic locations throughout its surface and interior to measure how susceptible different organs and tissue may be to radiation damage.

The research is critical to understanding how to protect astronauts from radiation as they spend long durations in space on board the space station, or in a possible journey to the moon and Mars, as proposed recently by President Bush.

"The challenge is the radiation that astronauts are exposed to is of many different types and we really don't understand it yet," said Steve McKeever, a physicist at Oklahoma State University in Stillwater, and one of the scientists who contributed an instrument to Matroshka's array. "It's a real soup of radiation up there."

Hazardous Activity

Radiation is energy in transit in the form of high-speed particles and electromagnetic waves. While minimal amounts of radiation reach people on Earth, it is much more prevalent and intense in space.

The pummeling particles originate as flares from our sun or from cosmic rays zooming in from distant solar systems. This means an astronaut taking a walk in space is exposed to about 27 times more radiation particles than the average person on Earth.

That kind of exposure, if extended, can lead to all kinds of nasty problems from damaged tissue cells to cancer to cataracts and central nervous system injury.

Matroshka is able to take intricate readings of such damage. The mannequin's name takes inspiration from Russian matrioshka dolls that fit one inside the other. Similarly, Matroshka is made up of layers that can be taken out in slices. Distributed throughout these slices are small crystals, known as dosimeters, that record the amount of penetrating radiation.

Michael Golightly at NASA's Johnson Space Center in Houston explains that scientists will use these readings to help ensure that astronauts' exposure to radiation levels stays within strict limits. According to NASA policy, people working for the agency may not be exposed to radiation throughout their careers that would raise their chances of developing cancer by more than 3 percent of the average population.

"We turn that consideration into a number, which varies with the age of the person, the amount of exposure and their sex," he explained.

Younger people are generally more vulnerable to damage than older people, he said. And because of their risk for breast cancer, women are about twice as vulnerable as men to developing cancer from radiation exposure.

"It poses an ethical problem," Golightly said. "Is it ethically better to pick people who you know have a lower risk of cancer, or do you pick people based on merit and demographics? It's something we'll need to address at some point."

Data from Matroshka's flight, which will include the year outside the station in a protective case that mimics an astronaut's spacesuit, and a shorter stint inside the space station, may help shed light on such issues.

Space Dummies: The Early Days

Space mannequins already have a long history of paving the way for human space travel.

The first-known mannequin to travel to space was a wooden dummy nick-named Ivan Ivanovich, which traveled alongside a small dog on board a Soviet Sputnik capsule in 1961. When Soviet engineers found the dog unharmed in the spaceship and the dummy in one piece in a snow drift after ejecting from the craft, they felt assured the journey was a safe one and the first man in space, Yuriy Gagarin, would soon follow the dog and dummy's lead.

It was also a dummy, not a man, who first traveled around the moon. Recently, the Russian Academy of Sciences announced that a Soviet mannequin, composed of wheat gluten made the seven-day journey in September 1968.

Why wheat gluten?

"The chemical composition of wheat is very similar to that of human tissue," Vladislav Petrov of the Russian Academy told Itar-Tass. This allowed scientists to get a sense of how deep radiation might penetrate human skin during space travel.

Since those days, mannequins like Matroshka have become more sophisticated. NASA has its own test mannequin, known as Fred the Phantom, that's made up of human bone and complex plastics like Matroshka. Fred has made five trips on board space shuttles and on two occasions, stayed for a while on board the space station.

Matroshka may not be the first mannequin in space, but it will be the first to spend time outside the space station. And that feat should earn it a place in space dummy history.

Space Walk Leaves Station Empty

At the same time, today's space walk to place Matroshka is unique in another way. When Astronaut Michael Foale and cosmonaut Alexander Kaleri venture outside the International Space Station it will be the first time the space station has been left unattended during a spacewalk.

NASA has no choice in the matter. Since the space shuttle fleet was grounded after the Columbia accident, crews have been limited to two people because of the reduced supply system.

Usually two crew members go out, and the third person stays behind to monitor the situation. That won't be possible on this space walk, which had some at NASA initially concerned. But they think they have minimized the risks, and are comfortable with no support on the ISS from a third crew member.

Mike Suffredini, the International Space Station Operations Manager, noted: "After you think it through a little while you decide that the third crew member is there for moral support mostly, until they can get the hatch open."

Foale and Kaleri will also retrieve some science experiments during the five-and-a-half-hour space walk, and they will also check the exterior of the space station for signs of damage from debris. Last November, the crew heard a loud bang that NASA still hasn't been able to explain.

Flight controllers are taking precautions to make sure something doesn't go wrong. They have come up with 13 flight rules about what to do if the space station spins out of control or a system breaks down.

This may be the first time for a space walk like this, but it won't be the last. Shuttle flights won't resume until 2005 at the earliest, so the next two-man space station crew will be expected to execute two more space walks.

ABCNEWS' Gina Treadgold contributed to this report.