The Phantom Torso - Space Radiation

An unusual space traveller named Fred is orbiting Earth aboard the International Space Station. His job? To keep astronauts safe from space radiation.

Fred has no arms. He has no legs. His job is keeping astronauts safe.

Fred is the Phantom Torso, an approximately 95-pound, 3 foot high mock-up of a human upper body. Beneath Fred's artificial skin are real bones. Fred's organs -- the heart, brain, thyroid, colon and so on -- are made of a special plastic that matches as closely as possible the density of human tissue.

Fred, who's spending four months on board the International Space Station (ISS), will measure the amount of radiation to which astronauts are exposed. High-energy particles that pass through the human body can disrupt the way cells function. Although no astronaut has ever been diagnosed with space radiation sickness, excessive exposure could lead to health problems.

"We believe the current dose [of radiation to the crew of the ISS] is too small to be of concern," says Dr. Gautam Badhwar, the study's principal investigator at the Johnson Space Centre. "The one possibility for radiation sickness might be an EVA situation during a solar event, if perhaps a crew member couldn't be brought back inside safely." But there's still lots to learn, he added, and that's where Fred can help.

The Phantom Torso is designed to do three things, explains Badhwar. Firstly, it will determine the distribution of radiation doses inside the human body at various tissues and organs. Secondly, it will provide a way to correlate these doses to measurements made on the skin. "In the past we've typically recorded doses only on the skin," explains Badhwar, "whereas the risk to crew members is established by exposure to internal organs. Finally, the Phantom will help check the accuracy of models that predict how radiation moves through the body.

The Phantom Torso, also known as "Fred," is an anatomical model of a human torso and head. Fred contains hundreds of radiation monitoring devices. [more information]

Three types of radiation can endanger astronauts in space.