Space Shields
Can magnets help protect astronauts?
By Mara E. Vatz

Researchers in mit’s aeronautics/­astronautics and physics departments are developing a new way to protect astronauts from cosmic radiation by adapting an age-old mechanism: the magnetic shield. The earth’s magnetic field has protected the planet from cosmic rays for billions of years; but according to former astronaut Jeffrey Hoffman, one of the project’s lead researchers, scientists have only recently developed the superconducting magnetic technology necessary to replicate its protective effects.

Now, Hoffman is studying whether this technology can be made light enough to be launched into space. A magnetic shielding system will require a significant additional load of electrical, cooling, and structural apparatus and may turn out to be just as heavy as a system that blocks cosmic rays with thick layers of aluminum. “If the masses turn out to be similar, then there’s no point going to the trouble of building a complex magnetic system,” says Hoffman. But preliminary calculations done by other researchers are promising.

The research, made possible by funding from the NASA Institute for Advanced Concepts, won’t be put into use until astronauts travel farther from the earth than they have yet done. Short trips to the moon, for example, don’t usually pose real radiation risks, says Hoffman. “It’s during eventual trips to Mars—and beyond—that you really have to start worrying about radiation protection.” That’s because a single solar flare can dish out a lethal dose of radiation, and there’s also a possibility that chronic exposure to nonlethal radiation doses could shorten crew members’ life spans. However, if magnetic shields are ever put into use, Hoffman says, they “would really enable people to go into regions where they’ve never gone before.”