A Force Field For Astronauts

Right: How the voltage would vary above a lunar base for the sphere configuration shown above. You can learn more about this and other configurations in the report Analysis of a Lunar Base Electrostatic Radiation Shield Concept.

Placing the spheres far overhead would reduce the danger of astronauts touching them. By carefully choosing the arrangement of the spheres, scientists can maximize their effectiveness at repelling radiation while minimizing their impact on astronauts and equipment at the ground. In some designs, in fact, the net electric field at ground level is zero, thus alleviating any potential health risks from these strong electric fields.

Buhler and Lane are still searching for the best arrangement: Part of the challenge is that radiation comes as both positively and negatively charged particles. The spheres must be arranged so that the electric field is, say, negative far above the base (to repel negative particles) and positive closer to the ground (to repel the positive particles). "We've already simulated three geometries that might work," says Buhler.

Image courtesy ASRC Aerospace. One scenario for how an electrostatic radiation shield could be deployed for mobile lunar exploration vehicles. Inverted green cones denote regions of partial radiation protection.

Portable designs might even be mounted onto "moon buggy" lunar rovers to offer protection for astronauts as they explore the surface, Buhler imagines.

It sounds wonderful, but there are many scientific and engineering problems yet to be solved. For example, skeptics note that an electrostatic shielOne scenario for how an electrostatic radiation shield could be deployed for mobile lunar exploration vehicles. Inverted green cones denote regions of partial radiation protection. d on the Moon is susceptible to being short circuited by floating moondust, which is itself charged by solar ultraviolet radiation. Solar wind blowing across the shield can cause problems, too. Electrons and protons in the wind could become trapped by the maze of forces that make up the shield, leading to strong and unintended electrical currents right above the heads of the astronauts.

The research is still preliminary, Buhler stresses. Moondust, solar wind and other problems are still being investigated. It may be that a different kind of shield would work better, for instance, a superconducting magnetic field. These wild ideas have yet to sort themselves out.

But, who knows, perhaps one day astronauts on the Moon and Mars will work safely, protected by a simple principle of electromagnetism even a child can understand.