In 2001, a NASA study found that at least 39 former astronauts suffered cataracts after flying in space, 36 of whom had taken part in missions beyond Earth's orbit. Separately, the agency has tentatively estimated that a trip to Mars and back would give a 40-year-old non-smoking man a 40 per cent risk of developing fatal cancer after he returned to Earth, or twice the terrestrial risk. Scientists now believe they have found a way of protecting astronauts from a dangerous source of space radiation. Space weather is one of the greatest challenges facing Mission Red Planet sketched by the United States and Europe for some three decades from now. Even the shortest round trip would take at least 18 months. During this time, the crew would be exposed to sub-atomic particles that whizz through space, capable of slicing through DNA like a hot knife through butter and boosting the risk of cancer and other disorders. Our Earth’s weak two-pole field deflects incoming cosmic rays, protecting life on Earth as well as astronauts in low Earth orbit. An idea, born in the 1960s, would allow the spacecraft to generate a magnetic field hundreds of kilometers across, around the craft.

The device would weigh around "several hundred kilos" and use only about a kilowatt of energy, or around one-half to one third of the typical power consumption of today's communications satellites. The ‘Mini magnetosphere’ concept is being pitched to the European Space Agency (ESA) and NASA.

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