Video: Spaceship shield

Mars travellers will need more than just funny space suits (Image: Fritz Goro/Getty)

Interplanetary adventurers must contend with deadly solar radiation – but the moon’s magnetic memories may hold the key to safe space flight

BORED on their six-month journey to Mars? Not a bit of it. Whenever the astronauts look out of the window, they find themselves mesmerised by the glowing, shimmering sphere of plasma that surrounds their spacecraft. Hard to believe that the modest electromagnet at the heart of their ship can produce something so beautiful.

Not that the magnet’s raison d’être is aesthetic, of course. Its main function is to keep the astronauts from a slow, horrible death by radiation sickness.

NASA is nervous about sending astronauts to Mars – and understandably so. Six months’ exposure to the wind of high-energy particles streaming from the sun could indeed prove deadly. But a team of researchers at the Rutherford Appleton Laboratory (RAL) near Oxford, UK, has hit upon a phenomenon that might just solve the problem. They have shown that a magnet no wider than your thumb can deflect a stream of charged particles like those in the solar wind. It gives new life to an old idea about shielding spacecraft, and might just usher in a new era of space travel. “Space radiation has been called the only showstopper for the crewed exploration of space,” says Ruth Bamford of RAL. “Our experiment demonstrates there may be a way the show can go on.”

The inspiration behind the idea is as old as the Earth. Life thrives on our planet because its core is a churning …