The material of choice for most manned spacecraft is aluminum. But future craft — especially those designed for trips to the Moon or Mars — may have large sections made of plastic. That’s because an experiment in lunar orbit has shown that plastic is better at screening out harmful cosmic rays.
Any trip beyond Earth orbit exposes a crew to several forms of radiation. First, there’s Earth’s own radiation belts, which trap charged particles from the Sun. Next, there’s radiation from the Sun itself — especially the powerful outbursts known as solar flares. And finally, there are cosmic rays, which come from exploding stars and other objects outside the solar system.
The Apollo astronauts received only minor doses of radiation because they were outside Earth’s protective air and magnetic field for only a few days. But trips to Mars, or long stays on the Moon, would be more troublesome, so spacecraft would need extra shielding.
An experiment aboard the robotic Lunar Reconnaissance Orbiter has shown that plastic is better at blocking cosmic rays than aluminum. So engineers may want to think about using plastic when they build future spaceships — either in the ship itself or in a special shelter — to keep astronauts safe from the dangers of cosmic radiation.
And the Moon and a bright companion are in fine view early tomorrow. Jupiter, the largest planet in the solar system, looks like a brilliant star to the upper right of the Moon at first light.
Script by Damond Benningfield, Copyright 2013
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