Plastic spaceships?

NASA scientists have invented a new polyethylene-based material called RXF1 that's even stronger and lighter than aluminium and could be used to shield spacecraft from deep-space radiation.

"This new material combines superior structural properties with superior shielding properties," says Nasser Barghouty, Project Scientist for NASA's Space Radiation Shielding Project at the Marshall Space Flight Center.

Protecting astronauts from deep-space radiation is a major problem. Some scientists believe that materials such as aluminium, which provide adequate shielding in Earth orbit or for short trips to the Moon, would be inadequate for the trip to Mars.

Barghouty is one of the skeptics: "Going to Mars now with an aluminium spaceship is undoable," he believes.

Plastic is an appealing alternative: Compared to aluminium, polyethylene is 50% better at shielding solar flares and 15% better for cosmic rays.

The advantage of plastic-like materials is that they produce far less "secondary radiation" than heavier materials like aluminium or lead.