Imagine how many exploratory space probes could be built and then sent off into space to travel the universe.
A new type of solar sail has been woven by a team of scientists in Finland. The spiderweb-like sail is designed to catch the wind of ionised gas that blows from the Sun, carrying spacecraft to the outer reaches of the solar system, or letting them tack back and forth through the asteroid belt on exploration or mining missions.
The new sail differs from the more conventional type of solar sail, which is designed to use the gentle pressure of sunlight to move a spacecraft.
Instead of catching sunlight, Pekka Janhunen of the Finnish Meteorological Institute in Helsinki is aiming to sail using the solar wind, a tenuous plasma of electrons and positive ions blowing out through the solar system at speeds of hundreds of kilometres per second.
Janhunen’s plan is to reel out long wires from a spacecraft and pump a positive electric charge into them, so that they repel the heavy positive ions in the solar wind. That way a wire only microns across can feel the force of a broad swath of passing plasma, behaving like a sail many metres across.
One problem is the high-velocity micrometeoroids shooting through interplanetary space. “They would break these metal filaments,” says Janhunen.
To make them more robust, sections of sail will be woven from four strands of wire: two straight parallel strands running a couple of centimetres apart, held together by two more strands that crisscross between them.