I don't know how long this solar sail idea has been here , the Planetary society's second solar sail failed to achieve its objective right ? I am interested in the applications of this technique. 1) Is it possible to use them to deflect large asteroids and comets away from the earth ? 2) Is it possible to propel a spacecraft with solar sail using a powerful laser or some other kind of focused beam of light to interstellar destinations ? even though it might take a long time to reach there. 3) Is it possible to propel it beyond , say Jupiter, Saturn just by sunlight ?