Sailing through space on solar winds was first suggested by astronomer, Johannes Kepler, 400 years ago. Now, such a thought is becoming a reality. Below is an artist rendition of the 10 square meter solar sail that is now the first of its kind in earth's orbit. It relies on small, but continuous pressure from sunlight in order to thrust. From time to time, it will shine brightly as it passes overhead in the night sky, so it should be easily visible to the eye.