Sailing is a popular summer sport, enjoyed around the world.
It's exciting to watch the sail fill with wind, and feel the boat carried across the water without the loud noise of a motor. Sailing doesn't require motors or fuel, just skill to read the winds and a good breeze. Some NASA scientists think perhaps we could someday sail through space in a similar way. The concept of solar sails has been around for centuries. Nearly 400 years ago astronomer Johannes Kepler observed the way comets' tails always point away from the sun.