The U.S. military said on Tuesday it is now tracking 800 maneuverable satellites on a daily basis for possible collisions and expects to add 500 more non-maneuvering satellites by year's end. The U.S. Air Force began upgrading its ability to predict possible collisions in space after a dead Russian military communications satellite and a commercial U.S. satellite owned by Iridium collided on Feb. 10. General Kevin Chilton, commander of U.S. Strategic Command, called the collision the "seminal event" in the satellite industry during the past year and said it destroyed any sense that space was so vast that collisions were...