its surface area. Five Comets visited by Spacecraft Image credit: NASA/JPL-Caltech/UMD Comet 9P Tempel 1 (4.7 miles), was impacted on 4 July 2005 by NASA’s Deep Impact mission, later re-purposed for the Hartley 2 rendezvous. Comet 19P Borrelly (5.4 miles) was photographed in 2001 by the spacecraft Deep Space 1 . Comet