June 2, 2005: On July 4, NASA's Deep Impact spacecraft will attempt an extraordinarily daring encounter with the far-flung comet Tempel 1 hurtling through space at tens of thousands of miles per hour. As if that is not challenging enough, the comet's size, shape and other characteristics are not entirely known.
Two of NASA's eyes in the sky, the Spitzer and Hubble Space Telescopes, helped scientists prepare for the comet encounter. From their orbits high above Earth, the telescopes watched Tempel 1 in early 2004. Together they came up with the best estimates of the comet's size, shape, reflectivity and rotation rate. The data may help Deep Impact snap pictures of the dramatic rendezvous and increase the probability of making contact with the comet.See the rest:
Credit: NASA/Jet Propulsion Laboratory-Caltech and T. Pyle (Spitzer Science Center)