  Deep Impact was launched on Jan. 12, 2005, on a solar orbit to
rendezvous with Comet Tempel 1. The spacecraft had two primary
sections, the impactor and the flyby spacecraft. The impactor
was built around a copper and aluminum mass with a small, guided
propulsive stage. The comet’s constituents could be identified
from the spectral makeup of the vaporized ejecta. The mass and
velocity would allow scientists to deduce the structure of the
comet from the crater that was formed. The Impactor Targeting
Sensor doubled as an experiment camera during final approach.
The flyby spacecraft carried two primary instruments, high- and
medium-resolution imagers, with the radio system used as a third
experiment to measure possible velocity changes due to the
comet’s mass or atmospheric drag. The imagers had filters to
highlight diatomic carbon and cyanogen molecules in the debris.
An infrared spectrometer was designed to detect water, carbon
monoxide, and carbon dioxide. The impactor was released on July
3, 2005, and stru