"Deep Impact"

The Deep Impact spacecraft launched on January 12^th, 2005 set a precedent in space exploration. Never before had a spacecraft (or part of a spacecraft) been designed to impact a comet to observe the outcome. Scientists went through rigorous calculations to send Smart Impactor, a 370kg copper slug, 431 million km through space and hit Templar 1, a comet half the size of Manhattan Island. On the morning of July 4^th, 2005 the Impactor collided with the comet providing the 650 kg Flyby craft with footage and scientific data of the impact. The impact part of the craft smacked into the comet at a relative speed of 10 km/s and released kinetic energy equivalent to around 5 tons of TNT. The collision is expected to have changed the comets velocity by only 0.0001 mm/s and the expelled matter is expected to follow the comet in its orbit. As Tim May stated in our interview:

It was a pretty impressive challenge to get a rocket up there and have it point in there and blast. There were a lot of people watching it from earth to see what kind of change happened in the comet. It got quite bright, actually. They were actually taking spectra of what came of the comet. They actually got some new information from it. It was like a giant snow drift

The Impactor before destruction, Flyby aircraft, space telescopes and observatories recorded a myriad of scientific data from the one time event. The data brought startling insight into how the Earth was formed and promoted the theory that many of the necessities to create life were brought to this world by a comet.

On July 21^st, the Flyby spacecraft executed a trajectory change that is expected to have the craft fly past the Earth on December 31^st, 2007. At that time NASA will consider capturing the craft and sending it to another comet.

Sources:

http://deepimpact.jpl.nasa.gov/home/index.html

http://www.nasa.gov/mission_pages/deepimpact/main/

http://en.wikipedia.org/wiki/Deep_Impact_(space_mission)