Deep Impact Headed for July 4 Crash with Comet

This July 4, NASA is preparing for fireworks in space, when the comet Tempel 1 will smash into a probe set in its path. Scientists hope the mission, called Deep Impact, will reveal what comets are made of and how they're put together.
As it nears Tempel 1, the Deep Impact mother ship will release an impactor to be hit by the comet at 23,000 mph. The impactor carries a copper slug weighing more than 300 pounds -- to ensure the collision packs a punch -- and an onboard guidance system to keep the oncoming comet in its crosshairs.
Just before 2 a.m. Eastern Monday, the spacecraft will .... go the link to read on
Deep Impact Story