After months of delays in development of its elaborate guidance software system, NASA’s Deep Impact unmanned space probe is launched on a mission to intercept, and fire an impactor into, Comet Tempel 1 half a year later. In order to catch up with the comet, Deep Impact is lofted into orbit by a Delta II rocket, which puts the spacecraft on a precise course at a speed of roughly 64,000mph. Deep Impact will fire the impactor into the comet in July to study the distribution and composition of the debris scattered by the resulting impact.
