JPL is planning another Comet rendezvous

     Much has been written about how much damage a comet or meteor impact could do to our planet. Now, JPL is planning a mission to a comet where we will impact the nucleus in an attempt to answer some of the many questions we have about these wandering snowballs. Called the Deep Impact mission,  it will be the first mission to ever attempt to impact a comet nucleus. Design plans have been completed and approved and a  preliminary construction phase has been approved by NASA to begin full-scale development for a launch in January 2004.

      The team includes scientists, engineers and mission designers from  the University of Maryland, NASA's Jet Propulsion Laboratory and Ball Aerospace and Technologies Corporation, Boulder, Colorado.

      The comet chosen for this mission is Comet Tempel 1, discovered in 1867. It is a dim comet and it is not possible to see it with the naked eye.
The comet orbits the Sun every 5.5 years, making many passages through the inner solar system.  It has been observed many times and therefore its' orbit is well known, which makes it a good target.

      Comets are the senior citizens of the solar system, ancient snowballs wandering along an ancient path they have perhaps traveled for billions of years. They may contain some of the secrets of the evolution of the solar system and perhaps even life itself.  Comets are composed of ice and dust, primitive debris from the birth of the solar system some 4.5 billions years ago.  It has been theorized that some comets could just contain organic molecules, the building blocks of life. Some scientists have even theorized that indeed life on Earth could have originated from the impact of a comet carrying organic molecules.

      Although a good deal has been learned from comets over the past few decades, even more questions have evolved. Scientists want to learn much more about a comet's composition, structure and how its interior is different from its surface. The controlled cratering experiment of the Deep Impact mission will provide answers to
these questions.

      When the impactor collides with the comet it will cause gases and ice inside the comet to be exposed and expelled outward by the impact. The flyby spacecraft will take images and measure the composition of the outflowing gas.  The images and data will be transmitted to Earth as quickly as
possible.  Many observatories on Earth should be able to see the comet dramatically brighten just after the impact on July 4, 2005.

       The Deep Impact team is completing the final design details and will begin building the mission's two spacecraft: a flyby spacecraft and a 350-kilogram (771-pound) impactor spacecraft.   They will be launched together in early 2004 and travel to Comet Tempel 1's orbit where they will separate and operate independently.  The flyby spacecraft will release the impactor into the comet's path, then watch from a safe distance as the impactor guides itself to collide with the comet, making a football field-sized crater in the comet's nucleus.

     Images and more information about the mission are available on the Web at: http://deepimpact.jpl.nasa.gov. A mirror site is available at http://deepimpact.umd.edu .