BEIJING, July 4 -- An "impactor" fired by the Deep Impact spacecraft is due to smash into the comet known as Tempel 1 later today.

 

The Deep Impact spacecraft has successfully deployed its coffee table-sized 'impactor' into the path of a comet in the final stage of a mission to trace life on Earth to its celestial origins, NASA scientists said on July 3, 2005.(Reuters photo)

    The impactor was on track to collide with the Tempel 1 comet at 10:52 p.m. PDT on Sunday (1:52 a.m. EDT, 0552 GMT on Monday), as Deep Impact's fly-by spacecraft, watching from a safe distance, captures images and data with its onboard instruments, scientists at NASA's Jet Propulsion Laboratory (JPL) said.

    Beiing 133 mln kilometres from Earth, Comets are made of gas, dust and ice from the solar system's farthest regions.

    The impactor is fortified with copper to create a spectacular collision that scientists hope will blast a hole in the comet's ten-mile-wide nucleus.

    The size of the resulting crater could range from a large house to a football stadium, and be from two to 14 stories deep. Bursts of debris from the cosmic collision could be visible to the naked eye in some areas of the world, scientists said.

    The aim of the mission, the first to come in direct contact with a comet's nucleus, is to photograph pristine material formed billions of years ago during the creation of the solar system.

    The climax of the $333 million (¡ê188 million) mission will also be watched by Nasa's space-based Hubble, Chandra and Spitzer telescopes. The European Space Agency¡¯s Rosetta spacecraft, on its way to a 2014 rendezvous with a comet, will also watch, as will professional astronomers from dozens of observatories in 20 countries.

    Deep Impact was launched from Cape Canaveral in Florida on January 12 for its six-month, 268-million-mile voyage. Tempel 1, discovered in 1867, moves around the Sun in an elliptical orbit between Mars and Jupiter every six years or so. Enditem

    (Agencies)