Tags:
Journalism of Courage
Nasa8217;s Deep Impact spacecraft is closing in on its historic rendezvous with comet Tempel 1, a culmination of what Jet Propulsion Laboratory Director Charles Elachi called 8216;8216;one of the most daring and risky missions we have ever undertaken.8217;8217; If all goes well, the spacecraft8217;s 820-pound impactor will smash into the comet8217;s core at 1:52 p.m. EDT on Sunday.
The cosmic collision and its aftermath will be observed by three telescopes in orbit and every major telescope on the Earth8217;s surface. Images of the collision will provide not only 8216;8216;the most detailed pictures we have ever seen of a comet,8217;8217; said Lindley Johnson, the program executive, but also a first glimpse of the material inside a comet. That, in turn, could give valuable new information about the formation of the solar system.
Their target is a 8216;8216;jet-black, pickle-shaped icy dirtball the size of Washington, D.C.,8217;8217; said JPL8217;s Don Yeomans, a co-investigator for the mission. It is about 9 miles long and 3 miles wide.
Deep Impact8217;s goal of crashing a small probe into a comet is unprecedented. So far, the mission has gone perfectly. Deep Impact, launched on a Delta II rocket from Cape Canaveral Air Station in Florida on January 12, has been streaking across the solar system at nearly 50,000 mph to intercept Tempel 1 near its perihelion8212;the closest point in its orbit to the sun8212;just short of the orbit of Mars, about 83 million miles from Earth.
The craft will take progressively sharper pictures of the nucleus and transmit them to the mother ship for relay to Earth. The last one could be snapped as few as three seconds before impact. Meanwhile, the mother ship will be monitoring the collision and aftermath with its own telescope and instruments.
If, for some unforeseen reason, the impactor does not separate from the mother ship, engineers will crash the entire assembly into the comet. 8212;LAT-WP
