CAPE CANAVERAL, Fla. -- A four-year mission to send a probe closely past the heart of at least two comets began with a perfect launch Wednesday from Florida.
"This is pretty exciting. We're on our way," said Joseph Veverka, CONTOUR's principal investigator from Cornell University, Ithaca, N.Y.
If all goes as planned, the spacecraft will fly as near as 62 miles (100 kilometers) from the nucleus of a comet, closer than any previous mission, to obtain detailed data on these diverse objects.
"It's truly exciting to have the opportunity to fly this close to the nucleus of a comet for the first time," said Paul Mahaffy, a co-investigator at NASA's Goddard Space Flight Center in Greenbelt, Md.
Liftoff of the $159 million Comet Nucleus Tour (CONTOUR) spacecraft atop a Boeing Delta 2 rocket from pad 17A at Cape Canaveral Air Force Station came at 2:47:41 a.m. EDT (0647.41 GMT).
A Monday launch attempt was called off last week when inspections showed a fine layer of dust was present on CONTOUR's solar array. The delay allowed engineers to take care of their concerns.
Trailing fire and smoke from its single main engine and quartet of solid rocket boosters -- and looking itself much like a comet on fire -- the 13-story rocket climbed out over the Atlantic Ocean toward space.
Some 63 minutes later the probe arrived in its parking orbit over Earth and separated from the third stage of the 13-story launch vehicle.CONTOUR will remain in Earth orbit until 4:46 a.m. EDT (0846 GMT) Aug. 15. That's when a small solid rocket motor attached to the base of the probe will fire for 50 seconds and boost it out of Earth orbit to circle the sun.
Flying a looping path through the sky, CONTOUR will return to the vicinity of Earth four times during the next four years, with the first swing-by set for Aug. 15, 2003.
CONTOUR's primary targets are comets Encke in November 2003 and Schwassmann-Wachmann 3 in June 2006. But following up-close-and-personal probing of those two objects, CONTOUR's mission team can steer the solar-powered probe to a scientifically attractive "new" comet should the opportunity arise.
During the encounters, CONTOURs four scientific instruments will take pictures and measure the chemical makeup of the nuclei while analyzing the surrounding gases and dust.
"We're about to enter into a golden era of comet investigation," said Colleen Hartman, director of NASA's solar system exploration division in Washington, D.C.
Scientists hope the information CONTOUR sends back to Earth will offer clues about the origins of our solar system.
"Comets are the solar system's smallest bodies, but among its biggest mysteries," Veverka said. "We believe they hold the most primitive materials in the solar system and that they played a role in shaping some of the planets, but we really have more ideas about comets than facts."
CONTOUR is one of ten Discovery missions approved by NASA to demonstrate a "faster, better, cheaper" approach to space science missions. Others have included Mars Pathfinder, Near Earth Asteroid Rendezvous and Genesis.
Another of the Discovery missions is Stardust, a comet sample mission that was launched in February 1999. It is due to encounter comet Wild 2 on Jan. 2, 2004; scoop up some cometary dust and return the material to Earth on Jan. 15, 2006.
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