Liftoff was scuttled five times last week by technical concerns and bad weather.
Scientists want to know more about how the planets and the solar system were formed, and they think they can find out by catching the solar wind. Genesis will do that, from about a million miles out. It'll return in just over three years, bringing back the first pieces of another world since the Apollo moon missions.
"I'm excited, but the real excitement comes in September 2004 for us," said California Institute of Technology geochemistry professor Don Burnett, the lead scientist.
That's when the solar samples will fly back in a capsule, dropping by parachute and then parafoil over the Utah desert with a helicopter making a dramatic midair catch.
It's a 20-million mile round-trip.
Meanwhile, CBS News Space Consultant William Harwood reports the shuttle Discovery's countdown continued to tick smoothly toward liftoff Thursday afternoon.
There were no technical problems at pad 39A and forecasters continue to predict a 60 percent chance of acceptable weather during the shuttle's five-minute launch window.
The main concern is a chance of showers generated by afternoon sea breezes.
CBS News Space Consultant William Harwood has covered America's space program full time for more than 15 years, focusing on space shuttle operations, planetary exploration and astronomy. Based at the Kennedy Space Center in Florida, Harwood provides up-to-the-minute space reports for CBS News and regularly contributes to Spaceflight Now and The Washington Post.
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