Space trek to end over Utah

For three years and nearly 2 million miles, NASA's Genesis space capsule drifted through the depths of space, most of that time collecting particles of the solar wind. Wednesday morning it returns to Earth, streaking through the atmosphere — to be snagged in midair above western Utah.

Genesis project leader Donald Burnett seemed nervous about only one aspect of this amazing feat, in an interview late last month: the weather over Dugway Proving Ground, where helicopters will chase the probe.

A thunderstorm could prevent crews from catching the capsule with its delicate collector arrays. If the weather looks too awful, NASA can wave off the spacecraft and make another try in six months. But once it enters the atmosphere, it must come down.

So the concern is a sudden rain squall.

"If it's pouring down rain on the morning of Sept. 8 . . . the helicopters couldn't get up." The probe would suffer a hard landing on the desert of Dugway Proving Ground.

That would not mean the $264 million project was a failure, he said, but some of the collector plates would break.

Burnett, professor of nuclear geochemistry at the California Institute of Technology, need not have been too worried. According to the National Weather Service prediction Sunday, recent storms have passed and Wednesday should have reasonably good weather for capturing a space probe: partly cloudy with temperatures reaching the upper 80s.

That is, if an unexpected front doesn't blow in.

Genesis was launched from Cape Canaveral, Fla., on Aug. 8, 2001, on a looping, 1.86-million mile journey. It cruised around the "Lagrange 1 point" nearly a million miles out — the area of space where the sun's and Earth's gravity balance each other. There it gathered material blowing off the surface of the sun in the solar wind.

The probe exposed small hexagonal collector plates to the wind of charged particles. The plates are made of silicon (basically glass), gold, sapphire and carbon in what NASA terms a "diamond-like" form. Particles of material from the sun that impacted the plates would be embedded in them.

Following 850 days of catching bits of the sun, the petal-like collector plates were stowed in the spacecraft and the capsule closed up for the trip back to Earth.