A pair of helicopters flown by stunt pilots were set to hover nearly a mile above the Utah desert, ready to help snatch the refrigerator-sized capsule's parachute with a hook as it floats down at 400 feet a minute, or more than 6 feet per second.
"All systems are go," Don Sevilla, Genesis payload recovery leader, said Tuesday when the capsule was 134,000 miles above the Earth's surface. If all goes as planned, the mid-air capture was to take place Wednesday.
The capsule's charged atoms — a "billion billion" of them — should reveal clues about the origin and evolution of our solar system, said Don Burnett, Genesis principal investigator and a nuclear geochemist at California Institute of Technology.
"We have for years wanted to know the composition of the sun," Burnett said. "In some cases we will be analyzing it one atom at a time."
Genesis has been moving in tandem with Earth outside its magnetic shield on three orbits of the sun. It was to pick up speed rapidly as Earth's gravitational pull brings it closer before the atmosphere abruptly slows the descent.
That's when the helicopters take over.
Both Cliff Fleming, the lead helicopter pilot, and backup pilot Dan Rudert have replicated the retrieval in dozens of practice runs, and will have five chances to snag the capsule. If they fail, it will hit the ground and shatter the fragile disks holding the atoms. Once captured, the capsule will be tethered to a cable to cushion the impact.
Fleming and Rudert, stunt pilots by trade, were drafted for the $260 million mission because of their expertise flying high and capturing objects. Fleming has swooped after sky surfers in the action movie "XXX" and towed actor Pierce Brosnan through the air in "Dante's Peak." He just worked on "Batman 4."
Fleming said the current job is tricky since he won't have any visual reference to judge the speed or distance of the 400-pound capsule as he closes in from behind it. Among the risks is a sudden updraft that could entangle the capsule's parachute in his tail rotor.
"Because you're up nearly in space, you can't see the wind," Fleming said Tuesday at a U.S. Army hangar here. "There's no movement of trees or brush or dust, so that makes it difficult."
Once the sample container is safely brought down, it will be packed up and driven with a convoy of armed guards to Houston's Space Center in a truck outfitted with air suspension for a gentle ride.
From there, the solar particles — a storehouse of 99 percent of all the material in our solar system — will be parceled out for analysis to the University of California at Los Angeles and the University of Chicago's Argonne National Lab.
The Genesis mission, launched in 2001, marks the first time NASA has collected and returned any objects from farther than the moon, said Roy Haggard, Genesis' flight operations chief and CEO of Vertigo Inc., which designed the capture system.
Together, the charged atoms captured over 884 days on the capsule's disks of gold, sapphire, diamond and silicone are no bigger than a few grains of salt, but scientists say that's enough to reconstruct the chemical origin of the sun and its family of planets.
Scientists will keep busy for five years after Genesis completes its wild ride back to Earth. It will take at least six months before they expect to learn much from the solar wind particles.