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06 Sep 2004 16:24
In a harrowing feat high over the Utah desert on Wednesday, two helicopter stunt pilots will try to snatch a floating space capsule that holds “a piece of the sun” and bring it safely down.
Their biggest fear: what if they flub it on live television? And that’s entirely possible. The pilots rate it eight or nine on a difficulty scale of 10.
“It’s like flying in formation with a giant floating jellyfish,” says pilot Dan Rudert.
The stuntmen will be trying to hook the 180kg Genesis capsule as it hurtles 120m a minute.
Inside it are fragile solar-wind particles—so small they’re invisible—which scientists hope will reveal clues about the origin of our solar system.
The biggest challenge, the pilots say, will be flying at 64kph a kilometre above the desert without any visual reference points to judge distance or speed as they close in with hook and cable on the capsule.
The helicopter pilots will have five chances to snag the capsule in mid-air.
Military pilots were unavailable for a mission that required them to commit to a task six years in the future.
If they miss and the Genesis capsule hits the ground hard, scientists say they will have to spend months sorting through broken disks holding the tiny solar-wind particles.
There are also other opportunities for the $260-million mission to go awry.
For Nasa engineers, a white-knuckle moment will be when the capsule must be steered through a “keyhole” high in the Earth’s atmosphere. If the experts at California’s Jet Propulsion Laboratory can’t line up the precise entry and angle, Genesis will be waved off on an elliptical orbit of Earth, and another attempt will be made in six months.
Genesis has been moving in tandem with Earth outside its magnetic shield on three orbits of the sun. Now on a trajectory back home, it is picking up speed rapidly as Earth’s gravitational pull brings it closer and will hit a top speed of 39 600kph before the atmosphere slows the descent.
The Genesis mission marks the first time Nasa has collected and returned any objects from farther than the moon, said Roy Haggard, Genesis‘s flight operations chief and CEO of Vertigo, which designed the capture system.
Together, the charged atoms captured 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.
But they expect to learn the precise composition of the sun, which “has them all excited and drooling”, said Don Sweetnam, Genesis programme manager, who said the discovery could rewrite textbooks for the next generation.
“We’re going to bring a piece of the sun down to Earth,” said Dr Charles Elachi, director of the Jet Propulsion Laboratory in Pasadena, California. “That’s going to give us some fundamental understanding of our origin.”
The electrically charged atoms Genesis has been collecting won’t be like anything found on Earth, said Don Burnett, Genesis principal investigator at the California Institute of Technology. Scientists think these solar ions were found in the solar nebula, a giant molecular cloud of gas and dust that collapsed 4,6-billion years ago to form the sun and spin off the makings of hard rock planets.
Scientists have an easier time explaining how an object more than a kilometre wide can grow with the accumulating power of gravity into the size of the Earth, but aren’t certain how a nascent planet forms from a cloud of gas and dust, said Burnett, who is a geochemist.—Sapa-AP
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