Image right: Dramatic liftoff of Genesis on a Delta rocket as it enters the only cloud in the Florida sky. Credit: NASA
How will Genesis end?
The question may seem phrased nonsensically, since genesis refers to a beginning. But the NASA Genesis mission to sample solar wind will end September 8th in a dramatic finish. The capsule will not only return the first extraterrestrial samples brought to Earth since Apollo, but will also land on firm ground. This trajectory contrasts with the familiar Pacific 'splashdown'. Genesis will end its multi-year recovery of less than a few grains of pristine dust over the Utah desert.
To make the landing softer, a crew of Hollywood stuntmen were called upon. The stunt proposed by the Genesis mission team includes picking an aerofoil out of the cloudtops while still falling from 4,000 feet above the desert floor. A pair of helicopters manned by 6 pilots and mission operators will attempt to hook the capsule's parachute, reel out 100 feet of a tether and then gently place Genesis on the ground.
During the August 19 NASA press conference, one of the helicopter pilots was unavailable to explain the stunt. He was doing double-time in Chicago. Halfway across the country, the shooting of aerobatics for the next "Batman" movie had the second helicopter pilot busy studying a script other than the Genesis one.
Project manager Don Sweetnam, acknowledges, "We must get the spacecraft to return to a tiny spot in the Utah desert and then snag it with a helicopter before it hits the ground.''
"Each helicopter will carry a crew of three," said Roy Haggard, chief executive officer of Vertigo Inc. and director of flight operations for the lead helicopter. "The lead helicopter will deploy an eighteen-and-a-half foot long pole with what you could best describe as an oversized, Space-Age fishing hook on its end. When we make the approach we want the helicopter skids to be about eight feet above the top of the parafoil. If for some reason the capture is not successful, the second helicopter is 1,000 feet behind us and setting up for its approach. We estimate we will have five opportunities to achieve capture."
Image left: A helicopter practices midair retrieval with a mock sample return capsule. Credit:NASA/JPL
Within two hours after a successful capture, scientists hope to seal the deal. To remove chances for long-term contamination, a purge of nitrogen gas will prepare the Genesis capsule for a week-long trip to a cleanroom at Johnson Space Center in Houston. That Utah to Houston trip will finish the space part of the mission, but begin the scientific journey to clarify how the early solar system formed.
According to Caltech's Don Burnett, the Genesis principal investigator, the current best picture of the Sun and planets is framed by its origin as a gas nebulae. This molecular cloud was amorphous--the Void.
From the void of light gases, gravity took over and increasingly larger particles began to clump. These building blocks eventually became a rapidly rotating disk, a flattened cloud which helps scientists understand the orbital plane that the planets occupy today when orbiting the Sun. This cloud-to-planet transformation has left little modern evidence except the particles that spew daily as part of the solar corona. Sampling that wind defined the primary Genesis mission.
Image right: Artist's concept of the sample return capsule. Credit:NASA/JPL
The motivation to sample solar wind from outside the influence of the Earth's magnetic field was well considered, since the Earth is protected from these charged particles except on the sun-ward side of our orbit. So Genesis sat in what scientists call the 'parking lot' for sun watchers. This point in space is called L1, or the inner libration point. From this position the spacecraft can sit idly at the gravitational balance point between the Earth and Sun. Since closing up its collection trap, Genesis has pointed itself homeward and eventually to Utah.
Tallying up the 'firsts' for Genesis is daunting: the first extraterrestrial samples that are not lunar; the first NASA try at a overland parachute snatch; the first use of Hollywood stunt teams to pull off the trick; the first chance to peek at the early solar system; and the first pure solar wind chemistry to view without contamination.
Genesis will likely occupy solar scientists for decades. Like the moonrocks that are still kept in Houston cleanrooms, the solar wind will become a standard to develop new instrument methods and analytical benchmarks.
"I understand much of the interest is in how we retrieve Genesis," added Burnett. "But to me the excitement really begins when scientists from around the world get hold of those samples for their research. That will be something."
In answering the question, when will Genesis end?, the obvious answer is September 8, but its scientific story has only started a beginning chapter of another genesis.
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