Genesis capsule slams back to Earth
BY WILLIAM HARWOOD
STORY WRITTEN FOR CBS NEWS "SPACE PLACE" & USED WITH PERMISSION
Posted: September 8, 2004
A small spacecraft carrying priceless samples of the sun crashed into the Utah desert today when its stabilizing parachute failed to deploy, bringing an innovative $264 million mission, NASA's first sample return flight since the Apollo moonshots, to a disappointing end.
But a drogue chute needed to stabilize the craft before deployment of its large parafoil never fired and the craft slammed into the ground at about 193 mph.
Video showed the canister half buried in the Utah desert, largely intact. It was carrying 20 to 30 micrograms of solar wind material, the equivalent of a few grains of salt. The atoms were embedded in fragile glass-like wafers.
Even so, project scientists were hopeful about salvaging at least some of the mission's science objectives.
"The canister within the capsule has suffered a rupture so that you can actually see into it," said Steve Brody, Genesis program executive at NASA headquarters. "That is not as we would have liked, certainly.
"What is has enabled us to do, though, is to actually see some of the collector surfaces inside the canister. Some of those surfaces are intact on the structure which they are mounted, which is a very good sign.
"So that means not only have we returned a piece of the sun - here it is in Utah - but we fully expect that we will be able to make good use of those materials and derive some science."
The 1,400-pound Genesis probe, a relatively low-cost Discovery-class mission, was launched Aug. 8, 2001, from the Cape Canaveral Air Force Station atop a Boeing Delta 2 rocket.
To collect pristine samples of the solar wind, the spacecraft was fired on a long, looping trajectory that carried it to a point about a million miles toward the sun where the gravity of Earth and its star essentially cancel each other out.
Genesis spent 27 months in a so-called halo orbit around the Lagrange 1, or L1, point, periodically exposing its five collectors to the passing solar wind. The collectors measured about one yard square and were each made up of 55 hexagonal tiles about four inches across. The tiles, in turn, were made up of various materials, ranging from silicon and germanium to artificial diamond. The materials were selected because of their ability to capture specific elements in the solar wind.
The re-entry vehicle, carrying the sealed sample container inside, separated from the main body of the spacecraft earlier today and made a pinpoint re-entry.
Hitting the atmosphere at 24,700 mph, the 420-pound sample canister's energy of motion was equivalent to that of a 4.5-million-pound freight train moving at 80 mph. In seconds, most of that energy was converted into heat, subjecting the probe's heat shield to temperatures up to 4,700 degrees and slowing the craft with a braking force of 30 times Earth's gravity.
Two minutes after entry began, at an altitude of about 21 miles, the small drogue parachute was to have unfurled to stabilize the craft and four minutes after that, at an altitude of about 22,000 feet, a wing-like parafoil was to deploy, slowing the craft's descent to a gentle 10 to 12 miles per hour.
Down below, two helicopters piloted by Hollywood stunt pilots were waiting, flying a criss-cross pattern along the spacecraft's ground track across the Utah Test and Training Range, an isolated military reservation where munitions and unpiloted aircraft are tested.
After attaching a nitrogen purge to protect the solar particles from earthly contamination, the sample canister was to have been trucked to the Johnson Space Center in Houston and moved into an ultra-clean laboratory for detailed scientific analysis.
But it was not to be. An on-board malfunction of some sort prevented a pyrotechnic device from firing as planned to release the drogue parachute. Six such "pyros" were on board and none of them fired. That could be due to a variety of problems, including trouble with a sensor needed to trigger the re-entry procedure or problems with an on-board battery needed to supply the necessary power.
The battery was a source of concern early in the mission when engineers ran into problems with a radiator needed to keep the unit cool. As a result, the battery ran quite a bit hotter than expected but extensive testing with similar batteries on the ground indicated that would not affect the flight hardware's performance.
"Cells like the ones in our battery have been ... under test about once a month the whole time we've been out there," said Bob Corwin, recovery operations team chief with spacecraft-builder Lockheed Martin. "So that battery has been requalified to a temperature about 5 degrees (Celsius) beyond what it's been exposed to during that period of time."
But, he told a reporter, "if you had completely no battery, once you don't fire the first (pyro) it doesn't matter, you don't fire the rest. So the battery is a possible cause for not firing the initial pyros."
Genesis project manager Don Sweetnam said all of the craft's systems were thoroughly tested over the last several months and there were no signs of any trouble.
"We thought things ought to work," he said. "But keep in mind when we buttoned the thing up at the Kennedy Space Center and launched it in 2001, the fate was sealed. There was really nothing we could do at this stage to change things."
Why did NASA spend more than $264 million to capture a few wisps of the solar wind? Because those traces are expected to serve as a sort of cosmic Rosetta stone, providing critical insights into the birth and evolution of our solar system.
In that sense, the solar wind is nothing less than a sample of the original cloud of gas and dust that coalesced to form the sun and its retinue of planet some 4.6 billion years ago. Capturing a sample of this raw material is the goal of NASA's innovative Genesis mission.
"The composition of the solar wind is a clue to the composition of the outer layers of the surface of the sun, which in turn is the composition of the solar nebula from which all the planets formed," Donald Burnett, principal investigator of the Genesis mission, said before launch in 2001. "That's the connection."
Scientists believe the sun and other stars in this neighborhood of the Milky Way galaxy formed inside a vast molecular cloud that has since thinned out and dissipated. The stars formed when areas of slightly higher density contracted under their own gravity to form flattened, rotating solar nebulae.
As gravitational contraction continued in a given cloud, densities in the inner region eventually reached levels high enough to trigger nuclear fusion and a star was born. Material circling the infant sun clumped together to form planets, moons, asteroids and comets.
So far so good. But the details of this complex process - how the solar system evolved from a fairly homogenous cloud of dusty debris to the myriad objects we see today - are poorly understood. By determining the initial composition of the solar nebula, scientists had hoped to fill in the blanks.
Knowing the actual starting composition would "have a tremendous impacting of these on our understand areas."
"The sun has basically more than 99 percent of the mass of the solar system in it," Wadhwa said. "So if we know the composition very well of the sun, we basically understand the starting composition of the initial solar nebula."
A key goal of the Genesis mission was to precisely measure the abundances of three isotopes of oxygen: Oxygen-16, the most common form, with eight protons and eight neutrons; oxygen-17, with nine neutrons; and oxygen-18, which has 10 neutrons.
Scientists already understand the relative abundances of these isotopes in asteroids, Earth, the moon and Mars. But the ratio of the isotopes in the sun, and hence the original solar nebula, is not well understood.
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