A May 2 article on the Genesis space probe incorrectly described the surface area of platinum foil used to collect radionuclides from the solar wind. The correct surface area is 1,240 square inches, not 1,240 square centimeters.
Teams Pry Secrets From What's Left of Genesis
Monday, May 2, 2005
HOUSTON -- Stunt helicopters were supposed to pluck the Genesis space capsule gently from the sky as it parachuted earthward, but the hoped-for Hollywood thriller turned into a sour farce when the parachutes failed to open and it plummeted to the ground like a B-movie flying saucer.
That was Sept. 8, 2004, the beginning of what Eileen Stansbery called "a stressful, tension-filled time" for a NASA-led team of forensic specialists who spent 26 days in a makeshift clean room trying to salvage a priceless treasure -- particles from the sun like those that gave birth to the solar system 4.5 billion years ago.
Eight months later, however, the Genesis project is "open for business," said Stansbery, assistant director of astromaterials research and exploration science at Houston's Johnson Space Center. Samples are available to researchers for study, and it appears the project will probably realize all the science it hoped for, although "maybe not with the same precision" and not "as quickly as we originally wanted," she said.
Some research is already underway. A team at Washington University in St. Louis anticipates little problem gleaning samples of noble gases -- helium, neon, argon, xenon and krypton that came from the sun -- from the shiny surface of Genesis's aluminum heat shield.
At the University of California at Berkeley, however, cosmochemist Kunihiko Nishiizumi is seeking suggestions as he struggles to figure out how to straighten sheets of crumpled platinum foil that hold traces of radioactive isotopes of beryllium, aluminum, manganese and other elements.
Genesis was launched Aug. 8, 2001, and eventually spent 850 days collecting particles of the solar wind by exposing a variety of surfaces to the sun's rays. Over time, the heat shield, the foil and hundreds of four-inch-wide ceramic "wafers" were impregnated with samples of all the elements and isotopes spewed by the sun -- a benchmark for studying how the solar system's chemistry evolved on Earth and elsewhere.
The particles were precious -- the equivalent of a few grains of salt in all -- and NASA had devised the midair helicopter recovery to eliminate the jolt of a touchdown and to keep the fragile hexagonal wafers intact. Instead, the capsule crashed into Utah's Dugway Proving Ground at 193 mph, split open and came to rest waist-deep in a salty mud flat.
One silicon-on-sapphire wafer was intact, two others were broken in two, and two more were in "a few large pieces," Stansbery said. But the 301 ceramic hexagons and half-hexagons that began the trip were in tens of thousands of pieces, most of them an inch in diameter or smaller. Virtually all were contaminated with various combinations of dust, mud, salt and mashed-up pieces of spacecraft.
NASA's Dugway team had planned for various contingencies. This one was worse than the one they had called "hole in the side" of the capsule, but not as bad as "shards across the desert."
Two tasks were crucial: map the location of the pieces inside the container so forensic specialists could identify which wafers they came from; and use a variety of packaging methods, so if one piece of wafer was ruined in transit, others would survive.
"We had field kits -- five-gallon buckets, trowels, zip-lock bags, cameras," Stansbery said in an interview. The team worked in a temporary clean room at Dugway, packed the shards in one- and two-inch vials, wafer containers, plastic and glass jars, tissue culture dishes, aluminum foil wrappers and 96-hole sample trays.
On Oct. 4, a NASA plane flew the salvaged material to the Johnson Space Center, where it is stored in low-humidity nitrogen gas in a repository below the Lunar Sample Laboratory Facility that houses moon rocks from the Apollo era.