The Forensics of Genesis
|Genesis capsule soon after impact. |
Eileen Stansbery, assistant director of astromaterials research and exploration science at NASA’s Johnson Space Center (JSC) in Houston, has been working on the Genesis collector materials since September 8, when the space capsule crash-landed to Earth.
"There is nothing that is a total loss," says Stansbery. "We’ve been able to recover every different collector type that we flew, and every different regime that we captured."
|Gold foil fragments post-recovery. Credit:NASA/JPL|
The materials are still located at the temporary clean room set up at the U.S. Army Proving Ground in Dugway, Utah. Stansbery says they are packaging the materials so they can be safely transported to JSC.
Each collector segment will get its own ID number, photograph and carrying case. The samples and shipping containers fill the space of about two refrigerators.
Three of the four concentrator collectors are intact: two silicon-carbines, and one carbon-13 diamond. The fourth segment, a diamond-on-silicon collector, was broken, but more than 85 percent was recovered.
|Intact but bent metal piece post-recovery. Credit:NASA/JPL|
The concentrator segments acted as a kind of magnifying glass, concentrating a large amount of solar wind into a small sample. The concentrator segments were used to measure the isotopic oxygen composition of the sun. This information could determine the role oxygen played in the formation of the solar system.
Gold foil contained on the canister’s lid was designed to collect nitrogen isotopes in the solar wind. Analyzing the sun’s nitrogen could help determine how the atmospheres of the planets in our solar system evolved. Stansbery says this foil was not damaged by the impact.
The capsule also had a polished aluminum collector designed to measure noble gas elements in isotopes. This collector was bent during the impact, but can still be used to recover science data.
|Sifting sample fragments post-recovery. Credit:NASA/JPL|
The array of hexagonal collector wafers did not come out of the crash landing as well, and most of these shattered into large and medium-sized fragments. There were a few silicon-on-sapphire and gold-on-sapphire wafers that didn’t crack.
"The optimum size for analyzing materials is one square centimeter, so we were always intending to have to subdivide the collectors to make them available to the scientific community," says Stansbery. "There’s less subdividing that will need to happen, although we anticipate still having to do that since we did recover some full pieces."
|Semiconductor grade hexagonal collection plates post-recovery. Credit:NASA/JPL|
Wafers that were still connected to the retaining rings fared the best, while "those that were on the edge of the canister impact are pretty dusty."
A metallic glass collector used to measure helium and neon survived the impact intact. The sample return capsule lid foil collectors, which collected molybdenum and platinum to measure solar wind radioactive nuclei, were contaminated and rumpled.
Stansbery says they probably will be able to make the samples available to the scientific community in a few months, but first all the materials will have to be cleaned. Since cleaning could damage the atom-sized samples of solar wind embedded in the collectors at a depth of about a hundred nanometers, they won’t begin that task until after the samples are moved to JSC.
"We have a variety of different contaminant sources on the collector materials," says Stansbery. "Everything from Utah Range soil, to salts from the soil, to pieces of the sample return capsule itself, pieces of the science canister itself, insulation materials that were on the spacecraft, to fragments of the other collectors. For any particular collector, any of those items can be a contaminant."