NSLS News 2006

January 25, 2006

NSLS to Examine Pieces of Star Dust

Beginning in early February, the NSLS will host a series of very exciting experiments - the analysis of space dust collected by NASA's Stardust spacecraft, which, after nearly seven years collecting cosmic matter during its travels through the solar system, landed safely in Utah on January 15.

(From left) George Flynn (SUNY Plattsburgh), Lindsay Keller (NASA), Larry Carr (NSLS), and Randy Smith (NSLS) examine samples from the Stardust mission at beamline U10A.

Launched on February 7, 1999, Stardust's mission was to collect dust and carbon-based compounds from a passing comet, as well as tiny amounts of interstellar dust streaming towards Earth from deep space. Its delivery of this material marks the first time since Apollo 17 that a NASA spacecraft has successfully brought back a space-matter sample.

Now, at the NSLS and other synchrotron facilities, portions of that teaspoonful-sized amount of comet and star dust will be studied to determine its composition and properties. The variety of research techniques available at the NSLS will allow researchers to maximize the amount and type of information learned about the dust particles. The information scientists will gather could help answer some very important, very fundamental questions about the formation of the solar system and the Earth in particular.

The initial analysis of these samples, known as the Preliminary Examination Period, has already begun in the Stardust Laboratory at NASA's Johnson Space Center. Following these first studies, the samples will then be divided, prepared, and distributed to qualified investigators, including those at the NSLS, for more intensive studies. These scientists are members of the Stardust Preliminary Exam Team.

Stardust particle (crystalline object with dark borders), embedded in the aerogel collector. (Photo courtesy of NASA)

At the NSLS, analyses will take place at beamline X26A, led by physicist and Stardust co-investigator George Flynn (SUNY Plattsburgh). Flynn is leading a worldwide group of scientists who will perform chemical composition measurements on the comet samples collected by Stardust. The extremely tiny and bright x-ray beams produced at beamline X26A will be an excellent tool for analyzing the particles, which are just 10-20 millionths of a meter in diameter (so small that five particles fit across the width of a single human hair). Using these capabilities, the X26A scientists will be able to extract chemical and mineralogical information from the sample without the need to remove the dust particles from the "aerogel" substance used to capture them in space.

After particles are extracted from the aerogel, they will be analyzed at other beamlines using both x-rays (X1A1), and infrared light (U10A and U10B). At beamline X1A1, a powerful imaging device called a scanning transmission x-ray microprobe (STXM) will be used to collect detailed images of the particles. The STXM employs a technique known as x-ray absorption near-edge structure (XANES) to gather information about the elemental makeup of the particles, especially the carbon found in organic compounds. Flynn's studies using the STXM may be able to identify organic compounds within some of the smallest Stardust particles - compounds that may have formed at the birth of our solar system.

In a concurrent set of studies, Flynn and Stardust co-investigator Lindsay Keller will use infrared light to identify specific minerals within the dust particles. Keller, who leads the group of scientists who will perform optical studies of the Stardust samples, is a lunar and planetary scientist with NASA's Johnson Space Center. The far-infrared microscope at beamline U10A, which can sense the unique vibrations of atoms in crystalline solids, is an excellent tool for identifying specific minerals within the Stardust sample. The mid-infrared light produced at beamline U10B will also be used to characterize any organic material found in the particles. Unlike x-ray methods, the information collected using these infrared techniques can be compared with the astronomical observations of distant interstellar dust clouds, including those involved with the formation of planetary systems like ours.

For more information on the Stardust mission, see the NASA website at:
http://stardust.jpl.nasa.gov/news/bios.html
http://stardust.jpl.nasa.gov/news/bio_science.html

ARTICLE BY: Laura Mgrdichian