GSA Annual Meeting in Indianapolis, Indiana, USA - 2018

Paper No. 284-7
Presentation Time: 3:20 PM


STROUD, Rhonda M., DE GREGORIO, Bradley and BURGESS, Katherine, Materials Science and Technology Division, U.S. Naval Research Laboratory, 4555 Overlook Ave. SW, Washington, DC 20375

The NASA Stardust mission provided the planetary materials community with two milestone sample collections: particles from comet Wild 2, and particles from the contemporary interstellar dust stream. The Preliminary Examination periods for these collections ended in 2006 and 2014, respectively. Stardust samples are available to the international community for laboratory studies, and can be requested from the curators at NASA Johnson Space Center. Although new comet sample return and interstellar dust return missions are currently under development, mission timeline constraints mean that the Stardust collections will remain the only sources for cometary grains of known provenance and for contemporary interstellar dust over at least the next two decades. The Wild 2 sample collection provides opportunities to investigate diverse cometary components, ranging from refractory grains that represent the earliest solids formed in the Solar System to organic matter that comprises components necessary for the emergence of life on Earth. The interstellar collection provides the possibility of direct analysis of individual contemporary interstellar dust grains for testing the models used to interpret telescope and spacecraft-based measurements. As with all returned sample collections, the range of the scientific questions that can be addressed grows over time through improvements in the available laboratory instrumentation and methods. Recent advances in the scanning transmission electron microscopy, focused ion beam microscopy, and secondary ion mass spectrometry are especially critical to these studies, because they enable coordinated elemental, structural and isotopic measurements at micrometer to nanometer scales. We will present a summary of major results from these collections to-date, identify some of the outstanding questions, and discuss needs for instrumentation advances and new sample return collections.