Preliminary examination (PE) of the aerogel tiles and Al foils from the Stardust Interstellar Dust Collector has revealed multiple impact features. Some are most likely due to primary impacts of interstellar dust (ISD) grains, and others are associated with secondary impacts of spacecraft debris, and possibly primary impacts of interplanetary dust particles (IDPs) [1, 2]. The current focus of the PE effort is on constraining the origin of the individual impact features so that definitive results from the first direct laboratory analysis of contemporary ISD can be reported. Because crater morphology depends on impacting particle shape and composition, in addition to the angle and direction of impact, unique particle trajectories are not easily determined. However, elemental analysis of the crater residues can distinguish real cosmic dust from the spacecraft debris, due to the low cosmic abundance of many of the elements in the spacecraft materials. We present here results from the elemental analysis of 24 craters and discuss the possible origins of 4 that are identified as candidate ISD impacts

NASA's interstellar collector from the Stardust mission captured several particles that are now thought to be of interstellar origin. We analyzed two of these via nanodiffraction at the European Synchrotron Radiation Facility (ESRF) and found them to contain crystalline components. The unit cell of the crystalline material is determined from the diffraction patterns and the most likely mineral components are identified as olivine and spinel.

Some bulk properties of interstellar dust are known through infrared and X-ray observations of the interstellar medium. However, the properties of individual interstellar dust particles are largely unconstrained, so it is not known whether individual interstellar dust particles can be definitively distinguished from interplanetary dust particles in the Stardust Interstellar Dust Collector (SIDC) based only on chemical, mineralogical or isotopic analyses. It was therefore understood from the beginning of the Stardust Interstellar Preliminary Examination (ISPE) that identification of interstellar dust candidates would rest on three criteria - broad consistency with known extraterrestrial materials, inconsistency with an origin as secondary ejecta from impacts on the spacecraft, and consistency, in a statistical sense, of observed dynamical properties - that is, trajectory and capture speed - with an origin in the interstellar dust stream. Here we quantitatively test four interstellar dust candidates, reported previously [1], against these criteria.

FROM THE STARDUST INTERSTELLAR COLLECTOR. R. M. Stroud, C. Allen, S. Armes, S. Bajt, A. Ball, R. Bastien, H. Bechtel, J. Borg, F. E. Brenker, J. C. Bridges, D. E. Brownlee, M. J. Burchell, M. Burghammer, A. Butterworth, R. Chater, P. Cloetens, G. Cody, A. Davis, T. Ferroir, C. Floss, G. Flynn, D. Frank, Z. Gainsforth, E. Grün, P. R. Heck, J. Hillier, P. Hoppe, F. Hörz, L. Howard, B. Hudson, G. R. Huss, J. Huth, A. T. Kearsley, B. Lai, M. Landgraf, J. Leitner, L. Lemelle, H. Leroux, L. Nittler, R. Ogliore, M. C. Price, F. Postberg, S. Sandford, S. Schmitz, G. Silversmit, A. Simionovici, R. Srama, F. Stadermann, T. Stephan, S. Sutton, R. Toucoulou, M. Trieloff, J. TrigoRodriguez, P. Tsou, A. Tsuchiyama, T. Tyliczszak, B. Vekemans, L. Vincze, J. Warren, A. J. Westphal, M. E. Zolensky. Affiliations are listed at http://ssl.berkeley.edu/~westphal/ispe.

STARDUST AEROGEL INTERSTELLAR DUST COLLECTOR A. J. Westphal, C. C. Allen, S. Armes, S. Bajt, A. D. Ball, R. Bastien, H. Bechtel, J. Borg, F. E. Brenker, J. C. Bridges, D. E. Brownlee, M. J. Burchell, M. Burghammer, A. L. Butterworth, R. Chater, P. Cloetens, G. Cody, A. M. Davis, T. Ferroir, C. Floss, G. F. Flynn, D. Frank, Z. Gainsforth, E. Grun, P. R. Heck, J. Hillier, P. Hoppe, F. Horz, L. Howard, G. Howe, B. Hudson, G. R. Huss, J. Huth, A. T. Kearsley, B. Lai, M. Landgraf, L. Lemelle, J. Leitner, H. Leroux, R. Lettieri, W. Marchant, L. Nittler, R. Ogliore, M. C. Price, F. Postberg, S. A. Sandford, S. Schmitz, G. Silversmit, A. S. Simionovici, R. Srama, F. Stadermann, T. Stephan, R. M. Stroud, S. Sutton, R. Toucoulou, M. Trieloff, J. Trigo-Rodriguez, P. Tsou, A. Tsuchiyama, T. Tyliczszak, B. Vekemans, L. Vincze, J. Warren, M. E. Zolensky, >28,800 Stardust@home dusters. Affiliations are listed at http://ssl.berkeley.edu/~westphal/ispe.

In January 2006, the Stardust sample return capsule returned to Earth bearing the first solid samples from a primitive solar system body, Comet 81P/Wild2, and a collector dedicated to the capture and return of contemporary interstellar dust. Both collectors were approximately 0.1m(exp 2) in area and were composed of aerogel tiles (85% of the collecting area) and aluminum foils. The Stardust Interstellar Dust Collector (SIDC) was exposed to the interstellar dust stream for a total exposure factor of 20 m(exp 2) day. The Stardust Interstellar Preliminary Examination (ISPE) is a three-year effort to characterize the collection using nondestructive techniques.