A team of researchers partnered with the NASA Lunar Science Institute (NLSI) has developed a new hypothesis for the origin of crater ejecta-debris that is launched out of a crater during meteorite impacts. These ejecta offers a unique view into the subsurface conditions

These findings may help scientists target samples for extraction  during future missions to asteroids and terrestrial bodies such as Mercury, Venus, the moon and Mars. The results are published in the  Sept. 21, 2011, issue of the Elsevier journal, Earth and Planetary  Science Letters.

The science team, led by professor Gordon Osinski at The University of  Western Ontario, London,  ntario, compared observations of ejecta  from all terrestrial planets. The observations showed that ejecta deposits all contained more than one layer.

"Understanding ejecta is critical for understanding the context of  samples collected by humans and robots during previous missions and  may aid in targeting future sample return missions to the moon, Mars and beyond," said Osinski.

Craters formed on the surfaces of planetary bodies, including the  Earth, by high-speed impacts, are a basic landform on all the solid planets in the solar system. In prevailing models, a continuous sheet  of ejected material forms during the excavation stage of cratering.
Osinski and his team suggest that this stage is followed by a second  major episode of ejecta emplacement during the final moments of  crater formation – something that has not been taken into account in  any previous models of crater formation. This second episode takes  the form of flows of material molten by the impact event, which  originates from deeper below the surface, potentially offering a  unique window into planetary interiors. A more thorough understanding
of the composition of planetary interiors reveals important insights  into the history of how our solar system formed.

"It is rewarding to see that our international collaborations within the NASA Lunar Science Institute continue to make an impact on current theories and challenge fundamental principles in the field of  lunar science" said NLSI Director Yvonne Pendleton.

This research primarily was supported by the Industrial Research Chair in Planetary Geology held by Osinski and funded by the Natural Sciences and Engineering Research Council of Canada (NSERC), MacDonald, Dettwiler and Associats and the Canadian Space Agency  (CSA). The NLSI is a virtual organization that enables collaborative,  interdisciplinary research in support of NASA lunar science programs.  The institute uses technology to bring scientists together around the  world and comprises competitively selected U.S. teams and several  international partners. NASA's Science Mission Directorate and the  Human Exploration Office in Washington, fund NLSI, which is managed by a central office at Ames.

For more information about the Canadian Lunar Research Network visit: http://clrn.uwo.ca