Scientists from the University of Western Ontario in London, Ontario (UWO) have partnered with researchers from the NASA Lunar Science Institute to study crater ejecta – the debris that is launched out of a crater during meteor impacts. They have developed a new theory, which will help future scientists when they examine samples of crater ejecta returned from the Moon, asteroids and terrestrial planets.
The science team, led by professor Gordon Osinski of UWO 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 are visible on all the inner planets in the solar system (Mercury, Venus, Earth and Mars) and the hundreds of moons of all of the planets. They are formed by high-speed impacts of rocky bodies called meteoroids. The process of making craters acts as an excavator, bringing material deep under ground to the surface. During the moonwalks, Apollo astronauts visited the rims of large craters to obtain samples of lunar material brought to the surface as a result of the impact. 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 (NLSI) 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 Associates and the Canadian Space Agency (CSA). Osinski recently established the Canadian Lunar Research Network (CLRN), a network comprised of scientists, engineers and entrepreneurs from throughout Canada. In July 2008, CLRN became the first international affiliate partner of NASA’s Lunar Science Institute.
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.