Secondary impacts from meteorites may endanger lunar missions

BBC : Meteorites frequently reach the lunar surface because of the Moon’s minimal atmosphere. The Lunar Impact Monitoring Program has recorded more than 300 impacts since 2005. Mark Robinson of Arizona State University and his colleagues were examining images of a collision that occurred on 17 March 2013 when they found that the impact had created a wide spread of secondary impacts outside of the normal ejecta pattern. The 18-m crater they found was surrounded by 248 smaller indentations, which were scattered up to 30 km away. Robinson’s team calculated that the secondary impacts, all of which were much less energetic than the initial strike, were still traveling nearly 100 m/s when they struck the Moon’s surface. With several new efforts from various nations to send landers and even manned missions to the Moon, it will be important to take into account the risk posed by such secondary impacts.