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SMALL BODIES meteorites, classified as shergot- tites. Together with nakhlites and chassignites, shergottites make up the total of more than 140 samples of Martian rocks known to date, ascribed to 69 different episodes of impacts against the Earth's surface. Even though they were in each case only small objects (just 3 above 10 kg), they are nonethe- less extremely important since they represent different mo- ments of the geological evolu- tion of Mars. In order to make the most of this evidence, it is however necessary to know the exact place of origin of the pre- cious rocky material, consisting basically in identifying an im- pact crater with features compa- tible with the properties of cer- tainMartianmeteorites. The start- ing point is to obviously analyze the mineralogical properties of these latter ones, which is in it- self relatively simple since they are physically available and be- cause they can be subjected to various laboratory tests. From the countless analyses of recent decades has emerged that near- I n these images it is possible to ob- serve the morphol- ogical characteris- tics of the rays of ejecta surrounding the Mojave Crater and the manner in which they extend. [Science/AAAS] ly all those meteorites are mineralogically re- lated to the three groups mentioned above, that three-quarters of them belong to the shergottites group and that the time spent in space by the original rock material before falling to Earth is about 11 million years for the nakhlites and chassignites, and 1 to 5 million years for the shergottites. Since the time elapsed from reaching Earth and their