Curiosity Impact
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Curiosity Impact

December 11, 2012
MSL (Curiosity) in cruise configuration jettisoned two 75-kilogram tungsten blocks just before atmospheric entry, used as cruise balance masses. A CTX image was acquired at the predicted impact site for these blocks, revealing four large impact markings that appear very recent.

We were expecting to see just two impacts sites here--from the tungsten blocks--and it is highly unlikely that these dense blocks broke apart in the atmosphere. The only other source of impacts at nearly the same time and place is the cruise stage itself, which was more likely to break apart in the atmosphere. The impacts were highly oblique, as shown by the asymmetric morphologies of the individual impacts and the elongation of the strewn field.

The large impacts created craters with diameters ranging from 3 - 5 meters diameter, about what was expected from the 75-kilogram tungsten blocks. Which two of the four impacts came from the tungsten blocks? The two central impacts that are close to each other and of similar size probably originated from the tungsten blocks. The other two impacts, which have more asymmetric ejecta, may be from the cruise stage, which broke apart into two main pieces. The many smaller impacts may have been formed by secondaries from the large impacts and additional pieces of the cruise stage.

Although hundreds of new impact sites have been imaged on Mars, we do not know the initial size, velocity, density, strength, or impact angle of the objects. However, for the MSL hardware we do have such information, so study of this impact field will provide data on impact processes and Mars surface and atmospheric properties.

Written by: Alfred McEwen

Credits: NASA/JPL/University of Arizona

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