SMART-1's view of Crater Hopmann: on the shoulder of a giant


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SMART-1’s view of Crater Hopmann: on the shoulder of a giant
European Space Agency
3 May 2006

This image, taken by the advanced Moon Imaging Experiment (AMIE) on
board ESA’s SMART-1 spacecraft, shows one quarter of crater Hopmann -
an impact structure about 88 kilometres in diameter.

AMIE obtained this image on 25 January 2006 from a distance of about
840 kilometres from the surface, with a ground resolution of 76 metres per
pixel.

The imaged area, not visible from Earth because it is located on the
far side of the Moon, is positioned at latitude of 51.7? South and
longitude 159.2? East. It covers a square of about 39 kilometres per side.

The crater (centred at 50.8? South, 160.3? East) is situated on the
edge of the giant South Pole-Aitken basin SPA, the largest impact crater in
the solar system with a diameter of 2500 kilometres and a depth of 13
kilometres. The SPA basin shows distinctive chemical composition with
unusual mineralogy types, and possible exposure of rocks from the lower
crust or the upper mantle.

The hills on the lower left side are the crater wall of Hopmann. This
crater is very old - many small craters can be seen on its flat floor,
the largest one showing an interesting double-ringed structure. The
outer rim has been also eroded by later impacts.

The small crater chains to the left of Hopmann can be interpreted as
series of so-called “secondary craters”, created by the impact of the
material ejected from a nearby large impact. This ejected material
flies away in molten state, and fall in large “droplets”. When these impact
on the surface, they form typical crater chains as those visible in this
image.

The crater is named after Josef Hopmann (1890-1975), an astronomer that
worked in Bonn, Leipzig and as Director of the Vienna Observatory.

For more information:
Jean-Luc Josset, SPACE-X Space Exploration Institute
Email: jean-luc.josset @ space-x.ch

Bernard H. Foing, ESA SMART-1 Project Scientist
E-mail: bernard.foing @ esa.int