Dawn's asteroid exploration

Article By:

Raymond, Carol Anne Jet Propulsion Laboratory, California Institute of Technology, Pasadena, California.

Åkerman, Johan Department of Physics, University of Gothenburg, Gothenburg, Sweden.

Last reviewed:2014

DOI:https://doi.org/10.1036/1097-8542.YB140227

The objective of the Dawn mission is to study the origin of the solar system by taking a journey in space to map objects that have recorded the events of the earliest days of the solar system. The targets chosen were the second most massive asteroid in the main belt, 4 Vesta, which was first observed on March 29, 1807, by H. Olbers, and the most massive asteroid and dwarf planet, 1 Ceres, which was discovered on January 1, 1801, by G. Piazzi. These bodies are believed to be intact survivors of the tumultuous history of collisions experienced in the asteroid belt and the inner solar system as the giant planets formed and migrated. These two bodies are quite different. Vesta has a basaltic crust and an iron core somewhat like those of our Moon. Ceres is believed to contain a great deal of water in the form of hydrated minerals and possibly liquid water and ice. Vesta has revealed itself to terrestrial scientists through the howardite, eucrite, and diogenite (HED) meteorites that have fallen on Earth, but the meteorite record has revealed nothing about Ceres. See also: Evolution of Asteroid 4 Vesta

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