MESSENGER Mission News (MESSENGER website)

MESSENGER Team Member Stan Peale was among the researchers to recently announce the discovery of strong evidence that the planet Mercury has a molten core. The finding explains a more than three-decade old planetary mystery that began with the flight of the Mariner 10 spacecraft. MESSENGER Principal Investigator Sean Solomon talks about the significance of this discovery at a Science magazine podcast, available online at Dr. Solomon’s summary of the team’s work and its importance, written as a “Perspectives” piece in the May 4, 2007, issue of Science, is available online at

MESSENGER (MErcury Surface, Space Environment, Geochemistry, and Ranging) is a NASA-sponsored scientific investigation of the planet Mercury and the first space mission designed to orbit the planet closest to the Sun. The MESSENGER spacecraft launched on August 3, 2004, and after flybys of Earth, Venus, and Mercury will start a yearlong study of its target planet in March 2011. Dr. Sean C. Solomon, of the Carnegie Institution of Washington, leads the mission as principal investigator. The Johns Hopkins University Applied Physics Laboratory built and operates the MESSENGER spacecraft and manages this Discovery-class mission for NASA.

The Carnegie Institution of Washington, a private nonprofit organization, has been a pioneering force in basic scientific research since 1902. It has six research departments: the Geophysical Laboratory and the Department of Terrestrial Magnetism, both located in Washington, D.C.; The Observatories, in Pasadena, California, and Chile; the Department of Plant Biology and the Department of Global Ecology, in Stanford, California; and the Department of Embryology, in Baltimore, Maryland.