UND space scientist helps NASA probe protoplanet


David L. Dodds

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UND space scientist helps NASA probe protoplanet

In its first global analysis of the giant asteroid Vesta, NASA’s Dawn mission has confirmed Vesta’s status as a special fossil of the early solar system and revealed a world more varied and diverse than originally thought. Dawn’s work at Vesta now marks it as NASA’s first “reverse” sample return mission in which we had identified samples before we visited the body.

Dawn has now provided a full picture of the body, showing that Vesta is the only known intact, layered planetary building block with an iron core surviving from the earliest days of the solar system. It therefore more closely resembles a small planet or the moon than other asteroids. The first published results from Dawn appear in six papers released by the journal Science today.

“Dawn’s visit to Vesta has confirmed our broad theories of this giant asteroid’s history, while also helping to fill in details it would have been impossible to know from afar,” said Carol Raymond, deputy principal investigator based at NASA’s Jet Propulsion Laboratory, Pasadena, Calif. “Dawn’s residence at Vesta of nearly a year has made Vesta’s planet-like qualities obvious and shown us our connection to that bright orb in our night sky.”

These composite images from the framing camera aboard NASA's Dawn spacecraft show three views of a terrain with ridges and grooves near Aquilia crater in the southern hemisphere of the giant asteroid Vesta. NASA/JPL-Caltech/ UCLA/MPS/DLR/IDA

“We know a lot about the moon, but we’re only now coming up to speed on Vesta, said Vishnu Reddy, a member of the University of North Dakota Space Studies faculty now based . as a framing camera team member at the Max Planck Institute for Solar System Research. “Comparing the two gives us two storylines for how these fraternal twins evolved in the early solar system.”

UND planetary geologist and Chester Fritz Distinguished Professor of Space Studies Mike Gaffey also is a member of the Dawn team.

Vesta’s geologic complexity is related to a process, known as “differentiation,” that segregated Vesta into a crust, mantle and core about 4.56 billion years ago, very close to the birth of the solar system itself. This history makes Vesta similar to terrestrial planets and our moon, which also are segregated into crust, mantle and core. In fact, Dawn has been able to confirm that Vesta has an iron core with a radius of about 110 kilometers, which proves that Vesta differentiated.

Launched in 2007, Dawn began its exploration of the approximately 330-mile-wide (530-kilometers) asteroid Vesta in mid-2011. The spacecraft's next assignment will be to study the dwarf planet Ceres in 2015.

Dawn's mission to Vesta and Ceres is managed by NASA's Jet Propulsion Laboratory, Pasadena, Calif., for NASA's Science Mission Directorate in Washington. JPL is a division of the California Institute of Technology in Pasadena. Dawn is a project of the directorate's Discovery Program, managed by NASA's Marshall Space Flight Center in Huntsville, Ala. UCLA is responsible for overall Dawn mission science. Orbital Sciences Corp. in Dulles, Va., designed and built the spacecraft. The German Aerospace Center, the Max Planck Institute for Solar System Research, the Italian Space Agency and the Italian National Astrophysical Institute are international partners on the mission team.

David Dodds

University Relations Editor

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