Halley's comet

Astronomer Dr. Donald K. Yeomans has been named project scientist for the NASA portion of a joint U.S.-Japanese mission that will be the first ever to send a lander and robotic rover to an asteroid, and return an asteroid sample back to Earth.

Yeomans is a senior research scientist at JPL and supervisor of the Laboratory's Solar System Dynamics Group, which is responsible for tracking all the planets, natural satellites, comets and asteroids in the solar system. He specializes in identifying the orbital paths of comets, asteroids and other bodies. Yeomans will lead the work of the U.S. science team in utilizing the scientific instruments on the tiny book-size rover being built at JPL for the asteroid lander mission, which is called MUSES-C. The U.S. and Japanese science teams will collaborate on the analysis of scientific data returned by the spacecraft, including work on the asteroid sample that will be brought back to Earth.

Scheduled for launch from Kagoshima, Japan on a Japanese M5 rocket in January 2002, MUSES-C will be the world's first asteroid sample return mission and will be the first space flight demonstration of several new technologies. "MUSES-C" stands for Mu Space Engineering Spacecraft (the "C" signifies that it is the third in a series). It is part of a series of flight technology and science missions managed by the Institute of Space and Astronautical Science of Japan (ISAS). NASA's Jet Propulsion Laboratory (JPL) in Pasadena, CA, is managing the U.S. portion of the mission. Ross M. Jones is the project manager at JPL.

Asteroid 4660 Nereus, a small, near-Earth asteroid nearly one mile in diameter, is the target of the MUSES-C mission that will set a lander down on the asteroid's surface, let loose a miniature rover to gather photos of the terrain, and collect and return to Earth three samples from the asteroid's surface. The lander and sample return vehicles are provided by Japan and the rover is being provided by JPL. All three vehicles will be combined as one package for flight to the asteroid.

Asteroids are thought to be remnants of the material from which the inner solar system was formed 4.6 billion years ago. They are representative of the fundamental building blocks that coalesced into the terrestrial planets -- Mercury, Venus, Earth and Mars. Scientists want to study asteroids because of the clues these small bodies may hold to the origin and evolution of the solar system. Eventually, metal-rich asteroids could also serve as resources for space mining and human exploration.

Yeomans is well-known for his precise orbit determinations of solar system objects. He provided the accurate position predictions that led to the first telescope sighting of comet Halley on its return visit to the inner solar system in 1982. He provided the predictions that led to the successful flybys of five international spacecraft past comet Halley in March 1986. Yeomans also provided the position predictions for asteroids 951 Gaspra and 243 Ida that helped the Galileo spacecraft to make the first close-up images of an asteroid. More recently, he worked with Dr. Paul Chodas, also of JPL, to provide the accurate predictions for the impacts of comet Shoemaker-Levy 9 with Jupiter in July 1994. Yeomans is currently a science investigator on a NASA mission to fly past three different comets. He is also the radio science team chief for NASA's Near-Earth Asteroid Rendezvous (NEAR) mission, a spacecraft headed for an encounter with the asteroid Eros.

Yeomans has been given seven NASA awards including an Exceptional Service Medal in 1986. In addition, he was presented with a Space Achievement Award by the American Institute of Aeronautics and Astronautics, an award of appreciation by the Goddard Space Flight Center, Greenbelt, MD. Asteroid 2956 was re-named 2956 in Yeomans' honor. He has authored four books and more than 80 technical papers on comets and asteroids.

A native of Rochester, NY, Yeomans received his bachelor's degree in mathematics in 1964 from Middlebury College in Middlebury, VT, and a master's degree in 1967 and doctorate in astronomy in 1970 from the University of Maryland. Yeomans and his wife, Laurie, have two adult children and reside in La Canada-Flintridge, CA

JPL is a division of the California Institute of Technology.

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