Named in honor of Christopher F. Chyba (b. 1959), who holds the Carl Sagan Chair for the Study of Life in the Universe at the SETI Institute of Mountain View, California. Chyba, who has also worked recently at the University of Arizona and on the U.S. White House science staff, has done pioneering work in understanding the role of impacts in forming the atmospheres of the earth and Mars and in transporting organic chemicals to the inner solar system. He studied the physics of atmospheric entry and applied the results to analysis of the Tunguska object and to determination of the risk threshold for small minor planets colliding with the earth. Chyba currently chairs NASA's Solar System Exploration advisory committee. Citation written by D. Morrison at the request of the discoverer.