• Ph.D. University of Maryland, Astronomy
• M. Sc. University of Maryland, Astronomy
• B.A. Middlebury College

• Motions and characterization of comets and asteroids
• Near-Earth objects
• Solar System Dynamics
• Ephemeris development
• History of astronomy

• Manager, NASA’s Near-Earth Object Program Office (1998 - )
• Supervisor, Solar system Dynamics Group (343R, 1992 - )
• JPL Fellow (2010 - )
• JPL Senior Research Scientist (1994 - )
• Detection co-lead for NASA report to Congress; Near-Earth Object Survey and Deflection Study (2006).
• Provided oral testimony on next generation search for near-Earth objects to U.S. House of Rep. Subcommittee on Space and Aeronautics (Nov. 8, 2007).
• Chair and Vice Chair, AAS Division of Planetary Sciences (1996 – 1999)
• Chair and Vice Chair, AAS History of Astronomy Division (2003 – 2006)
• Member, JPL Senior Research Scientist Promotion Advisory Board (2006- )
• Chair, JPL Division 31 Principal Promotion Advisory Board (2004)
• Member, JPL Division 31 Principal Promotion Advisory Board (2005, 2006, 2007)
• Chair, Division of Dynamical Astronomy, Brouwer Award Committee (2005)
• Chair, NASA Near-Earth Objects Review Panel (1999-2000, 2003-2004)
• Chair, NASA Planetary Astronomy Review Panel (1994-95)
• U.S. delegate for Interagency Consultative Group (NASA, 1998)
• Discipline Specialist for Astrometry, International Halley Watch, (1982 - 1989)

• U.S. Project Scientist, Japanese Hayabusa mission to asteroid Itokawa (1998 - 2012 )
• Near Earth Asteroid Rendezvous Radio Science Team Leader (1994 – 2001)
• Co-I, Deep Impact and EPOXI projects (1999 - )
• Co-I, CONTOUR (1997 – 2002)
• Radio Science Team Leader, Comet Rendezvous-Asteroid Flyby mission (1986 – 1992)

• NASA Distinguished Service Medal (2009)
• NASA Exceptional Service Medal (1986)
• 16 NASA Group Achievement Awards (1986 - 2009)
• Distinguished Alumnus Award, Dept. of Astronomy, Univ. of Maryland (2005)
• Middlebury College Alumni Achievement Award (Oct., 1987)
• Smithsonian Institution’s National Air and Space Museum Aerospace Trophy For Current Achievement (2001). (To NASA’s Near-Earth Asteroid mission team).
• Space Act Award for “Horizons On-Line Ephemeris and Data System.” (1998).
• Asteroid 2956 Yeomans, (1986).
• William H. Pickering Lecturer, American Institute of Aeronautics and Astronautics, August 2005.
• Cited in American Men and Women of Science, Dictionary of International Biography, and Who's Who in America.
• 17 NASA Group Achievement awards

Publications