David Fulmer Bender died in San Diego, California, on 13 September 2004, at the age of 91. His heart stopped suddenly while he was dancing. His pioneering work in establishing comprehensive, computer-accessible ephemerides of asteroids and comets found many applications, including the first-ever visit to an asteroid, Gaspra, by an interplanetary spacecraft.
Dave was born in Reno, Nevada, on 10 February 1913, to Homer Charles Bender and Susan Bowers Bender. The family moved to Spokane, Washington, while Dave was very young. His father was a civil engineer and a graduate of MIT, who helped design bridges and dams throughout the Northwest, including the Grand Coolie Dam. Dave had a brother, Phillip (now deceased), who was one year younger.
Advancing rapidly in the Spokane school system, Dave finished high school when he was 15 years old. At 16 he moved to Pasadena, California, and began his studies at the California Institute of Technology (Caltech). In addition to pursuing his course work, he was active in track and football, a tendency toward physical exercise that stayed with him for the rest of his life. It was probably during these years that Dave heard a lecture by Albert Einstein, as mentioned to colleagues many years later. Dave received a BS degree in physics in 1933, an MS in 1934, and a PhD in 1937, all from Caltech. His dissertation was entitled, "The Index of Refraction of Air in the Photographic Infrared." During his sophomore year he found his way to Pomona College in Claremont, California, where he met his future wife, Elizabeth Boyden at a social gathering. They were married in 1935.
Dave's academic career spanned the years from 1937 to 1970, initially at Louisiana State University, Vanderbilt University, and then Fisk. As a life-long pacifist and conscientious objector, Dave served alternate duty during World War II. In 1946 he joined the faculty of the physics department at Whittier College in California, where he became the department chair and remained until 1970. Here Dave's strong personal interest in the students became evident. During each year's spring break, he and Beth led a car caravan of interested astronomy and physics students to Death Valley for primitive camping, exploring the desert, studying the stars, and shooting off rockets. Beth organized all the food and Dave cooked the breakfasts, with French toast being his specialty. This tradition was so popular that many students returned year after year, long after having left the college. Dave enjoyed leading the astronomy club at Whittier College, and also participated in a municipal astronomy club.
In the sixties, in addition to his job at the college, Dave worked part time at the Space Science Laboratory of North American Aviation (later North American Rockwell and now Boeing). Dave co-authored, with Gary Mc Cue and others, several papers on orbital rendezvous techniques, a capability of prime interest to the Apollo program. Soon apparent, however, was Dave's interest in the hundreds of asteroids whose orbits were known at the time. In his spare time he punched their orbital elements into computer cards and initiated a long career of searching for opportunities for spacecraft to flyby or rendezvous with one of these minor planets. He learned enough Russian to read books important at the time on the subject of asteroid orbits. In 1966 he had enough data to publish a paper on some possible asteroid encounters by human missions to Mars. Through conferences of the American Astronautical Society, Dave became acquainted with Roger Bourke, the group supervisor of the Advanced Projects Group at the Jet Propulsion Laboratory (JPL), which is managed by Caltech for NASA. In 1970, Dave retired from Whittier College and began working full time for Roger at JPL.
JPL was still working on missions to the inner planets and was starting to develop missions to the outer planets. Roger understood the potential of having Dave pursue his interest in the small bodies and of having him create a comprehensive set of ephemerides that would be available for the Advanced Projects Group to use for mission planning purposes. Dave worked with Phil Roberts, Carl Sauer, and others who were creating mission design software at the time to ensure that the asteroid file would be compatible with these computer programs. Dave, himself, authored many papers documenting trajectories he discovered to various asteroids, comets, and Lagrange points, along with the search techniques he used. He also documented surveys of opportunities, some for use with low-thrust propulsion as well as the more common chemical propulsion. Along with Raymond Jurgens, Dave published opportunities for radar astronomers to view asteroids passing close to the Earth. Dave did not restrict his investigations to small bodies. He also published papers on Venus missions, lunar swingby techniques, Jupiter gravity assist trajectories to Kuiper belt objects, and multibody-assist trajectories for missions to Jupiter's satellite Europa (the latter two in the 1990s!).
Brian Marsden recalls that in1980 Dave visited him at the new facilities of the Minor Planet Center in Massachusetts and left with a box of new computer cards punched with the orbital elements of the 2000 asteroids known at that time. Colleagues at JPL remember how excited he was when he returned from that trip. As more asteroids were discovered, he would add their orbital elements to the file. Because of Dave's pioneering work in making the asteroid orbits accessible for mission studies before most people cared about these bodies, he can be credited in part for the mission Galileo's close flyby of both Gaspra (in 1991) and Ida (in 1993), along with the discovery of Dactyl, the first confirmed asteroid satellite. Dave eventually passed the responsibility of maintaining the small body file to Donald Yeomans and Ravenel (Ray) Wimberly at JPL. Now called DASTCOM, it includes elements for over 260,000 bodies, most of them asteroids.
Dave retired from JPL in 1987. At a party in his honor, Eleanor Helin, a JPL colleague and persistent asteroid hunter, announced that an asteroid that she and, then student, Schelte (Bobby) Bus, had discovered in 1978 at Palomar would henceforth bear Dave's name.
Dave was devoted to Beth. They participated in many activities together that strengthened their relationship. He wrote her love poems, sometimes quoting from The Prophet by Kahlil Gibran. Beth passed away in 1990. Dave lived another fourteen years, continuing an active life. He is survived by his son and daughter-in-law, Robert and Leta Bender of Jamul, California, his daughter, Susan Rodrigues, of Tucson, Arizona, and three grandchildren.
Dave is remembered as a visionary, whose enthusiasm for space mission design was unstoppable; as someone who was still jogging and playing softball in his seventies; as a modest, kind, and generous human being; and as a caregiver who genuinely believed that the most important thing in life is love.
How fitting it would be for a space vehicle to visit asteroid "2725 David Bender" one day. How pleased the mission planners would be to find in their research that the namesake of the object of their interest was a pioneer in their field of endeavor.