2001 Tycho Brahe Award

Presented to: Dr. Robert W. Farquhar

Citation: For analysis and implementation of halo orbits and multiple lunar swingbys, enabling pioneering trajectories and first science missions to L1, Earth’s magnetotail, and a comet.


Dr. Robert W. Farquhar served as a NASA employee from 1966 to 1990. He served as flight director for deep-space projects, including the first mission to a Lagrange point (ISEE-3) and the first encounter with a comet (International Cometary Explorer), and as program manager for the Discovery Program of low-cost planetary missions at NASA headquarters.

Dr. Farquhar studied halo orbits (a term he coined) in his dissertation (Stanford University, 1969). He conceived the orbit, and worked with scientists and engineers at NASA Goddard to design the spacecraft and the mission of the ISEE-3. Control and navigation were central for the practical implementation of this mission. Four years after launch, he conceived of the idea of taking ISEE-3 out of the halo orbit and using multiple lunar swingby maneuvers to first study the Earth's magnetotail, and then go into heliocentric orbit to make it the first encounter with a comet. While he got assistance from others in calculating the trajectory, he had the basic ideas, and without his close guidance, this complex trajectory would not have been calculated in time. He was also instrumental as flight manager, overcoming numerous navigation, guidance, and control problems to direct the team to successfully fly this ambitious extended mission. The mission was renamed International Cometary Explorer (ICE) on Dec. 23, 1983, when the last of five lunar swingbys kicked the spacecraft into the heliocentric transfer orbit that intercepted the comet Giacobini-Zinner on Sept. 11, 1985. The double lunar swingby, exploited in this mission, was conceived by Dr. Farquhar.

Since 1990, Dr. Farquhar has worked at Johns Hopkins' Applied Physics Laboratory where he was mission director for several flight projects including the Near-Earth Asteroid Rendezvous (NEAR)to asteroid 433 Eros mission that was launched on Feb. 14, 1996, the Comet Nucleus Tour (CONTOUR), the Messenger mission to Mercury, and the New Horizons mission to Pluto/Sharon.