Robert Willard Farquhar (1932–2015) was a distinguished American mission design specialist renowned for his innovative contributions to space exploration. As a key figure at NASA, he played pivotal roles in several landmark missions, including the Near Earth Asteroid Rendezvous (NEAR) mission to asteroid 433 Eros, the International Cometary Explorer's (ICE) encounter with comet Giacobini-Zinner, and the trajectory planning for the New Horizons mission to Pluto. His expertise in trajectory design and mission planning significantly advanced our understanding of asteroids, comets, and the outer reaches of the solar system.

Early Life and Education

Born Robert Greener on September 12, 1932, in Chicago, Illinois, Farquhar developed an early interest in aviation, often reading about it and building model airplanes of his own design. After serving in the U.S. Army during the Korean War, he pursued higher education, earning a bachelor's degree in aeronautical engineering from the University of Illinois in 1959. He later completed a master's degree at the University of California and obtained a Ph.D. in astronautics from Stanford University in 1968. His doctoral dissertation on libration points laid the groundwork for future space missions. ([en.wikipedia.org](

Career at NASA

Farquhar's career at NASA spanned over two decades, during which he became a leading expert in mission design and trajectory analysis. His doctoral research on libration points formed the basis for the International Sun-Earth Explorer-3 satellite's orbit. He later developed a trajectory that allowed the spacecraft to intercept the Giacobini-Zinner comet in 1985, a feat that garnered recognition from President Ronald Reagan. ([en.wikipedia.org](

In 1990, Farquhar joined the Johns Hopkins University Applied Physics Laboratory (APL), where he continued to apply his trajectory design skills to a range of deep-space missions. Notably, he conceived and served as the flight director for the NEAR mission to asteroid 433 Eros, the first launch of NASA's Discovery program. Launched in 1996, NEAR reached Eros in February 2000, becoming the first spacecraft to orbit, study, and safely land on an asteroid. This mission provided valuable insights into the composition and origin of asteroids. ([science.nasa.gov](

Farquhar also played a critical role in other APL-led Discovery missions, including the Comet Nucleus Tour (CONTOUR) and the Mercury Surface, Space Environment, Geochemistry, and Ranging (MESSENGER) mission to Mercury. Additionally, he served as the first mission manager for New Horizons, which, following a trajectory that Farquhar envisioned, flew past Pluto and its moons in July 2015. ([science.nasa.gov](

Innovations in Trajectory Design

One of Farquhar's most significant contributions was the development of halo orbits around Lagrange points—positions in space where the gravitational forces of two large bodies, such as the Earth and the Moon, balance the centrifugal force felt by a smaller object. This innovative approach allowed spacecraft to maintain stable positions relative to these bodies with minimal fuel consumption. The International Sun-Earth Explorer-3 mission was the first to exploit this concept, leading to the successful encounter with comet Giacobini-Zinner in 1985. ([en.wikipedia.org](

Recognition and Legacy

Farquhar's exceptional contributions to space exploration were widely recognized. In 2012, he was elected to the National Academy of Engineering for his work on deep-space missions to asteroids and comets and for leading the NEAR mission to Eros. His innovative trajectory designs and mission planning have left a lasting impact on the field of space exploration. ([nationalacademies.org](

Robert Farquhar passed away on October 18, 2015, at the age of 83. His legacy continues to inspire mission designers and space enthusiasts worldwide, reflecting his profound influence on the exploration of our solar system. ([legacy.com](

Sources

  • NASA — Robert Farquhar (1932-2015) —
  • Wikipedia — Robert W. Farquhar —
  • National Academy of Engineering — Memorial Tributes: Volume 25 (2023) —
  • — Robert Farquhar 1932-2015 —
  • Legacy.com — ROBERT FARQUHAR Obituary (1932 - 2015) —