Jet Propulsion Laboratory (U.S.). Office of Engineering and Review.

Robert Crabtree started with JPL about 1960. He was assigned Test Director for the Ranger Project, beginning October 1960. By April 1965, he was Test and Operations Manager for the Ranger 6, 7, 8 and 9 flight missions.

During April 1965 - January 1968, he was assigned as Section Manager, System Test and Launch Operations for the Surveyor Project. He also wrote a System Test and Operations paper, Surveyor I Design and Performance Symposium, 1966.

Starting in January 1968, he was Space Flight Operations Director for the Mariner '69 Project. As SFO Director, he also was acknowledged as one of the co-authors for writing Mariner Mars 1969 Project Report, Performance, Technical Report 32-1460, Volume II, March 1, 1971.

In 1969-76 Crabtree worked for JPL on the Viking Project as Orbiter Mission Operations Manager, Mission Director for Cruise Operations and Deputy Mission Director for Lander Operations. Upon completing his multiple managers' tasks with the Viking Project from May 1980 - October 1982; he was assigned military tasks with the U.S. Army Mobile Automated Field Instrumentation System Engineering and Review Division, as Project Manager.