BY RICHARD H. BATTIN

JOHN VALENTINE BREAKWELL, professor of astronautics at Stanford University, died on April 16, 1991, at the age of seventy-three. John was admired and respected throughout the community of guidance, control, and astrodynamics specialists. His contributions have been fundamental and broad. He was a rare combination of the scholarly professor and the practical engineer. His modest and unassuming manner, coupled with a giant intellect, endeared him to all his colleagues and students.

Elected to the National Academy of Engineering in February 1981, John will be remembered as a key founder and major developer of astrodynamics. During a career spanning more than four decades, he was one of the most skillful contributors in trajectory optimization, differential-game theory, and their aerospace applications.

John was born in Ville Nueve, Switzerland, on December 6, 1917. He received his B.A. with first-class honors in mathematics from Oxford University in 1939. England was then at war, and John left for the United States in 1941 to become an instructor (later assistant professor) in applied mathematics at Tufts University in Medford, Massachusetts. At the same time he was a doctoral student at Harvard University and received his Ph.D. in mathematics from Harvard in 1947.

John was attracted to the new field of ballistic missiles, but a security clearance was required for classified work. He applied