WASHINGTON — Spaceflight pioneer Aaron Cohen, who was at the helm of NASA’s Johnson Space Center (JSC) during the Challenger shuttle tragedy and the agency’s subsequent return to flight, died Feb. 25 after a lengthy illness. He was 79.

Cohen, who spent 33 years with NASA, was serving as acting deputy administrator in 1993 when he left the agency to accept an appointment as a professor at his alma mater, Texas A&M University in Bryan, Texas.

“Aaron Cohen was one of my early mentors here in NASA and he was instrumental in the success of numerous pivotal achievements in human space flight,” NASA Administrator Charles Bolden said in a Feb. 25 statement. “His engineering expertise and rigor were tremendous assets to our nation and NASA. Aaron provided the critical and calm guidance needed at the Johnson Space Center to successfully recover from the Challenger accident and return the space shuttle to flight. We will miss him as a colleague, mentor, and a friend. Our hearts go out to his wife, Ruth, and the rest of his family.”

Cohen joined NASA in 1962 and served in key leadership roles during the agency’s Apollo lunar program. From 1969 to 1972 he managed the Apollo Command and Service Module efforts. He subsequently oversaw the design, development, production and test flights of the agency’s space shuttle fleet as manager of NASA’s Space Shuttle Orbiter Project Office from 1972 to 1982. After serving as director of engineering at Johnson for several years, he was named center director in 1986, serving in that post until 1993.

Cohen earned the Presidential Rank of Distinguished Executive in 1982 and 1988, the highest award given to federal executives. He also was a three-time recipient of NASA’s Distinguished Service Medal. Cohen was a member of the National Academy of Engineering and a fellow of the American Astronautical Society and the American Institute of Aeronautics and Astronautics in Washington.

He was a distinguished alumnus of Texas A&M, from which he earned a bachelor’s in mechanical engineering in 1952. He earned a master’s in applied mathematics from Stevens Institute of Technology, Hoboken, N.J., in 1958. He also was a recipient of honorary doctorates from Stevens Institute and from the University of Houston, Clear Lake.