Dr. James A. Turnock Jr., 63, a researcher with The Analytic Sciences Corp. in Alexandria and a former official of the National Aeronautics and Space Administration and International Business Machines, died Sunday at Potomac Hospital in Woodbridge. He was stricken at his home in Occoquan, Va.

Dr. Turnock was born in Chicago and grew up in Evanston, Ill. He earned a bachelor's degree in mathematics at the University of Illinois. During World War II, he was a navigator in the Army Air Froces and flew in B29 bombers in the Pacific Theater. He was recalled to active duty with the Air Force during the Korean War.

Having earned his doctorate at the University of Illinois in 1954, Dr. Turnock moved to the Washington area in 1955 and went to work in the IBM office here. Among the projects on which he worked for IBM were computer tracking systems for space satellites and work on the Mercury manned space flight program.

About 1961, he joined NASA, where he became deputy director for programs in the Apollo effort which culminated with landings on the moon. His responsibilities included work on data processing systems.

Dr. Turnock left NASA about 1969. In the late 1970s, he went to work for the American Communications Corp. He joined The Analytic Sciences Corp. in 1980 and remained there until his death.

Survivors include his wife, Elizabeth, and his daughter, Anne Sawyer, both of Occoquan; one sister, Natalie Samson, of St. Petersburg, Fla., and three grandchildren.