Donald “Dele†Slayton (1924-1993) Mercury, Apollo astronaut. Slayton was selected to pilot the second American manned orbital spaceflight, but was grounded in 1962 by a heart murmur. He then served as NASA's director of flight crew operations, making him responsible for crew assignments at NASA from November 1963 until March 1972. At that time he was granted medical clearance to fly, and was assigned as the docking module pilot of the 1975 Apollo–Soyuz Test Project, becoming, at that time, the oldest person to fly in space at age 51. Three hand-written, one signed, “D K Slayton,†test papers and class notes, from 1955, mostly in pencil, written by Slayton during a series of performance flights tests at Edwards Air Force Base, California. Two are 8 ½†x 11†with file holes in the left margin and the third is a partially printed “Flight Data Sheet.â€