Deke Slayton, the Slayton Case, and MA-7

Deke Slayton had been named in the fall of 1961 to pilot MA-7, the follow-on mission to John Glenn’s Friendship 7. But in the months leading up to what was to have been Slayton’s flight, persistent worries about his health resurfaced, much to Slayton’s consternation. Prior to the high-G centrifuge runs in August 1959 at the Aviation Medical Acceleration Laboratory (AMAL)—just six months after the physically grueling selection process—medics detected cardiac arrhythmia in Slayton. Dr. William Douglas, the Project Mercury physician, sent the astronaut to the Philadelphia Navy Hospital for a workup, where he was diagnosed with idiopathic atrial fibrillation. A muscle at the top of his heart sometimes beat in an irregular fashion, cause unknown. Follow-up medical examinations took place at the Air Force’s School of Aviation Medicine at Brooks A.F.B., which confirmed the diagnosis.

Although rare in highly fit 35-year-olds like Slayton, the condition was not initially viewed as an impediment to his career as an astronaut or pilot. The matter was dropped. But as flight assignments were made and announced in 1961 and 1962, a member of the internal medicine staff at Brooks A.F.B. wrote a letter to NASA administrator James Webb. His recommendation: “Slayton should not be assigned a flight.”1

Very early in 1962, as Slayton’s mission approached, Webb remembered the medical dissent and directed “a complete reevaluation of the case.”2 At this point, a contest of wills appears to have emerged at NASA. On the one hand were Slayton loyalists at Langley—including Dr. William Douglas, the entire Project Mercury medical team, and the other six astronauts. On the other hand was NASA administrator Webb, at the Washington, D.C., headquarters, who “referred the [Slayton] case to a group of three nationally eminent cardiologists.” Their judgment? “If NASA had an available astronaut who did not ‘fibrillate,’ then he should be used rather than Slayton. . . . The Slayton decision was irrevocable.”3

The decision devastated Slayton and was denounced, in private, by nearly everyone at Langley. It was amid this general turmoil that Space Task Group director Robert R. Gilruth announced on March 15, 1962, that Carpenter, who had been Glenn’s alternate for MA-6, would be the prime pilot for MA-7 because he was the readiest to fly. Wally Schirra, who had been Slayton’s alternate, was named Carpenter’s backup pilot and assigned the follow-on flight, MA-8.