Mar. 15, 1962 - Major Donald K. Slayton (left) of the Air Force has been ordered for medical reasons to withdraw as the Project Mercury pilot scheduled to take the next orbital flight. NASA announced that the withdrawal had been ordered after the 38-year-old astronaut had shown a recurrence of a heart palpitation condition. M. Scott Carpenter (right), a 36-year-old Navy lieutenant commander, was designated as the substitute astronaut to take the three-orbit flight, scheduled for early May. Commander Carpenter served as “back-up pilot” to Marine Lieut. Col. John H. Glenn Jr. in his orbital flight on Feb. 20. Major Slayton, who had been in intensive training for three years for the orbital flight, was described as “extremely disappointed” at his disqualification so shortly before the planned launching. In its announcement, NASA said that Major Slayton had shown a recurrence of a heart condition described by physicians as an “erratic heartbeat.” In medical terms, the condition was described as an “idiopathic atrial fibrillation.”
