Although it had been announced on November 29, 1961, that Donald Slayton would be the prime astronaut for the second U.S. manned orbital mission, on March 16, 1962, NASA announced that he would be replaced by M. Scott Carpenter, alternate pilot in the Glenn mission. This decision, made at NASA Headquarters, was prompted by a minor heart defect, on record since 1959. The physical disability which caused Astronaut Slayton's disqualification was described as "recurring arterial fibrillation without heart disease." Little positive information was available concerning either the etiology or prognosis of this condition. Since the medical profession did not establish a firm prognosis in this case, the decision whether Slayton would fly the mission was one that had to be made by management.
This decision by NASA was to be discussed extensively by the press following
a news conference held by NASA at noon that day, with Dr. Hugh Dryden,
Deputy Director, NASA; Dr. Roadman, Director, Aerospace Medicine; Astronaut
Donald K. Slayton; and John H. (Shorty) Powers, Public Affairs Officer,
For example, in an interpretive report, William Hines of the Washington
Sunday Star wrote:
Following extensive observation and examination by eminent specialists,
including Dr. Paul Dudley White (who had attended U.S. former President
Eisenhower), it was recommended by the Director of Space Medicine, Office
of Manned Space Flight, that Astronaut Slayton be removed from consideration
"for any Mercury flights."5
On July 11, NASA reported:
3. Transcript of News Media Conference, Pilot Change in Mercury-Atlas No. 7, 12:15 p.m., Friday, March 16, 1962.
4. William Hines, "Slayton's Grounding Raises Questions on Space Program," The Sunday Star (Washington), Mar. 18, 1962. See also NASA Press Release No. 62-67, Mar. 17, 1962.
5. Brig. Gen. Charles H. Roadman, Director, Aerospace Medicine, Office of Manned Space Flight, Memo for D. Brainerd Holmes, Director of Manned Space Flight, July 10, 1962.
6. NASA Release No. 62-161, July 11, 1962. Subsequently, Major Slayton resigned from the Air Force and assumed important duties with MSC in a civilian capacity.