Donn Eisele was part of NASA’s third group of astronauts, selected in October 1963. In early 1966, Eisele was quietly selected as Pilot for the Apollo 1 crew, along with Command Pilot Virgil I. “Gus” Grissom and Senior Pilot Edward H. White. But after dislocating his shoulder twice during training, Eisele was replaced with Roger B. Chaffee. After corrective surgery in January 1966, Eisele was named to the crew for the second manned Apollo flight, with Command Pilot Walter “Wally” Schirra and Pilot R. Walter Cunningham. At this time, Eisele was promoted to the Senior Pilot position. But as the launch date approached, his participation was at risk, due to Eisele’s involvement in an extramarital affair with a woman who would later become his second wife. Astronaut Office Chief Deke Slayton had warned the crew that they were all “expendable”, and that any extramarital affairs must not become public.Donn Eisele remained in the crew, and on October 11, 1968, Eisele was launched on the 11-day flight of Apollo 7 — the first manned flight test of the third generation United States spacecraft. By this time, the “Senior Pilot” title was changed to ” Command Module Pilot”. Together with spacecraft commander Schirra and Lunar Module Pilot Cunningham, Donn Eisele performed simulated transposition and docking maneuvers with the upper stage of their Saturn IB launch vehicle, and acted as navigator, taking star sightings and aligning the spacecraft’s guidance and navigation platform. The crew completed eight successful test firing maneuvers of the Service Module’s propulsion engine. They also tested the performance of all spacecraft systems, and broadcast the first live televised coverage of crew activities.

Apollo 7 was placed in an Earth-orbit with an apogee of 153.5 nautical miles (284.3 km; 176.6 mi) and perigee of 122.6 nautical miles (227.1 km; 141.1 mi). The 260-hour, four-and-a-half million mile (7.25 Gm) shakedown flight was successfully concluded on October 22, 1968, with splashdown occurring in the Atlantic, eight miles (15 km) from the carrier USS Essex and only .3 miles (0.48 km) from the predicted target). Donn Eisele logged 260 hours in space. Donn Eisele served as backup Command Module Pilot for the 1969 Apollo 10 flight. He was excluded from Apollo 13 because of his reluctance to interrupt their tests aboard Apollo 7 for public television coverage NASA requested, and for the extramarital affair that had almost caused his replacement. Eisele resigned from the Astronaut Office in 1970 and became technical assistant for manned spaceflight at the NASA Langley Research Center, a position he occupied until retiring from both NASA and the Air Force in 1972. Donn Eisele died at the age of 57 of a heart attack while on a 1987 business trip to Tokyo, Japan, where he was to attend the opening of a new Space Camp patterned on the one at the U.S. Space & Rocket Center in Huntsville, Alabama. He was survived by his widow Susan, their two children, and three of his four children from his previous marriage to Harriet. Eisele was cremated in Japan, and his ashes were buried in Arlington National Cemetery.