Although he might have been offered command of an Apollo lunar landing mission, McDivitt chose to leave the Astronaut Corps after Apollo9, becoming manager of the Apollo Spacecraft Program later in 1969. Scott was soon given another spaceflight assignment as backup commander of Apollo 12, and then was made mission commander of Apollo 15, landing on the Moon in 1971. Schweickart volunteered for medical investigation of his spacesickness, but was unable to shake its stigma, and was never again assigned to a prime crew. He took a leave of absence from NASA in 1977 that eventually became permanent. Eugene Cernan, commander of Apollo 17, stated that when it came to understanding spacesickness, Schweickart "paid the price for them all".