(John Glenn had retired from NASA in January 1964 and Scott Carpenter, who was blamed by some in NASA management for the problematic reentry of Aurora 7, was on leave to participate in the Navy's SEALAB project and was grounded from flight in July 1964 due to an arm injury sustained in a motorbike accident.
(John Glenn povukao se iz NASA-e siječnja 1964., dok je Scott Carpenter, kojeg je dio NASA-ine uprave krivio za problematičan povratak u atmosferu letjelice Aurora 7, bio na dopustu radi sudjelovanja u mornaričkom projektu SEALAB, te je bio prizemljen od srpnja 1964.