Flight crew of a Convair B-36 Peacemaker, 4925th Test Group (Atomic) during Operation Teapot, 1955. The crewmen are wearing David Clark Co. S-2 capstan-type partial-pressure suits for protection at high altitude. The two white helmets are early K-1 “split shell” 2-piece helmets, while the green helmets are later K-1 1-piece models. (U.S. Air Force via Jet Pilot Overseas)