Douglas Aircraft Company, Inc., completed an engineering study on the feasibility of designing a man-carrying satellite. The study showed that if a vehicle could be accelerated to a speed of 27 360 km per hr and aimed properly it would revolve on a circular orbit above the Earth's atmosphere as a new satellite. Such a vehicle would make a complete circuit of the Earth approximately every hour and a half. Additional Details: Douglas Aircraft Company study on the feasibility of a man-carrying satellite..
USAF approved Western Development Division proposals to inaugurate a second ICBM airframe, which became the Titan ICBM (SM-68). References: 17 .
Members of STG presented the proposed advanced manned spacecraft program to Wernher von Braun and 25 of his staff at Marshall Space Flight Center. During the ensuing discussion, the merits of a completely automatic circumlunar mission were compared with those of a manually operated mission. Further discussions were scheduled. References: 16 .
Manned Mercury-Redstone (MR-3) launch postponed because of rain squalls in the recovery area. References: 18 .
The Air Force Manned Orbiting Laboratory Systems Program Office requested that MSC present a briefing to selected office and contractor personnel on NASA's progress in safety studies and tests associated with fire hazards aboard manned space vehicles. Information was requested for the MOL program to help formulate studies and activities that would not duplicate MSC efforts. The briefing was given at MSC May 10. References: 16 .
The N1 program was cancelled before the next test flight. Mishin was removed as head of NPO Energia. Kozlov is first asked to replace him, but he prefers to stay in Samara. Glushko is appointed as the second choice. Two fully assembled (serial numbers 8L and 9L), and four partially assembled rockets were available at time of cancellation. These would have been the first to use the new modernized series NK-33/NK-39 engines. 8L was planned for launch in the fourth quarter of 1974. Confidence was high that, based on the massive telemetry received on the 7L flight, that all problems would have been rectified. A total of 3.6 billion rubles was spent on the N1-L3 program, of which 2.4 billion rubles went into N1 development. Those on the project felt that they were within months of finally providing the Soviet Union with a heavy-lift booster. Instead the work was discarded, and Glushko began design of the RLA/Vulkan with entirely new configuration and engines. References: 23 , 69 .
Development of the Block Sr for the N1M cancelled; work on the smaller Block R LH2/LOX stage was resumed. This stage was eventually to have been used on the Buran / Vulkan launch vehicles. References: 21 .
Under US pressure Italy had signed the Nuclear Non-proliferation Treaty on 2 May 1975. Work on nuclear-tipped ballistic missiles ended.
Plane 2. Ascending node 199.4 degrees. Not in service.
Plane 2. Ascending node 199.3 degrees. Not in service.