Nuclear Engine for Rocket Vehicle Application

The Nuclear Engine for Rocket Vehicle Application (NERVA) was a U.S. nuclear thermal rocket engine development program that ran for roughly two decades. NERVA was a joint effort of the U.S. Atomic Energy Commission (AEC) and NASA, managed by the Space Nuclear Propulsion Office (SNPO) until both the program and the office ended at the end of 1972.

NERVA demonstrated that nuclear thermal rocket engines were a feasible and reliable tool for space exploration, and at the end of 1968 SNPO certified that the latest NERVA engine, the NRX/XE, met the requirements for a human mission to Mars. Although NERVA engines were built and tested as much as possible with flight-certified components and the engine was deemed ready for integration into a spacecraft, much of the U.S. space program was cancelled by Congress before a manned mission to Mars could take place.

NERVA was considered by the AEC, SNPO and NASA to be a highly successful program; it met or exceeded its program goals. Its principal objective was to "establish a technology base for nuclear rocket engine systems to be utilized in the design and development of propulsion systems for space mission application". Virtually all space mission plans that use nuclear thermal rockets use derivative designs from the NERVA NRX or Pewee.

Los Alamos Scientific Laboratory began researching nuclear rockets in 1952, accelerating into Project Rover in 1955 when the deputy director of Lawrence Livermore National Laboratory, Herbert York, postulated a way to shrink reactor weights considerably. By 1961, after unexpectedly fast-paced progress on the part of Project Rover, NASA's Marshall Space Flight Center began to use nuclear thermal rockets in their mission plans. Marshall planned to use a nuclear-powered rocket from Los Alamos to power a RIFT (Reactor-In-Flight-Test) nuclear stage to be launched as early as 1964, and the need for planning and oversight led to the formation of the Space Nuclear Propulsion Office. SNPO was formed so that the AEC and NASA could work together, and H. B. "Harry" Finger was selected as its first director. Finger made a decision to delay RIFT, and he defined strict objectives for nuclear rocket engines to achieve before RIFT would be allowed.

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