Giving Wings to the Atom
Aircraft Nuclear Propulsion
NEPA and GE 1946-1961
Unofficial Archives
Giving Wings to the Atom - Aircraft Nuclear Propulsion - NEPA and GE 1946-1961 - Unofficial Archives

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Hello and Welcome!
This is about the United States nuclear jet engine and nuclear-powered aircraft program.

In the 1950s, two nuclear development programs were underway: one to design the airframe for a nuclear-powered engine and the other to develop the engine, better known as Aircraft Nuclear Propulsion (ANP). The Consolidated Vultee Aircraft Company (Convair) conducted the airframe research and development program. Pratt & Whitney and the General Electric Company researched the propulsion program.


Presentation to the
Mound Museum of Science and Energy
February 28, 2024


The ANP program studied two methods for nuclear-powered jet engines: the Direct Air Cycle and the Indirect Air Cycle. Pratt & Whitney attempted the Indirect Air Cycle, and General Electric in Evendale, Ohio, developed the Direct Air Cycle. While the Indirect Air Cycle could not solve the excessive weight issues, the Direct Air Cycle was popular because it was simple, reliable, and doable.

Direct Air Cycle engines were able to start quickly; they worked by passing compressed air through the reactor where it was heated before moving into the turbine and out the nozzle. First tested using the J47 engine, the GE X-39 engine proved to be highly successful with several upgrades made to the system at later stages of the development program.

All together, the propulsion program and the airframe research and development program cost $24 billion (1950s), $2 Billion of which paid for the engine development program. Added benefits grew from the research, forming a long list of significant contributions to the nuclear field, including reactor size reduction, shielding improvements, new alloys and new metallurgical understandings, fuel element improvements, synthetic oils, improved reactor theory calculations, shielding for electronics, and greatly improved safety measures.


Archives for this project are enormous and scattered among various classified and unclassified documents within government agencies, contractors, the Mound Science and Engineering Museum, and the engineering library at the University of Cincinnati. This website is a depository for a small collection of unclassified program documents, public articles, and information that describes the $2 Billion (1950s) ANP program. This website is a tribute to the 13,000 Americans who were employed by the program.

For Further Study:

Mound Science and Energy Museum
1075 Mound Road, Miamisburg, OH 45342
(937) 353-4457

View their YouTube Channel for past presentations.
The Mound Science and Energy Museum collects, preserves, and makes publicly accessible the remaining heritage of the Mound Laboratory, its workers, and its site.

Those Magnificent Men and Their Atomic Machines Blog

This fascinating blog by Mark details our extensive history of using nuclear power.


General Electric Company (GE)
Aircraft Nuclear Propulsion (ANP)
Nuclear Energy for Propulsion of Aircraft (NEPA)

Aircraft Nuclear Propulsion Office (ANPO)
Nuclear Materials and Propulsion Operation (NMPO)
Space Power Propulsion Systems (SPPS)
Nuclear Systems Enhanced Performance (NSP)
Energy Systems Program (ESP)
Advanced Energy Program (AEP)

National Reactor Test Site (NRTS)
Replaced by Idaho National Engineering Laboratory (INEL)
Replaced by Idaho National Engineering and Environmental Laboratory (INEEL)
Replaced by Idaho National Laboratory Idaho National Laboratory (INL)

Former ANP employee George Pomeroy provided declassified archives
 and historian Lee Hite
em@il of Cincinnati, Ohio, provides the website.

All documents on this website have been officially released in writing
to the public domain by GE Legal and the Department of Energy.