In fact, the aviation history would have undergone a radical change with the introduction of the first nuclear-powered bomber, the XB-70 Valkyrie; had the Kennedy Administration not ended the program.
The entire process of developing the Valkyrie took place during a period when the future of the manned bomber was uncertain.
Powered by six General Electric J-93 turbojet engines, each producing approximately 30,000 pounds of thrust, the XB-70 was designed to be the ultimate high-altitude strategic bomber to be used by the US Air Force. The model was actually a prototype of the proposed B-70 nuclear armed deep penetration bomber.
Prior to the conceptualization of the B-70, the U.S. made use of the B-52 as a long range jet powered strategic bomber during the 1950s. But the need for high-altitude and extreme speed led the Pentagon to look for replacements and research began focusing on ways to install a nuclear reactor in a plane.
The concept of the B-70 thus evolved with a planned cruise speed of Mach 3 and an operating altitude of 70,000 feet.
To achieve the Mach 3 performance, the model was designed in such a manner that it can ride its own shock waves, similar to how a surfer rides the ocean waves. The amount of lift produced was increased by using a technology wherein the wing tips folded halfway to produce a tunnel below the fuselage thereby focusing the shock waves.
Two prototypes of the B-70 was built and tested throughout the 1960s. However, the concept never went into production because by the time the model was operational, new evolved concepts in strategic bombing like the ICBMs and ballistic missiles started taking form.
The XB-70 Valkyrie acted like the perfect test-bed for supersonic transport research (SST) by some US research centers. Dozens of test flights were conducted using these prototypes which, eventually, laid the foundation for the creation of many other high speed flight systems.
But in June 1966, one of the prototypes crashed due to a midair collision with a NASA F-104N chase plane. The deaths of the co-pilots Joe Walker and Carl Cross and the destruction of the prototype led to a pause in the research plan.