Kraft’s involvement in solving issues with the Navy’s new supersonic F8U jet fighter found him working with Marine Maj. John Glenn. In 1958, when NASA was authorized, Kraft was among the NACA personnel asked to join the agency, where he became NASA’s first flight director overseeing the Mercury, Gemini, and Apollo missions, and Glenn its first astronaut to orbit the planet.

NACA research led to General Electric developing the nuclear-warhead-carrying blunt nose Mark 2 re-entry vehicle for the Thor, Jupiter, and Atlas ballistic missiles.

Though the swept-wing design proved to be the key to practical supersonic flight, it had not provided a complete solution to drag problems encountered by aircraft flying at transonic and low Mach speeds. In 1952, Richard Whitcomb, an aerodynamicist at NACA’s Langley Aeronautical Laboratory, discovered and verified a solution: a design called “area rule.” It was “a method of designing aircraft to reduce drag and increase speed without additional power.” The rule states that “in order to produce the least amount of drag when approaching supersonic flight, the cross-sectional area of an aircraft body should be consistent throughout the aircraft’s length. To compensate for the place on an aircraft where the wings are attached to the fuselage, the fuselage needs to be made narrower so that the cross-section remains the same.” In other words, the fuselage is pinched where the wings are joined to it. The result is a fuel-efficient fuselage shape variously described as “Coke bottle” or “wasp waist.” It was a revolutionary design because it ran counter to prevailing thought that called for a straight-line fuselage.

Also in the early 1950s the NACA began to seriously study the problems likely to be encountered by spacecraft then beginning to appear on the drawing tables, and nuclear warhead-carrying ballistic missiles re-entering Earth’s atmosphere. The most vexing was finding a solution to dissipate heat buildup caused by atmospheric friction. Early wind tunnel tests focused on various needle-like designs. But so much heat accumulated in the vehicles that some models literally burned up.

The same year that Whitcomb at Langley announced area rule, H. Julian Allen at the NACA’s Ames Aeronautical Laboratory made what amounted to another counter-intuitive discovery. Instead of trying to create a shape with the narrowest possible profile to slice through the atmosphere, Allen discovered that “by increasing the drag of the [re-entry] vehicle, he could reduce the heat it generated.” Allen’s tests revealed that much of the heat caused by re-entry was actually deflected away from the craft. Together with scientist Alfred J. Eggers, Allen discovered that craft designed with blunt noses, rather than needle noses, were far more efficient in deflecting heat away from the craft. The blunt shape formed “a thick shockwave ahead of the vehicle that both deflected the heat and slowed it more quickly.”

H. Julian Allen stands beside the observation window of the test section of the NACA Ames Unitary Plan Wind Tunnel. Allen is best known for his “Blunt Body” theory of aerodynamics, a design technique for alleviating the severe re-entry heating problem that was then delaying the development of ballistic missiles. Applied research led to applications of the “blunt” shape to ballistic missiles and spacecraft that were intended to re-enter the Earth’s atmosphere, such as the Mercury, Gemini, and Apollo spacecraft. NASA image

NACA research led to General Electric developing the nuclear-warhead-carrying blunt nose Mark 2 re-entry vehicle for the Thor, Jupiter, and Atlas ballistic missiles. Tests showed that the Mark 2’s blunt nose did indeed deflect much of the heat and help brake the vehicle’s descent. But the superheated plasma that formed in front of the nose still generated so much heat that some penetrated the vehicle. The problem was fixed using a heat-sink design composed of a thick layer of copper just below the outer shell of the vehicle. Though it worked, the drawback was weight. The copper’s extra weight meant a trade-off in a lighter payload, thus limiting the size of the warhead. And, when applied to piloted and photoreconnaissance spacecraft, the problems were magnified.