The National Aeronautics and Space Administration (NASA) Lewis Research Center acquired two North American AJ-2 Savages in the early 1960s to fly microgravity-inducing parabola flight patterns. Lewis was in the midst of an extensive study to determine the behavior of liquid hydrogen in microgravity so that proper fuel systems could be designed. Jack Enders was the primary pilot for the program and future astronaut Fred Haise worked with the cameras and instrumentation in the rear of the aircraft.
North American developed the AJ-2 for the Navy in the mid-1940s as a carrier-based bomber. By the 1960s the Savage was no longer considered a modern aircraft, but its performance capabilities made it appealing to the Lewis researchers. The AJ-2 ‘s power, speed, response time, structural robustness, and large interior space were applicable to the microgravity flights. The AJ-2 could also accommodate a pilot, flight engineer, and two observers. Lewis engineers installed a 100-litre liquid hydrogen dewar, cryogenic cooling system, and cameras in the bomb bay.
The AJ-2 was flown on a level course over western Lake Erie then went into a 20-degree dip to generate 375 knot. At 13,000 feet the pilot pulled the nose up by 40 degrees. The speed decreased and both latitudinal and longitudinal accelerations were nullified. Upon reaching 17,000 feet, the pilot turned the aircraft into a 45-degree dive. As the speed reached 390 knots the pilot pulled the aircraft up again. Each maneuver produced approximately 27 seconds of microgravity.