The B-52H crew were trying to thread a needle through an invisible point in the sky to hit the correct launch conditions for the test flight of the X-51A Waverider hypersonic demonstrator.
Everything had to be just right, so the pressure was intense. It was May 1 and the fourth and final opportunity for the X-51A test team to prove that a hydrocarbon-fueled, air-breathing vehicle could accelerate and fly hypersonically for a sustained period until its fuel ran out. But the actual flight of the small, missile-like vehicle was only one part of the story. The weather had to be good at Vandenberg AFB, Calif.; the main diversion airfield, the Point Mugu test range to the west of Los Angeles, had to be “green” and clear; the NASA chase aircraft had to be in position; and the X-51A needed to be primed to go at just the right time.