As one of the 118 engineers and scientists of the German V-2 missile program who surrendered to Americans toward the end of the war, Dr. Stuhlinger played the quiet, behind-the-scenes scientist to the more charismatic Dr. von Braun. He was director of science at the NASA Marshall Space Flight Center in Huntsville in the early decades of the space age.

The Marshall center, established around the nucleus of the von Braun team, led the development of several generations of rockets, culminating in the most powerful of all, the Saturn 5's that propelled astronauts to the Moon in the Apollo program. Dr. Stuhlinger's expertise was in the guidance and navigation instruments for space flight.

In fact, friends and former colleagues recall that his ingenuity was critical to the first successful American space launching, almost four months after the Soviet Union surprised the world with Sputnik 1. In the frenzy to catch up, an Army team including the German-born engineers and the Jet Propulsion Laboratory in California was ordered to get the Explorer 1 satellite up, double-time.

The rocket was a combination of V-2 technology and American upper stages. The timing of the second-stage firing had to be exact if the satellite was to achieve orbit. There was no time for elaborate designs and tests. So Dr. Stuhlinger retired to his home garage and, in a few hours, emerged with a clever timing device made of ordinary wires, screws and nuts.