Ernst Stuhlinger, who died Sunday at 94, was Wernher von Braun’s chief scientist and a key designer of American rockets from the first satellite launches of the late 1950s through the space shuttle.

Stuhlinger was originally a nuclear engineer and space scientist who worked on Germany’s atomic energy program before World War II. He later joined von Braun’s team at Peenemünde, where V-2 rockets were produced by slave labor under the supervision of the SS. After Hitler’s suicide, the group surrendered to American troops. The bulk of the program — more than 100 scientists and massive quantities of parts — was quietly transported to America under Operation Paperclip. Eventually, it was set up in Huntsville, Ala., as the Ordnance Missile Laboratories, the basis of the American space program. The Army, sensitive to the bad publicity and hurt feelings that might erupt, said the mysterious immigrants were a band of gypsy musicians.

“He was the chief scientist and was also considered to be the ambassador of science for the team,” a former director of the U.S. Space and Rocket Center, Ed Buckbee, said.

Stuhlinger was also among the earliest to envision what eventually became the Hubble Space Telescope. He also helped engineer the ion thruster, a method of powering spacecraft with solar-generated electricity that remains more the provenance of science fiction than science fact. Stuhlinger dubbed the craft using the thruster a “sunship.”

Born in 1913 in Niederrimbach, Germany, Stuhlinger received his Ph.D. in physics in 1936 from the University of Tübingen. He served in the German army during World War II, and saw action at Stalingrad as a foot soldier before being transferred to Peenemünde, where he worked on guidance systems for the V-2. The notoriously inaccurate V-2 was deployed in the late stages of the war as a terror weapon against Great Britain.

After being transferred to the Redstone Arsenal in Huntsville, Stuhlinger worked on plans for rockets that would use ion drives for interplanetary journeys. Meanwhile, he helped lead a team that reassembled the old V-2s and began sending them to record heights. He also helped develop more practical rockets that were the lineal descendents of the V-2, including the Redstone, the Atlas, the Jupiter, and the massive Saturn V that would send astronauts to the moon in 1969. The program’s missiles also powered America’s ICBMs. In his 1995 memoir “Wernher Von Braun: Crusader for Space,” Stuhlinger displayed an acute awareness of the irony that rockets were instruments for peaceful exploration and also for war.

After an initial burst of optimism, the Huntsville center became a bit of a backwater. Stuhlinger and von Braun complained that their research capability wasn’t being made use of. President Eisenhower, leery of militarizing space, went so far as to forbid the Army from orbiting anything “by accident.” Idled German engineers took to calling themselves “prisoners of peace.” Things changed after the Soviet space program succeeded in launching the Sputnik satellite in 1957. In early 1958, just 16 weeks after Sputnik, the U.S. succeeded in launching its own satellite, the Explorer 1. Weeks before, according to an article in the Los Angeles Times, Stuhlinger had become a father for the first time. “Okay, I had my little satellite,” his wife told him. “Now you have yours.”

In 1960, Stuhlinger was named director of the Space Science Laboratory at NASA’s Marshall Space Flight Center in Huntsville, where von Braun was overall director. Between 1968 and 1975, Stuhlinger served as the center’s associate director for science.

Optimism ran high during the Apollo project’s boom years. In 1965, Stuhlinger told journalist Oriana Fallaci that they had calculated that by 1980, tickets to the moon would sell for about $20,000.

Stuhlinger became an American citizen in 1955.

In a 2007 interview with IEEE Spectrum magazine, Stuhlinger said he was in some ways glad that the Soviets had beaten America into space, because “Sputnik had done so much to open doors and change opinions, that it helped us become a space-faring nation.”