Oscar Holderer, the last known engineer who left Germany after World War II to work on the US space program, died at the age of 95.

Holderer, who worked alongside aerospace-legend Wernher von Braun, was part of "Operation Paperclip" that moved hundreds of engineers from defeated Germany to the US right after the war came to a close.

The operation took advantage of the extensive engineering knowledge Germans built up developing secret weapons for the Nazi regime during the war years, particularly the revolutionary V-2 missile.

America used the engineers' know-how from creating the world's first guided ballistic missile to boost the country's own rocketry program.

Holderer "was a gifted design engineer," his son Michael told AFP. Holderer passed away Tuesday from a heart attack in the state of Alabama.

Holderer worked for years in the development of the American Saturn rocket series, the system that took US astronauts to the moon for the first time in 1969.

He became a US citizen in 1955 and retired in 1974.