Qian, also known as Tsien Hsue-shen, began his career in the U.S. and was regarded as one of the brightest minds in the new field of aeronautics before returning to China in 1955, driven out of the United States at the height of anticommunist fervor.

Qian set up China's first missile and rocket research institute, which later helped start China's space program.

He led the development of China's first nuclear-armed ballistic missiles and worked on its first satellite, launched in 1970.

He retired in 1991, the year before China's manned space program was launched. But his research formed the basis for the Long March CZ-2F rocket that carried astronaut Yang Liwei into orbit in 2003.

In August, Chinese Premier Wen Jiabao visited Qian and praised him for dedicating his life to China's defense technologies, according to Xinhua.

"I'm trying to live to be 100 years old," Qian told him.

Born in 1911 in the eastern Chinese city of Hangzhou, Qian left for the United States after winning a scholarship to graduate school in 1936. He studied at the Massachusetts Institute of Technology and later at the California Institute of Technology, where he helped start the Jet Propulsion Laboratory.

During World War II, Qian helped to design ballistic missiles for the U.S. military. In 1945, as an Army colonel with a security clearance, he was sent to Europe on a mission to examine captured rocket technology from Nazi Germany.

He studied the German V-2 rocket and interviewed its chief designer, Wernher von Braun, who would go on to play a key role in the American manned space program.

After the war, Qian married the daughter of a military adviser to Chinese leader Gen. Chiang Kai-shek. In 1949, he applied to become a U.S. citizen, shortly before Chiang's Nationalist forces were defeated by Mao Zedong's communists.

As anticommunist unease in the United States mounted, the FBI confronted Qian in 1950 with a U.S. Communist Party document from 1938 that listed him as a member.

Qian denied being a communist, but he was briefly arrested and lost his security clearance. Washington began hearings to deport him, though he was never charged with a crime.

After five years of virtual house arrest and secret negotiations between Washington and Beijing, Qian left for his homeland in 1955.

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