Why was Qian Xuesen detained by the United States for two years?

In mid-September 1950, Qian Xuesen resigned from his position as director of the California Institute of Technology's Supersonic Laboratory and head of the "Guggenheim Jet Propulsion Research Center" and went through the procedures to return to China. He bought a plane ticket from Canada to Hong Kong and handed his luggage to the moving company for shipment.

However, just two days before he planned to leave Los Angeles, he suddenly received a notice from the U.S. Immigration and Naturalization Service - he was not allowed to return to the country! The Immigration Bureau threatened that if you leave the country without permission, you will be fined or even jailed if you are caught!

A few days later, Qian Xuesen was arrested and taken to the U.S. Immigration and Naturalization Service detention center on the charge of "participating in a political party that advocates the use of force to overthrow the U.S. government."

The luggage Qian Xuesen handed over to the moving company was inspected by U.S. Customs and the FBI, and it was said that telegram codes, weapons blueprints, etc. were "discovered" from it. The Immigration and Naturalization Service wanted to "interrogate" Qian Xuesen, saying that Qian Xuesen was a "member of the American Communist Party." Later, it also said that several of the American classmates Qian Xuesen met when he was studying in the United States were members of the American Communist Party. . The Immigration and Naturalization Service threatened that Qian Xuesen had "violated U.S. immigration laws" and would "deport" Qian Xuesen. Not long after he said this, he quickly changed his words. Because Qian Xuesen was to be "deported", which was exactly what Qian Xuesen wanted! In the detention center, Qian Xuesen was imprisoned like a criminal. Qian Xuesen once recalled: "In the 15 days I was detained, I lost 30 pounds. In the detention center, every night, the secret agents would come in and wake you up every hour, so that you could not get any rest, and mentally Trapped in a state of extreme tension.”

The Immigration and Naturalization Service’s persecution of Qian Xuesen aroused public outrage in the American scientific community. Many friendly people in the United States came forward to rescue Qian Xuesen and find him a defense lawyer. They raised 15,000 US dollars as a deposit to release Qian Xuesen from the detention center.

In June 1955, Qian Xuesen wrote to Comrade Chen Shutong, then vice chairman of the Standing Committee of the National People's Congress, requesting the party and government to help him return to the embrace of the motherland as soon as possible. Premier Zhou took the matter very seriously after learning about it and instructed relevant personnel to handle the matter at the appropriate time. After hard work, on October 18, 1955, Qian Xuesen and his family finally returned to their motherland after 20 years of absence. Soon, he was appointed director of the Institute of Mechanics, Chinese Academy of Sciences.