China wasn’t the only country worried about overpopulation at the time. The rapid rise in the global population in the 1960s and ‘70s prompted fears that humanity would reproduce faster than food production could rise, an idea argued nearly two centuries earlier by economist Thomas Malthus.

Chinese officials were increasingly reviving scientific research after the Cultural Revolution. While social scientists had been persecuted by Mao’s Red Guards, others doing work related to the military had been partly shielded. 

The group included Song Jian, a protégé of the father of China’s atomic-bomb program and one of China’s top scientists working on satellites and rockets. Song had studied in Moscow, where he got advanced degrees in a branch of mathematics known as control theory and in military science. Military officials sent him to a launch site for rockets and satellites in the Gobi Desert to escape the chaos of the Cultural Revolution.