[1] He was also the chief designer for the Long March 3 launch vehicle, Fengyun, and SJ (Shijian) series satellites.

After the outbreak of the Second Sino-Japanese War in 1937, he took refuge in Chongqing where he studied gun design at the National Institute of Technology, Ministry of Military Administration.

[2][5] After the Second World War, Ren read a book authored by Qian that roused his interest in rocket science.

[3] A colleague recalled, in a 2014 documentary, Ren leading a successful five-day march in 1967 in the cold western desert seeking a downed test rocket as one anecdote from his long career.

[3] Ren's insistence on applying LOX/LH2 rocket engines led to the success of the Long March 3 in 1984, even though he had suffered numerous failures, and then faced the resulting backlash.

[8] Ren married Yu Shuangqin (Chinese: 虞霜琴), the daughter of a Nationalist government official, in 1944.