Why Chinese rockets produce giant red gas clouds

Footage of China’s most recent Long March 3B Y90 rocket launch surfaced last week. The rocket launched and emitted some red-looking plume as it did so.

When asked about this plume in the past, both scientists and rocket experts said “if you ever see it, run.”

The rocket took off from Xichang Satellite Launch Center, which is located in Sichuan Province, southwest China, the rocket sent a Gaofen-13 (02) orbital satellite into geosynchronous transfer orbit on March 17, according to China’s Aerospace Science and Technology Corp (CASC). 

Several commentators on the video stated that the clouds seen in the video above are the result of a chemical known as dinitrogen tetroxide (N2O4) being used as part of the rocket’s hypergolic propellant. Hypergolic propellants allow rocket engineers to do away with ignition systems that could possibly fail.

“Oxidizers’ such as dinitrogen tetroxide spontaneously ignite when they come into contact with a fuel source (typically from within the hydrazine family of chemicals) in the rocket’s engine. The reaction between the dinitrogen tetroxide and the fuel is exothermic and releases a tremendous amount of heat energy and toxic gas.

Manley goes on to say that dinitrogen tetroxide molecules are made up of two nitro groups, each consisting of a nitrogen atom and a pair of oxygen atoms. The two groups are joined by a weak bond between nitrogens. Dinitrogen tetroxide is an extremely hazardous substance that can cause severe skin burns and eye damage. This substance can be fatal to humans if it is inhaled.