What is Propellant, Used in Takata Airbags, C3, and Rockets?

Certain vehicles are being recalled due to faulty airbags caused by potential degradation of propellant, a chemical often used in aerospace. Is your car affected?

Vehicle Recalls Due to Faulty Airbags

Vehicle recalls have become common due to faulty airbag systems. The issue stems from the potential degradation of propellant, a chemical used in aerospace.

The Case of Citroën

Stellantis subsidiary, Citroën in Europe, has had to issue massive recalls for its C3 and DS3 models. The airbags, supplied by Japanese manufacturer Takata, were found to be defective and hazardous. According to Rappel Conso, “The propellant in the driver’s airbag can deteriorate over time. If the airbags deploy, this could cause inflator fragments to injure vehicle occupants”.

What is Propellant?

Propellant is a propulsion product consisting of a mixture of oxidizer and fuel. Used in various states (gas, liquid, solid, or plasma), it provides energy through a chemical reaction. In the context of airbags, “its combustion, electrically initiated by the impact of the accident, generates the gases needed to inflate the airbag within milliseconds”, according to an article by the French Chemical Society.

Propellant in Aerospace

Propellant is also employed in aerospace. It has been used in the boosters of the Ariane 5 launcher and more recently in the solid propellant engine of Ariane 6. It was also tested in 2020 for the demonstration of a reusable first-stage launcher called Themis. In 2024, China conducted 68 launches, several of which utilized solid propellant rockets. That same year, American company SpaceX successfully tested refueling its tanks, filling over 4.5 tons of propellants.