OVERVIEW OF MORE THAN TWO DECADES OF COOL GAS GENERATOR TECHNOLOGY DEVELOPMENT

Over the last two decades, The Netherlands Organization for Applied Scientific Research (TNO) developed and matured the cool gas generator (CGG) technology into a game-changing technology for various application's such as satellite propulsion systems, reentry heat shields and other inflatable structures. The origin of the nitrogen CGG technology lies in the former Union of Soviet Socialist Republics and was transferred to TNO at the end of last century. Subsequently, the CGG technology matured while gas generators were developed for producing other pure gases, such as oxygen, carbon dioxide, and hydrogen. All these types of CGGs share the same technology, but all have their specific challenges and application areas. An advantage of the CGG is that gas is produced on demand. The CGG can be stored for many years and is activated to produce gas when needed. During storage or launch, there are no pressurized vessels and there is no leakage of gas. The gas produced by a CGG is very pure and, upon release, the temperature of the gas is ambient, without the need for heat sinks. For in-space application, TNO is developing CGGs for applications such as a hypersonic inflatable aerodynamic decelerator and pressurant for propellant storage tanks. More exotically, the development of a xenon CGG started in 2023 to store the propellant of an electrical propulsion system. The TNO gas generator technology has been commercialized and there are three companies that are licensed to produce nitrogen, carbon dioxide, or oxygen CGGs. The future of the CGG technology is interesting and challenging; the xenon-producing CGG and the methane-producing CGG are on the drawing board.