Environmentally Sustainable Liquid Gas Generator Formulations

Nora Dimas | Aerojet Rocketdyne



The objective of this project is to develop an environmentally sustainable, commercially realizable, non-hydrazine monopropellant composition for liquid-based gas generators. This composition will be a safe, clean-burning liquid monopropellant formulation that provides performance exceeding hydrazine yet is compatible with common engineering alloys (e.g., Inconel, Hastalloy) without the human health and environmental issues associated with hydrazine. In essence, the goal is hydrazine performance – a versatile liquid formulation capable of addressing a variety of technical applications, with reliable ignition and moderate hardware costs – without the toxicity and flammability of a hydrazine fluid.

Back to Top

Technical Approach

The target composition will draw heavily from the large class of well-established and well-characterized energetic ionic liquids (EILs) funded by the Air Force Office of Scientific Research and Office of Naval Research for the last decade. Beginning with a literature review, candidates will be selected from existing compounds previously isolated, and formulated to create thermally moderated, oxygen-balanced gas generating compositions for study. The effort will capitalize on the combined experiences of Aerojet Rocketdyne, the Air Force Research Laboratory-Edwards AFB, and the U.S. Army Aviation and Missile Research, Development and Engineering Center (AMRDEC) in the areas of propellant formulation and test. The evaluation criteria will include safety / hazards and human / environmental assessments in keeping with ASTM E2552–08, as well as performance calculations, thermal stability, and materials compatibility. In the laboratory, materials will be scaled up in quantity from the gram to 500g quantities for candidate compositions that can pass through increasingly rigorous down-select criteria. Toxicological modeling will make use of methods developed at the University of Delaware and testing will build on the expertise at the U.S. Army Public Health Command. Performance screening tests of candidates will take advantage of Aerojet’s portfolio of heterogeneous decomposition catalysts and use Aerojet’s heavyweight workhorse thruster test stand, culminating with validation tests under conditions representative of Department of Defense (DoD) / Missile Defense Agency (MDA) field applications.

Back to Top


There is currently strong international demand for a high performance, green replacement for hydrazine in propulsion applications. Hydrazine fuel comes with multiple safety concerns and added costs that satellite manufacturers would prefer to eliminate from the satellites’ overall life cycle cost. DoD missile defense applications likewise have a strong interest in replacing the current toxic fuels that are used in programs like SM-3 and THAAD. A next-generation standard missile is currently in development; a green solution can spiral into several forecast gas generator applications that MDA is considering. A high performance green propellant replacement would offer substantial cost savings to DoD in reduced handling costs, provide improved safety to DoD service personnel, and enable higher performance options for many DoD applications like shipboard defense systems. By avoiding the expense and weight penalty of specialty refractory components necessitated by other high temperature systems such as MMH bipropellant blends, this research has the potential to provide an affordable and more quickly achievable solution to meet critical mission needs. (Anticipated Project Completed - 2017)

Back to Top

Points of Contact

Principal Investigator

Nora Dimas

Aerojet Rocketdyne

Phone: 540-854-2199