F. Barato, D. Pavarin
DOI Number XXX-YYY-ZZZ
Conference Number HiSST-2022-201
Hybrid rockets are a specific type of propulsion system characterized by the use of a liquid oxidizer and
a solid fuel. This peculiarity provides very specific features respect to the other chemical propulsion
systems. Compared to solid rockets, hybrids are throttleable and restartable, they are environmentally
friendly and much safer to manufacture, store, manage and operate with a dramatic impact on costs.
Respect to liquid propulsion systems, hybrids are much simpler since the combustion chamber is not
regeneratively cooled and they need less than half of the liquid feed system. Thanks to these
peculiarities hybrid rocket propulsion systems are perfectly suited to be installed and operated on low
costs, partially reusable test platforms for hypersonic in-flight test. These affordable flight test platforms
can be used to provide otherwise not or only partially available real test data on components or
subsystems in the hypersonic regime, as, for example, thermal and mechanical loads, advanced
materials behavior, aerodynamics, air-breathing propulsion. University of Padua and T4i started doing
research in this field since 2006, acquiring a unique in the world expertise in the frame of paraffinbased hybrid rockets together with a wide expertise on nitrous oxide and hydrogen peroxide as
oxidizers. Different type of motors up to 25 kN of thrust have been designed, developed and tested.
Starting in 2019 a sounding rocket has been developed as a low-cost test platform for flight
demonstration of new technologies, including propulsion. The presentation provides an overview of the
work performed up to now and describes the new interesting opportunities made possible by advanced
hybrid rocket systems applied to hypersonic flight test platforms.