Bridging the Technology Gap: Strategies for Hybrid Rocket Engines

Abstract

Hybrid rocket propulsion, first demonstrated by the Russian GIRD-09 rocket in 1933, combines liquid oxidizer and solid fuel for thrust generation. Despite numerous advantages, such as enhanced safety, controllability, and potential environmental benefits, hybrid propulsion has yet to achieve its full potential in space applications. In recent years, the research on hybrid propulsion has gained enormous momentum in both academia and industry. Recent accomplishments such as the altitude record for student rockets (64 km), the launch of the first electric pump-fed hybrid rocket, and a successful 25 s hovering test highlight the potential of hybrid rockets. However, although the hybrid community is growing constantly, industrial utilizations and in-space validations do not yet exist. In this work, we reassess the possibilities of hybrid rocket engines by presenting potential fields of applications from the literature. Most importantly, we identify the technical challenges that hinder the breakthrough of hybrid propulsion in the space sector and evaluate the technologies and approaches necessary to bridge the gaps in hybrid rocket development.

Comprehensive Six-Degrees-of-Freedom Trajectory Design and Optimization of a Launch Vehicle with a Hybrid Last Stage Using the PSO Algorithm

“…The limited operational examples of multi-stage launch vehicles utilizing hybrid rocket motors further contribute to a hesitancy among researchers and engineers to delve into this lesstraveled domain. Despite these challenges, the dynamic nature of the rocket propulsion environment indicates that research interests are shifting and a focus on hybrid rocket mo-tors has begun, as technologies advance, the industry needs to evolve, and early adopters demonstrate success in the field of hybrid propulsion for multi-stage launch vehicles [11]. Therefore, the optimization studies conducted for multi-stage launch vehicles in the literature are quite limited due to the complexities they entail.…”

“…Therefore, the optimization studies conducted for multi-stage launch vehicles in the literature are quite limited due to the complexities they entail. Specifically, the number of publications on hybrid rocket motors used in multi-stage launch vehicles is significantly less compared to those on solid-and liquid-fueled rockets [11]. Among the challenges encountered in these studies, obtaining high I sp over a minimum of 280 s is deemed most critical.…”

Regression Rate and Combustion Efficiency of Composite Hybrid Rocket Grains Based on Modular Fuel Units

“…However, the following issues with HRE are still unresolved: the different phases of the propellants and the diffuse combustion characteristics result in the low combustion efficiency of fuel grains [10][11][12][13]. Both low regression rates and oxygen-to-fuel ratio shift will affect engine performance, and proper regression rates can reduce oxygen-to-fuel ratio shift [14]. Therefore, research has focused on improving the regression rates.…”

Numerical Study on Post-Combustion Chamber Impact on Hybrid Rocket Performance

“…However, most studies in past and current research where conducted for laboratory scale engines. This is considered as one of the main reasons HRM did not yet reach their full potential and therefore commercial applications [3]. The combustion within the engines is characterized by a diffusion flame with an oxidizer rich core flow and a fuel rich zone within the boundary layer.…”