Space propulsion system is essential for orbit transfer and attitude control of a spacecraft. Depending on its application, typical thrust level of space propulsion system ranges from tens to thousands of Newton. Conventional space propulsion systems have been built on monopropellant hydrazine or monomethyl hydrazine-nitrogen tetroxide hypergolic bipropellant. These hydrazine-based propellants are highly toxic and carcinogenic, which incur high cost in system development and testing to protect the personnel from the toxic fume of the propellants. Investigation on nontoxic green propellants for space propulsion system has been gaining momentum in Europe and the US since 1990. The author would like to present the research activity of Rocket Lab KAIST on green propellants for the past twenty years. Hydrogen peroxide and ammonium dinitramide (ADN) monopropellants with their decomposition catalyst will be examined. Development of hydrogen peroxide monopropellant thruster and their system implementation will be discussed. Design, fabrication and firing test of the thrusters will be presented. For orbit transfer of spacecraft, higher specific impulse thruster with high thrust level is necessary. Bipropellant thruster with hydrogen peroxide as an oxidizer was developed and tested for this purpose. Finally, hypergolic bipropellant thruster with hydrogen peroxide and fuel with additive was developed and tested. Comparison of hydrogen peroxide and conventional propellants will be discussed.

Mr. Haot will present the development progress and milestones reached in the development of the Launcher E-2 liquid rocket engine.
Launcher’s goal with E-2 is to produce the world’s highest performance liquid rocket engine for the small launcher category.
Launcher E-2 Specification: Thrust: 10 tf, Propellant: LOX/RP-1, Specific Impulse: 365s with vacuum nozzle, 98% Combustion efficiency (c*), LOX cooled, Copper Alloy, 3D printed.

Kakuda Space Center is a research and development hub for JAXA’s space propulsion technology. The center is used for various tasks from research of fundamental technologies to development and tests of rocket engines. The center had engaged in R&D and test work on LE-5 engine, Japan’s first LOX/LH2 engine which settled the basis of Japan’s large-sized rocket engines. The center is now developing the upgraded LE-5B-3 engine, and the most advanced LE-9 engine for Japan’s Next Generation Launch Vehicle H3. The research of reusable rocket engine and scramjet engine aiming at fully reusable future launch system are also investigated. The facilities are open to private businesses, universities, and foreign space agencies such as NASA. The presentation will describe the future research and development of space propulsion system, following the history of research and development at the Kakuda Space Center.

What is curved compression? In short words, it is a compression mode under which all compression surfaces participate in compressing supersonic flow. It is a compression mode under which flow is compressed on “every inch of compression surface”. Curved compression is usually accompanied by curved shock wave.
According to research, curved compression system has advantages in reducing total-pressure loss, shortening compression length, avoiding boundary layer separation, improving non-design point performance, reducing drag, tolerating non-uniform coming flow. Therefore, curved compression inlet gradually draws attention, explorations and detailed researches have been carried out for design method, performance and application of such flow field, and rich achievements have been made.

There are two kind of inverse design methods. The design idea and process of the first kind of inverse design are introduced, namely design for the whole compression surface based on existing flow parameter distribution. The focus of flow field design is the design of one or more curved shock waves and obviously the solution is not unique.

The second kind of inverse design is introduced, namely design for compression surface shape and the whole compression flow field based on the specified pressure distribution on compression surface or design for geometric shape of compression surface and the whole curved shock wave compression flow field based on the specified compression surface deceleration rule.

With the increasing inward turning inlet research, design of axisymmetric reference flow field has become a key problem. The process and details of designing axisymmetric reference flow field with inverse tangent pressure rising rule of wall, inverse tangent decelerating rule of wall and other method by fully using the second kind of inverse design method are introduced. A new method is provided for designing excellent-performance inward turning inlet.

The design processes, model experiments and partial experiment results of these inlets for design of hypersonic two dimensional inlet, hypersonic axisymmetric inlet, hypersonic sidewall compression inlet and hypersonic inward turning inlet with the inverse design methods, are introduced. In order to adapt to the needs in wide Mach number working range, both the concept of curved shock wave curved compression surface and concept of adaptive variable geometric elastic curved compression surface are proposed. The performance advantages and future development of this new design concept are discussed.