Today, JAXA is conducting an intensive study on the new LOX/LH2 liquid rocket engine, which is low-cost andhighly-reliable, for Japan's next flagship launch system. The engine concept, which received a hint from the failureof the H-II Flight #8, is a blend of Japan's experience in developing simple and robust upper stage engines (LE-5series), and high-pressure / high-thrust booster stage engines (LE-7 series). The engine is presently called LE-X. Aspecial feature of the LE-X engine is its robustness and safety, as it has an inherent potential to avoid catastrophicengine failures. Technologies obtained from LE-X are expected to be utilized not only for booster engines, but alsofor upper stage engines of human space flight where higher thrust level is required. The R&D program of the LE-Xengine consists of two steps, where the first step is a technological demonstration phase for the critical enginecomponents such as the thrust chamber assembly (TCA) and the fuel turbo-pump (FTP), and the second step is anactual development phase of the engine. Currently, we are at the middle point of the technological demonstrationphase. Preliminary tests for the TCA segments including injectors are almost completed and the results are beingreflected to the hardware design. Also, similar tests for the FTP segments are currently underway and the hardwaredesign will be fixed by the end of this fiscal year. Furthermore, in order to renovate the design methodology of liquidrockets, probabilistic risk based design methods are under research for developing highly reliable engine effectively.Such method is based on evaluation of failure modes with understanding the physics of the failure phenomena. Aspart of this research, the engine design technology enhancement activities, such as for combustion instabilities,combustion chamber life, supersonic turbines, and engine hazard simulations are also underway. The final goal of thetechnological demonstration phase is the full-scale TCA / FTP hot firing tests which are planned from late 2012 toearly 2013 (Japan fiscal year). The results will be utilized for validating our high fidelity simulation and design tools,which are to be used in designing and developing an actual engine in the next phase.
展开▼
