Japan launched a public-private council for aircraft decarbonization in 2022. This manuscript provides the overview of UK FlyZero projects and its 25 open reports and invite readers to consider Japanese strategy.

For the comprehension of the shock wave velocity modulation mechanism, one-dimensional numerical simulation and the theoretical analysis of the Riemann problem was conducted. From the numerical simulation, the shock wave velocity mechanism was summarized as the following four hypothesizes. 1) The shock wave can be accelerated in the temperature increasing region, and decelerated in the temperature decreasing region. 2) The shock wave velocity can be smaller than the initial velocity even at the region just recovered to the initial temperature due to the interaction with the reflected waves. 3) The multi-reflected shock wave generated between contact surfaces can be converged with repeating reflection. 4) The shock wave gradually accelerated due to the overtake effect of the multi-reflected shock waves and can reach the converged state. From the theoretical analysis, the above hypothesizes were confirmed. Based on these analyses, the shock wave velocity modulation mechanism can be explained due to the interaction with the waves generated at the contact surfaces.

It has been proposed a flight simulator for flight test engineering's training. The flight simulator can be used for training many staffs simultaneously. A distance learning system can increase the number of training staffs using the flight simulator simultaneously.

The unsteady aerodynamic characteristics of an impulsively started NACA0012 wing were experimentally investigated in a towing tank at a low Reynolds number of 36000. The flow field variation between rest to steady state was discussed based on the measured lift and pitching moment coefficients. The trend of the time-series variation in the aerodynamic coefficients depends on the angle of attack. The nondimensional towing distance required to steady-state also depends on the angles of attack. The distance required to reach the corresponding steady state is more than ten times the chord length at low angles of attack and large angles above the stall. The measured lift and pitching moment coefficients indicate that the boundary layer attaches on the wing surface at the early stage of the translation below the stall angle. The laminar separation occurs during the acceleration process. The flow field variation from the occurrence of the boundary layer separation to its steady state depends on the angle of attack. The dependence causes different unsteady aerodynamic characteristics compared to those of flat plate wings reported in previous studies.

Fukuoka Airport is one of the most convenient airports in Japan. The airport has one runway and the congestion is normalized. It is keenly desired to be solved by all means. In this paper, the authors focused on the flow of arriving traffic at Fukuoka Airport, and analyzed the trigger factors of the radar vectors in the Fukuoka approach control area using CARATS Open Data and a Support Vector Machine which is a type of supervised machine learning. SHAP (SHapley Additive exPlanations) is used to visualize the analysis results of the trigger factors. The result showed that the simultaneous approach from the east and the west direction of the approach control area has the greatest effect on the start of the radar vector in the Fukuoka approach control area.

JAXA's sounding rocket flights are confined to brief durations of five to ten minutes, a limitation that is inherently too brief compared to most spacecraft missions. In contrast, researchers concerning of inflatable structures might find focusing on shorter missions advantageous, as it facilitates the creation of practical systems capable of operating in space without the need for rigidizing. This study focuses on inflatable structures that can be implemented within brief time scales. In space, these inflatable structures are expected to serve as supporting devices for various JAXA sounding rocket experiments. For demonstration purposes, a space experiment was proposed using a JAXA sounding rocket, in which an equilateral triangular extension mast was constructed at low cost. This mast, measuring 3m in total length with cross-sectional sides of 18 cm, was engineered as a truss structure using inflatable polyimide tubes. In the space demonstration experiment with the S-520-33, which was successfully conducted, the mast, composed of an inflatable truss, extended as designed. During this process, the effectiveness of the launch-locking method, which is used to transport the stowed inflatable structure to space, was confirmed. Static (shape realization accuracy) and dynamic (vibration) characteristics of the inflatable structure were measured aboard the mast following deployment.

Propellant flow in a vacuum chamber, a test facility for electric propulsion systems, influences electric propulsion system performance evaluation. Reflection phenomena on the vacuum chamber wall have a strong influence on the propellant flow, however, it has been difficult to evaluate the phenomena on the actual vacuum device wall because the size of the measuring device for the phenomena is larger than the typical vacuum chamber size. In this study, the wall reflection phenomenon can be measured and evaluated in a 1m³ class vacuum chamber by downsizing the measuring device using a rarefied flow measuring device, which had developed in our previous works.

We introduce the novel concept of “Microsatellite-Friendly Multi-Purpose Propulsion (MFMP-PROP)'' as a pioneering low-toxicity propulsion system specifically tailored for microsatellites. Our ongoing research endeavors are focused on its modularization, a crucial step towards its practical implementation. The modular configuration of MFMP-PROP encapsulates all essential components of a propulsion system within a compact 1U form factor. Notably, this innovative design enables seamless operation in both monopropellant and bipropellant modes, affording microsatellites the flexibility to deploy small impulse bit and substantial thrust within a singular unit. Despite initial iterations falling short of performance targets outlined in preceding reports, our iterative approach has led to notable enhancements. Specifically, adjustments were made to the thruster's surface area, complemented by the incorporation of preheating mechanisms facilitated by dedicated heaters. This meticulous optimization process has yielded promising results, with MFMP-PROP now surpassing predefined benchmarks within the monopropellant mode, achieving a specific impulse exceeding 110 seconds. Such advancements underscore the efficacy and viability of our proposed propulsion system for microsatellite applications.

So far, this study has revealed that the Mars Airplane is prone to transitions to the backside region and that its control system is vulnerable to time delay elements. Based on these characteristics, this paper describes the results of a new flight plan study and initial design of the control system for the high altitude flight test for the Mars Airplane Balloon Experiment 2 (MABE-2). The proposed flight plan and control system are evaluated for validity and performance from nominal and Monte Carlo simulations. Finally, we summarize the indexes obtained from this research for the control system design of this test aircraft and the Mars Airplane.