Air traffic increase causes congestion at hub airports and in their terminal airspaces. Currently, air traffic is controlled per air sector/airspace. In order to assure that controllers can safely handle the air traffic in their sector, the number of aircraft in each sector is limited. One way to reduce congestion in a specific airspace is to assign the time at which an aircraft should fly over the assigned entry waypoint (fix). This control method is referred to as “time-managed flow.” In this study, we investigate the effect of time-managed flow on arrival traffic into Tokyo International Airport (Haneda Airport). The analysis uses past radar data (CARATS Open Data), provided by the Japan Civil Aviation Bureau. First, we set the congestion area as the target airspace and adjust the entry time assuming enroute time flow management. For each flight, a new trajectory is modeled based on its shortened flight time, which results from time-managed inflow. The new trajectory is selected by substituting the original trajectory with one from the dataset that matches the required flight time. The results show that time-managed traffic flow can lead to reductions in flight distance and number of heading changes in congested airspace.

The Space Robotics Laboratory (SRL) of Tohoku University and ALE Co., Ltd. developed a 60-kg-class microsatellite known as the ALE-1, which was launched in January 2019. The main mission was to generate artificial meteors. To achieve this, the temperature of the ALE-1 on-board components must be strictly maintained within specified ranges of safe operation. This is particularly critical because high power consumption is required for the mission. The purpose of this study is to propose a heat transfer parameter determination method using an experimental equation to calculate the thermal contact conductance. Additionally, to improve the accuracy of the heat transfer parameter determination, a thermal vacuum test was conducted and the experimental equation was calibrated. This study also discusses the significance and necessity of calibrating the experimental equation. Finally, the validity of the heat transfer parameters obtained by the ground test was evaluated by comparison with actual flight data. In the flight data analysis, the change in solar cell absorptivity owing to variations in the battery state-of-charge is also considered. The flight data analysis covers the early orbit entry phase and the period after high power consumption.

JAXA and some universities have proposed a hypersonic flight experiment named “HIMICO: High Mach Integrated Control Experiment” using a 1.5-meter class vehicle launched by the S-520 sounding rocket. The experiment aims to establish an integrated control method including the interference between the airframe and engine under the actual Mach 5 flight condition. Two flight experiments are planned step by step to reduce technical risks. Feasibility studies have been conducted by experiments and CFD analysis. This paper reports the summary of the flight test plan and preliminary studies on the vehicle shape, flight trajectory, component design and technical issues.

This research establishes a coupled analysis method of aerodynamics, structure, attitude, and trajectory aiming at a precise computation of attitude and trajectory of a space probe with membrane structures. By means of a simulator invented based on the proposed method, a feasibility study of Mars aerocapture using spinning solar sail is performed. This proposed method enables a coupled computation of attitude and trajectory taking account of membrane deformation due to aerodynamic forces, which will extend a possibility of interplanetary exploration missions around planets with atmosphere. As a practical example, a solution of Martian orbit insertion using a cubesat-class probe with a membrane is successfully found.

In recent years, the movement to re-recognize starry sky as a regional resource and to utilize it as regional added value attracts many people. At the same time, however, the increase in the brightness of nighttime lighting due to the spread of LEDs etc. causes the night sky to gradually become brighter, and the situation in which the value of the starry sky is lost is also progressing. In order to protect the value of the starry sky, it is important to quantify the effects of nighttime lighting on the night sky brightness and to provide basic data useful for discussion on the balance between light pollution control and citizen life. From this point of view, we are promoting a project for protecting the starry sky by combining observation of nighttime lighting from space with nano-satellite and night sky brightness observation on the ground.

The Space Robotics Laboratory (SRL) of Tohoku University has developed a 50-kg-class microsatellite called RISESAT, which was launched in January 2019. The main missions of this satellite are to conduct earth observation using a high-resolution telescope and perform a demonstration of optical communication. To achieve these missions, it is necessary to maintain the on-board components in a specified safe temperature range. In this satellite, on-board components such as the battery and power control unit are mounted to the central pillars of the satellite structure, which are insulated from the outer panels, and are thus not easily affected by the external environment. Therefore, it is important to determine the amount of heat generation by the components as well as the heat transfer parameters between structure panels. The purpose of this study is to determine the parameters such as thermal contact conductance between structure panels and heat generation of the components. We conducted the thermal vacuum tests to improve the accuracy of the determination of these parameters. Finally, we analyzed the flight data and evaluated the validity of the parameter determination using data from the regular operations phase of the mission. The seasonal effects on the thermal design were also evaluated using data from the first 480 days after launch.

Japan Aerospace Exploration Agency (JAXA) has planned High-Mach Integrated Control Experiment (HIMICO), which is a flight experiment under hypersonic conditions. The ramjet engine used in the experimental aircraft is designed for self-ignition of the fuel to occur due to high temperature caused by aerodynamic heating in hypersonic flow. We confirmed that self-ignition occurred under some test conditions in the combustion test. However, conditions of the incoming air and the injected fuel where self-ignition occurred were not clear. In this study, we develop a chemically reacting flow solver for investigating the self-ignition. Large-eddy simulations of the combustor of the HIMICO engine are performed using a detailed hydrogen-air reaction mechanism. The results show that qualitative prediction whether self-ignition occurs is possible by Large-eddy simulations using the solver. In the simulations, self-ignition occurs even under conditions where self-ignition did not occur in the test. On the other hand, it is found that the selection of the boundary condition of the injector outer walls has a great effect on the time to self-ignition. For improving the accuracy of prediction, it is necessary to consider turbulence and three-dimensional flow due to the intake and the effects of heat exchange on the injector outer walls.

In this paper, the conceptual design of reusable winged suborbital vehicles with rocket propulsion is investigated considering two mission configurations: 1) the satellite-launch configuration in combination with an expendable upper stage and 2) the high-altitude suborbital-flight configuration in combination with an external payload carrier. It is expected that such a multi-purpose vehicle concept can save the total development cost of orbital and suborbital transportation systems. However, the transportation performance of the multi-purpose vehicle may be inferior to that of single-purpose vehicles specialized for specific missions, since the suited vehicle design depends on the mission trajectory. Considering this issue, this paper conducts multidisciplinary design optimization with two objectives for maximizing orbital and suborbital transportation performances. In order to optimize the vehicle design, the satellite-launch trajectory, and the suborbital flight trajectory in an integrated and efficient way, a decomposition-based multi-objective evolutionary algorithm and a gradient-based optimization method are applied to vehicle design and trajectory design, respectively, with a nested structure. The obtained solutions reveal the tradeoff characteristics of these two missions, and they provide some information on the feasibility of this multi-purpose vehicle concept.

The trajectory optimization for sub-orbital planes using aerodynamic coefficients obtained by panel method and CFD analysis are compared since flow around the vehicle is difficult to incorporate with the panel method. The resulting trajectory from the difference in aerodynamic coefficients is identified. From the result, it is evident that there are no significant difference in the time to reach the highest altitude and the maximum down range, but differences are found in the flight path of ascent and the center of gravity. Therefore, an effective solution for the sub-orbital plane can be obtained to an extent by using panel method when the critical design parameter is in the supersonic speed region.

Life support of crew in long-duration space missions will be highly dependent on supply of food, O₂ and clean water regenerated by plants in space farming. Therefore, the space farming system with scheduling of crop production, obtaining a high yield with a rapid turnover rate, converting atmospheric CO₂ to O₂ and purifying water will be important. Sweetpotato has been one of candidate crops in space farming. Sweetpotato has a high yield of edible biomass with a little inedible part as waste, because it can be utilized for the leafy vegetable as well as the root crop. In this study, nutritional values of tuberous roots and shoots of sweetpotato were investigated and the balance of yields of tuberous roots and shoots including stems and leaves was examined in order to obtain a fundamental knowledge of harvest management for tuberous roots and shoots as edible biomass in a single leaf and node cutting culture method applicable in space farming. As a result, sweetpotato can be utilized for the leafy vegetable as an antioxidative functional diet as well as the root crop as a high energy diet. Harvest timing of lateral shoots influenced the balance of the biomass yields of tuberous roots and shoots. Frequent harvest of young lateral shoots from plants sustainably having an unfolded leaf increased the tuberous root yield with the less lateral shoot yield and maintained mostly the constant total edible biomass yield.

This paper discusses the ongoing activities of the STEP-UP Project aimed at proliferating space science and technology in the Philippines. The STEP-UP Project is a research project funded by the Department of Science and Technology that undertakes the establishment of a university consortium on space science and technology applications. The consortium will serve as an avenue for nationwide and global collaboration for university-based space-related research activities. The institutions invited as founding members of the consortium are strategically located across the three major islands in the Philippines, serving as central hubs for cooperation and providing access to knowledge and facilities within their respective regions. Among the activities of the STEP-UP Project are the offering of a graduate track on nanosatellite engineering with hands-on development and testing of a 1U CubeSat that will be launched to an ISS orbit, the development and setup of amateur radio and satellite stations in partner universities, and the continuous enhancement and offering of undergraduate courses and trainings on space engineering. In proliferating space science and technology, the STEP-UP Project expands the human resources critical in sustaining the country's space activities.