Aerodynamic characteristics of a wing with a smart flap under the ground effect are studied through the integration of computational fluid dynamics. A parametric bending profile of a smart flap is designed considering different types of beams. Here, a cantilever beam with uniformly varying load with roller support at the free end is considered. The shape of the smart flap is fixed and its advantage comes from its smooth connection to the main wing. In this research, a pressure-based implicit procedure is used to solve Navier-Stokes equations. A non-orthogonal mesh with collocated finite volume formulation is utilized to simulate flow around the wing under the ground effect. First, the method is validated against experimental data. Then, the algorithm is applied for turbulent aerodynamic flows around a wing with smart and conventional flaps for different flap angles and ground clearance. The results of the two wings are compared. It is found that the pressure coefficient distribution for a wing with smart flaps is smoother than that of a wing with conventional flaps, and tip vortexes of the flap and wing diminish for low ground clearance. Finally, the maximum lift-to-drag ratio (L/D) is obtained for a smart wing when the angle of flap (AOF)=7.5° and h/c=0.3.
Molecular contamination is a concern for sensitive optics of astronomy satellites and earth observation satellites. The contaminants decrease the transmittance of lenses and optical filters, and the reflectance of mirrors. The absorptance of the diethylhexyl phthalate, as a model contaminant, depended on ultraviolet irradiation time and the contaminant thickness.
The BepiColombo is an international Mercury exploring mission which will be launched in 2014 and reach the planet in 2020. In this paper, we show the development status of the extreme ultraviolet (50-155 nm) detector for the mission. We have optimized the geometry of the micro channel plate that can achieve highest quantum detection efficiency. Furthermore, we have evaluated the quantum detection efficiencies of cesium iodide-coated micro channel plate which have been exposed to the air or dry nitrogen, in order to determine the treatment procedure to prevent performance degradation until the launch.
This paper presents a novel attitude control device which is called three dimensional reaction wheel (3DRW). 3DRW consists of only one levitated spherical mass which can rotate around arbitrary axes. This leads to the reduction of the weight and volume of the device as compared to existing reaction wheel. Furthermore, this device has no mechanical contact between rotor and stator, so the failure caused by the mechanical contact would be reduced. In this paper, the results of the analysis and experiment on the dynamics and control of 3DRW are shown. In the experiments of the rotation control, the air bearing system is used. Using this device, the characteristics of rotation of the spherical mass are obtained. To verify the feasibility of the concept of 3DRW, the experiments of angular velocity feedback control are carried out. The results of experiments are applied to the numerical simulation of the attitude control for microsatellites, and the feasibility of 3DRW is verified.
This paper introduces the activity of the newly launched JAXA Space Biomedical Research Office, including ongoing space clinical medicine research. It also explains the new office's goals, policy, criteria for prioritizing research themes, and process for conducting research, as well as some topics of space biomedical research.
We observed Al droplets near propellant surface with the CMOS camera, achieved the observation of Al droplets near propellant surface through 1MPa to 8MPa and measured the diameter of Al droplets near the burning propellant surface. We also observed the propellant section cut by the microtome and measure the size of Al droplets in the pockets. We investigated the relationship between the diameter of Al droplets near the burning propellant surface and the pocket sizes. When the direction of acceleration is the same to the burning direction, the acceleration affect the diameter of Al droplets, and the size of Al droplets become larger than those under static conditions.
New apparatus for microgravity experiments was developed in order to obtain fundamental data of single droplet evaporation and combustion of palm methyl ester (PME) for understanding PME spray combustion in internal combustion engines. n-hexadecane droplet combustion and evaporation experiments were also performed to obtain single-component fuel data. Combustion experiments were performed at atmospheric pressure and room temperature. For droplet evaporation experiments, ambient temperature and pressure were varied from 473 to 873 K and 0.10 to 4.0 MPa, respectively. Microgravity conditions were employed for evaporation experiments to prevent natural convection. Droplet diameter history of a burning PME droplet is similar to that of n-hexadecane. Droplet diameter history of an evaporating PME droplet is different from that of n-hexadecane at low ambient temperatures. In the latest stage of PME droplet evaporation, temporal evaporation constant decreases remarkably. At ambient temperatures sufficiently above the boiling temperature of PME components, droplet diameter history of PME and n-hexadecane are similar to each other. Corrected evaporation lifetime τ of PME at 873 K as a function of ambient pressure was obtained at normal and microgravity. At normal gravity, τ monotonically decreases with ambient pressure. On the other hand, at microgravity, τ increases with ambient pressure, and then decreases.
The Japan Aerospace Exploration Agency (JAXA) is studying the feasibility of using the solar power sail as a new propulsion engine for deep space exploration missions. In this paper, the sail shape and equipment layout for missions utilizing small-sized solar power sails are proposed. The two-stage deployment method of the sail is also proposed. The sail need to be deployed statically at the first stage, and two types of deployment mechanisms are introduced. On the other hand the second stage of the deployment can be performed dynamically, and the oscillating motion of the membrane is converged by tethers connecting the membrane to the main body. The deployment motions are analyzed by numerical simulations using multi-particle models in order to verify the deployment. They are compared with the results calculated by finite element method models. The numerical simulation results are discussed from the technological viewpoint of the sail deployment dynamics and mechanisms.
This paper provides an overview of a low-cost small university satellite. In June 2006, JAXA announced a program for the selection of H-IIA piggyback passengers to small-satellite projects performed by universities and regional communities in Japan. In this context, we started the satellite project named QSAT (Kyushu Satellite) in 2006. The primary objectives of the QSAT mission are 1) to investigate plasma physics in the Earth's aurora zone in order to better understand spacecraft charging, and 2) to conduct a comparison of the field-aligned current observed in orbit with ground-based observations. QSAT has two payload instruments, two plasma probes and a novel magnetometer. The laboratory of Spacecraft Environment Interaction Engineering of Kyushu Institute of Technology has the responsibility of the development of plasma probes, whereas, the Space Environment Research Center of Kyushu University has the responsibility of the development of the new magnetometer. The spacecraft bus is being developed at the Department of Aeronautics and Astronautics of Kyushu University with collaboration of Fukuoka Institute of Technology.
Radiation damage on dielectric thin-layer was studied. The dielectric multilayer coating is a promising technology for the use of solar light collection optics in Space Solar Power System (SSPS) in the geostationary orbit. We estimated spatial distributions of numbers of displacement atoms using a Kinchin-Pease model for the proton incidence, and Frenkel pairs created via self-trapped exciton process initiated by electron excitation in the target for the proton and electron incidences. Proton incidence gives damages near the surface of the target due to low energy protons dominating its energy spectrum. Proton irradiation experiment for a thin layer of several dielectric targets shows toughness for about 10-year-equivalent exposure time at geostationary orbit.
MAGnetic Data Acquisition System (MAGDAS) of the Circum-pan Pacific Magnetometer Network (CPMN) is introduced. MAGDAS/CPMN measures the ground magnetic field all around the world and sends the measured data to Space Environment Research Center (SERC), Fukuoka, Japan, via Internet, telephone line or satellite phone line. As examples of the phenomena observed by MAGDAS/CPMN, we present observations of the equatorial electrojet, Pi 2 waves near the dip equator, and SC-associated ionospheric electric field; Pi 2 is a transient ULF wave taking place at the beginning of a phenomenon called substorm, and SC (sudden commencement) is a phenomenon taking place as an interplanetary shock arrives at the Earth. We also compare ground-based estimations of the space plasma density with simultaneous direct observations by spacecraft.
The Balloon-born Experiment with a Superconducting Spectrometer (BESS), aiming to search for antiparticles/antimatter in the cosmic radiation, successfully carried out the second scientific flight over Antarctica in 2007/2008 (BESS Polar-II), in the solar minimum period. The newly developed BESS Polar-II spectrometer including the solar-cell power supply system worked well during the flight, and more than 4.6 billion cosmic ray events were recorded for 24.5 days. This report describes overview of the scientific flight.
Tokai University student rocket project (TSRP) was established in 1995 for a purpose of the space science and engineering hands-on education, consisting of two space programs; the one is sounding rocket experiment collaboration with University of Alaska Fairbanks and the other is development and launch of small hybrid rockets. In January of 2000 and March 2002, two collaborative sounding rockets were successfully launched at Poker Flat Research Range in Alaska. In 2001, the first Tokai hybrid rocket was successfully launched at Alaska. After that, 11 hybrid rockets were launched to the level of 180-1,000 m high at Hokkaido and Akita in Japan. Currently, Tokai students design and build all parts of the rockets. In addition, they are running the organization and development of the project under the tight budget control. This program has proven to be very effective in providing students with practical, real-engineering design experience and this program also allows students to participate in all phases of a sounding rocket mission. Also students learn scientific, engineering subjects, public affairs and system management through experiences of cooperative teamwork. In this report, we summarize the TSRP's hybrid rocket program and discuss the effectiveness of the program in terms of educational aspects.
The Unmanned Space Experiment Recovery System (USERS) Project has been completed with full success, and the Service Module (SEM) of the USERS Spacecraft, which supported the recovery portion of the spacecraft which was left on the orbit, was properly disposed to the maximum extent as possible according to the IADC debris mitigation guideline and re-entered the atmosphere on June 15, 2007 (JST). USERS spacecraft disposition by possible means available at the mission completion showed good example of realizing debris mitigation purpose in spite of originally different design baseline, and obtained actual data and experiences to be reflected for future space programs.
The application of the variable geometry (VG) wing to a lifting re-entry body is expected to enhance the control capability of its aerodynamic characteristics and, as a result, to widen the corridor for the flight trajectory. In the present study, the flow field around a plain delta wing having three chord-wise hinges, one is on the wing root and the others on both sides of the mid-span of the wing, at Mach number 3 is numerically investigated by solving the Euler equations. The effects of the angle of attack and the “tip-down” bending angles around these hinges are clarified. The results show that the lift-to-drag ratio is hardly affected by the tip-down angle and that the overall lift and drag forces vary almost proportional to the change in the projected wing area by taking the tip-down configuration. The center of pressure moves backward by the tip-down effect.
A method of motion reconstruction from a image streak taken by a single video camera, and a procedure to calculate aerodynamic force and moment from the motion are proposed.In this method the motion of an object is separately measured with translational and rotational motion.For the translational motion, the size and its location of a moving object is used to get the instantaneous position of the object.For the rotational motion, the attitude of the object is calculated by tracking featured points on the object.In addition to accomplish the aerodynamic measurement by this method, an evaluation was done for the measurement errors in the aerodynamic force, which are caused from image distortion by aberration of a lens.A series of the experiments for the flying ball showed the validity of the proposed method and the aerodynamic characteristics of the flying ball were analyzed using this method.
This paper presents a program for the multidisciplinary optimization and identification problem of the nonlinear model of large aerospace vehicle structures. The program constructs the global matrix of the dynamic system in the time direction by the p-version finite element method (pFEM), and the basic matrix for each pFEM node in the time direction is described by a sparse matrix similarly to the static finite element problem. The algorithm used by the program does not require the Hessian matrix of the objective function and so has low memory requirements. It also has a relatively low computational cost, and is suited to parallel computation. The program was integrated as a solver module of the multidisciplinary analysis system CUMuLOUS (Computational Utility for Multidisciplinary Large scale Optimization of Undense System) which is under development by the Aerospace Research and Development Directorate (ARD) of the Japan Aerospace Exploration Agency (JAXA).
This paper presents a new attitude determination algorithm for a spacecraft in low earth orbits using magnetic sensors and rate sensors (e.g. quartz rate sensor gyros) for generic missions including earth observations. The algorithm is applicable to mainly a three-axis spacecraft, including when it is tumbling just after the separation from a launch vehicle or due to some anomaly. The advantage of the proposed approach is that it does not require additional attitude sensors such as sun sensors. First, an attitude determination algorithm using only magnetic sensors is introduced presuming that the attitude change during the measurement period is very small. Then the algorithm is extended to combine magnetic sensors with rate sensors, where both the three-axis attitude and rate sensor biases are estimated. The estimation error is statistically analyzed. Numerical examples are given to validate the proposed algorithm and its accuracy evaluation.
We are working in the development of a compact, low power water recycling device that can supply delicious drinking water which can be consumed safely and with peace of mind in order to help astronauts lead a healthy and comfortable life in space. This device uses electrolysis to decompose ammonia and organic matter, purifies the water using a reverse osmosis membrane, adds minerals to the water, and then sterilizes the water, thereby maintaining water quality. An online system for measuring TOC and harmful substances is also used to manage the water quality.
As the power level of Geostationary satellites increases, discharge phenomena on solar array are becoming serious threat to safe operation. Arcs on solar array can short-circuit the satellite circuit, decrease the satellite power, and then cause the satellite permanent failure. To prevent the failure caused by charging and arcing, it is necessary to investigate the mechanism of satellite charging and arcing phenomenon. The purpose of this paper is to investigate the occurrence condition of a secondary arc by measuring arc plasma characteristics in ground test. We measured the arc plasma temperature and identified the materials emitted using spectrometer at arbitrary time during arc occurring. We investigated the difference of secondary arcs occurrence condition during secondary arcs. From the spectroscopic measurement results, we found that it was necessary for shifting to the secondary arc that the metallic vapor same as the cathode material was emitted. In case of primary arc (PA) dimension changes, the probability of secondary arc and TSA occurrence became high. And plasma temperature was not affected by PA dimension, however the metallic vapor emission of silver was greatly affected. Thus, secondary arc occurrence greatly depends on metallic vapor emission from cathode.
