Results Of Flight Experiments Research Articles

A Study of the Flow Characteristics in Air-Water two-Phase Flow under Microgravity(Results of Flight Experiments).

Reliable design of space thermal management systems requires a through understanding of the hydrodynamic characteristics of two-phase flow influenced by the change in gravity. The data of flow patterns, void fraction, frictional pressure drop associated with its characteristics were obtained at normal gravity and in microgravity and hyper-gravity (2g) conditions aboard MU-300 aircraft capable of parabolic trajectory flying. Some experiments were performed for an air-water two-phase flow through 10mm diameter adiabatic test section with 600mm length of transparent acrylic resin horizontal tube. The results obtained at three gravity levels (µg, 1g and 2g) are compared with some of the existing flow pattern transition, void fraction and frictional pressure drop models and correlations. The gravity dependency of flow patterns was more clearly appeared with the decrease in gas and liquid flow rates. The effect of gravity on two-phase flow was insignificant for the turbulent flow regions.

Application of Force Control to the Robot of the Engineering Test Satellite VII.

The ETS-VII is the first unmanned satellite with robot arm in the world. Three types of force/torque control functions based on active compliance control were applied to the robot for on-board local compensation of tele-operation and autonomous dexterous task operations. Various robot experiments for on-board servicing technology were conducted successfully with using the force/torque control functions. This paper describes the force control methods, results of flight experiments using the functions and their evaluation.

外乱収束性能を最適化したモデル追従制御則―ＭｕＰＡＬ‐αの横／方向運動制御への適用とその飛行実験結果―

This paper considers a model-following controller with optimal disturbance attenuation. The controller design process follows a similar approach to the MDM/MDP (Multiple Delay Models/Multiple Design Points) design method, in which the controller performance is evaluated only at selected design points and optimization is performed numerically. Unlike the MDM/MDP method, however, performance is evaluated over the whole range of uncertainties, and is optimized with a method which has a convergence property. In this design process, the performance of the disturbance attenuation is defined as a quadratic cost function and the design problem is formulated with one convex and one non-convex condition, but this is not easily solvable. A design procedure that uses an iterative algorithm, which is easily solvable and has the convergence property, is presented to render the problem tractable. Next, model-following controllers for the lateral/directional motions of MuPAL-α, one of the National Aerospace Laboratory’s flight experiment aircraft are designed with the proposed method, and the results of flight experiments to verify their performances are presented.

A Study of Flow Characteristics in Air-Water Two-Component Two-Phase Flow under Microgravity. Results of Flight Experiments.

In order to better understand the effect of gravity on two-phase flow, the microgravity experimental tests were conducted aboard MU-300 aircraft capable of parabolic trajectory flying. They are carried out in an air-water two-phase flow through 10 mm diameter adiabatic test section, which is 600 mm lengths of transparent acrylic resin horizontal tube. The obtained experimental data covered a range of liquid and gas flow rates with the liquid superficial velocity ranging from 0.095 m/s to 2.56 m/s, and the gas superficial velocity ranging from 0.032 m/s to 21.08 m/s. Flow pattern results obtained under μg, 1 g and 2 g conditions were compared with void fraction based flow pattern transition models developed by Bousman (1995). The effects of the gravity change on flow patterns were significantly large at low gas and liquid superficial velocities. In the comparisons of the microgravity void fraction results with the correlation proposed by Inoue-Aoki (1970), it was found that the micorgravity void fraction was greater than the model as 42% for bubbly flow region. Two-phase frictional pressure drops obtained under three g-levels were compared with each other, and it was also found that frictional pressure drop were well fitted with the Lockhart-Martinelli-Chisholm model. The effect of gravity change on the pressure drops was insignificant for the turbulent flow reginos.

Neutron measurements onboard the space shuttle

The radiation environment inside a shielded volume is highly complex, consisting of both charged and neutral particles. Since the inception of human space flights, the charged particle component has received virtually all of the attention. There is however, a significant production of secondary neutrons, particularly from the aluminum structure in low earth orbiting spacecrafts. The interactions of galactic cosmic rays (GCR), and solar energetic particles with the earth's atmosphere produce a non-isotropic distribution of albedo neutrons. Inside any reasonable habitable module, the average radiation quality factor of neutrons is about 4–5 times larger than the corresponding average quality factor of charged particles. The measurement of neutrons and their energy spectra is a difficult problem due the intense sources of charged particles. This paper reviews the results of Shuttle flight experiments (made during both solar maximum and solar minimum) to measure the contribution of neutrons to the dose equivalent, as well as theoretical calculations to estimate the appropriate range of neutron energies that contribute most to the dose equivalent.

The Origin and Development of Thermal Radiolocation at the Department of Professor Krasovskii

The history of the origin and development of aviation thermal radiometry (thermal radiolocation) at the department of Professor A.A. Krasovskii, starting in 1957, is briefly set out. Some original results of flight and terrestrial experiments are presented.

High undercooling of Ni59Nb41 alloy in a containerless electrostatic levitation facility

Utilizing the containerless electrostatic levitation facility at NASA/MSFC, we were able to undercool the Ni59Nb41 (atomic) alloy by 210 K which was 160° farther than the results of previous flight experiments. Undercoolings were clustered around 200 K during the repeated melting–freezing cycles on a single sample. Prior to this work, a metastable liquid separation had been presumed to limit the undercooling of this alloy. However, microstructural observations have revealed that undercooling was limited by crystal nucleation.

Robust Flight Control Law Design for Automatic Landing Flight Experiment

Automatic Landing FLight EXperiment, ALFLEX, is conducted by National Aerospace Laboratory (NAL) and National Space Development Agency of Japan (NASDA) in order to develop the automatic landing technology for future unmanned reentry space vehicle, HOPE(H- II Orbiting PlanE). Total of 13 flight experiments were conducted at Woomera Australia in 1996, and all flight experiments were perfectly completed. Because ALFLEX vehicle, which is dynamically similar sub-scaled model(37%) of HOPE, is the unmanned and autonomous vehicle which has tip-fin wings, the flight control law has to achieve high-response-performance and robustness simultaneously. In this paper, the design method, which connects the MDM/MDP(Multiple Delay Model/Multiple Design Point) and the H∞ control design method combined with Exact Model Matching to achieve the objectives, is presented. And the results of flight experiment about the performance and the robustness are also presented.

Monitoring solidification of an alloy by thermoelectric effects: results of the MEPHISTO-USMP1 flight experiment

During the directional solidification of a metallic alloy, the interface between the solid and the liquid can be looked upon as a thermocouple junction, provided that the two phases show a difference of thermoelectric power. Thermoelectric measurements made under microgravity conditions are discussed here. When the interface is planar, i.e. isothermal, the measured voltage is proportional to the temperature of the interface and correlation with solidification phenomena is straightforward. If now this interface is cellular, we show that a local thermoelectric current density appears. A modelling of the voltage drop due to these currents is proposed. It is shown that to the leading order, the measured voltage depends on three unknowns: the average liquid fraction, the temperatures at the tip and at the bottom of the structure. A good agreement is found between the theoretical calculated voltage and the measurements made on metallographies. It is also demonstrated that thermoelectric currents appear in the solid phase because of the concentration inhomogeneities. These currents cause a peak to appear on the signal. At least, we show how to deduce the liquid fraction, the temperature at the tip and at the bottom of the interface directly from the recorded signal.

Large inflatable deployable antenna flight experiment results

Large space-based deployable antenna structures are needed for a variety of applications. However, recent reductions of antenna user resources have resulted in a real need for low-cost, large-size, light-weight, and reliable deployable space antenna structures. Fortunately, a new class of deployable space structures, called “inflatable space structures” is under development at L'Garde, Inc. The potential of this new concept was recognized by NASA who selected it for a flight experiment. The objective of the experiment was to develop a large, low-cost inflatable antenna structure and demonstrate its mechanical performance in the space environment. The carrier for this free-flying experiment was the STS-launched and recovered Spartan spacecraft. The experiment hardware consisted of a 14-meter diameter off-set parabolic reflector structure. The Spartan 207/IAE was successfully flown on STS 77, deployed on May 20, 1996 with Spartan recovery on May 21,1996. The basic antenna structure deployed successfully, but in an uncontrolled manner, that clearly demonstrated the robustness of this new type of space structure. The low cost of the flight antenna structure hardware and the outstanding mechanical packaging demonstrated on orbit clearly validated the potential of this new class of space structure for enabling new, low-cost missions.

United States and Russian Thermal Control Coating Results in Low Earth Orbit

Both the United States and Russia have conducted a variety of space environment effects on materials flight experiments in recent years. Prime examples are the long duration exposure facility, which spent 5 years and 9 months in low Earth orbit from April 1984 to January 1990, and the removable cassette container experiment, which was flown on the Mir orbital station from Jan. 11, 1990 to April 26, 1991. Thermal control coating materials data generated by these two missions are evaluated by comparing environmental exposure conditions, functionality and chemistry of thermal control coating materials, and preand postflight analysis of absorptance, emittance, and mass loss due to atomic oxygen erosion. These are noticeable differences in the United States and Russian space environment measurements and models, which complicates comparisons of environments. Nevertheless, the results of both flight experiments confirm that zinc oxide and zinc oxide orthotitanate white thermal control paints in metasilicate binders are the most stable upon exposure to this space environment. Russian flight materials experience broadens to the use of silicone and acrylic resin binders whereas the United States relies more heavily on polyurethane.

The role of signal systems in cell gravisensitivity

Reception of physical environmental signals caused by alteration of the gravitation field leads to the shift of morpho-physiological cell characteristics. The gravity influence on a cell may be direct or non direct, its extent varying in dependence of the cell model applied. Direct influences are more pronounced in vitro, while non direct influences are usually expressed in the community of unicellular organisms (in vivo). Gravity affects morphogenesis processes, such as locomotion, adhesion, intercellular contacts, etc. At the same time, all the processes named are under control of cell integral systems of the signal transduction. Minor disturbances in this system coming from the environment, due to amplification, may provide significant modulations of the signals. So, studies of this system at the level of molecular cell reception is of great interest. Results of flight and model experiments are discussed in the present manuscript.

Peculiarities of ultrastructure of Chlorella cells growing aboard the Bion-10 during 12 days

The ultrastructure of Chlorella cells grown in darkness on a solid agar medium with organic additions aboard the Bion-1O biosatellite was studied. Certain differences in submicroscopic organization of organelles in the experimental cells were revealed compared to the Earth control. The changes are registered mainly in ultrastructure of energetic organelles - mitochondria and plastids of the experimental cells, in particular, an increase of mitochondria and their cristae size, as well as an increase of the total volume of mitochondrion per cell were established. The decrease of the starch amount in the plastid stroma and the electron density of the latter was also observed. In many experimental cells, the increase of condensed chromatin in the nuclei has been noted. Ultrastructural rearrangements in cells after laboratory experiment realized according to the thermogram registered aboard the Bion-10 were insignificant compared to the flight experiment. Data obtained are compared to results of space flight experiments carried out aboard the Bion-9 (polycomponent aquatic system) and the orbital station Mir (solid agar medium).

Microgravity generated by space flight has little effect on the growth and development of chick embryonic bone.

Seven days' space flight of fertilized chicken eggs pre- incubated for 7 and 10 days on earth caused no differences in the morphology of osteoblasts, osteoclasts, and osteocytes of humerus and tibia from those of control embryos. Bone-resorbing and -forming activities of the femur were not different between control and flight groups. As a consequence, calcium and phosphorus contents of the femora between control and flight groups were not changed. Alkaline phosphatase activity of 3 different regions (resting cartilage, growth cartilage, and cortical bone) of tibia showed no significant difference between control and flight groups. No significant difference of gene expressions of hepatocyte growth factor and receptors of fibroblast growth factor was observed in perichondrium, trabecula, and skeletal muscles and tendons of hind limbs between control and flight groups. Unlike the results of previous space flight experiments in which young growing mammals were used, these morphological and biochemical results indicate that microgravity has little effect on bone metabolism of the chick embryo.

Mass transport phenomena during solidification in microgravity; preliminary results of the first Mephisto flight experiment

The MEPHISTO space facility flew on the Columbia space shuttle in October 1992. The preliminary scientific results, mainly based on the analysis of the Seebeck signal, are presented in this paper. Valuable information was obtained for both planar and cellular solidification regimes. It is shown that mass transfer in the melt during the flight was principally diffusive; however, even in microgravity, slow growth rates may result in significant convective transport. A tentative interpretation of the Seebeck signal for destabilized interfaces is also proposed.

GPSを用いた航空管制用レーダの較正のための飛行実験

This paper describes the method and the results of flight experiments carried out for calibrating a radar used for air traffic control by using GPS. Two GPS sensors, i.e., one equipped on an aircraft and another installed at the control tower of Kushiro airport, were used for the experiments. Offline DGPS data processing was carried out for improving the positioning accuracy. The tracks of the aircraft were observed by the radar and by the airborne GPS sensor. Two tracks were compared with each other in order to estimate the biases in the range and azimuth measurement systems of the radar. The biases were estimated on the basis of the least squares method. Reconstructed radar tracks based on the estimated biases were in good agreement with those of DGPS/GPS after compensating the biases.

Effects of microgravity and clinostating on plants

Abstract Results of many space flight and clinostate experiments performed with growing and developing lower and higher plants, tissue and protoplast cultures are presented. Biological effects of gravity changes on organism, cellular, subcellular and membrane levels are described. Regularities of rearrangements of organelle structural-functional organizations and cell metabolism as well as possible cell mechanisms of the adaptation to microgravity are discussed.

Space construction results: The EASE/ACCESS flight experiment

This paper describes NASA ground and flight test activities in the development of in-space construction techniques for the assembly of Space-Station-sized structures. In November 1985, the first experiments on space construction using EVA astronauts were flown aboard the Space Shuttle, with spectacular and highly visible results. The EASE and ACCESS flight experiments are described and the ground and water tank test program and operations in-flight including instrumentation are presented, together with illustrations of assembly and disassembly of both the EASE and ACCESS experiments. The flight test results are presented and learning and productivity curves are discussed, with differences between free EVA vs EVA using foot restraints compared. Two weeks after the flights, the Space Station structural assembly technique was selected to be EVA astronaut assembly of the truss, based on the flight experiment results.

Spacelab experiments on space motion sickness

Recent research results from ground and flight experiments on motion sickness and space sickness conducted by the Man Vehicle Laboratory are reviewed. New tools developed include a mathematical model for motion sickness, a method for quantitative measurement of skin pallor and blush in ambulatory subjects, and a magnitude estimation technique for ratio scaling of nausea or discomfort. These have been used to experimentally study the time course of skin pallor and subjective symptoms in laboratory motion sickness. In prolonged sickness, subjects become hypersensitive to nauseogenic stimuli. Results of a Spacelab-1 flight experiment are described in which four observers documented the stimulus factors for and the symptoms/signs of space sickness. The clinical character of space sickness differs somewhat from acute laboratory motion sickness. However SL-1 findings support the view that space sickness is fundamentally a motion sickness. Symptoms were subjectively alleviated by head movement restriction, maintenance of a familiar orientation with respect to the visual environment, and wedging between or strapping onto surfaces which provided broad contact cues confirming the absence of body motion.

磁気コンパス旋回誤差の飛行実験的研究

To clarify the whole behavior of turning errors of the magnetic compass, many turns are conducted from various courses by the trainers of Civil Aviation College. In turning to the right, the maximal lag error of the compass occurs between the heading of 10° and 40°, and the maximal lead error occurs between the heading of 130° and 160°. The extent of the maximal error depends upon the angle of aircraft bank. An angle of bank has the greatest effect on compass errors among the flight characteristics of an aircraft. The effect of flying speed, the time rate of bank and flying altitude are investigated. The results of flight experiments quite agree with those of computing errors through Lindemann's procedure. As a result of the studies, turning error curve is proposed. The computed turning error curves to one angle of bank are almost the same for the compasses used today. This curve can be applied to any turning by using the magnetic compass.