A qualitative theory of an electric discharge method for visualizing three dimensional shock shapes around hypersonic models was established by considering the relation among the radiation intensity from the electric discharge, the excitation function vs. electron energies, and the gas molecular number density. By establishing the qualitative theory of the visualization, it was found there exists the most suitable experimental condition for visualizing shock shapes. Three dimensional shock shapes have been visualized successfully by utilizing the knowledge.
This paper presents an on-going program for research and development of a free-flying space telerobot. The proposed telerobot will perform extra-vehicular activity taking over human astronauts. A manufactured ground experimental model has inertial sensors and thrusters for maneuver, and two manipulators and one capturing mechanism for manipulation. We experimented with this model on 2 dimensional flat test bed that simulates zero-gravity and non-constraint condition on earth ground. The experimental results showed that the telerobot had good performance in an assumed task for retrieving a drifting satellite.
An investigation is conducted to experimentally verify an analytical method that determines the thermal contact resistance between the balls and the inner and outer rings of a space-use ball beardng. A single row bearing made from stainless steel 440C is tested in a vacuum environment, and steady-state temperature distributions are measured to evaluate the heat flow across the stationary bearing. Test results are given for the conditions of axial, radial and combined loading. Excellent agreement between the measured and predicted values of the thermal contact resistance is found under all types and magnitudes of the applied loads. It is concluded that the proposed calculation method accurately predicts the thermal contact resistance between the elements of a dry bearing with smooth contact surfaces.
A large deployable antenna is essential for effective mobile communication satellites. This paper describes the characteristics of various scale models of the large deployable mesh reflector antennas and a study on space verification test plan using the scale models. Our ultimate goal is a deployable mesh reflector antenna with 30m diameter. Two electrical scale models of the mesh reflectors have been constructed to evaluate the electrical performance of a mesh reflector antenna. The mechanical models consist of two partial deployable models that were designed and constructed to help develop the deployable reflector with 30m diameter. One of the models is the Hexa-Link Truss structure, and the other model is the TETRUS structure. Diameter of these models are 3m. The experimental measurements and calculations of these electrical and mechanical models are also described.
Approach paths of a single aircraft coming into a terminal area were solved numerically. The problem of calculating approach paths was formulated in terms of the optimal control problem. And then, inequality constraints of a state variable and control variables were taken into account so that numerical results might be consistent with approach paths of an actual aircraft. It was shown how the approach paths of a single aircraft depended upon functionals, inital conditions and terminal conditions.