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The problem of the formation of an optimal control program spacecraft with low thrust at flight between the noncoplanar elliptical and geostationary orbits is considered. A scheme for the joint change of orbital elements within the simple structure of the thrust vector control on the circuit is offered. [ABSTRACT FROM AUTHOR]

According to the mission requirements of the carrier-based unmanned aerial vehicle (UAV), a mode level flight was established to calculate the thrust requirements from altitude 9 km to 13 km. Then, the estimation method of flight profile was used to calculate the weight of UAV in each stage to get the specific fuel consumption requirements of the UAV in standby stage. The turbofan engine of carrier-based UAV should meet the thrust and specific fuel consumption requirements. Finally, the GSP software was used to verify the simulation of a small high-bypass turbofan engine. The conclusion is useful for the turbofan engine selection of carrier-based UAV. [ABSTRACT FROM AUTHOR]

Flight mechanics with a low-thrust is a new chapter of mechanics of space flight, considered plurality of all problems trajectory optimization and movement control laws and the design parameters of spacecraft. Thus tasks associated with taking into account the additional factors in mathematical models of the motion of spacecraft becomes increasingly important, as well as additional restrictions on the possibilities of the thrust vector control. The complication of the mathematical models of controlled motion leads to difficulties in solving optimization problems. Author proposed methods of finding approximate optimal control and evaluating their optimality based on analytical solutions. These methods are based on the principle of extending the class of admissible states and controls and sufficient conditions for the absolute minimum. Developed procedures of the estimation enabling to determine how close to the optimal founded solution, and indicate ways to improve them. Authors describes procedures of estimate for approximately optimal control laws for space flight mechanics problems, in particular for optimization flight low-thrust between the circular non-coplanar orbits, optimization the control angle and trajectory movement of the spacecraft during interorbital flights, optimization flights with low-thrust between arbitrary elliptical orbits Earth satellites. [ABSTRACT FROM AUTHOR]

The control algorithm for the parameters of the geostationary spacecraft orbit was developed using low-thrust engine. We consider only flat parameters determining the geostationary spacecraft's position in the orbit plane, namely, orbital period, eccentricity and longitude point of standing. The terminal control problem of geostationary spacecraft has been stated. It is assumed that the corrective maneuver is implemented by creating a small transversal acceleration using electric low-thruster. There is a developed discrete model of the geostationary spacecraft motion in the orbit plane under the influence of small transversal acceleration. The solution of this problem involving the use of the traditional dynamic programming method based on the use of Bellman equation is difficult to obtain, because the discrete model of geostationary spacecraft motion is a nonlinear system of equations. Therefore, the paper proposes approximate scheme for solving the problem based on the three-step algorithm of terminal control of the orbital period, eccentricity and longitude point of standing. The solution of the plane problem of the terminal control has been obtained in the analytical form. Analytical expressions for the cost estimate of characteristic speed of corrective maneuver have been obtained. When modeling the motion of a geostationary spacecraft under the influence of a small transversal acceleration the algorithm has showed high accuracy of solving the terminal control problem. [ABSTRACT FROM AUTHOR]

With results of testing various models for several last years, the article will describe the capabilities of the IT- 302M hotshot wind tunnel in terms of modeling of high-velocity flows in the Mach number range from 4 to 20 for external flow regimes and from 2 to 6 for the attached pipeline regime with the following flow parameters: total pressure from 5 to 1000 bar and total temperature from 700 to 3500 K. Some of these pioneering activities are unique: for instance, a positive thrust force was obtained in a scramjet model for the first time; a series of tests was performed for comparisons of the results of inlet flows obtained in hotshot and blow down wind tunnels, including shock starting of the inlet and a possibility of its modeling by using a special device in the long-duration wind tunnel. A new concept of a short-duration wind tunnel with opposing pistons of pressure multipliers has been considered. [ABSTRACT FROM AUTHOR]

This study explores the dynamic characteristics of the combined aircraft-engine system, based on the general theory of the state variables for linear and nonlinear systems, with details leading first to the separate formulation of the longitudinal and the lateral directional state variable models' followed by the merging of the aircraft and engine models into a single state variable model. The linearized equations were expressed in a matrix form and the engine dynamics was included in terms of variation of thrust following a deflection of the throttle. The linear model of the shaft dynamics for a two-spool jet engine was derived by extending the one-spool model. The results include the discussion of the thrust effect upon the aircraft response when the thrust force associated with the engine has a sizable moment arm with respect to the aircraft center of gravity for creating a compensating moment. [ABSTRACT FROM AUTHOR]

Clusters of orbital thrusters are an attractive option to achieve graduated thrust levels and increased redundancy with available hardware, but the heavily under-expanded plumes of chemical attitude control thrusters placed in close proximity will interact, leading to a local amplification of downstream fluxes and of back-flow onto the spacecraft. The interaction of two similar, parallel, axi-symmetric cold-gas model thrusters has recently been studied in the DLR High-Vacuum Plume Test Facility STG under space-like vacuum conditions, employing a Patterson-type impact pressure probe with slot orifice. We reproduce a selection of these experiments numerically, and emphasise that a comparison of numerical results to the measured data is not straight-forward. The signal of the probe used in the experiments must be interpreted according to the degree of rarefaction and local flow Mach number, and both vary dramatically thoughout the flow-field. We present a procedure to reconstruct the probe signal by post-processing the numerically obtained flow-field data and show that agreement to the experimental results is then improved. Features of the investigated cold-gas thruster plume interaction are discussed on the basis of the numerical results. [ABSTRACT FROM AUTHOR]

This paper present experimental test results of separator and shift angle influence on Crossflow vertical axis wind turbine. Modification by using a separator and shift angle is expected to improve the thrust on the blade so as to improve the efficiency. The design of the wind turbine is tested at different wind speeds. There are 2 variations of crossflow turbine design which will be analyzed using an experimental test scheme that is, 3 stage crossflow and 2 stage crossflow with the shift angle. Maximum power coefficient obtained as Cpmax = 0.13 at wind speed 4.05 m/s for 1 separator and Cpmax = 0.12 for 12° shear angle of wind speed 4.05 m/s. In this study, power characteristics of the crossflow rotor with separator and shift angle have been tested. The experimental data was collected by variation of 2 separator and shift angle 0°, 6°, 12° and wind speed 3.01 – 4.85 m/s. [ABSTRACT FROM AUTHOR]