Propellant acquisition vanes (PAV) are the key parts of vanetype surface tension tank (STT)，and its transportation performance of fluid will determine management ability of STT under microgravity environment.In present paper，a model test system is established.Based on experimental study of fluid transportation behavior of propellant on the PAV with different section forms conducted on microgravity drop tower，some important conclusions are obtained.According to experimental tests，PAV with different section forms influences the fluid transportation performance of STT remarkably.Thus，it is an effective way to control liquid transportation velocity by reasonably design of section form of PAV，and it used to supply pressurized hydrazine fuel to the spacecraft’s propulsion system thrusters.Present experimental results can not only provide a guideline for optimized design of newstyle vane type management assembly，but also present a new way for liquid control in space environment.

The reentry trajectory optimization problem with terminal constraints and path constraints of a lunar return vehicle is considered in this paper. By defining the performance index function as a square sum of the reentry terminal position errors, the reentry trajectory design problem is transformed into the optimization problem with terminal constraints and state equation constraints. First, in the presence of the state equation constraints only, the necessary conditions of the optimization problem are obtained by using the maximum principle, and the optimal control is solved using the conjugate gradient method. Then, in the presence of path constraints, we have studied the relationship among the overload, the distance of the orbit phase, the flight path angle and the bank angle. Based on the above, a method of initial bank angle value adjustment is presented to satisfy the path constraints. This approach, with definite physical meaning and simple implementation, circumvents the shortcoming of the punishmentfunction method which involves too many adjusted parameters. Finally, a numerical example for Apollo reentry trajectory optimization is given to illustrate the effectiveness of the algorithm.

A numerical study of spray performance in a bipropellant coaxial centrifugal injector is proposed by using the large eddy simulation (LES) method, based on the multiphase volume fraction model of the gas and liquid. The results show that the spray velocity ejected from the inner flow passage is larger than the outer flow passage, and the spray angle increases slightly when both of the two flow passages simultaneously inject. The spray velocity and flow coefficient increase with the decrease of the injector exit length and increase of the injector pressure drop. The spray droplet size (SMD) decreases and the spray angle increases with the increases of the injector pressure drop.

A new PIDlike attitude control law with saturated integrals is proposed for the control of spacecraft. The control law can not only eliminate the influence of constant disturbances, but prevent the control torque from getting too large by means of saturation constraint on the integrals. With the associated theory of forwarding system, it is rigorously proven that the closed loop is globally asymptotically stable, and the corresponding sufficient conditions of the relevant parameters are also derived. Numerical simulations demonstrate the effectiveness of the proposed approach.

The magnitude of lift force of reentry vehicles with fixed angle of attack is not controllable. The control of the flight path can only be achieved by rollaxis control action. In order to accurately steer the fixed angle of attack reentry vehicle, a rollingguidance law based on fixed trimmed angle of attack(FTAA) is presented. The FTAA vehicle motion equation with respect to the target placement is established. The physical meaning of the motion equation is analyzed. The basic guidance method of the rollingguidance is put forward. The correctness of the guidance method is proved. The calculation method of the rollingguidance command is also given. The ballistic characteristic of the rollingguidance is analyzed by a mathematical simulation. The simulation result illustrates that, by certain rolling strategy, the rollingguidance law can consume the extra lift, achieving the accurate landingpoint control of the vehicle.

To improve the Xray pulsarbased navigation (XNAV) practice performance in engineering, a novel navigation system using single Xray detector is proposed. The fundamental observed quantity is the difference between the observed arrival time and the predicted arrival time of pulse . The batch weighted least square filter used in Deep Space 1 of USA is applied to estimate the position and velocity of the spacecraft in the interplanetary cruise phase. The condition of Deep Space 1 is adopted in the simulation. The influence of the factors such as number of pulsars, the batches of the measurement data and the orbit determination period, is analyzed in the simulation. The comparison between the batch weighted least square filter and the Kalman filter is made as well. The simulation results show that the proposed system is feasible and effective in the spacecraft interplanetary cruise phase.

The control moment gyroscope (CMG) is one of the important actuators for attitude control, and it is also the main noise source of the space station. The noise of 1000N·m·s CMG is completely tested, and the results show that the maximum noise of the 1000N·m·s CMG reaches 90.9dB. Based on the analysis of the noise testing results, the main noise sources and their action mechanism are determined, which provides the theoretical basis for the subsequent study of the denoising method.

An ActiveXbased distributed simulation system named AgSimu was proposed in order to satisfy the requirement of MultiAgentbased autonomous system for distributed spacecraft systems.The COM/ActiveX Component was used to build all kinds of Agent，and ActiveX container was designed to act as Agent container，build up multiagent object model and manage the configuration and communication of these agents.Some different architecture of distributed agent systems can be made up and their realtime interaction and coordinated work can be simulated.By using ActiveX in Sfunction of Matlab/Simulink，the system can cooperate with models in Simulink.Therefore the closeloop simulation include controlled objects can be realized.

Collision probability represents the risk of collision between two spacecrafts during the encountering phase. Collision probability calculation is the basis of designing the collision avoidance maneuver strategy. If the relative velocity between two spacecrafts is large and the encountering time is short, the relative motion is approximately linear. Under this assumption, the problem of solving the threedimensional probability density is reduced to a twodimensional problem. Numerical integral methods are usually used to calculate the collision probability. An analytical solution based on probability integral is derived, which can reduce the amount of computation while the decreased accuracy is not so much. A case study is presented to validate the given method.

To analyze how the bipropellant thruster injection angles influence the liquidfilm distribution, we propose a numerical method to calculate the distribution of the liguidfilm on the inwall of combustion chamber with different injection angles by using the finite volume method. The proposed approach is based on the gasliquid biphase model under the assumptions there is no combustion in the combustion in the combustion chamber, and the propellant is all NTO. The calculation results show that the liquidfilm moves to the direction of injector as injection angle increase. The lengths of liquidfilm are all around 30mm under different injection angle. However, the liquidfilm thickness changes a lot when half injection angle is between 45°and 55°.

It is trajectory correction maneuver (TCM) that is absolutely important and has to be solved as the key problem during the EarthtoMars trajectory in the Mars exploration. Firstly, the B plane reference frame based on the target planet and target parameters are introduced. Then formulas of B plane parameters are deduced. In succession, it is validated that linear relationship exits between target parameters and the velocity correction value. Meanwhile the corresponding arithmetic flow chart is proposed. In the next place, taking the rational velocity maneuver error and the orbit measurement error into account, a control strategy containing three main TCMs, one contingent TCM and one backup TCM is proposed and is proved possible and feasible by the simulation eventually.