A modeling analysis is given to investigate the plasma flow and heat transfer of lowpower (kW class) archeated thrusters (arcjets). The hydrogen/nitrogen mixtures are chosen as the propellants to simulate decomposed ammonia and hydrazine. The temperature and velocity distributions in the arcjets with different inlet pressures and arc currents are presented. The modeling results show that with the increase of the arc current, the temperature along the axis increases, and the velocity at the exit plane and the specific impulse also increase. With the increase of inlet pressure, the mass flow rate and velocity at the center of nozzle exit also increase. A numerical simulation is carried out for the NASA 1kW class arcjet thruster, and the results are almost consistent with the available experimental data.

A backstepping direct adaptive attitude and vibration control method is proposed for flexible spacecraft with piezoelectric vibration suppression sensor and actuator pairs. Firstly, the attitude maneuver and vibration control model of a flexible spacecraft is derived, and the almost strict positive real property of the dynamics subsystem is discussed. Then, an attitude maneuver and vibration controller is designed based on backstepping directive control method, and the closedloop stability is proved. Finally, the controller is applied to a flexible spacecraft in different initial conditions. Theoretical analysis and simulation results validate that the controller has strong robustness against the spacecraft inertial and flexible model uncertainties. Both the attitude maneuver and vibration suppression can be accomplished effectively.

To analyze the closedloop stability of the phaseplane jet control system, a method is proposed to obtain the numerical describing function, by which the effects of control variables on the frequency domain properties can be studied. An analysis method is given to decide the stability and the stability margin of the closedloop system. An instance is given to illustrate how to apply the given methods to predict the stability properties of a designed phaseplance thrust control system effectively. The advantage of this technique in redesigning the phaseplane controller and achieving better robust properties are also illustrated by another example.

Highprecision payloads require both ultraquiet and agility performances of satellite platform, which brings several design challenges. The gyroscopic precession induced by actuator isolation and its impact on the agility performance are investigated, and a parameter selection principle is proposed based on the estimation of the precession decay time. The noncollocated control problem caused by payload isolation is studied and a design principle is proposed based on damping constant isolation. Simulations show that both ultraquiet and agility performances can be ensured by using the proposed design method.

Concerning requirements for the onorbit release and separation of nanosatellitefractionated payloads, a design of the springloaded separation system is presented. It is aimed at the problem that the international commercialofftheshelf products are inadaptable for the nonstandard ratio of weight and volume. The separation system is able to support 6 U (1 unit = 1 dm3 volume) and 10 kg payload. Taking into account the design constraints, the plan consists of the central bearing frame, separation mechanisms and the docking ring. Modal and acceleration loading analyses are carried out.  Accordingly the onorbit simultaneous separation process of two opposite ones is presented. Analyses results show that the structural design meets the requirement for launching. The designed plan serves as an effective and applicable solution for the mission.

Continuous electric thrust control strategy is studied for orbit transfer from GTO to GEO. The optimization of orbit transfer is simplified to twostage strategy in view of the onboard computing ability, and the thrust direction is fixed during each stage. Meanwhile, the space environmental influences are analyzed since the electricthrustbased orbit transfer lasts longer than chemical thrust maneuver. The transit from Earths ionosphere and radiation belts is investigated. Finally, to reduce the influences of Earths ionosphere and radiation belts, the feasibility of using the orbit of which the apogee is higher than that of the normal GTO orbit as the initial orbit is discussed.

The sun sensor is usually placed on the surface of a spacecraft and receives the radiation of sunlight directly. By adopting the opticselectronics integrative design method, the heat stabilization of optical system and the working temperature of electronic device can be ensured simultaneously. To analyze the temperature distribution of integrative sun sensor, the optical and thermal models are combined. Based on the given temperature boundary condition, the heat of sunlight is also considered when the thermal analysis and thermal verification are carried out. The results show that the working temperature of sun sensor satisfies the thermal design criterion even if the temperature of the shell is 55℃ and the radiation of sunlight is 1 constant. The data of verification are coincident with the analysis results well.

As a key mechanical component providing the stable support in a flywheel, the vibration properties of bearing assemblies have significant influence on the microvibration properties of flywheels. Based on the principle of axial preload on a bearing assembly, a precise rigid preload approach is employed to apply a set of positional preloads on the bearing assembly, and a vibration test system for bearing assemblies is established to capture the vibration properties of the bearing assembly with the preloads. The effects of preloads on the harmonic frequencies, the natural vibration and the ball passage vibration are analyzed. Based on the tests, the effects of the preloads on the vibration properties are analyzed and the optimized regime of the preloads is derived. The reseach suggests the existence of an optimized rigidpreload regime for the bearing assembly.

Due to the limited power of lamplight, the target spacecraft cannot be identified on the television during manual controlled rendezvous and docking in shadow and remoter region. Five object identification methods are proposed to solve the problem, including increasing the lamplights power, using target lamps, using laser radar data, pasting flaring material on the target spacecraft and spanning different regions. With these approaches, the problem of object identification in the shadow and remoter region can be solved availably. These methods are effective and applicable.

In this paper the necessity and feasibility of the BIT (built in test) technology is applied to the satellite electronic devices are analyzed, based on the investigation of the development of BIT technology. A BIT test system is constructed via using hierarchical ideology to suit for the satellite electronic equipment. A new method is proposed to develop the testability of satellite electronic equipment.

This article introduces the kinds of DC/DC convertor’s transient responses and analyzes the principle of these transient responses including the transient voltage, current and power. The uncontrollable transient responses can endanger the DC/DC convertor. In order to ensure these transient responses under control and enhance the reliability of the convertor, the influence of the DC/DC convertor’s transient responses is analyzed, and the results of the test are given.

Focusing is a key problem in the design and production of a star sensor. Accurate focusing can improve the star sensor’s measuring accuracy and sensitivity so as to assure the performance. Focus position, nonsuperposition between optical system axes and CMOS chip normal, chip installment accuracy and centroid stability are analyzed in the paper. Finally, the focusing methods are summarized and given.