Spacecraft Thermal Test Research Articles

Research on pipeline connection structure of microwave load water-cooling system for spacecraft thermal test

The microwave load water-cooling system was operated in a vacuum cold black environment, and the pressure difference between the inside and outside of the water pipe could reach 0.3 to 0.4 MPa. To ensure the tightness of the water pipe, a conical seal structure was selected, the macro-static model and micro-boundary element contact model were established for the two forms with and without the Viton seal. The macro model simulation was performed by the finite element method to obtain the stress distribution inside the conical structure under different preload stress, the relationship between the contact pressure of the conical sealing interface and the contact area of the O-ring sealing interface as a function of preload stress; the method was used to calculate the micro-contact model, and the critical contact pressure and contact area to achieve the sealing requirements were obtained respectively without Viton seal and with Viton seal. As a result, a conical seal structure with a Viton seal was finally chosen for application. After verification, the structure meets the requirements for the use of microwave load water-cooling systems during the vacuum thermal test.

Application of laser displacement measurement system in thermal test of aircraft

At present, there is no research on nanosecond displacement measurement technology for spacecraft thermal test in China. Firstly, the principle of laser displacement sensor measurement is introduced. A system of hardware and software design and implementation was designed. Finally, a set of test system is built to verify the application of laser displacement meter in the spacecraft vacuum thermal test displacement measurement system. The experimental results and data analysis show that the laser displacement meter can meet the nanosecond displacement measurement requirements of spacecraft in vacuum and low temperature environment.

Research and Realization of Grouping Collection Algorithm of Infrared Cage Heating Circuit for Spacecraft Vacuum Thermal Test

In the process of spacecraft thermal test, the infrared cage is mainly used to simulate the heat flow outside the space. In the design, the infrared cage is divided into several heating zones corresponding to the spacecraft. The heating strip of the infrared cage is divided into heating circuits, the heating circuits are grouped and collected, and the infrared cage heating node table is defined as an important basis for controlling the infrared cage. At present, there is a single method of grouping and gathering heating circuits, which is mostly limited by manual adjustment based on experience and lack of automation. In order to solve the shortcomings of the existing technology, this paper adopts the genetic algorithm hybrid BFD based on reinforcement learning to group and collect the heating circuits, and optimize the design results according to the constraints. The user interaction interface is designed to facilitate the user to do further analysis. Thereby improving the level of business automation, optimizing working procedures and reducing costs.

Research on High Temperature Protection Technology of Infrared Temperature Measuring Equipment in Space Environment

With the increasing complexity of spacecraft structure and thermal design, it is more difficult to implement surface temperature measurement technology, and the temperature measurement area tends to diverse. Therefore, there is an increasing demand for the application of non-contact temperature measurement technology in spacecraft thermal test. This paper takes the application of infrared temperature measuring equipment in vacuum and high temperature environment as the research object, designs the thermal protection scheme and device of the equipment, and simulates and analyses the thermal protection of infrared temperature measuring equipment based on node network method. Through physical test, the device can effectively realize the thermal protection of equipment in vacuum and high temperature environment, and ensure that the equipment is in the normal working temperature range and its temperature measurement algorithm model is not affected, the accuracy of temperature measurement is better than ±2°C, which meets the use requirements in spacecraft thermal test.

Research on Fault Diagnosis Technology of Thermal Test Measurement and Control System Based on Data Driven

Temperature data, as one of the most important parameters in spacecraft vacuum thermal test, is also an important characteristic parameter for fault detection of spacecraft thermal test system. From the perspective of numerical heat transfer, the physical and mathematical models of thermal test specimens are established by using finite difference method. Based on the data driving of specimen measurement temperature and heating power, the mathematical model coefficients are fitted by the combination of least squares and sliding window filtering, and then realize the on-line prediction of temperature data and fault detection of thermal test measurement and control system. Based on the thermal test data of the solar wing of a certain type of spacecraft, the above-mentioned method was verified by physical experiments. The experimental result shows that the method can accurately and effectively realize the temperature prediction not less than 2 periods, and the prediction accuracy is less than ±2°C. It can provide an effective fault detection means for the thermal test measurement and control system.

The research on Power Supply Array Intelligent Management Technology for Spacecraft Thermal Test

The thermal test of spacecraft has a large demand for the program-controlled power supply, which was configured as array. In this paper, the intelligent management technology of program-controlled power supply is researched. Base on the analysis of the history fault type of power supply, the fault detection technology of power supply is studied. Then, combined with the technology of power supply redundancy switching, an on-line switching device is designed. Through the verification experimental, the experimental results show that the system can quickly realize the detection and positioning of the fault power supply, and can finish the online switching of the fault power supply to the backup power within the second-level time. The research of intelligent management technology enhances the management efficiency of the large scale power supply array, and improves the operational reliability of the spacecraft thermal test.

The Investigation of Anti-Jamming Technology For Temperature Measure System in Spacecraft Thermal Test

At present, the spacecraft thermal test temperature measurement system has not been designed effectively. In the spacecraft experiment, the defects of anti-interference ability and system instability are exposed. Firstly, the composition and status of the temperature measurement system of spacecraft thermal test are analyzed. And then we set up a system to interfere with fault tree according to existing problems, locate the problem and determine the source of the interference. Finally, the anti-interference scheme and implementation are developed, and the test data of anti-interference test system is set up. The anti - jamming performance of the anti - jamming scheme of thermal test temperature acquisition system was evaluated. The results show that it can improve the anti-jamming capability of the spacecraft thermal test temperature acquisition system and improve the stability of the system.

Design and calibration of a novel transient radiative heat flux meter for a spacecraft thermal test.

Radiative heat flux measurement is significantly important for a spacecraft thermal test. To satisfy the requirements of both high accuracy and fast response, a novel transient radiative heat flux meter was developed. Its thermal receiver consists of a central thermal receiver and two thermal guarded annular plates, which ensure the temperature distribution of the central thermal receiver to be uniform enough for reasonably applying lumped heat capacity method in a transient radiative heat flux measurement. This novel transient radiative heat flux meter design can also take accurate measurements regardless of spacecraft surface temperature and incident radiation spectrum. The measurement principle was elaborated and the coefficients were calibrated. Experimental results from testing a blackbody furnace and an Xenon lamp show that this novel transient radiative heat flux meter can be used to measure transient radiative heat flux up to 1400 W/m(2) with high accuracy and the response time of less than 10 s.

Structure Design and Optimization of Vacuum Vessel for Spacecraft Thermal Test

The space environment simulator is a facility used to conduct thermal test for spacecraft, and vacuum vessel is the main body of it. During the test process, the vacuum vessel is exerted an external pressure of 0.1MPa, and there are various pipe orifices on the body of the vessel, therefore the intensity and stability should be taken into account carefully. This paper introduces three approaches for the design of structure intensity and stability of vacuum vessel, and takes GVU-600 space environment simulator as an example, which is the first aerospace facility developed by China for Russia. One approach is calculation by rules, and the second method utilizing finite element analysis, which could check details of the structure, but the efficiency of the previous two methods is low. In the end, a mathematics approach is introduced, which utilizes the optimization model, and the design parameters could be calculated accurately and efficiently.

NTC热敏电阻的标定及阻温特性研究

The resistance of NTC thermistors is decrease with the increase of temperature,and they generally have nonlinear resistance(R)-temperature(T) behavior.In practice,such thermistor sensor needs to be individually calibrated over the operating temperature range to ascertain the R-T characteristics.The MF501 thermistor applied in spacecraft thermal test was illustrated in this paper to introduce a simple and effective calibration and data processing method.The fitting residual,average error and function transfer error were selected to assess the adequateness of the method.The result showed that the calibration error could be controlled within 0.45 ℃ based on three-point calibration over the operating temperature range and the precision was fully satisfied.Calibration precision could be improved with increasing the calculated calibration points.

Some remarks on the determination of unknown parameters in large nonlinear systems- a problem in spacecraft thermal test evaluation

As a special case of large nonlinear systems with many imprecisely known parameters, this paper considers the thermal behaviour of a spacecraft. It is simu lated in the steady state by a mathematical model consisting of a system of nonlinear equations and in the transient state by a system of nonlinear differ ential equations. The system contains a large number of parameters, many of which cannot be calculated or measured directly with satisfactory precision. The estimated parameters of the initial mathematical model can be improved by analysing the results of thermal tests performed on the spacecraft itself. The objective is to minimize the differences between measured and calculated temperatures. Since the temperatures are nonlinear functions of many para meters, the minimization is a difficult task. Methods which transform the nonlinear functions into linear ones may not result in the minimization of the temperature deviations. The major disadvantage of linearizing methods is the restriction of the validity of the first-order terms to the vicinity of the point about which the linearization was made. Therefore there cannot be a universal, straightfor ward procedure to evaluate a great number of unknown parameters in complex nonlinear systems. Engineering methods for special solutions need to be developed and made as general as ingenuity can make them.