According to the requirement of aircraft test mission, a set of radiant heat simulation system which can be used in complex extreme environment is developed in this paper. The system is mainly composed of optical subsystem, mechanical structure, cooling subsystem and control subsystem. The design process of this system mainly includes optical system design, mechanical structure design, cooling system design, control system design and environmental adaptability design. The radiant heat simulation system needs to ensure the normal operation under the extreme environment of low pressure (5kPa), high humidity (90%RH), high temperature (75°C) and low temperature (-20°C). In order to solve this difficulty, the system developed a special light source protection cabin. The protection chamber can provide normal temperature, normal pressure and low humidity working environment for the light source. With the help of cooling system and control system, the environment adaptability of radiant heat simulation system is ensured effectively. After the development of the radiant heat simulation system, six indexes including irradiance, spectrum, illumination area, irradiation uniformity, irradiation stability and environmental adaptability were evaluated according to the test standards. At present, the radiant heat simulation system has been involved in part of the aircraft test, the effect has been recognized by the test department.
To help China's first Mars mission go smoothly and improve the performance of the solar cells mounted on the rover in illumination conditions on the Martian surface, the project team launched a study to simulate the sky light on the Martian surface.This paper focuses on the influence of Martian sky light on solar array output at different solar elevation angles and light depths.Based on the approximate model of sky light radiation, a set of sky light simulation equipment on the surface of Mars is developed.The advantages and disadvantages of using LED light source and metal halide light source to simulate sky light are compared and analyzed.The sky light simulator can simulate the sky light with the solar elevation Angle of 75°, 60° and 45°, and the sky light with the optical depth of 0.9, 0.7 and 0.2.According to the requirements of the test department, the simulation effect was tested with instruments such as spectrometer.The test results were approved by the test department, and the skylight simulator has been applied to subsequent Mars rover tests.
Photogrammetry technology has been gradually applied in the development of large satellite antenna, and the experimental evaluation method for deformation measurement of large satellite antenna proposed in this paper is derived from the development task of large flexible antenna, which needs to conduct reflector measurement in a vacuum and cryogenic environment based on the principle of photogrammetry.Therefore, it is necessary to establish an evaluation method for large satellite antenna deformation measurement based on photogrammetry.The repeatability and accuracy of the measurement results can be judged by the method.In this paper, a method of measuring repeatability and measuring accuracy is proposed, and the measurement results are evaluated by defining the concepts of single point measuring evaluation factor and length measuring evaluation factor.This evaluation method has been successfully applied to the measurement of large antenna deformation in vacuum and cryogenic environment.
In order to meet the requirements of Mars rover test, the Mars surface illumination environment simulation system was developed, which is mainly composed of optical subsystem, mechanical and control subsystem. It can simulate the solar elevation angle at a large angle and solar spectrum on Mars surface, etc. It is of great significance for development of Mars rover and the improvement of its ability to perform space exploration missions. After the system was developed, six indexes including irradiance, spectrum, solar elevation angle, illumination area, irradiation uniformity and irradiation stability were evaluated according to the test standards. The irradiance meets the requirement of 0.3 solar constant in the direction of vertical illumination. The spectrum meets the spectral requirements of the landing area; Mars surface illumination environment simulation system can be simulated 75° ~ 90° solar elevation angle, at the same time can be simulated illumination area of more than 10 m × 10 m; The irradiation non-uniformity of this system is ±14% ;Irradiation stability is expressed by irradiation instability, and the irradiation instability of the system is ±4.5% within 2 hours continuously. At present, the Mars surface illumination environment simulation system has participated in the Mars rover test, and the illumination effect has been affirmed by the test department.
Based on photogrammetry, antenna deformation measurement in vacuum and cryogenic environment has been widely carried out. The strength of measuring network will affect the accuracy, repeatability and stability of the measured results. A method for evaluating the strength of photogrammetric network based on attenuation factor is proposed, that is, a strong correlation is established between the measurement accuracy and spatial network parameters through the formula of attenuation factor of network strength ,according to the factor value, the network layout can be evaluated . In this paper, the reliability of this method is verified by experiments. The method can obtain a better network design before measurement and avoid a lot of repetitive work. The evaluation method is applied to deformation measurement test for large aperture antenna in the vacuum and cryogenic environment .Thus reduces the test cost and the risk, enhances the measurement accuracy and the stability.
In order to meet the experimental requirement of in-situ measurement for spectral reflectance of advanced thermal control coatings, a high accuracy in-situ measurement system for spectral reflectance of thermal control coatings of spacecraft is developed based on dual-beam spectrophotometry. The measurement wavelength range is 200 to 2500 nm, and the measurement accuracy is better than 0.5%. In the space ultraviolet radiation environmental effect test, it can realize the integrated test process of sample delivery, sampling, separation, in-situ measurement of spectral reflectance in vacuum.
In order to meet the requirement of high precision thermal distortion measurement foraΦ4.2m deployable mesh antenna of satellite in vacuum and cryogenic environment, based on Digital Close-range Photogrammetry and Space Environment Test Technology of Spacecraft, a large scale antenna distortion measurement system under vacuum and cryogenic environment is developed in this paper. The antenna Distortion measurement system (ADMS) is the first domestic independently developed thermal distortion measurement system for large antenna, which has successfully solved non-contact high precision distortion measurement problem in large spacecraft structure under vacuum and cryogenic environment. The measurement accuracy of ADMS is better than 50 μm/5m, which has reached international advanced level. The experimental results show that the measurement system has great advantages in large structural measurement of spacecrafts, and also has broad application prospects in space or other related fields.
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