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Cold-rolled 2024–T3 sheet alloy was subjected to bobbin-tool friction stir welding (BTFSW). The microstructural characteristics and mechanical properties of the nugget zone in the as-welded state were investigated. The results show that the equiaxed grain size of BTFSW 2024–T3 alloy decreases from 7.6 to 2.8 μm as the welding speed is increased from 80 to 120 mm/min; in addition, fine grains are generated in the nugget zone and the size distribution is non-uniform. All Al2CuMg (S′) precipitates dissolve into the Al matrix, whereas Mn-rich phases confirmed as T phases (Al20Cu2Mn3, Al6Mn, or Al3Mn) remain unchanged. The optimized parameters for BTFSW are verified as the rotation speed of 350 r/min and the travel speed of 100 mm/min. The variations in precipitation and dislocation play more important roles than grain size in the nugget zone with respect to influencing the mechanical properties during the BTFSW process. After the BTFSW process, the fracture mode of base material 2024–T3 alloy transforms from ductile rupture to ductile-brittle mixed fracture.

Al-Li 2198-T8 alloy sheet was processed by friction spot welding (FSpW). The microstructures and tensile properties of FSpW 2198-T8 alloy were studied by means of optical microscopy (OM), transmission electron microscopy (TEM), scanning electron microscopy (SEM), X-ray diffraction (XRD) and tensile testing. The results show that the grain size of Al-Li 2198-T8 alloy processed by FSpW was refined with the strengthening precipitates dissolved into Al matrix and dislocation density decreased. Hence, the plasticityin thermo-mechanical coupling zone (TMCZ) of FSpW 2198-T8 alloy was improved, while the yield strength (YS) of TMCZ zone was lower than the original material (239 MPa

The support structure of large aperture mirror of space remote sensor is the key of the space remote sensor development. In this paper, the size of the large aperture mirror is Φ700mm,which is supported in the back of mirror with 3 points ,the composite structure of ball joint and flexible groove is adopted in support structure which can guarantee the mirror surface satisfy the requirement of optical design under the coupled load of gravity and heat. At the same time, the mirror subassembly should have a high enough stiffness through the reasonable lightweight to ensure the camera in transportation and launch process can withstand severe vibration condition. In order to validate the rationality of the design,the finite element analysis is done to the mirror subassembly,which indicates that the shape error variation of mirror RMS is better than λ/50 and PV is better than λ/10 in the coupling load of gravity and heat,and the first natural frequency of the mirror subassembly is higher than the design requirements. Dynamics calculation results of mirror subassembly consistent with mechanics experiment results；the surface precision of the mirror subassembly obtained from the ZYGO interferometer consistent with the results of finite element analysis and meets the design requirements.

The object of study is the electric control box of a certain type of space remote sensor. In view of the existing shortcomings of the original electric control box, the electric control box is designed reasonably. In the result, the design of electronic control box supported by the cylindrical multi-point is proposed, which can solve the series of problem of the original program, such as the large volume, heavy weight, large signal interference. The camera control box is made of magnesium alloy which has light weight and high strength; by the structure design of stacked, the electronics system is classified integration; through the local shielding program, the problem of anti radiation and interference of electronics system is solved; by using the multi supporting structure scheme, the structural rigidity of the electric control box is improved, the modal by 57Hz increased to more than 120Hz, which meet the 100Hz technology of the design specifications; the box body is adopted by nickel for protection, which eliminating the possibility of air and humid environment on the corrosion of magnesium alloy. At present, the electric control box designed has been completed the 2014 SPIE.

On the basis of characteristics of optical system of Large aperture three-mirror off-axis, the mirrors’ support structure and the overall frame structure of the optical system was designed and investigated, the first and foremost is the lightweight of the support structure and the overall frame structure, the structure design of the three-mirror off-axis optical system was completed, which characteristic is integrative design of the overall frame structure , also the 3D model of the structure of the optical system was built, by means of the finite element analysis techniques, the modal analysis was done to the overall structure, the analysis results indicate that the first natural frequency of the overall structure is 162Hz，which is higher than 120 Hz requested by the overall structure of the optical system ,the overall structure have a high enough dynamic stiffness and reasonable distribution of modal, which ensure the overall structure in transportation and launch process to withstand severe vibration condition, and the shape error variation RMS and PV of optical mirror which are important indexes of image quality under the comprehensive influence of gravity and thermal load which is in the control range meet the design index.

In course of developing, testing, launching and working in orbit, Space camera has to undergo the shock of external loads and changing environment. The optical performance of a long focal length space camera is largely determined by external mechanical loads and ambient temperature. The performance of the camera is a result of the interaction between environment factors. The performance of the optical system should be making an accurate forecast when a modern optical instrument is designed. In this paper, the research methods are reviewed firstly. Then the related technologies are described. The analysis methods of environment temperature and structural characteristics effecting space camera imaging performance are also discussed.