With the rapid progress of technology and manufacture, the number of telescopes in space is mounting dramatically. Considering launch cost, more and more engineers nowadays pursue lightweight and compact design of telescope in space. Traditional design scheme usually has a support plate for primary reflective mirror. It will take some space for other parts. The paper, taking a primary reflective mirror with 600mm in diameter as an example, put forward a novel design of circle support component instead of traditional support plate. It utilized a special structural layout to save more space. The paper specified this design scheme and made comparison between these two design schemes. The paper also gave the assembling method of the primary reflective mirror and circle support component, which would verify its feasibility in engineering practice in a virtual way. The novel structure design in this paper will give some guidance to engineers and designers, who are devoting themselves to designing space telescopes.
The number of space optical instruments is growing with a quick pace. Reflective mirror is always a significant part in a space optical system, especially in the laser communication system. Support is used to connect reflective mirror to other structure. The paper focused on designing a cylinder support. Considering thermal condition in space, the paper gave a special design of support with some soft links. The paper made a comparison between traditional design scheme of cylinder support and new design scheme of special cylinder support. From the comparison, it could be concluded that new design scheme had better performance in the thermal condition. Later, modal analysis and some vibration analyses were done to verify the reliability and feasibility of the new design. The result showed the design scheme was good.
Mechanical structure, of which a trade-off between weight and strength has always been considered primely, is important for a space camera as a hub for other assemblies such as optics parts, electronic parts, etc. Traditionally the space camera is composed of a nearly line-up of arrangements containing different units, which is easy to assemble and manufacture, however, not a good type for mechanical properties due to the cantilever structure. We present a new type of unitized design for the structure of the space camera, which unite the tube and the electric cabinet as one unit, with the PCBs (Printed Circuit Boards) surrounded. The main frame is optimized by using topology optimization, improving the characteristic of the structure. The maneuverability has also been considered. Compared with some traditional type, the new type proved to be lighter and more compact, which is beneficial to the mechanical properties and the cost control of satellite launching.
The status of ocean remote sensing is becoming more and more important. There are all kinds of resources in ocean and many ships on the sea. It is necessary for people to detect or observe these objects to know more about the natural resources and to ensure safety of ships. The paper concentrated on a compact design of a small space camera. An oscillating mirror was designed in the camera for a small volume. After that, structure analysis was done by traditional method and reduced method. The key step of reduced method was to get the reduced model. The analysis result showed that the reduced method could not only cut down the cost of computing, but also give a result with good accuracy. Besides, the analysis result indicated that the small space camera could undergo the strict load cases smoothly. The design in this paper may give some guidance to other designers and engineers when they are going to make a small space camera for ocean remote sensing.
The research on space laser communication has become a hotspot in recent years. The research trend of it is high speed transferring, networking and integration. Integration design means that the structure should be compact and reliable. CPA (Coarse Pointing Assembly) is an important component in space laser communication system. The paper makes design of CPA reflective mirror. On one hand, it is expected that the reflective mirror is as light as possible with small size. On the other hand, it is expected that the structure is reliable with high stiffness. These two aspects are contradict. And several factors make influence on these two aspects, such as the thickness of mirror, the size of bottom holes, the thickness of ribs and so on. The paper makes sensitivity analysis and chooses proper design variables for further optimization. And then, the paper makes a multi-objective optimal design based on factors mentioned above. In the process of optimization, a special objective function is deduced. At last the optimal design is obtained. The result shows that optimal design scheme has good characteristics.
With the wide use of earth-based laser communication system, more and more engineers like to pursue the design of lightweight structure. Nowadays, engineers often firstly depend on the project experience to design the lens hood, then make analysis based on finite element method to verify its feasibility, but it costs too much time. The paper attempts to give a new optimization design method. Surrogate model are widely used in the fields of aerodynamics parameters optimization, but barely used in design of optical structure. The paper makes an optimal design about lens hood with wide aperture based on surrogate model. First of all, the paper generates some samples by finite element method; secondly, uses the samples to get the surrogate model by surface interpolation; then finds the optimal solution by surrogate model and constraint conditions. The aperture of the lens hood in this paper is 450 mm. One end of the lens hood is attached to main structure, and the other end is free. Middle part of the lens hood is supported by rods which are made of carbon fiber. The optimization variables in this paper is the thickness of the lens hood and the location of the supports robs. The purpose of the optimization is to find the case that the weight is light and displacement of the free end is small. It will not let the miscellaneous light make a negative effect on incident or outgoing path of light. In other words, it will ensure the quality of imagining or effect of detection. The appropriate solution is found by the method proposed in this paper.
Considering of orbital environments and working mode of the reflectors, thermal model of the 45-degree reflector assembly in satellite optical terminals on orbit is established to obtain temperature distribution of the reflectors(the extreme low temperature is -38.0°C, the extreme high temperature is 32.2°C and the max temperature gradient is 3.3°C), meanwhile, a thermal-optical vacuum experiment based on the analysis results is conducted to check the effect of temperature distribution on reflectors .the results shows: if temperature of the reflector is ≥-10°C, the reflector shape accuracy PV will be better than λ/3, and the RMS will be better than λ/30 (λ=632.8nm), but it becomes worse and is not able to meet application requirement when the temperature decreases continuously(-40°C ~-10°C). So it is necessary to design reasonable active heating loops for reflector assembly to guarantee its performance on orbit.
For the diameter of 150mm elliptical flat mirror that used in the space, selected the zerodur material and a lightweight design is conducted in the way of selected back-open-architecture with symmetrical axisymmetric arrangement, and in order to evaluate the effect of thermal stress from -10°C to 45°C on the mirror, a reflection mirror is designed based on the multipoint flexible support. The mirror component's mechanic and thermodynamic characteristics is analyzed with the simulation software, the support structure parameters are optimized, that can be used to evaluate the effect of gravity, assembly stress, and thermal stress load on mirror, while ensuring the component's stiffness and strength. According to the design condition developed a product and carried out mechanic and thermodynamic environment, the product could meet the shape accuracy PV λ/3, RMS λ/30 in the condition of thermodynamic environment, and the shape accuracy PV λ/5, RMS λ/40 in the condition of ground gravity and assembly stress (λ=632.8nm), while the product can withstand with the mechanical oscillation environment sinusoidal oscillation 10g, RMS random oscillation acceleration 14.4g.
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