In order to achieve higher-resolution space observation goals, countries around the world have successively proposed a series of large-aperture telescope survey plans, such as the Hubble Space Telescope (HST), the James Webb Space Telescope (JSWT), and the Large Synoptic Survey Telescope (LSST) [
1]. China has also begun implementing survey missions, the Guo Shoujing Telescope [
2] has completed its first phase of operation, releasing over 9 million survey spectral data. The Chinese Space Station Telescope [
3], mentioned in this article, is the largest applied payload in the manned space station project and, together with the survey platform, forms the survey space telescope, as shown in
Figure 1. The telescope adopts multiple backend scientific instruments, with a heat dissipation power of 1310 W. According to thermal control analysis, an area of 12.22 m
2 is required to meet the heat dissipation requirements. Based on thermal source distribution, equipment structural characteristics, vibration suppression, and on-orbit maintenance of modules, a large-sized body-mounted radiator is an ideal choice for heat exchange equipment. However, there are significant differences in the load conditions experienced by the large-sized body-mounted radiator before and after orbital insertion [
4,
5]. During the launch phase, the space radiator experiences vibration loads of up to 10 g. Compared to the launch phase, the difference between the lowest operating temperature during on-orbit operation and the ground assembly temperature can reach up to 80 °C. This large temperature difference can cause thermal stress deformation in the radiator, thereby affecting the outer frame and internal optical system of the space telescope through the radiator support structure [
6,
7]. The radiator support structure is a key connecting component between the outer frame of the space telescope and the radiator. The key technology for the future design of large-sized body-mounted radiator support structures lies in how to release the thermal stress generated by the large-sized body-mounted radiator due to temperature loads without affecting the imaging quality of the space telescope and meeting the launch mechanical requirements.
Currently, the support structures used for space telescopes can be classified into three categories: rigid support, flexible support, and kinematic support. Rigid support refers to the support of the camera and platform through rigid connections, such as cylindrical support and truss support structures [
8]. This structure has ordered reliability, a simple design, and is suitable for space telescopes with low thermal adaptability and low imaging accuracy requirements. Flexible support [
9] is designed based on the principle of flexible hinges and has good thermal adaptability. It can release the stress transmitted by the platform through the elastic deformation of its own flexible joints. The current research focus is on large deformation flexible hinges [
10,
11], among which the large stroke flexible hinge is an improvement on the cut-spherical hinge-type flexible hinge. By increasing the radial and axial dimensions, the stroke can be greatly increased. The stacked flexible hinge guide table [
12] can significantly increase the stroke while maintaining high linearity of the flexible hinge micro-displacement table. The flexible hinge with a multi-leaf spring series-parallel configuration [
13], designed using the principle of axis drift compensation, has a large rotation range and can be used as a flexible bearing. By uniformly arranging curved, thin, flexible plate units in a plane space with a point as the center, a new type of annular flexible hinge [
14] can be obtained, which can provide a larger rotational stroke. However, the characteristics of flexible hinge structures weaken the structural stiffness and result in lower natural frequencies, making them unsuitable as bottom supports in scenarios with severe vibration loads or high structural stiffness requirements. Kinematic support is designed based on the theory of complete constraints, adapting to thermal loads through rigid body motion instead of deformation. Common forms of kinematic support include the “3-2-1” type [
15] and the “Hexapod” type [
16]. The “3-2-1” support mode refers to the “point-V groove-plane” support mode. The WFC3 module of the Hubble Space Telescope uses this support mode. Through tests such as degree-of-freedom analysis, structural design, mechanical analysis in launch state, and displacement analysis under gravity release in orbit, it was demonstrated that this kinematic support structure meets the design requirements. The “Hexapod” form of kinematic support is generally a three-point support, consisting of six connected support rods, with 12 connection points using spherical hinges. The rotation of the spherical hinges at both ends of the support rods can eliminate the effects of gravity unloading, stress unloading, and thermal deformation after the sensor is launched. This support form is commonly used on space telescope mirrors and can adjust the position in various directions. The main support structure of the German DGT telescope and the secondary mirror of the MMT telescope adopt the “Hexapod” support form. However, currently, kinematic support structures are mostly applied to small-sized remote sensing cameras, and their application in large-sized structures is limited.
This article proposes a floating combination stress release support mechanism that has both the high reliability of rigid support and the high thermal adaptability of flexible support, while satisfying the theory of complete constraint. Through a reasonable layout, especially in large-scale structures of space telescopes, it can achieve stress release goals and meet the mechanical requirements during the launch phase. Considering the multi-dimensional thermal stress release of the large-scale body-mounted radiator of the space telescope and its adaptation to launch mechanical requirements, this article designs the layout of the stress release support mechanism in an “orthogonal + parallel” manner. The layout model is simplified into a four-point model consisting of “one fixed support + two line degree-of-freedom release mechanisms + one plane degree-of-freedom release mechanism” for the purpose of degree-of-freedom analysis. Subsequently, targeted design is carried out for the support mechanism. Finally, the reliability of the stress release mechanism is verified through finite element simulation and testing.