With the maturity of optical fiber signal rotational transmission technology, optical fiber slip ring (FORJ) has also become an option for the design of rotational transmission inside satellites. FORJ, also known as smooth ring, optical fiber rotary connector and optical fiber rotary connector, is mainly divided into active FORJ and passive FORJ, among which passive FORJ can be refined into single-channel FORJ and multi-channel FORJ according to the number of channels. At present, passive multi-channel FORJ is widely used in many fields, such as radar, photoelectric pod, photoelectric mast, photoelectric theodolite, sonar and tethered balloon, etc. However, there are relatively few reports about its application in the field of inter-system communication within satellites.
Design considerations for passive multi-channel spaceborne FORJ
Reliability and life：With the increase in the type and number of signals, as well as the increase in bandwidth and speed, the advantages of multi-channel FORJ are fully demonstrated. As a key intermediate hub for signal transmission, FORJ has strict requirements for its reliability and working life. Therefore, when selecting FORJ, priority should be given to mature and reliable designs and to ensure that they have been adequately verified for reliability.
Vacuum environment：In high vacuum environments, the main concerns are the abnormal expansion effect caused by pressure differences, the risk of volatilization contamination, and the rational choice of heat dissipation and lubrication methods. In the design of the internal structure, it is necessary to consider the feasibility of non-airtight enclosed chambers or the maintenance ability of the environment, and to implement degassing treatment for processes involving the use of glue. For the materials and adhesives used, it is necessary to analyze their volatilization characteristics and design anti-spill structures, and then carry out volatilization related tests to verify their applicability. In view of the fact that the heat dissipation conditions in a vacuum environment are very different from those in a ground environment, the corresponding tests should be designed and validated in accordance with the mode of use, the characteristics of the environment and the heat and heat dissipation performance of the FORJ itself. For the parts that need lubrication inside FORJ, the most suitable lubrication method should be carefully selected according to the performance index, service life and related sensitivity factors.
The effect of the Earth's gravity：When working on the ground, the abrasive dust generated by the rotation and wear of the mechanical equipment will naturally fall off under the action of gravity or accumulate on the surface. However, in the weightless conditions of the space environment, these chips will be suspended in the internal space of the equipment. Therefore, it is necessary to conduct a comprehensive analysis of the grinding debris that may occur in the rotation process and its potential impact, and take effective control and preventive measures against the possible adverse effects.