Implementation of “digital twin” technology within the thermo-elastic distortion testing of a precision carbon fiber reflector for the spacecraft antenna subsystem

Mirror antenna subsystems (AS) with the deployable reflectors are important integral parts of the telecommunication spacecraft payloads and provide reception and transmission of the information in a given service area [1-4]. The reflector design shall provide strength and stiffness, specified radiofrequency (RF) characteristics and antenna pattern boresight error of the AS. Performance compliance shall be approved in the frame of ground experimental testing, and thermo-elastic distortion (TED) testing to assess their effect on the antenna pattern boresight error is the part of the ground testing. This testing is hard to carry out because of the following aspects resulting in lack of the guaranteed achieved criteria to assess the test results: - considerable difference of thermal and physics behavior between carbon-fiber-reinforced polymer (CFRP) filler and epoxide component and the steep CFRP anisotropy result in increased variation of the layer strain-stress state and internal stresses which make the design behavior undefined under thermal environment; - it is almost impossible in the frame of the testing to implement and maintain the real map of the thermal fields of specified accuracy on the large-sized object due to the fact that the temperature in a giant thermal chamber is extremely varying; - in the frame of testing it is possible to carry out few optical measurements for the deformed reflector surface points which are not enough to provide the required level of confidence for geometric parameters ‘variation; - the test lasts 50 days and requires cost-intensive chamber exploitation, huge power consumption & operating fluid rate (liquid nitrogen), expensive equipment providing thermal modes. Development and implementation of the cutting-edge “digital twin” technology is the effective method to address TED testing issue. The main idea of the technology is to substitute real object to be tested with digital model verified based their parameter compliance using convergence criteria. The paper presents technology block diagram, convergence criteria and correlation technique of the predicted and measured TED cases. Evaluation data of the deformed reflector effects on AS RF performances are given and demonstrate that performances comply with the specified requirements and qualify successfully the “digital twin” technology under real testing. The “digital twin” was successfully implemented in 2019 year in JSC “RESHETNEV” in the frame of reflector TED testing for RF antenna subsystem with shaped antenna pattern for “Express- AMU7” spacecraft, which was launched and accepted for the flight operation in 2021. This is the first time in the Russian space industry tests using the “digital twin” technology of a domestic reflector for RF space AS with parameters at the imported analogues level have been successfully qualified. The qualification of this technology will ensure the competition of domestic high-tech developments and will solve the problems of import substitution and increase the share of the Russian component in the global space telecommunications market.