To evaluate the reliability of space reusable locking device performing locking separation actions on orbit

aiming at the combined effect of spacecraft rendezvous and docking shock and performance degradation in the space environment

a reliability evaluation model considering interdependent competitive failure was established. Firstly

based on the function

structure and working principle of the device

the reliability characteristics were determined by the main fault modes on orbit. Secondly

considering both extreme and cumulative shock

a performance degradation model under shock was constructed. In view of the characteristics of small sample

high reliability and long life

accelerated degradation test and Bayesian method were implemented to estimate model parameters. Then

a reliability evaluation model was attempted based on the interdependent competitive failure theory of shock and degradation processes. Finally

taking a space reusable locking device as an example

the on-orbit shock simulation test and acceleration performance degradation test of the device were carried out. The model parameters were estimated by integrating the historical test data of similar products according to Bayesian formula

and the reliability function curve of the device was obtained. The result shows that in line with engineering practice

the device can still operate with a high reliability of 0.973 after 25 years on orbit. The proposed method and model proves to be capable of following closely the working conditions

and conducting a comprehensive reliability evaluation on the basis of the test and data available

providing an effective technical approach for mission reliability analysis and a theoretical basis for the design improvement and formulation of use strategy.