Method for designing and developing space mechanisms with specified dependability

Abstract

Aim. According to the established concept of space launch, practically each of the spacecraft in a near-Earth orbit needs to separate from the launch vehicle and deploy its folded structures (solar panels, antennas, reflectors, rods, etc.) in the operational position and only then is able to become fully functional for its intended purpose. The reliability requirements for single-operation mechanisms are so high, that any unidentified potential threat of critical failure in the course of design, development, manufacture and operation may make the creation of such spacecraft pointless, which is confirmed by the fatal results of the missions of the Sinosat- 2, Ekspress-АМ4, Kanopus-ST, Zuma, Chinasat-18 and many other satellites and space objects. The design of space mechanisms with a specified dependability is complicated by the fact that practically all of them are unique, highly critical systems that are supposed to be as reliable as possible, are unique or rare in terms of their design, are manufactured at most in small series and operate in unique environments. Statistical data on the dependability of components and elements of mechanisms that operate in the open space environment is at best insufficient for obtaining reliable dependability calculation results using the statistical methods of the modern dependability theory, while at worst they do not exist at all. In the context of constantly growing complexity of space technology and increasing costs of any in-orbit failure there is an objective necessity for developing a method for designing space mechanisms based on the evaluation of the specified dependability using the engineering solutions (without involving statistical methods of dependability) and early failure prevention procedures. Methods. The paper presents a method for designing and developing space mechanisms based on the design engineering analysis of dependability. Results. The method proposed in the paper allows modifying the analytical verification toolkit, thus migrating from design and expert methods (e.g., Stage-Gate or FMEA) of product design to purely engineering ones that are based on engineering disciplines and design engineering methods of ensuring quality and dependability. The use of design engineering analysis of dependability as part of the design and development enables dependability assurance as a natural and integral part of a designer’s work that enables engineering decision-making in accordance with the specified dependability requirements (rather than in an isolated manner).