Demisability and survivability multi-objective optimisation for preliminary spacecraft design

In a period where the evolution of the space environment is causing increasing concerns for the future of space exploitation and sustainability, the design-for-demise philosophy has gained an increased interest. However, building a spacecraft such that most of it will demise through design-for-demise strategies may lead to designs that are more vulnerable to space debris impacts, thus compromising the reliability of the mission. Demisable designs will tend to favour lighter materials, thinner structures, and more exposed components, whereas survivability oriented designs will favour denser materials, thicker structures, and more protected components. Given the competing nature of the demisability and the survivability, we developed a multi-objective optimisation framework to evaluate the effect of preliminary design choices on the survivability and demisability of spacecraft components since the early stages of the mission design. The framework relies on a demisability and a survivability model, whose output is used to compute the fitness functions of the multi-objective optimisation. The paper presents the latest development of the survivability model, including a novel methodology to compute the vulnerability of spacecraft components. In addition, a representative test case of tank assemblies of Earth observation and remote sensing missions is studied with the multiobjective optimisation framework.