On-Orbit Maintainability Considerations for Artemis

Designing for maintainability of critical systems that support sustained and continuous crewed missions has proven essential throughout the life of the International Space Station. The ability to quickly replace a subsystem or component experiencing a failure, off-nominal condition or routine maintenance mitigates the chances of a loss of mission or vehicle. Space flight hardware designed specifically for crew interaction carries with it significant design complexity due to rigorous requirements, but this initial investment is far outweighed by the benefits to the mission overall. With the advent of low-cost flights to low Earth orbit in recent years, the launch cost for subsystem orbital replacement units (ORUs) is reviewed in this paper in the context of hardware supplied by Collins Aerospace. As the space industry has shifted focus to supporting the early stages of Artemis, provisions are already in place for on-orbit maintainability for the Lunar Gateway architecture for future mission stages that involve sustained crew presence. This paper reviews the serviceability approach for the active thermal control and heat transport system (ATCHTS) supplied by Collins Aerospace for the habitat and logistics outpost (HALO). The details on low-mass, component level ORU design is reviewed and compared against legacy approaches. Estimated lunar resupply launch costs and are also studied, with the basis of estimate being limited to the thermal control system hardware.