Arches are structural forms that have been used for thousands of years and rely on gravity for their inherent stability. Currently, given the space race for lunar and martian exploration, it has become apparent that soon enough, there will be a need to design and build the first resilient shielding structures on the Moon and Mars against extreme radiation. Arches represent an ideal option for such structures given that they are durable and can be easily built. This paper is based on previous work of the authors and focuses on the stability of circular and parabolic arches with different embrace angles subjected to different levels of equivalent inertial loading in low-gravity conditions. More specifically, it reveals that although parabolic arches can be much more efficient than the corresponding circular for gravitational-only loading, this is not the case for different combinations of inertial loading and embrace angles where the opposite can be true. It highlights the dominant effect of low-gravity conditions on the minimum thickness requirements for both types of arches and considers the effect of a potential additional infill for radiation shielding. Furthermore, this study reveals a self-similar behavior and introduces a “universal” inertial loading.