Spacecraft operate in harsh environments with temperatures changes in the tens to hundreds of degrees centigrade. The delicate electrical components, therefore, require protection against these conditions. Currently, specially-designed thermal regulators allow spacecraft to maintain their internal temperature, but the heat transfer rate and mission flexibility are low. The state-of-the-art technology uses moving parts and chemical phase changes. Recent discoveries in the field of thermoelectrics propose the viability of thermoelectric modules as a solid-state thermal switch, benefiting from its low maintenance requirements and light weight. Within this work, we explore the comparatively desirable designs of thermoelectric modules in contrast to current thermal regulators. Using theoretical heat modeling and ANSYS simulation software, different models compete to fulfill strict operation criteria defined by the National Aeronautics and Space Administration (NASA). We then compare the limitations of employing different high-performance thermoelectric materials for the device to address NASA’s requirements. With a successful design, thermoelectric modules reduce cost and increase mission flexibility, keeping future exploration vehicles safe throughout their journey.