Session: 13-02-02: Advances in the Mechanics of Architected Materials II

Paper Number: 167126

Lightweight Space Radiators With High Thermal Conductivity and High Stiffness Enabled by Multifunctional Architected Composites 

Lightweight materials with high thermal conductivity and high stiffness are increasingly important in extreme environments, particularly for space applications. For example, spacecraft in orbit experience drastic changes in the radiative environment, transitioning between intense solar irradiation and eclipse. These fluctuations, combined with limited surface area for heat rejection, pose significant thermal management challenges. Small satellites and satellite microsystems, such as CubeSats that are becoming increasingly popular, must be able to mitigate widely varying internal and external heat loads while maintaining structural integrity. As small spacecraft and spacecraft-deployed microsystems evolve to handle more complex functions, there is a need to dissipate larger amounts of heat, requiring effective conduction pathways to deployed radiators – thin and large surface area structures which must also have low thermal resistance. Simultaneously, these deployable radiators need to exhibit sufficient stiffness to manage dynamic loads, mitigate thermal distortions, and avoid mechanical resonances that could lead to structural failure. While in conventional design, thermal and mechanical functions can often be handled separately, for deployable radiators, the limitations on size and weight require a unified approach that simultaneously optimizes for high thermal conductivity, high stiffness, and low mass. Here, we present a modeling approach for creating multifunctional architectures that integrate high thermal conductivity and high stiffness within a single lightweight structure. To design the conductive and stiff radiator core, we explore two-dimensional extrusion-based patterns and three-dimensional structures incorporating an embedded micro heat pipe network. Extrusion-based patterns provide simpler topologies amenable to rapid design iteration, while three-dimensional topologies enable unique anisotropic properties with superior thermal and mechanical performance. We use a coupled finite element model to systematically evaluate the thermomechanical behavior of candidate unit cell architectures. Specifically, we analyze the effective properties of these microarchitected, non-uniform structures through a parametric study of unit cell width, thickness, and the arrangement of heat pipes within the radiator. Next, we explore a range of candidate materials, focusing on space-grade alloys of aluminum, copper, and magnesium. Our results identify optimal design parameters that balance desired thermomechanical properties against the mass of the structure. Key metrics include specific thermal conductivity, specific stiffness, and overall effectiveness in transporting and rejecting heat under dynamic loading conditions. Finally, we discuss approaches for additive manufacturing of these architected structures through direct metal laser sintering. Our results show that merging thermal and structural functions into a single architecture could be beneficial for advanced thermal control in next-generation small satellites and other space systems where mass and volume are tightly constrained. Ultimately, these multifunctional architectures could improve spacecraft reliability and enable enhanced mission performance in harsh orbital and deep-space environments.

Presenting Author: Karl Pederson University of Minnesota, Twin Cities

Presenting Author Biography: Karl Pederson is a graduate student in the Department of Mechanical Engineering at the University of Minnesota, Twin Cities.

Authors:

Karl Pederson University of Minnesota, Twin Cities
Daniel Kindem University of Minnesota, Twin Cities
Hayden Hommes University of Minnesota, Twin Cities
Sam Keller University of Minnesota, Twin Cities
Ognjen Ilic University of Minnesota, Twin Cities