Traditionally, NASA has relied primarily on pumped, single-phase liquid systems to collect, transport, and reject heat via single-phase radiators. The heat-rejection system used on the space shuttle orbiters consists of over 250 small, one-dimensional tubes embedded within a honeycomb structure. Heat is transferred by convection to the tube walls, conduction through the honey-comb structure, and finally, through radiation to space. NASA is currently developing nuclear electric propulsion engines to power next generation spacecrafts to transit to Mars and beyond, and these spacecrafts need heat rejection systems with performance capabilities significantly better than those provided by current systems.

The origins of a heat pipe go back over 60 years, but there is still room for new ideas to grow. Traditional heat pipe consists of an open adiabatic zone, with a mesh wick lining the inside of the tube wall to aid in transportation of condensed liquid from the condenser side to the evaporator side. A biomimetic, multi-function concept developed at New Mexico Tech (NMT) has an architecture consisting of interconnected pores graded radially as well as longitudinally can be implemented for heat pipe to allow heated fluid to flow radially as well as longitudinally. This configuration promotes fast convection of the heat from evaporator end to the tube walls and dissipates heat more evenly throughout the radiator lateral surface.

Past experiments done at NMT using samples with biomimetic design demonstrated that upon localized heating, there can be an induced convective transport of thermal energy as fluid passes through a closed-loop porous layer. The goal of on-going investigation is to highlight how biomimetic architecture may provide the required thermal performance simultaneously reducing heat rejection system mass.