A planetary outpost flexible heat pipe heat rejection radiator was designed to reject 25 kW of waste heat. To confirm its performance, a representative segment of this radiator was constructed. The segment was delivered to NASA JSC for future thermal vacuum chamber testing. The innovative portion of this radiator is the heat pipe envelope material; it is a polymer/metal laminate that is lightweight, flexible, heat sealable, vacuum tight, and resistant to UV radiation.The radiator segment consisted of eighty-four (84) vertically oriented, reflux boiling type heat pipes with water as the working fluid. Each heat pipe was 1.9 cm in diameter and 100 cm long. The condenser portion of the heat pipe was constructed from the laminate material; the evaporator portion was 8 cm long and constructed from copper. Integrated into the evaporator was a flow-through porous media heat exchanger that permitted direct circulation of the lunar outpost cooling fluid.