Thermal protective materials suitable for use in a spacecraft include a substrate, such as carbon fibers or carbon felt, and cyanate ester resin or phthalonitrile resin, and cross-linkers. These thermal protective materials have a density of about 0.2 to about 0.35 g/cm3. Methods of making the thermal protective materials include mixing a cyanate ester resin or a phthalonitrile resin and a cross-linker to result in a resin solution, infusing the resin solution into a substrate, and curing the resin to result in the thermal protective material.