Thermoplastic elastomeric ablative insulation having good mechanical properties at extremely low temperatures are disclosed. The insulation is based upon a polyamide-ether resin and includes carefully selected fillers to possess good low temperature mechanical properties and still provide suitable charring and ablative insulation performance at low temperatures (-65.degree. F.). A typical insulation within the scope of the present invention includes a polyamide-ether thermoplastic elastomeric polymer resin, an inorganic phosphorus containing compound, such as ammonium polyphosphate, present in the insulation from about 5 to about 60 phr, and a polyhydric alcohol present, such as pentaerythritol, in the insulation from about 1 to about 30 phr. The insulation compositions within the scope of the present invention optionally include silicone resin present in the insulation in range from about 0 to 15 phr. Chopped fiber filler may also be present in the insulation in range from about 0 to 100 phr.