The General Electric (GE) Co., Thermal Systems Programs, in Tacoma, Wash., has developed a medium-density rigid structural polyurethane foam insulation material to withstand thermal stresses imposed by temperatures down to absolute zero 0 K (−460°F). Structural test results according to ASTM standards are presented for tensile, compressive, and shear strength and moduli. Other structural properties presented are Poisson's ratio and creep characteristics. Thermal test results according to ASTM standards are presented for thermal conductivity and expansion/contraction. Foam thermal/structural performance at cryogenic temperatures as low as LN2 (liquid nitrogen) and LH2 (liquid hydrogen) conditions, 77 K (−320°F) and 22 K (−420°F), respectively, are also related. Applications for liquefied natural gas (LNG) ships and LH2 fueled subsonic transport aircraft are discussed. In part, a lot of technical information presented herein was used to obtain conceptual approval complete from the U.S. Coast Guard for the insulation of LNG ships utilizing GE cryogenic polyurethane foam.