Tunable variable emissivity materials, methods for fabricating tunable
variable emissivity materials, and methods for controlling the
temperature of a spacecraft using tunable variable emissivity materials
have been provided. In an exemplary embodiment, a variable emissivity
material has the formula M1.sub.(1-(x+y))M2.sub.xM3.sub.yMnO.sub.3,
wherein M1 comprises lanthanum, praseodymium, scandium, yttrium,
neodymium or samarium, M2 comprises an alkali earth metal, M3 comprises
an alkali earth metal that is not M2, and x, y, and (x+y) are less than
1. The material has a critical temperature (T.sub.c) in the range of
about 270 to about 320K and a transition width is less than about 30K.