This paper describes a VO2-based smart structure with an emittance that increases with the temperature. A large tunability of the spectral emittance, which can be as high as 0.90, was achieved. The transition of the total emittance with the temperature was fully reversible according to a hysteresis cycle, with a transition temperature of 66.5 degrees C. The total emittance of the device was found to be 0.22 and 0.71 at 25 degrees C and 100 degrees C, respectively. This emittance performance and the structure simplicity are promising for the next generation of energy-efficient cost-effective passive thermal control systems of spacecrafts. (C) 2013 American Institute of Physics. [http://dx.doi.org/10.1063/1.4792277]