Electrochromic devices were investigated as a means of efficiently modulati
ng the IR emissivity of space structures. The optical properties of electro
chromic materials are modified upon application of a voltage allowing a hig
h degree of control of the modulation. This degree of control is necessary
for some low earth orbit space missions where effects such as rapid changes
in the earth's albedo can change the temperature of a satellite. Optical c
onstants of semicrystalline WO3 and NiO in their unintercalated and fully i
ntercalated states were measured by variable angle spectroscopic ellipsomet
ry over a spectral range of 2-14 mu m. Ta2O5 optical constants were measure
d for use as a hydrogen ion conductor and Au and ITO optical constants were
measured for use as electrodes. Calculations were made of the emissivity m
odulation of an electrochromic device structure for a 300 K blackbody based
on the measured optical constants. (C) 1999 Elsevier Science S.A. All righ
ts reserved.