  Mirror thermal noise is and will remain one of the main limitations to the
sensitivity of gravitational wave detectors based on laser interferometers. We
report about projected mirror thermal noise due to losses in the mirror
coatings and substrates. The evaluation includes all kind of thermal noises
presently known. Several of the envisaged substrate and coating materials are
considered. The results for mirrors operated at room temperature and at
cryogenic temperature are reported.
