A comparison of infrared-emittance measurements and measurement techniques.

Values of directional and hemispherical emittance of twelve coatings were needed in support of a spacecraft experiment. Laboratory measurements were made by two calorimetric and four reflectance techniques and with two portable devices designed for field or laboratory operation. The measurement results are compared, primarily on the basis of hemispherical emittance values deduced from each; and the limitations and uncertainties of each technique are summarized.