Planetary Emissivity Laboratory (PEL) measurements of directional emissivity

Kurzfassung

At PEL we set-up an experiment to measure the emissivity of two fine powdered (<25 µm) asteroid analogues: meteorite Millbillillie and a synthetic enstatite. Samples measured at surface temperature of 373K, with emerging angle (e) from 0° to 60°, with 5° or 10° step intervals. Two different FTIR Spectrometers used for emissivity measurements under purged air and under vacuum. Custom-designed wedges have been manufactured to tilt the samples at different emission angles. Samples had to be prepared to prevent powder to slipper from the sample cups (always happening for e>30°). Reflectance spectra of the samples was measured for comparison