Search Results

The Reflection Grating Spectrometer experiment (RGS) on the ESA corner stone X-Ray Multi-Mirror Mission (XMM) uses charge coupled devices (CCD) as detectors. Thermal requirements are the main driver for the layout of the detector housing. Parasitic heat inputs stem primarily from radiative coupling and from conduction over the structural support. Improvements in the design of the electro optical model (EOM) over the bread board model (BBM) resulted in a system that guarantees a CCD temperature of -130 °C at the end of the mission while not precluding the possibility to heat the detectors as high as +130°C which might be useful for annealing the CCDs.

In a thermal vacuum test chamber total hemispherical emissivities for different materials have been determined. Attention was focussed on coatings which have a clear relevance to application on space craft. Conditions during the measurements resembled closely the environment in space. Materials investigated include two black paints, electropolished steel, polished gold and aluminum tape. For gold and aluminum the drastic increase in emissivity as a consequence of contamination of the surfaces by cryodeposited water was quantitatively confirmed. Proton irradiation of black paint did not cause a significant change in emissivity.