Abstract: A reflector antenna is constructed for operation in at least two frequency ranges. For this purpose the concave surface of the antenna reflector body, which preferably has a paraboloid configuration, is provided with surface zones arranged in regular arrays or patterns. These surface zones provide antenna or reflector elements which are reflecting or transparent with regard to a particular frequency range or band width, while other surface zones of the antenna reflector surface are transparent or reflecting in another given frequency range or band widths. Thus, depending on the configurations and dimensions of these different surface zones one and the same antenna is capable of handling frequencies in a plurality of different band widths and different apertures.

Abstract: A star sensor arrangement for a satellite which on its orbit and/or during transfer into the orbit rotates at least with a part about an axis of rotation fixed with respect to the satellite, and which is equipped with a star sensor looking in the direction of the axis of rotation and likewise rotating about the axis of rotation, having a co-rotating mirror arranged in the viewing direction of the star sensor which is set obliquely with respect to said direction.

Abstract: A geostationary sun oriented communications satellite has an operational module with a payload platform rotating at one r.p. day. The antenna components are mounted on the platform. The antenna components are so oriented relative to each other and to the platform that an efficient folding and unfolding is possible without any complicated mechanism.

Abstract: The attitude of a satellite in an earth orbit is determined by a measuring arrangement which includes the body (1) of the satellite oriented with regard to the sun and a functional component (2) rotationally connected to the satellite body (1). The functional component 2, such as a turntable, carries functional elements, for example, antennas, which are directed or oriented toward the earth. During an earth orbit of the satellite, the turntable (2) carries out one full revolution in the direction of the earth orbit about a rotation axis (3) perpendicular to the orbit plane. A first star sensor (4) is arranged to sight in a direction along the rotation axis (3). In order to achieve a high attitude accuracy in the orientation of the turntable (2), the first star sensor (4) is mounted on the turntable(2) and at least one second star sensor (5) is also mounted on the turntable but with a sight direction (6) deviating from the direction of the rotation axis (3).