Abstract: A measurement method is presented for the determination of low levels of optical absorption in any material, with at least a quasi-simultaneous detection of the transmission intensities of a measurement light beam and a reference light beam, the wavelengths of which are different, such that, essentially, the measurement light is absorbed by the material to be tested, and with a joint analog acquisition of the detected measurement and reference signals, taking into consideration the natural difference in intensities between the measurement light beam and the reference light beam.

Abstract: A satellite adapted to be spin-stabilized in geostationary orbit having, coaxial with a spin rotation axis, a satellite surrounded with a solar generator. At least two equipments including an apogee maneuver system are disposed along the rotation axis. A set of generally annular antennas including at least one picture transmission antenna is disposed on one of the NORTH and SOUTH faces of the satellite so as to leave at its center a cylindrical space along the spin rotation axis to house one of the equipments. The other of the equipments is disposed on the other of the NORTH and SOUTH faces.

Abstract: A satellite adapted to be stabilized in terrestrial orbit by rotation about an axis oriented at least approximately NORTH-SOUTH has on its external wall a solar generator composed of a plurality of columns of solar cells divided into groups adapted to supply at least one given electrical voltage. In each of a plurality of groups equi-angularly distributed in the circumferential direction, the cells straddle two columns electrically connected by at least two electrical connections forming with the group(s) to which the connection belong an electrical loop. The clockwise or counterclockwise direction of current flow is the same for least the majority of the electrical loops and is so chosen that, at any time, the loops which are illuminated at this time by the Sun, by virtue of interaction with the terrestrial magnetic field, produce a compensating torque in the opposite direction to the solar radiation pressure torque.

Abstract: A satellite comprising a deployable solar generator that can be oriented relative to the satellite body is kept facing the sun at all times. It includes an attitude stabilization device comprising a superconductive material closed loop carried by a support coupled to the solar generator and disposed on a side of the support facing substantailly away from the sun. A secondary loop parallel to the closed loop is substantially the same shape and size as the closed loop, and is carried by the support near the loop. A resistive circuit is carried by the support near at least part of the closed loop. A selective electrical power supply circuit is connected electrically to the secondary loop and to the resistive circuit.