Purpose of the flight and payload description
The AGLAE program was born in the fall of 1974 to measure the far-infrared emission of cold matter in our galaxy, the existence of which had been predicted by Guy Serra from the gamma-ray data of the European satellite COSB. It was a development of the Centre d'Etude Spatiale des Rayonnements (CESR) with the collaboration of the Observatory of Paris, Meudon and the Centre d'Etudes Nucleaires (CEN), Saclay.
The optics of the instrument was composed of two identical systems (two wavelength channels) defined by reststrahlen filters connected to two identical Cassegrain telescopes with a focal length of 77 cm and whose spherical primary mirror, gilded, has a diameter of 14 cm. Both telescopes were parallel and pointed at a fixed elevation of 20º. In each channel, reflection filters defined the wavelength bandwidth with the nominal values of 114-196 microns and 71-95 microns. Behind the filters, a spherical mirror focused the IR beam onto gallium-doped germanium bolometers. All these elements were located on the cold plate of a cryostat cooled using liquid-helium. The signals from the bolometers along with data relating to the attitude of the gondola after amplification were transmitted to the ground, using analog telemetry at a rate of 5 kbit/s.
The gondola was azimuth stabilized and the rotation of the Earth was used to scan the sky with the instrument at constant elevation. A remote control allowed to change the azimuth angle aiming during the flight while the attitude of the gondola with respect to the local vertical was continuously monitored.
AGLAE was the precursor of another instrument denominated AROME developed also by the same scientific group in late 1980's.
Details of the balloon flight
Balloon launched on: 9/23/1976
Launch site: Centre de Lancement de Ballons CLBA, Aire Sur L'Adour, Landes, France
Balloon launched by: Centre National d'Etudes Spatiales (CNES)
Balloon manufacturer/size/composition: Zero Pressure Balloon
End of flight (L for landing time, W for last contact, otherwise termination time): 9/23/1976
This flight, the first for the instrument demonstrated the existence of a diffuse FIR emission of the interstellar medium, at a level consistent with the value predicted on the basis of phenomenological considerations made by Ryter and Puget (1976).
- Far infrared diffuse emission from the galactic plane. II - The longitude profile Astronomy and Astrophysics, vol. 76, no. 3, July 1979, p. 259-261
- The far-infrared emission of interstellar matter between galactic longitudes L equals 36 deg and L equals 55 deg Astrophysical Journal, Part 2 - Letters to the Editor, vol. 222, May 15, 1978, p. L21-L25
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