N° 7–1994: Meteosat 6 experiences anomaly

Successfully launched on 20 November 1993 on board an Ariane launcher, ESA's meteorological satellite Meteosat 6 is experiencing an anomaly in the functioning of the radiometer that affects the spacecraft's full operational capabilities.

Meteosat takes images of the Earth in three spectral channels, one visible and two infrared. The visible channel works correctly and delivers perfect images but the intensity of the signal of the two infrared channels is not stable. Much important meteorological information derived from Meteosat data - such as sea surface temperatures and distribution of cloud-top heights for instance - is based on infrared images, thus the accuracy of this information suffers from the anomaly.

The anomaly was discovered in December (see ESA Press Release nr. 52-93) during quality checks of the infrared images. A Task Force consisting of ESA and industrial members was established with the aim to analyse the problem. The origin of the anomaly appears to lie in the radiometer, an instrument which is part of the "telescope" that constitutes the "eye" of the spacecraft.

To review the findings of the Task Force and to recommend further action, as of 1 March 1994, the Directors General of ESA and EUMETSAT have set up an Enquiry Board with the following mandate:

 

• - identify the most likely cause of the anomaly and recommend actions to overcome the problem;
• - recommend measures to be taken for correcting the observed anomaly for following spacecraft of the same kind.

The Enquiry Board will present their first conclusions to ESA and EUMETSAT towards the end of March 1994.