Tracking the world's weather The first of three MSG spacecraft will be launched late in the year 2000, allowing Europe to maintain its leading role in gathering global weather data until at least the year 2012. Benefiting from Meteosat's pedigree of over 20 years, the MSG satellites represent a significant leap in technological capability and will provide meteorologists with much improved imagery and data. Like their Meteosat predecessors, the first of which was launched by ESA in 1977, the MSG satellites will operate from geostationary orbit. MSG will generate multi-spectral imagery of the Earth's surface and cloud systems at double the rate (every 15 minutes instead of every half an hour) of the current Meteosat, and for a much larger number of spectral channels (twelve compared to three for Meteosat). There will also be vastly improved geometrical resolution (1 km for the high-resolution visible channel and 3 km for the others). Eight of the channels will be in the thermal infrared, providing among other information, permanent data about the temperatures of clouds, land and sea surfaces. Using channels that absorb ozone, water vapour and carbon dioxide, MSG will also allow meteorologists to analyze the characteristics of atmospheric air masses making it possible to reconstruct a three-dimensional view of the atmosphere. The current Meteosat capabilities will be kept.