3 identical satellites were built for a total of EUR 2

12 instruments, 4 tons, EUR 800 million. The observation of the Earth from space is not given to everyone. With the weather satellite Metop program, the Eumetsat European organization offers the ultimate in discipline: the observation of the world continuously from a low Earth orbit. End of June, the first vehicle of this new generation must be launched from the Baikonur space centre in the Kazakhstan. Fly travelling in a polar orbit to 820 kilometers, it over continents and oceans at a revolution around the globe every 101 minutes in the North-South direction. All dressed in its thermal protections yellow metallic, this gear of 6.3 metres high suffered last checks in a white room of EADS Astrium in Toulouse. "This new generation will allow us to make the weather predictions for 2 to 5 days", provides Marc Cohen, responsible for the program at the European Organization.

The goal may seem modest, but it reflects the complexity of climate phenomena. It first to collect a massive amount of data on the atmosphere, cloud cover, wind, temperature, air humidity levels, the State of the oceans. Then, it must integrate these variables into predictive computer models. The combination of the two leads to the weather that everyone discovers the evening on television.

3 identical satellites were built for a total of EUR 2.4 billion. They will be launched at intervals of about five years, theoretical life of each spacecraft in orbit. "Continuity is a very important factor in this business." "With the Metop program, the service is provided at least until 2020," continues Marc Cohen. "It is a major investment for Europe in a project of extreme complexity." "It is both a weather and technological challenge," adds Peter Edwards, responsible for the project to the European Space Agency. The ESA funded program at height of 550 million euros, against 1.85 billion euros paid by Eumetsat.

This new generation of space observer includes several new features designed to improve the climate observation: speed and direction of winds at the surface of the oceans, temperature and humidity of the air of atmospheric layer, the layer of ozone profile, traces of SO2, movement of polar ice, methane detection, tectonic plates... A special detector operating in the infrared (IASI) will closely watch the physicochemical characteristics of the atmosphere with a specific goal: predict evolution and trajectory of the cyclones.

Measure the light

The satellite is also equipped with a clever atmospheric sounding. It uses the US GPS network (free) signal. Passing through the atmosphere, these signals are disturbed. This distortion analysis provides an indication of the atmospheric composition on the height of the atmosphere. The fact Ascat instrument he also appeal to a novel technique: it measures the retro light diffused by the oceans. "It's as if it measured the roughness of the surface of the seas", said Marc Cohen. From this parameter, it is possible to characterize the system of winds in a few kilometres. Software retrieves the speed and direction of the wind with a precision of the order of the metre - second (for speed) and 10 degrees (for direction). A service that will make dream all browsers overlapping fortieths, extreme latitudes forties and Golden screaming, where the wind systems remain unknown. In total, 50 industrial from 12 European countries cooperated to produce a jewel which cost 200,000 euros per kilogram. The first of the series should leave the kazakh ground on 30 June.