(Sen) - Europe's latest satellite to watch world weather blasted off into space last night atop an Ariane 5 rocket from Kourou, French Guiana.

Meteosat Second Generation-3 will gaze down from geostationary orbit, 36,000 km above the equator, to detect and help forecast highly disruptive weather such as fog and thunderstorms up to six hours in advance.

I was at mission control at Darmstadt, near Frankfurt, Germany, for Sen last night to witness jubilant scenes as the launch was relayed live from South America. There was wild applause as MSG-3 successfully separated and went into orbit just over half an hour later.

MSG-3 is the third in a series of four satellites whose job is to beam back highly detailed images of Europe, the North Atlantic and Africa every 15 minutes for use by meteorologists and national weather forecasters.

It was developed by the European Space Agency (ESA) in close cooperation with Eumetsat, the European Organisation for the Exploitation of Meteorological Satellites.

Just 34 minutes after lift-off, ESA's mission controllers at its European Space Operations Centre (ESOC) began helping the satellite through the critical early stages of its life.

Over around ten days, during what is called the launch and early orbit phase (LEOP), they will work to ensure that the 2,000 kg satellite's reaches geostationary orbit smoothly following separation from the Ariane 5. Then Eumetsat will take over and manage MSG-3 as it begins its routine observations.

Chris Watson, MSG-3 Spacecraft Operations Manager for ESA, said: "We have two main tasks during the 10-day LEOP. The first is to command a series of four engine burns to circularise its orbit into the final geostationary orbit.

"The second is to activate the instrument, release its covers and conduct decontamination, to ensure that no moisture nor any other contaminants remains on the instrument's critical surfaces (like the optics).

"We'll staff the Main Control Room 24 hours per day, so it will be a very intensive time."

An Arianespace video of the launch of Ariane 5 carrying MSG-3

The MSG satellites are all built by a European consortium led by Thales Alenia. The main instrument on board each of them is the Spinning Enhanced Visible and Infrared Imager (SEVIRI) which can continuously monitor cloud properties, atmospheric instability, storms, winds, rain and falling snow, aerosols and incoming solar radiation.

Its also observes snow and vegetation cover, surface albedo, volcanic ash, dust, land and sea surface temperature, and even fires.

Also on board MSG-3 is the Geostationary Earth Radiation Budget (GERB) instrument, developed by a European consortium led by the UK's Rutherford Appleton Laboratory (RAL) which is used to monitor reflected sunlight and thermal emissions from Earth.

Engineers make final checks to MSG-3 in the cleanroom. Credits: ESA/CNES/Arianespace

MSG-3 is needed now to ensure continuity of service because one of the existing first-generation spacecraft, Meteosat-8, is already well over its scheduled lifetime.

Leading mission control activities at ESOC's Darmstadt centre is British-born Nic Mardle, Deputy Flight Operations Director. She said simulations, or practice runs, had been carried out twice a week throughout the year.

Before lift-off, Nic told Sen: "After the launch we monitor the ascent, then we have a nervous few mintes before we get a signal from our ground station at Malindi in Kenya. Then the cover is ejected, the satellite is released and our work begins in earnest."

Nic added: "There's never such a thing as a routine launch. We prepare for the worst and hope for the best."

Ariane 5 was carrying a double payload. The other satellite, which was first to be released, was a commercial telecoms satellite, Echostar 17, built by Hughes Network Systems in the US.