Two atmospheric missions on one satellite

But before they do, members of the media were today invited to visit the cleanroom at OHB Headquarters in Bremen, Germany, for a final look at the instruments on their satellite.

The MTG-Sounder (MTG-S) satellite will provide improved data for weather forecasting and storm detection, while Sentinel-4 will monitor air quality over Europe.

Both MTG-S and Copernicus Sentinel-4 are world-class Earth Observation missions developed with European partners to address scientific and societal challenges, such as air pollution and extreme weather events.

According to Simonetta Cheli, Director of ESA’s Earth Observation Programmes, “These missions, which will launch together as one satellite, are the culmination of more than a decade of European partnership and dedication. They really underline the strength of Europe’s cooperation, involving thousands of people and more than 120 companies. ESA has played a central role in supporting these missions to improve data on air quality and weather systems, for the benefit of society.”

A guarantee for weather forecasting

The MTG mission already has one satellite in orbit – the MTG-Imager (MTG-I) – so MTG-S will be the second MTG satellite to be launched. Its Infrared Sounder uses interferometric techniques to capture data on temperature, humidity, wind and trace gases that are used to generate 3D maps of the atmosphere, improving the accuracy of MTG’s weather prediction.

The Infrared Sounder will be the first hyperspectral sounding instrument placed in geostationary orbit by a European-led mission. It will be positioned about 36 000 km above the equator and will maintain its position relative to Earth, following the same area on the planet’s surface as we rotate. It will provide coverage of Europe and part of northern Africa on a repeat cycle of 15 minutes, providing meteorologists with a complete weather picture of the region, complementing data on cloud formation and lightning from MTG-I.

Another imaging satellite will subsequently be launched to complete the first set of three MTG satellites. These will eventually be replaced by three more identical satellites (two more imagers and another sounder), to guarantee the continuity of data for weather forecasting from geostationary orbit for the next two decades. When all three MTG satellites are operational, the mission is expected to produce at least 50 times more data than its predecessor, the Meteosat Second Generation mission.

ESA’s MTG Project Manager, James Champion, said: “After years of developing the MTG-S satellite and following its lengthy build and test activities, including the integration of the Sentinel-4 instrument, it’s fantastic to see the first Sounder satellite finally ready for launch. This is yet another milestone on our way to having the second of the MTG trio of satellites in orbit. I’m thankful for all the hard work carried out by all the teams involved throughout Europe and we can’t wait for this new satellite with its ground-breaking Infra-Red Sounder instrument to start delivering data to improve weather forecasting for fast-developing storms over Europe.”

The air we breathe

The MTG-S satellite hosts the Copernicus Sentinel-4 mission by carrying the ultraviolet, visible, near-infrared light (UVN) spectrometer that captures data every hour to monitor air quality and pollution over Europe and North Africa.

The spectrometer delivers high-resolution data on gases that affect the quality of the air we breathe, including a wide range of atmospheric trace gases and pollutants such as nitrogen dioxide, ozone, sulphur dioxide and formaldehyde.

Thanks to its fixed position in geostationary orbit on board MTG-S, Sentinel-4 will be able to deliver data every 60 minutes during daylight to support the Copernicus Atmosphere Monitoring Service for rapid forecasting. The mission will complement the Sentinel-5 and Sentinel-5P missions, which provide daily observations of the Earth from their polar orbits.

Sentinel-4 is the European contribution to the global constellation of Geostationary Air Quality sensors. It will work alongside the Korean sensor Gems, observing air pollution over Asia, and NASA sensor Tempo, measuring air pollution over North America.

ESA’s Project Manager for the Sentinel-4 mission, Giorgio Bagnasco, said: “The teams at ESA and our industry partners have pooled their knowledge and experience to make this game-changer mission. Its final objective has motivated us thorughout these 11 years: providing data for air quality forecasts, health warnings and developing mitigation policies and strategies. It has been a pleasure working on Sentinel-4 to improve data on air quality all over Europe and northern Africa.”

Thales Alenia Space was the prime contractor for the overall MTG mission, with OHB Systems responsible for the MTG-Sounder. The prime contractor for Sentinel-4 is Airbus Defence and Space. Mission control and data distribution for both MTG-S and Sentinel-4 will be managed by Eumetsat.