Putting the S in the first Meteosat Third Generation Sounder
Following on from the launch of the first Meteosat Third Generation weather satellite, MTG-I1, last December, the focus is now on getting its partner satellite, MTG-S1, ready for liftoff next year – and a significant milestone has been reached. The satellite has been equipped with its main instrument, the Infrared Sounder, hence the satellite’s name, and also the Copernicus Sentinel-4 instrument, an ultraviolet, visible, near-infrared light spectrometer, or UVN for short.
Working alongside its MTG-I1 partner satellite, which carries an advanced imager (the Flexible Combined Imager), the MTG-S1 satellite will not only be used to further improve atmospheric observations for weather forecasting, but thanks to the Sentinel-4 UVN instrument, it will also deliver information every hour to monitor air quality and pollution over Europe.
Having spent a lot of time preparing for the delicate task of mounting the two huge instruments onto the satellite platform, engineers at OHB in Germany needed to work with extreme precision since the infrared sounder instrument and the Sentinel-4 spectrometer have to sit just 50 mm apart.
The infrared sounder instrument alone measures 1.7 x 1.9 x 2.0 m and weighs over 450 kg, while Sentinel-4 is 1.1 x 1.4 x 1.6 m and weighs around 200 kg.
To safeguard these huge but sensitive instruments and the satellite platform, the engineers first carried out a complete rehearsal of the integration using structural models of the respective instruments.
This allowed the teams to do a dry run, iterate and improve the procedures, which resulted in a very smooth integration with the real instruments.
ESA’s Christoph Goetz, who oversees the assembly, integration and testing for MTG-S, said, “Whilst this is a major step towards the completion of the satellite, the MTG-S1 satellite is not yet fully assembled as we still need to mount the solar array wings and several other smaller units.
“That said, it is the first time we can enjoy the full dimensions of this impressive satellite, standing more than five meters tall and weighing nearly two tonnes. When the satellite is fuelled for its life in geostationary orbit, it will weigh more than 3.8 tonnes.
“Both the industrial consortium and the ESA MTG and Sentinel-4 teams are very proud of what has been achieved.”
ESA’s MTG Engineering, Assembly, Integration and Testing Manager, James Champion, added, “The integration of these two instruments marks an important milestone as we now move on to focus on the satellite as a whole. We look forward to working with the various teams over the coming year to ready MTG-S1 for launch.”
Over the next 12 months, the full satellite will be put through a complete set of functional and environmental tests to ensure that following liftoff and its journey geostationary orbit, 36 000 km above the equator, MTG-S1 will perform as faultlessly as is the case today for MTG-I1.
“It is very pleasing to see this significant milestone accomplished and I congratulate all teams involved. This is not only important for the MTG and Sentinel-4 teams, but it also marks a significant step towards the completion of the MTG constellation and releasing its revolutionary capabilities to significantly enhance future weather forecasting and, in particular, early predictions of severe weather events,” highlighted Paul Blythe, ESA’s Meteosat Programme Manager.
“Once in orbit, this MTG-S1 satellite will bring a radically new ability to provide three dimensional images of Earth’s atmosphere, with the potential to pick up localised atmospheric instabilities that could indicate the development of major storms much earlier than the current MSG system can provide.”
Giorgio Bagnasco, ESA’s Project Manager for the Sentinel-4 mission, added, “We are thrilled to see the Sentinel-4’s UVN spectrometer now safely fitted to the MTG-S1 satellite.
“In conjunction with the MTG Infrared Sounder, it will provide measurements of pollutant gases, such as nitrogen dioxide, sulphur dioxide and formaldehyde, affecting the atmosphere over Europe.
“Remarkably, these measurements will be of unprecedented accuracy, and they will be delivered hourly – serving the needs of the European Union’s Copernicus Atmosphere Monitoring Service.”
The MTG mission is a cooperation between Eumetsat and ESA. ESA is responsible developing and procuring the MTG satellites. The full MTG system is based on a series of two types of satellite: four MTG-Imagers and two MTG-Sounders. Eumetsat defines the system requirements, develops the ground systems, procures the launch services, operates the satellites and makes the data available to users.
The MTG-Sounder satellites carry the Copernicus Sentinel-4 mission's UVN instrument.
