Second MTG-Imager satellite passes thermal vacuum test

There is no rest for the teams working on the MTG programme, which will provide data for weather forecasting from geostationary orbit for the next two decades. With two satellites now in orbit, eyes are already moving to the next of the satellites due to launch: MTG-I2, which will complete the first family of MTG satellites.

At the cleanroom in France, the satellite’s two instruments – the Lightning Imager and the Flexible Combined Imager – were successfully mounted on the satellite platform. The satellite then underwent a thermal vacuum test, which it passed with flying colours. This test ensures the satellite can operate perfectly even in the extreme temperatures of space, which, for satellites flying in a geostationary orbit, can range between -180 ºC to +150 ºC, depending on whether the satellite is in direct sunlight or in Earth’s shadow.

Francesco Cainero, Lead Space Segment engineer and responsible within ESA for safeguarding the assembly, integration and testing of MTG-I2, said, “These huge temperature variations pose difficulties and risks at both hot and cold plateaus during the testing of the survival thermal control; additionally, before reaching the extreme cold testing phase, there was the risk of corona discharge impacting the radio frequency equipment – but thanks to the expertise of all involved this risk was easily mitigated.”

The milestone was comfortably reached thanks to close cooperation between the teams at ESA, Thales Alenia Space, Eumetsat and Leonardo. The teams were able to build upon experience during the thermal vacuum test campaign for the first MTG-Imager, which allowed this thermal test to be shortened as there was no need for demanding qualification testing this time.

When MTG-I2 launches next year, it will join two MTG satellites already in orbit:

• The first MTG-Imager, MTG-I1, was launched in December 2022.
• And the second satellite in the series, the MTG-Sounder (MTG-S1) was launched in July this year and is still in its commissioning phase.

James Champion, ESA’s MTG Project Manager, said “We’re really pleased with progress on the MTG-I2 so far. Our industrial partners have worked very hard to get to this point, and we are looking forward to yet another busy couple of years for the MTG project that will see the completion of the first family of the MTG satellites in orbit – two MTG-Imagers and one MTG-Sounder – which will provide invaluable meteorological data well into the next decade.”

Once this first family nears its end of life, all three satellites will be replaced by three more MTG satellites for the remainder of the overall mission’s lifetime.

The Lightning Imager instruments on MTG’s two Imager satellites offer a completely new capability for European meteorological satellites. They will be able to continuously monitor more than 80% of Earth’s visible surface from geostationary orbit for lightning discharges, taking place either between clouds or between clouds and the ground.

The MTG mission is a cooperation between Eumetsat and ESA. ESA is responsible for developing and procuring the six MTG satellites. Eumetsat defines the system requirements, develops the ground systems, procures the launch services, operates the satellites, and makes the data available to users. Thales Alenia Space is the prime contractor for the overall MTG programme and the MTG-I satellites as well as the Flexible Combined Imager instrument, and Leonardo was the supplier of the Lightning Imager instrument.

What’s next for MTG-I2?

The next step for MTG-I2 is the completion of the mechanical integration of the solar arrays as well as the Data Collection Service (DCS) and the Geostationary Search and Rescue (GEOSAR) instrument receivers and the Ka-band antenna, at which point the satellite will be in its launch configuration – and ready for more testing.

Vibration testing will simulate the launch environment and aims to confirm the build quality of the overall satellite demonstrating that it will survive the extreme loads it will endure during the launch phase.

There will be a final series of tests, including a System Validation Test with the ground segment operator Eumetsat in the loop, before the satellite is readied for launch, planned in 2026.