First MetOp Second Generation-B satellite spreads its wing

The MetOp Second Generation (MetOp-SG) mission relies on a duo of complementary satellites to strengthen Europe’s weather forecasting capabilities from polar orbit.

The first, MetOp-SG-A1, was launched in August 2025, and engineers are now preparing its partner, MetOp-SG-B1, to join it in orbit this autumn.

Working together, the two satellites carry complementary suites of instruments – 11 between them – to deliver high-resolution measurements of temperature, precipitation, clouds, winds and other key atmospheric and environmental variables.

As one of the most advanced atmospheric monitoring systems ever deployed, the MetOp-SG mission comprises three successive pairs of satellites to supply meteorologists with the global data essential for predicting storms, tracking climate trends, and improving the accuracy of everyday weather forecasts for more than two decades.

The MetOp-SG B-type satellites carry five instruments: a scatterometer, to provide ocean-surface wind vectors and land-surface soil moisture, a radio occultation sounder (which is also on the A-type satellites) to provide atmospheric temperature and humidity profiles, as well as information about the ionosphere, a microwave imager to monitor precipitation and to assess sea-ice extent, an ice cloud imager to measure cloud-ice water, and an Argos-4 advanced data collection system which gathers and transmits data from surface, buoy, ship, balloon and airborne platforms.

Since last year, MetOp-SG-B1 has been undergoing rigorous environmental and functional testing at Airbus facilities in Toulouse, France. Among the most striking recent milestones has been the deployment of its large solar wing.

Spanning 11 metres when fully extended, and with a total surface of about 24 square meters, the four-panel solar wing is the satellite’s primary source of electrical power. It converts sunlight into the electricity needed to operate the satellite’s subsystems, communications links and scientific instruments throughout its mission in polar orbit.

Before launch, engineers must confirm that the solar wing’s hinges, hold-down and release mechanisms and deployment system function flawlessly.

Once in orbit, the solar wing will unfold automatically shortly after the satellite separates from its Ariane 6 rocket, a vital step before it can start its mission in orbit.

With these tests now complete, the next step is to weigh the satellite, followed by placement on a dedicated rig to measure its centre of gravity and moments of inertia. These are critical parameters for the rocket to optimise the satellite’s ascent to orbit – much as an aircraft crew verifies passenger load and fuel before take-off.

Afterwards, the satellite will be flight-ready. Following rehearsals of the procedures to be carried out at the launch site, it will be stored in an Airbus cleanroom for about four months before shipment to Kourou for launch, currently scheduled for October 2026.