Video showing the deployment of one of the Mercury Transfer Module’s 12 m-long solar wings in ESA’s test centre. The craft has two wings, spanning about 30 m from tip-to-tip when both are deployed.

In the test centre, the five panels were supported from above to simulate the weightlessness of space. The wings will be folded against the spacecraft’s body inside the Ariane 5 launch vehicle and will only open once in space. Mechanisms lock each panel segment in place. They can be rotated with the solar array drive mechanism attached to the main body.

The module will use a combination of electric propulsion and multiple gravity assists at Earth, Venus and Mercury to carry BepiColombo’s two scientific orbiters – ESA’s Mercury Planetary Orbiter and Japan’s Mercury Magnetospheric Orbiter – to the innermost planet in our Solar System.