Over the last few months, ESA’s Earth Explorer Biomass satellite has been going through a punishing series of tests to make sure that it will survive the unavoidable blasts of noise and shuddering during liftoff. Engineers have now also tested that it will unfold its solar wing in the correct sequence. Coming through all of this with flying colours, Biomass is a few steps closer to its mission in orbit: to deliver completely new information on our precious forests and the carbon they store.