ESA’s ‘Characterising Exoplanet Satellite’ mission, Cheops, underwent important testing last year to be ready for launch by the end of 2018. An important part of its prelaunch testing is qualifying the satellite’s solar arrays and their cells. This image shows part of the 12 solar cell assemblies at ESA’s ESTEC Test Centre, the Netherlands. See http://www.esa.int/spaceinimages/Images/2017/01/Cheops_solar_cells