Proba-V atop the Vespa (Vega Secondary Payload Adapter) adapter on 15 April 2013. The minisatellite will ride the adapter to orbit during its flight in May, with its fellow passengers stowed within it: Vietnam’s VNREDSat Earth observation mission and Estonia’s ESTCube-1 student nanosatellite, to test electric solar sail technology. The Vega launcher fairing is seen in the background.