Following the study of various designs and concepts, the ELDO arrived at a three-stage approach which was given the designation "Eldo A", this was later formally named as "Europa". According to Hill, the Black Prince and Europa were comparable launchers capable to delivering similar performance and roughly the same payloads, the overlap leaving little room for both programmes. However, there was criticisms that Europa would take longer to deliver than the Black Prince launcher for no significant improvement, while suffering from the same core economic problem of being too expensive for scientific satellites while too small for commercial communications satellites.