The rocket, named after Vega, the brightest star in the constellation Lyra, is a single-body launcher (no strap-on boosters) with three solid rocket stages: the P80 first stage, the Zefiro 23 second stage, and the Zefiro 9 third stage. The upper module is a liquid rocket called AVUM. The improved version of the P80 stage, the P120C, will be used as the side boosters of the Ariane 6. Italy is the leading contributor to the Vega program (65%), followed by France (13%). Other participants include Spain, Belgium, the Netherlands, Switzerland and Sweden.