Segment for solid rocket boosters

S1 segment


The S1 segment is one of three segments for the Ariane 5 booster and is fully manufactured in Avio’s Colleferro plant (Rome, Italy), except for the metallic component, manufactured by MT Aerospace.

The manufacturing process is:

• application of thermal protection;

• loading with 25 tons of solid propellant;

• inspections of forward and back chicanes – (in a series of inspections and checks to verify its compliance to the project).

The loaded segment is then shipped to French Guiana, where it is assembled to the S2 and S3 segments.

Segments for solid rocket boosters

S2 and S3 segments


The S2 and S3 segments (the metallic component is manufactured by MT Aerospace) once thermally protected (at Colleferro), are then shipped to French Guiana where they are each loaded with 107 tons of solid propellant by the Regulus company (joint venture 60% Avio and 40% Ariane Group). All the segments are then integrated by Europropulsion, a company equally shared by Avio and Ariane Group and assembled with the igniter and the nozzle by ASL.

The booster igniter is also manufactured in Colleferro plant. It has three stages: pyrotechnical igniter, intermediate and principal. The three stages are thermally protected, filled with propellant, and after being checked, they are shipped in French Guyana where they are assembled and integrated on the Ariane 5 boosters. Each igniter is filled with about 65 kilograms of propellant.