\<COLOUR 1> CONSTRUCTION: \<COLOUR 0> The SRB is constructed of 11 1.27-cm thick high- strength steel segments joined together, with a nose cap at front containing parachutes and a skirt aft; two clusters of four solid rocket separation motors in the nose and skirt move the SRBs away from the shuttle after separation
\<COLOUR 1> PARACHUTES: \<COLOUR 0> One pilot, one drogue and three main parachutes, each main 'chute 35 metres across
\<COLOUR 1> COMMENTS: \<COLOUR 0> Reusable: Two SRBs, strapped to the external tank, provide the shuttle with more than 70 per cent of lift-off thrust; they fire for two minutes before separating and parachuting back to the ocean.