The third stage uses of HTPB solid propellant and produces a maximum thrust of . Its burn duration is 113.5 seconds. It has a Kevlar-polyamide fibre case and a submerged nozzle equipped with a flex-bearing-seal gimbaled nozzle with ±2° thrust vector for pitch and yaw control. Roll control is provided by the fourth stage reaction control system (RCS) during thrust phase as well as during combined-coasting phase under which burnt-out PS3 remains attached to PS4.
the thiRD sTagE uses oF htPb sOLid proPellant AnD prOduces a MaxImuM thRuSt oF . ItS bUrn dUraTioN is 113.5 secoNdS. it hAs A keVlar-pOlyamide fibrE CasE aNd A submerGed nozZle eqUipped wiTh A fleX-BEAriNg-sEal gimbalEd Nozzle wiTH ±2° thruSt veCtor For PitcH AnD yAW contrOl. roLL cOnTrOL is proViDed by the FOurtH sTage reAcTIOn ConTROL System (rCs) dURiNg thrust phAse as WEll AS DurIng cOmbined-CoASTIng pHaSe UndEr which burnt-oUt PS3 remAiNs attached To ps4.