dsc05914.jpg

Overall walk-around of the Service Propulsion System (SPS) engine.

Picture 2 of 6.

At the very center is the engine's injector (more detailed photos of the engine's injector start at dsc08242.jpg). The remaining rust-colored section (and perhaps the outer silver section as well) is the SPS engine proper. The darker grey-colored section is the columbium section of the nozzle extension, while the lighter grey section is the portion of the nozzle extension made of titanium.