The service module, which sits below the crew module, is designed for one mission and hosts the spacecraft's solar arrays, launch-abort engines, and orbital maneuvering thrusters.
In all my years of following spaceflight, this is my first time noticing that the launch about motors for Starliner are on the service module. I don’t really like the sound of that: what if the problem occurs in the service module? I’m sure I’m not the first person to ask that question, but also this is Boeing we’re talking about.