Originally Posted by georgegassaway

Interestingly, on the Atlas, the verniers really were "verniers", for fine adjustment. The Atlas shut down the main engine a tiny bit early, before the intended final velocity was achieved. So the verniers kept firing to achieve exactly the velocity desired ot hit the target.

So, yeah, when I called those "small gimbaled engines" on the Soyuz verniers.....that was not being precise because they only serve for steering, not final velocity control. It is something many of us are familiar with from the Altas heritage.

Actually.....come to think of it..... it *IS* possible that for the original single stage (OK, stage-and-a-half) R-7 Semyorka ICBM version, the center core stage could have shut down the main 4-engine chambered engine first, and kept the little ones going as precision velocity verniers. But, I think that those little steering engines used the same main turbopump as the main engine, in which case that would not have allowed them to be used that way. No time to look it up but I'm more than 90% sure it was all or nothing (all running or none running).