Thanks for the reply. I had kind of realised MechJeb didn't have that functionality at the moment, I was just wondering whether it was in the pipeline for development. Autopilot and autothrottle tend to go hand in hand afterall. The problem with building symmetrically, is that multi-stage shuttles are fundamentally asymmetrical. This was more of a technical exercise to see if I could design a classic NASA style shuttle. I had been trying to use the throttle limiters to balance the CoM and CoT but encountered two problems: 1) Eyeballing the collinearity is inaccurate and pretty difficult and tedious. Plus, the starting point for each stage needs to be ascertained seperately, and changed midflight which is nigh on impossible, without some kind of automation. 2) The CoM constantly changes as the fuel is used, and therefore the CoT must be varied in real-time. Thanks! That has helped stability no end. I'm still running into trouble it high altitude, but I think I might be able to control that with a well timed manual throttle limitation! Begs the question why the base program doesn't do this already. Surely keeping you pointing where you want to go is the whole point in thrust vectoring?