The first x is for the x-direction, the second is for the y-direction, and the third is for the z-direction. IF I'm not mistaken. It makes sense though. ex: Pointing a craft to the sky and towards the east at an approximate 70 degree's would require "LOCK STEERING TO UP + R(0,0,180) + R(0,-30,0)" again, that is if I'm not mistaken. v(x,x,x) means Vector in a certain direction. Ex: v(0,90,0) (I never use the v(x,x,x) so I don't know much about it.) r(x,x,x) I guess means radians. I don't know though, it could just mean roll. Ex: r(0,0,180)