Reading a post below got me wondering. When the robotic arm is moving mass, what happens to the Shuttle? Is it heavy enough that the mass it's moving is negligible, and no compensation is needed? (I suspect this answer - any compensation can happen somewhere in the process or when it's done.)

Is compensation handled automatically, giving the arm operator a steady platform?

Is the commander or pilot controlling thrusters at the same time to steady the Shuttle?

If the latter is true, how could the two people coordinate closely enough to avoid unacceptably jerky movements?

Just curious.

Arf