This Handbook deals with control systems developed as part of a space project. It is applicable to all the elements of a space system, including the space segment, the ground segment and the launch service segment. It addresses the issue of control performance, in terms of definition, specification, verification and validation methods and processes. The handbook establishes a general framework for handling performance indicators, which applies to all disciplines involving control engineering, and which can be declined as well at different levels ranging from equipment to system level. It also focuses on the specific performance indicators applicable to the case of closed-loop control systems. Rules and guidelines are provided allowing to combine different error sources in order to build up a performance budget and to assess the compliance with a requirement. This version of the handbook does not cover control performance issues in the frame of launch systems.