In the past, to test a design, hardware was built and tested in the field. In many cases prototypes were damaged beyond repair or, for example, missiles, is completely destroyed. This build-and-break experimental method has almost been completely replaced by simulation based design and testing.
Only after a design has been thoroughly tested in simulation, is the hardware built. The benefits of the modeling and simulation approach include rapid growth in maturity and insight, while expensive hardware is built with lower risk. The modelling and simulation approach also provides earlier understanding, validation and the opportunity for refinement and improvement. This approach is particularly relevant for the development and evaluation of complex systems, such as aircraft self-protection countermeasures against missile attacks. The use of simulation also extends the evaluation to beyond that which is feasible with hardware-only evaluations.