  The optimal layout of a complex system such as aerospace vehicles consists in
placing a given number of components in a container in order to minimize one or
several objectives under some geometrical or functional constraints. This paper
presents an extended formulation of this problem as a variable-size design
space (VSDS) problem to take into account a large number of architectural
choices and components allocation during the design process. As a
representative example of such systems, considering the layout of a satellite
module, the VSDS aspect translates the fact that the optimizer has to choose
between several subdivisions of the components. For instance, one large tank of
fuel might be placed as well as two smaller tanks or three even smaller tanks
for the same amount of fuel. In order to tackle this NP-hard problem, a genetic
algorithm enhanced by an adapted hidden-variables mechanism is proposed. This
latter is illustrated on a toy case and an aerospace application case
representative to real world complexity to illustrate the performance of the
proposed algorithms. The results obtained using the proposed mechanism are
reported and analyzed.
