  Multidisciplinary Design Optimization (MDO) makes it possible to reach a
better solution than by optimizing each discipline independently. In
particular, the optimal structure of a drone won't be the same depending on the
material used. The CO2 footprint of a solar-powered High Altitude Long
Endurance (HALE) drone is optimized here, the structural materials being one of
the design variables. The optimization is preformed using a modified version of
OpenAeroStruct, a framework based on OpenMDAO. The originality of this work is
to include material choice from a discrete catalogue in the MDO approach. This
is achieved through a continuous variable, enabling the use of continuous
optimization algorithms. Our results show that, in our case, the optimal
material in terms of CO2 footprint is also the optimal material in terms of
weight. In order for a green surrogate material to enable a lower drone CO2
footprint, it must be almost as good in terms of weight.
