A relevant question in ESA’s Clean Space Initiative is: “What happens when one tries to apply EcoDesign to aeronautical industry?” This question arises in the context of environmental Impact and ESA programmes legislation.
EcoDesign and Life Cycle Assessment (ACV/LCA) are known methods applied in concepts such as eco-efficiency or “cleaner”production. In practical terms, EcoDesign provides a logical structure that, with the support of environmental information generated by an ACV, allows the identification of the main environmental challenges of a specific manufacturing product or process and, consequently, supports the identification of potential compromise solutions.
Thus the question “What happens when one tries to apply EcoDesign to aeronautical industry?” arises in the sphere of ESA’s Clean Space Initiative, that foresees the establishment of a common frame for the European space sector with respect to environmental impact assessment and complying with current legislation by ESA programs. As a main result, Clean Space foresees the development of an EcoDesign tool, to be integrated in its planning process in order to include environmental aspects in planning future space missions.
The main problem arises from the fact that the existent tools are specific for technologies still being applied, with emphasis in general consumption products and large-scale production practices. Therefore, the correct operation of this tool clearly depends on the inclusion of the specificities of this sector which, among others, include the use of singular materials, specialized manufacturing processes, lower production volumes or more demanding testing and functional requirements. In this respect, the question now is: “Which are the main challenges for the adaptation of ecological concession tools to demanding applications such as the ones in aeronautical industry?”
As a first attempt to address that question, ESA launched a call for Life Cycle Assessments (ACV) of a wide set of specific manufacturing materials, components and processes of this sector. This activity, in cooperation with ISQ, resulted in the findings below.
The majority of materials used in demanding applications are not properly modelled by the current tools.
This conclusion is patent in the vast majority of the analysed processes and components, with special incidence on the ones using specific properties materials. An excellent example is the high-strength aluminium alloys, such as light alloys or aluminium-lithium alloys. The results clearly show that small compositional differences in the alloys can lead to significant variations. In fact, some of the elements presents in this alloy type can significantly contribute to variations even in low concentrations. Therefore, this is a challenge for the application of EcoDesign in advanced applications, because it is expected that application that require specific properties obtained by special alloys present results substantially different than the ones provided by the current tools.
The use of specific materials leads to more emissions in the production stage.
The effective use of materials is especially important in demanding applications. An example of that are the components made by titanium alloys, such as the propellant storage tanks, in which the material removal rates can ascend to 95%, independently of its geometry. For instance, we can talk about the environmental assessment of the production of a cylindrical 1 m3 tank, covered by carbon fibre which main message patent here is that the environmental performance of the production of this type of component is clearly dependent on the base material recovery, more than any support structure of the process or consumed energy. In this sense, it is recommended for the use of materials with closed recycling cycles, with special incidence on those in which the properties of the materials are maintained after the recycling process.
The supply chain rupture risk can occur in an indirect way.
The dependence on essential raw materials can also occur indirectly from the use of materials in support functions. As the main example, stands out the fluorite used in the production of germanium, base-element for the photovoltaic panels used in space missions. With respect to the production of photovoltaic energy, currently the most used system corresponds to triple-junction solar cells composed of two layers of gallium-indium-phosphorus and gallium-arsenic supported over a structural layer of germanium. Its use is fundamentally justified by a higher efficiency, advantages in radiation and hardness, small temperature coefficients, high reliability, high tension and low current. This is clearly one of the advantages of using the ACV methodologies, because it facilitates the identification of special features in the several upstream and downstream stages of the process or product being analysed. In quantitative terms, it was also possible to conclude that, for example, for the production area of 1 m2 and a width of 150μm, 7.1 kg of fluorite are necessary.
Small quantities can contribute in great measure.
Such as it was verified in the production of different alloys or photovoltaic panels, small variations in variations in materials or concentration may lead to discrepant results, consequently, incorrect conclusions. Therefore, considering the specificity and singularity of many of the materials used by the aeronautical industry, it is recommended that all the present elements in the composition of any component are considered, aiming the achievement of results that reflect its real environmental performance.
The results indicate that the advanced manufacturing methods used by the aeronautical industry add particular properties when compared to the conventional ones. In fact, these methods are in the majority of the cases associated with lower environmental performances, which doesn’t mean that they should lack in an environmentally negative connotation. Actually, this reflection only focused in sharing ways of how to benefit from the Life Cycle Assessment methodologies and EcoDesign practices as support tools for the decision making process in this sector. Hence, answering the article’s initial question, it is concluded that supporting the decision making on existent EcoDesign tools can lead to incorrect compromise solutions. However, when adapted to the particularities of this sector, these offer a vital vision for supply chain of manufacturing materials and processes. Because of that, given this use, despite being associated with significant effort, the adaptation of these tools to demanding applications such as the aeronautical sector ones is extremely recommended. It is a future commitment in face of the sector demands.