The future of thermal insulation in space
Aerogels are manufactured by replacing the liquid from silica-based gels with a gas, resulting in a material with extremely low density and over 90 % air. The highly porous structure of this nanomaterial with extremely small pore size and intricate pore geometry makes it difficult for heat to pass through. As a result, aerogels are excellent thermal insulators. Researchers working on the EU-funded project AERSUS (Aerogel European supplying unit for space applications) found in this new nanomaterial the solution to improve the thermal protection of spacecraft, which is currently provided by multi-layer insulation (MLI). The basic materials for MLI, Kapton and Mylar, are procured by non-European companies. The AERSUS project brought together nine partners from across Europe with know-how in the manufacture of aerogels to reduce dependence on sources outside Europe. To tailor aerogels for the harsh environment in space, they first reviewed methods for synthesis. Together with the findings of a market study on end-users needs, these preparatory activities helped establish the engineering specifications. The next step was to synthesise different kinds of aerogels including organically modified silica-based aerogels and hybrid organic/inorganic silica aerogels. Their thermal conductivity was tested and benchmarked against thermal insulation materials currently used for space applications. Lastly, equipment for the fabrication of aerogels at industrial scale were designed and constructed. The joint efforts and close cooperation among AERSUS partners helped establish the required technical expertise in Europe to supply aerogels adapted to outer space applications. The new nano-structured materials could replace MLI blankets currently used for thermal protection of propellant tanks and pressurised compartments of spacecraft and planetary rovers. Although AERSUS aerogels are almost entirely tailored to the outer space environment, the applications are wide-ranging. One of the leading areas of application is in the construction sector for the thermal insulation of buildings.
Keywords
Thermal insulation, silica gel, aerogel, planetary exploration rovers, nano-structured material
