Atomic oxygen (O) is created with O2 molecules break apart, a process made easier in space because of the abundance of ultraviolet radiation. Atomic oxygen then reacts with organic surfaces on spacecraft and degrades them.
Engineers from Airbus Defence and Space and the Advanced Technology Institute at Surrey said that the newly developed nano-barrier and custom-built deposition system bonds to the surface of polymer or composite materials, protecting them from erosion.
According to Airbus, the nano-barrier allows for large-area, conformal coating on 3D structures such as spacecraft and optical mirrors. This eliminates the risk of contamination and the need to wrap instruments with multi-layer insulation, opening up opportunities to increase satellite performance.
“This breakthrough technology is an enabler for extremely agile, high performance space borne radar missions,” said Christopher Hess, head of Microwave Instruments at Airbus Space Systems. “It should have a huge positive impact on overall mission performance by offering higher flexibility in the acquisition as well as increasing the possible imaged area - giving our instruments greater performance.”
In a paper published in the journal ACS Applied Materials & Interfaces, engineers showed how they constructed the multilayer stack to overcome issues previously reported in space like coefficient of thermal expansion mismatch or surface undercutting erosion.
By applying a combination of a buffer and highly-dense amorphous layers, the team confirmed that thermal cycling and intrinsic stress effects were reduced. This enabled moisture and outgassing protection in tandem creating a dimensionally stable platform, thereby preventing oxygen degradation, researchers said.
Further oxide nano-layers were used to enhance atomic oxygen/UV protection and improve thermo-optical properties of the substrates by controlling the optical band gap of the entire nano-barrier stack. This facilitated radiative cooling by minimising the heat that could be built-up on the surface and degrade materials.
Researchers said the system ensures complete conformal coverage of the nano-barrier at room temperature, so sensitive polymeric and composite materials can be coated without approaching their glass transition temperatures.
The next step for the team is to work on industrialisation of the coating to enable the first LEO missions to be treated from 2022.