Nano-Coating ‘Space Skin’ Protects Spacecraft
A study conducted by a research team from the University of Surrey and Airbus Defense and Space found that a “space skin” could help protect spacecraft and satellites from solar radiation, while simultaneously collecting energy for future use.
The study, “Multifunctional Nanostructures with Controllable Band Gap Giving Highly Stable Infrared Emissivity for Smart Thermal Management,” was published earlier this month in the journal ACS Nano.
About the Coating
The developed nano-coating, called the Multifunctional Nanobarrier Structure (MFNS), can reportedly reduce the operating temperatures of space-qualified structures from 120 degrees Celsius (248 degrees Fahrenheit) to 60 C.
According to the University’s release, researchers were able to show that it is possible to use the MFNS alongside a craft's sensors and advanced composite materials thanks to the custom-built, room temperature application system.
“Space is a wondrous but dangerous place for us humans and other human-made structures. While solutions already on the market offer protection, they are bulky and can be restrictive when it comes to thermal control,” said professor Ravi Silva, corresponding author of the study and Director of the Advanced Technology Institute at the University of Surrey.
“Our new nano barrier is able to not only provide radiation and thermal protection but also harvest energy for use at a later date.”
Surrey U + Airbus - Space skin ??— I_van (@nanoLaniakea) January 17, 2023
"The researchers demonstrated that their novel nano coating, known as the Multifunctional Nanobarrier Structure (MFNS), can lower the operating temperatures of space-qualified systems from 120 °C to 60 °C"https://t.co/9sJ1vCQlrr
To ensure that payloads work as designed, spacecraft must account for huge variations of solar illumination and space radiation, with temperatures being maintained by balancing radiation and external weather with heat produced internally.
Additionally, atomic oxygen (AO) is created when oxygen molecules break apart, a process made easier in space because of the abundance of ultraviolet (UV) radiation. AO then reacts with organic surfaces on spacecraft and degrades them.
The University reports that the MSFN consists of a buffer layer made of poly(p-xylylene) and a diamond-like-carbon superlattice layer to give it a mechanically and environmentally ultra-stable platform. As a result, the MSFN can reportedly protect a craft from both AO and UV radiation.
Since it is dielectric in nature, or transparent across a wide range of radio frequencies, it can also be coated on highly sensitive payloads and structures, such as antennas, without interfering significantly with performance.
During the research, the team also reportedly found that it is possible to modify how much AO and UV a craft can absorb and harvest while a craft is in low-earth orbit.
“Our collaborative research with the University of Surrey has again proved fruitful with this latest development of a coating to protect satellites in orbit,” said Paolo Bianco, Global R&T Cooperation Manager at Airbus Defense and Space.
“The University of Surrey has a long and productive partnership with Airbus. Whether developing state-of-the-art nanostructures to help protect spacecraft or producing world-leading electric space thrusters with the Surrey Space Centre, this is a relationship that our local region and indeed the country should be proud of,” Silva concluded.
In 2021, Airbus and the Advanced Technology Institute at the University of Surrey also developed a nano-barrier to protect satellites in low-Earth orbit from UV and AO. The nano-barrier and custom-built deposition system reportedly bonds to the surface of polymer or composite materials, protecting them from the erosion caused by AO.
The nano-barrier allows for large-area, conformal coating on complex 3D structures such as spacecraft and optical mirrors, eliminating the risk of contamination and the need to wrap instruments with multi-layer insulation to open 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 at the time.
“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.”
Engineers showed in their research how they constructed the multilayer stack to overcome several issues previously reported in space, like coefficient of thermal expansion mismatch or surface undercutting erosion.
Thermal cycling and intrinsic stress effects are reportedly reduced by applying a combination of a buffer and highly dense amorphous layers. This reportedly enables moisture and outgassing protection in tandem creating a dimensionally stable platform, preventing material degradation.
Additionally, further oxide nano-layers are used to both enhance AO/UV protection and simultaneously improve thermo-optical properties of the substrates by controlling the optical band gap of the entire nano-barrier stack.
This, Airbus reported, effectively facilitates radiative cooling by minimizing the heat that could be built-up on the surface and degrade materials.