# Carbon Nanocomposites in Aerospace Technology: A Way to Protect Low-Orbit Satellites
## 4 Outlook  
The LEO space environment is dynamic and challenging and can significantly reduce the durability of spacecraft materials [98]. In addition to ionizing radiation, high vacuum, plasma, space debris and thermal cycling, \(AO\) itself or the synergetic effect are the main causes for degradation effects on spacecrafts in LEO. \(AO\) may affect the material properties by changing the chemical, electrical, mechanical, thermal or optical properties. Carbon nanomaterials and carbon-based nanocomposites were effectively employed for numerous applications in aerospace. This advanced carbon nanomaterial is capable of improving the mechanical strength of lightweight components and space environment resistance. Despite their impressive potential, space studies and modelling of some of the mechanisms and corrosion resistance of nano composites remain limited, and further studies are required to improve carbon nanocomposite derived solutions for future space applications. The problem of \(AO\)-induced erosion is a special case for the VLEO systems. Along with the more dense atmosphere at very low altitudes, these satellites should use atmospheric gas as a propellant for orbit keeping by air-breathing systems, that is, the intake devices and internal parts of thruster will be affected by the highly energetic oxygen ions. To protect the thruster, several ways may be suggested for the future research and design efforts:  
* Admixtures could be added to the air directly in the intake devices and internal parts of the thruster to make \(AO\) less chemically active and, thus, to reduce the erosion without the use of an additional protective material. However, it is worth noting that such additives could potentially lower the efficiency of these thrusters;
* Physical mechanisms and sub-systems could be used to neutralize oxygen by, e.g., chemical reaction with other substances producing oxides still suitable for the use as propellant, but less chemically aggressive;
* Special configurations of thrusters, such as electrodeless rotational systems [99] that prevent direct contact between electrodes and discharge chamber walls and oxygen plasma, could be very promising for VLEO applications;
* Self-healing materials could be promising, e.g., for super low perigee orbit satellites, where the material could self-heal during the high-altitude phase of orbit when the satellites are less affected by the exposure to atomic oxygen;
* Next, the most novel materials and nanocomposites, including advanced metallic propellants which potentially could be influenced by atomic oxygen [100], should be tested in typical VLEO environments to understand the impact of the latter;
* Finally, the ground-based facilities for the comprehensive testing of novel materials under the specific LEO and VLEO conditions need to be further designed to be more sophisticated and to accurately reflect the real conditions across their entire range. The toolkit of these technologies would significantly speed up innovation and promote the development of more diverse novel nanomaterials for space, enabled by affordable, rapid and readily available to many testing and optimisation facilities, alleviating the need for expensive in-space tests. Conceptualization, J.W. and K.P. ; formal analysis, J.W. ; data curation, I.L., J.W. and K.P. ; writing--original draft preparation, J.W. and K.P. ; writing--review and editing, I.L., J.M., E.T. and O.B. ; supervision, K.B. All authors have read and agreed to the published version of the manuscript. This work was supported by ANU Futures Fellowship (K.B) and Research Pipeline Seed Fund, College of Science ANU (J.A., K.P., J.M., E.T. and K.B.). [PERSON] acknowledges the support from the project funded by the National Research Foundation of Ukraine, under grant agreement No. 2020.02/0119, and NATO Science for Peace and Security Programme under grant id. G5814 project NOOSE. [PERSON] acknowledges the support from the Australian National University and NIE, Nanyang Technological University.