# Carbon Nanocomposites in Aerospace Technology: A Way to Protect Low-Orbit Satellites
## 1 Introduction
VLEO and LEO satellites offer many significant advantages yet at the same time face several significant challenges; with the present-day tendency to refocus many of the key missions to low orbits, among other problems of operating at these orbits, issues pertaining to material degradation and stability under these conditions must be properly addressed so as not to hinder future development of low orbit satellite technology. Research and development of space grade materials have a long history dating back to the beginning of space age. Presently available space materials were optimised to withstand the harsh conditions of the space environment, such as the effects of ultra-high vacuum, ionizing radiation, charge accumulation, UV radiation, thermal cycling and many other factors [15; 16]. General application requirements also need to be fulfilled, such as weight reduction, mechanical stability, chemical reactivity, and cost reduction. Now, when the LEO and VLEO satellites tend to occupy much lower orbits, special attention should be paid to the specific material-_AO_ interaction, and novel materials capable of operating for years in aggressive _AO_- enriched conditions at low orbits need to be designed. Nanomaterials have at least one dimension within the range of 100 nm or less, and they often demonstrate outstanding mechanical, electrical, thermal and optical properties. The replacement of conventional space materials with those based on nanomaterials and nanocomposites can significantly improve many important characteristics of the related structural and functional spacecraft components [17]. Graphene, fullerene, carbon nanotubes (CNT), nanofibers, nanoclays and others are examples of carbon-based nanomaterials used in space applications [18]. The advanced properties of carbon nanomaterials are due to the properties of carbon itself, as well as the dimensional effects resulting from the nanoscaled sizes of elements and structures present within these nanomaterials. The general properties of carbon in the context of structural materials are quite diverse due to many possible allotrope forms, and different allotropies demonstrate very different chemical and mechanical properties. From graphite (consisting of layers of graphene) which is soft enough to be used in pencils to diamond which is among the hardest materials in the Universe--this impressively wide range of properties is directly attributed to the existence of multiple carbon allotrope forms. Electric conductivity of carbon allotropes also varies across a very wide range, from high conductivity of graphite which is used for electrodes to low conductance of diamond. On the other hand, thermal conductivity of diamond and graphene-based allotropes exceeds that of any other known material. In terms of mechanical strength, graphene is considered as the strongest material in the Universe, with the tensile strength reaching 130 GPa [19; 20]. Not surprisingly, this unique family of materials attracted the attention of many researchers targeting various engineering problems, including protection from aggressive environments ranging from, e.g., marine fouling [21] to space propulsion thrusters and spacecraft [18; 22]. The purpose of the present work is to briefly discuss the key mechanisms responsible for material degradation under the conditions of low orbit environment. Insight and simulated experiments using carbon-based nanomaterials and their key findings, research trends and key challenges are also described.