Low Earth orbit satellite internet networks such as Starlink, OneWeb, and Amazon LEO (formerly known as Project Kuiper) have in recent years emerged as a new way to access the internet. These systems offer the possibility of high-speed and low-latency connectivity in remote regions, but have also been introduced as potential options for use in emergency situations. As these technologies become more commonly used for critical applications, it is important to analyze how resilient these networks are, and how they may be vulnerable to various threats. LEO satellite internet is enabled by a network of ground stations, satellites, and user terminals. Since the ground stations are terrestrial, they can be vulnerable to threats such as natural disasters or power outages. As a result, analyzing the effect of terrestrial disruptions on the performance of satellite networks provides insight into how the service can be adversely affected. Using simulated models of Starlink, OneWeb, and Amazon LEO combined with case studies based on the 2025 Iberian Peninsula power outage and the 1960 Valdivia earthquake, it was found that optical inter-satellite links (ISL) significantly contribute to the resilience against terrestrial disasters. ISL-enabled networks such as Starlink and Amazon LEO enable alternative connections to more distant ground stations, thus avoiding a loss of regional coverage. This rerouting results in an increased link latency within the region.Simulated disasters in space were also analyzed. A distributed attack on satellites based on their betweenness centrality revealed that constellations with a larger quantity of satellites degraded more slowly. Additionally, an analysis of regional satellite outages revealed that a damaged satellite cluster can propagate to different regions, causing a local decrease in the satellite density. By analyzing the motion of the satellite constellation after a 3000 km radius disruption, it was found that constellations containing different orbital altitudes experienced a passive redistribution of satellites over time, stabilizing after 2-4 days. Additionally, deliberate maneuvering restored the density in approximately 4 days for Starlink and OneWeb, with the lower-thrust Amazon LEO satellites taking approximately 7 days.This work aims to provide insight into an often overlooked aspect of the emerging satellite networks, by showing that the resilience of these networks is affected by many distinct factors such as inter-satellite connectivity, ground stations, orbital mechanics, and more.
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The goal of project Altus is to do an in-situ investigation of Polar Mesospheric Clouds (PMCs). These clouds form around an altitude of 84 km, and only for 60 to 80 days per year, during the summer. Normally, these clouds only form in the polar regions, from around 50◦ latitude north and south. Recently, however, PMCs have been observed as low as 40◦ north. There are theories linking this change in location, and other unexpected behaviours of PMCs, to climate change. However, further research is still required to confirm these theories. As these changes are happening at a slow rate, a database of PMC measurements would be extremely beneficial to track indicator values over time. Project Altus sets out to bridge this knowledge gap by taking regular measurements of PMCs over an extended period of time. ... Read more