Survivability Analysis of the Iridium Low Earth Orbit Satellite Network

Abstract

This thesis evaluates the survivability of the proposed Iridium Low Earth Orbit (LEO) Satellite Network. In addition to the complete Iridium constellation, three degraded Iridium constellations are analyzed. This analysis occurs via the use of simulation models, which are developed to use three dynamic routing algorithms over three loading levels. The Iridium network models use a common set of operating assumptions and system environments. The constellation survivability was determined by comparing packet rejection rates, hop\u27 counts, and average end to end delay performance between the various network scenarios. It was concluded that, based on the established scenarios, the proposed Iridium constellation was highly survivable. Even with only 45 percent of its satellites functioning (modeled with 36 failed Iridium satellites), the average packet delays were never greater than 178 milliseconds (msec), well within the real time packet delivery constraint of 400 msec. As a result, while additional research is necessary, Iridium has demonstrated the network robustness that is required within the military communications environment