Tradespace Exploration of the Next Generation Communication Satellites

Abstract

© 2019, American Institute of Aeronautics and Astronautics Inc, AIAA. All rights reserved. With this paper, we describe a tradespace exploration analysis for the next generation constellation of communication satellites resulting in a recommendation for a future system. In particular, we compare our proposal with ViaSat-3 and SpaceX’s Starlink constellation. In order to arrive at a recommendation for an optimal constellation design, we first identify the design space by creating a morphological matrix and applying necessary constraints (see Table 1 for the architectural decision). The morphological matrix decisions are selected based on variability in heritage versus state-of-the-art designs, and include options with different Technology Readiness Level (TRL). The resulting 3,120 feasible architectures are evaluated using both cost and performance estimates. Costs are determined from component costs, TRL, and heritage. Performance scoring is based on a modified Signal-to-Noise Ratio (SNR) calculation, which includes technical factors such as the downlink budget and latency, as well as system factors such as crosslinks, architectures, and coverage. The final design recommendation is a Radio Frequency (RF) crosslink, bent pipe, Ka/Ku-band satellite with an electronically steered antenna and projected mass of 125 kg. The system is a constellation of 312 satellites, spread across 6 orbital planes at 444 km of altitude with global coverage and an estimated system capacity of about 2 Tbps. Estimates place the cost at $8.9 billion with a NPV of $1.4 billion over a total lifetime of ten years. Latency is expected to be around 25 ms. As with many space systems, our proposed design comes with a number of risks. Outside of typical regulatory, technological, and programmatic risks, providing satellite communications, particularly data services, comes with a unique risk: the price of user terminals. In order to provide public consumer broadband, in addition to other attractive markets such as 5G, the price of user terminals must decrease to an affordable price of $100 per terminal.