Architecting CubeSat constellations for messaging service, Part II

Abstract

Data collection and exchange stand as a cornerstone technology driving the advancement of technological development over recent decades. However, many remote and hard-to-reach regions remain devoid of terrestrial communication infrastructure. Telecommunication satellites offer a comprehensive solution, facilitating data transfer to even the most remote areas and bridging existing connectivity gaps.

Currently, there are two distinct types of systems under development by private companies aiming to enable direct-to-handset connectivity. The first type strives to offer mobile connectivity based on 3GPP standards with unmodified smartphones but these satellites are expensive and heavy. The second type of satellites provides low data rates connectivity using Internet of Things technologies to send and receive data packets. These satellites, in contrast, are more lightweight, low-cost, and can take the form of CubeSats or even PocketQubes. This study proposes a fusion of the advantages of both systems, contemplating a constellation for messaging services employing low-power user devices and LoRa technology.

In Part I of the study the LoRa channel capability was analyzed to enable the transmission of at least 1 message per day in the area with the highest concentration of users, uncovered by terrestrial cell towers and downselected 73 different LoRa connectivity payloads. Part II concentrates on various aspects of constellation design, encompassing the sizing of the CubeSat platform, messages transmission simulation approach, and constellation launch strategies. Employing a trade-space exploration approach, the study identified a preferred Low Earth Orbit (LEO) constellation architecture out of a pool of 11 826, capable of satisfying 51% of the demand and yielding the highest revenue among all the considered constellations. The performance analysis revealed that coverage and spreading factor are the paramount factors in serving users.

The architectural analysis framework presented here can serve as a valuable tool for the preliminary design and sizing of a constellation for different services based on short data packets transmission, while the gained insights regarding performance drives have the potential to enrich the development of future Internet of Things connectivity projects.