Mission analysis for nanonats using a printed micro-thrust distributed propulsion system

Abstract

While the miniaturisation of satellites has made space more accessible, traditional propulsion systems struggle with size, power and mass constraints. Many small satellites launch without propulsion, limiting their orbital and attitude capabilities. This leads to most miniature satellites being constrained in a given altitude range to guarantee a practical operational lifetime. This thesis focuses on the operational analysis of small satellites using a novel propulsion system called the Distributed micro-Propulsion System (DμPS), a novel technology developed as part of a joint research project between two teams at the University of Southampton, to enable miniaturised satellites to operate at orbital altitudes beyond what is currently possible. When fired, the unique distributed architecture of the DμPS leads to torque generation, creating complex operational and modelling challenges. This thesis details the approach to these problems by introducing two novel mission concepts demonstrating the practical application of the DμPS on miniaturised satellites.

The thesis first reviews the literature on the state-of-the-art miniaturised propulsion system and highlights existing potential thrust generation principles for the DμPS. After presenting standard orbital and attitude dynamics modeling techniques, the limitations of existing software solutions are discussed. While there are numerous commercial software packages and published routines available to model attitude and orbital dynamics, none offer the flexibility required to model distributed propulsion systems at the necessary fidelity. Therefore, a bespoke coupled orbit-attitude simulator, the Comprehensive High-fidelity Attitude and Orbit Simulator (CHAOS), is developed to analyse the dynamics of spacecraft equipped with the DμPS.

The second part of this research analyses the potential of the DμPS as a de-orbiting device for 1U CubeSats. This chapter specialises the DμPS concept into the CubeSat De-orbiting All-Printed Propulsion System (Cube-de-ALPS), by adding required components, such as sensors and necessary control laws, thus fully defining the propulsion system. The attitude and orbit simulations components are also updated to better model Cube-de-ALPS distributed architecture. Its operation is outlined, and preliminary estimates of its performance in various configurations are performed before using CHAOS to confirm the concept’s viability. As a result, I show that Cube-de-ALPS can de-orbit 1U CubeSats from altitudes twice as high as naturally possible while remaining compliant with debris mitigation guidelines.

The last part of this thesis examines the DμPS’s performance in Very Low Earth Orbit (VLEO). The HexSat, a 2.5 cm thick flat hexagonal satellite architecture designed for efficient packing inside rocket fairings, is introduced. For actuation, HexSats use the DμPS, embedded in the satellite frame, which produces thrust on the order of micro-Newtons. This research investigates the DμPS’s capability to operate on HexSats at 250 km altitude in VLEO with available power exceeding 100 W. Compared to the Cube-de-ALPS system, the DμPS provides less altitude change due to the exponentially increased drag forces at lower altitudes. The angular acceleration, drag profiles, and expected performance are determined for different mission scenarios. The results show the DμPS enables HexSats to operate at 250 km whilst actively tracking up to 8 ground targets per orbit and providing
over 100 W of average payload power.

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Identifiers

ORCID for Kash Saddul: orcid.org/0000-0003-4876-7510

ORCID for Alexander Wittig: orcid.org/0000-0002-4594-0368

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