Analytical Framework for Staging of Space Propulsion Systems

2021 IEEE Aerospace Conference (50100)

Lozano

2021

Self Cite

This work analyzes the use of microfabricated electrospray thrusters in a staged configuration during detumbling of small asteroids. For asteroid redirection missions, keeping the asteroid in a static and controllable orientation greatly simplifies the redirection process. In order to achieve this, spacecraft with propulsion systems need to be landed on the surface of the asteroid in order to detumble it. Prior work has studied the optimal landing locations of these detumbling spacecraft as well as suggested that small spacecraft, such as CubeSats, may be ideally suited for this task. However, small spacecraft suffer from component reliability issues, particularly in the propulsion system where redundancy is not typically provided. A potential solution is to use staging, analogous to launch vehicle staging, in order to provide propulsion system redundancy directly on each spacecraft. Staging has primarily been studied for enabling deep-space CubeSat missions with microfabricated electrospray thrusters by bypassing the lifetime limitations of individual thrusters in order to increase the overall lifetime of the propulsion system, but it can also be use to provide redundancy. A small fleet of CubeSats, each equipped with a staged electrospray propulsion system can detumble a small asteroid, all while providing redundancy in the event of a propulsion system failure. This work estimates the size of asteroid that can be detumbled with microfabricated electrospray thrusters as well as the number of stages required in order to guarantee specified probabilities of mission success.

Section: Redundancy Via Stagingmentioning

confidence: 99%

Redundancy for Asteroid Detumbling via Staging

2021 IEEE Aerospace Conference (50100)

Lozano

2021

Self Cite

“…The drawback of using a stage-based approach is that it increases the mass and volume of the propulsion system over that of a conventional, "single-stage" system. Analytical methodologies for determining the required number of stages for a given mission, which sets the overall propulsion system mass and volume, are developed in [23]. For a mission, defined by its ∆V, the required number of stages, N , is…”

Section: Propulsionmentioning

confidence: 99%

Feasibility of a Deep-Space CubeSat Mission with a Stage-Based Electrospray Propulsion System

2020 IEEE Aerospace Conference

Lozano

Sternberg

et al. 2020

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Independent deep-space exploration with CubeSats, where the spacecraft independently propels itself from Earth orbit to deep-space, is currently not possible due to the lack of high-∆V propulsion systems compatible with the small form factor. The ion Electrospray Propulsion System (iEPS) under development at the Massachusetts Institute of Technology's Space Propulsion Laboratory is a promising technology due to its inherently small size and high efficiency. However, current electrospray thrusters have demonstrated lifetimes (500 hours) below the required firing time for an electrospray-thrusterpropelled CubeSat to escape from Earth starting from geostationary orbit (8000 hours). To bypass this lifetime limitation, a stage-based approach, analogous to launch vehicle staging, is proposed where the propulsion system consists of a series of electrospray thruster arrays and fuel tanks. As each array reaches its lifetime limit, the thrusters and fuel tanks are ejected from the spacecraft exposing a new array to continue the mission. This work addresses the technical feasibility of a spacecraft with a stage-based electrospray propulsion system for a mission from geostationary orbit to near-Earth asteroid 2010 UE51 through a NASA Jet Propulsion Laboratory Team Xc concurrent design center study. Specific goals of the study were to analyze availability of CubeSat power systems that could support the propulsion system and any other avionics as well as requirements for attitude control and communication between the spacecraft and Earth. Two bounding cases, each defined by the maturity of the iEPS thrusters, were considered. The first case used the current demonstrated performance metrics of iEPS on a 12U CubeSat bus while the second case considered expected near-term increases in iEPS performance metrics on a 6U CubeSat bus. A high-level overview of the main subsystems of the CubeSat design options is presented, with a particular focus on the propulsion, power, attitude control, and communication systems, as they are the primary drivers for enabling the stagebased iEPS CubeSat architecture.

“…Methods that target maneuver detection for an uncooperative spacecraft that performs maneuvers at an unknown time [20,21] or when telemetry may not be available during the maneuver [22,23] often leverage filtering which limits the reconstruction of earlier portions of the propulsion system thrust and may not efficiently use all available information. As such, methods directly targeted at thrust estimation for cooperative spacecraft based on iterative batch filters [24] or the ensemble Kalman update [25] have also been analyzed and both show promising results.…”

Section: Introductionmentioning

confidence: 99%

“…Both Refs. [24] and [25] require the use of multiple numerical simulations of the spacecraft trajectory-either for each iteration of the batch filter [24] or to estimate the optimal Kalman gain with ensemble approaches [25]-which can be computationally expensive, especially for high-fidelity models. Instead, this paper takes a more analytical approach to the thrust inference problem where only a single simulation of the spacecraft trajectory is required as a reference for a linear update to the propulsive acceleration profile.…”

Section: Introductionmentioning

confidence: 99%

Segmented Reconstruction of Low-Acceleration Orbital Maneuvers

Journal of Guidance, Control, and Dynamics

2023

This paper considers the problem of inferring the acceleration acting on a spacecraft in a near-circular orbit around a large planetary body when the acceleration is known to act in the along-track direction. A segmented approach is analyzed where the acceleration profile over a given period of time is approximated as a piecewise-constant profile. Noisy measurements of the spacecraft’s position are collected throughout the acceleration profile, from which the constant acceleration for each segment of the piecewise-constant profile can be inferred. The primary contribution of this work is an analytical approximation for the sensitivity of each measurement with respect to the constant acceleration of each segment. The resulting analytically approximated sensitivity matrix enables an analytical reconstruction of the acceleration profile given a numerically simulated reference trajectory. Applications of the segmented approach for thrust inference for both discontinuous and continuous thrust profiles are demonstrated. In particular, the reconstruction of a simulated thruster degradation profile over the course of 60 h is shown.