Autonomous Spacecraft Propellant Gauging via Thermal Modeling
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Solution Overview
Problem
Current propellant gauging systems for spacecraft are inaccurate due to uncertainties in thermal measurements and require additional equipment, making it challenging to estimate remaining fuel levels, especially in microgravity environments.
Innovation Solution
An autonomous propellant gauging system using a reduced order model (ROM) and machine-learning techniques to estimate temperature responses and automate propellant content estimation, which can be trained with detailed physics-based models and measured data, allowing for accurate and automated propellant mass estimation without additional equipment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If thermal capacitance-based PGS technique is used to estimate remaining fuel, then propellant gauging can be performed, but measurement precision is insufficient due to unquantified uncertainty
Solution Approach 1:
The patent implements a feedback mechanism where statistical uncertainty analysis results are fed back into the PGS model to continuously refine and quantify measurement uncertainty. The system uses measured temperature data, compares it with model predictions, and updates uncertainty estimates iteratively, allowing the system to learn from previous measurements and improve accuracy over time.
Solution Approach 2:
The patent replaces traditional mechanical/physical measurement systems with a computational/statistical approach. Instead of relying solely on physical thermal measurements, the system substitutes a statistical uncertainty quantification framework that uses probability distributions and Monte Carlo methods to assess and communicate measurement reliability.
2Reliability
If statistical approach is used to quantify PGS uncertainty, then uncertainty estimation is improved, but device complexity increases due to multiple parameter variations
Solution Approach 1:
The patent uses copying by creating simplified statistical representations (probability distributions) of complex physical parameters. Instead of directly measuring or modeling every physical parameter with high complexity, the system creates statistical copies that capture the essential uncertainty characteristics, enabling tractable analysis while maintaining reliability.
Solution Approach 2:
The patent transforms fixed physical parameters into variable statistical parameters with associated probability distributions. By changing parameters from deterministic values to probabilistic representations, the system enables uncertainty quantification while managing complexity through standardized statistical methods rather than complex physical models.
3Measurement precision
If heritage PGS approach is used for specific platform, then propellant gauging can be performed, but adaptability is limited to that specific platform
Solution Approach 1:
The patent implements universality by designing a platform-independent statistical uncertainty quantification framework. The core methodology uses generic statistical techniques (Monte Carlo simulation, probability density functions) that can be applied to any spacecraft platform regardless of specific hardware differences, making the system adaptable while maintaining measurement precision.
Solution Approach 2:
The patent segments the uncertainty quantification process into independent modular components: parameter definition, probability distribution specification, Monte Carlo simulation execution, and result analysis. This segmentation allows the same framework to be applied to different platforms by simply changing input parameters without redesigning the entire system.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The system provides quantified estimates of remaining propellant with uncertainty and confidence levels, improving accuracy and reducing costs by utilizing existing thermal control systems, and can be reused for similar spacecraft with minimal updates.
Implementation Method 1
The heating devices are used to heat up the propellant tank
Implementation Method 2
the temperature sensors sense the temperature of propellant content of the propellant tank
Data Source
AI summary
An autonomous spacecraft propellant-gauging system, the system including a propellant tank, one or more heating devices, at least one temperature sensor and a processor. The heating devices are used to heat up the propellant tank, and the temperature sensors sense the temperature of the propellant content of the propellant tank. The processor controls operations of the heating devices and the temperature sensor. The processor further executes an algorithm to automate gauging of the propellant content of the propellant tank based on a reduced order model (ROM) and a number of parameters, and reports out an estimate of the mass of the remaining propellant of the propellant tank.