Spacecraft Inertial Properties From Reaction Wheel Telemetry
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing methods for determining spacecraft inertial properties, such as those based on CAD models, often underestimate the true inertial properties due to manufacturing variances and post-launch changes, and in-flight measurements are challenging to perform without disrupting normal operations.
Innovation Solution
A method that utilizes data collected during normal spacecraft operations, including angular momentum and velocity of reaction wheels, to determine inertial properties by identifying qualifying changes in angular velocity, randomly sampling intervals, and combining estimates through bootstrapping techniques to achieve accurate and up-to-date measurements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If in-flight measurements of inertial properties are performed, then measurement precision is improved, but device complexity and operational disruption increase
Solution Approach 1:
The spacecraft uses its own operational telemetry data (reaction wheel angular momentum and spacecraft angular velocity) to determine its own inertial properties, eliminating the need for external measurement equipment. The system serves itself by processing data already collected during normal operations.
Solution Approach 2:
The patent replaces complex mechanical measurement systems with computational analysis of existing sensor data. Instead of using dedicated inertia measurement devices, the system uses software algorithms to process telemetry from reaction wheels and attitude sensors already present on the spacecraft.
2Measurement precision
If in-flight measurements are performed, then measurement precision is improved, but normal operations are disrupted
Solution Approach 1:
The measurement process continues alongside normal spacecraft operations without interruption. Telemetry data is collected continuously during routine operations, and inertial property calculations are performed using this ongoing data stream, allowing both operations and measurements to proceed simultaneously.
Solution Approach 2:
The spacecraft determines its own inertial properties using data from its own operational systems, eliminating the need for separate measurement campaigns that would require halting normal activities. The system extracts measurement information from routine operational telemetry.
3Device complexity
If CAD model estimates are used, then device complexity is reduced, but measurement precision deteriorates
Solution Approach 1:
The patent replaces physical measurement equipment with computational methods. Instead of building complex inertia measurement devices, the system uses software algorithms to calculate inertial properties from existing operational data, achieving high precision without additional hardware complexity.
Solution Approach 2:
The spacecraft uses its own operational data to determine its inertial properties, eliminating the need for external CAD modeling and manual estimation. The system extracts accurate measurements from its own telemetry, accounting for actual mass distribution including manufacturing variances and post-launch changes.
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
Enables precise and reliable determination of spacecraft inertial properties in-flight without interfering with normal operations, reducing costs and computational requirements by using telemetry data at lower sampling frequencies.
Implementation Method 1
information indicative of the angular momentum of a reaction wheel on-board the spacecraft
Implementation Method 2
the angular momentum of a reaction wheel on-board the spacecraft
Data Source
Figure 1
Figure 2
Figure 3
AI summary
A method of determining one or more inertial properties of a spacecraft. The method comprises: receiving data collected at different points in time during operation of the spacecraft. The data includes information indicative of: the angular momentum of a reaction wheel on-board the spacecraft, and the angular velocity of the spacecraft. The method further comprises: identifying changes in the angular velocity of the spacecraft based on the information indicative of the angular velocity of the spacecraft; and determining one or more inertial properties of the spacecraft based on the identified changes in the angular velocity of the spacecraft and the information indicative of the angular momentum of the reaction wheel.