Shared AO Sensor Telemetry Circuits for Spacecraft Resource Savings
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Solution Overview
Problem
Conventional spacecraft sensors for detecting atomic oxygen (AO) consume valuable resources, increase cost, mass, and complexity due to their dedicated nature, which is not efficiently addressed by existing sensor systems.
Innovation Solution
A sensor system for spacecraft that includes interchangeable sensor circuits for both atomic oxygen and temperature sensors, utilizing graphite strips to measure AO fluence and thermistors to measure temperature, with shared circuits that reduce resource consumption and complexity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If dedicated sensor circuits are used for atomic oxygen sensors, then measurement precision is improved, but device complexity increases
Solution Approach 1:
The patent implements a universal sensor circuit design that can serve both atomic oxygen sensors and temperature sensors (thermistors). The circuit includes an ADC, multiplexer, and processing unit that can selectively measure resistance changes from either sensor type through a single shared pathway, eliminating the need for separate dedicated circuits for each sensor type.
2Reliability
If dedicated sensor circuits are used for atomic oxygen sensors, then reliability is improved, but use of energy increases
Solution Approach 1:
The patent merges the atomic oxygen sensor circuit and temperature sensor circuit into a single shared circuit architecture. The ADC, multiplexer, and signal processing components are combined into one unified system that time-division multiplexes between reading atomic oxygen sensor resistance and thermistor resistance, thereby halving the power consumption compared to having two separate independent circuits.
3Measurement precision
If dedicated sensor circuits are used for atomic oxygen sensors, then measurement precision is improved, but quantity of substance increases
Solution Approach 1:
The universal sensor circuit uses a single ADC, multiplexer, and processing unit that can measure both atomic oxygen sensor output and thermistor output through resistance changes. This eliminates the need for duplicate ADCs, multiplexers, and processing circuits that would be required if separate dedicated circuits were used for each sensor type.
4Reliability
If dedicated sensor circuits are used for atomic oxygen sensors, then reliability is improved, but device complexity increases
Solution Approach 1:
The patent introduces a multiplexer as an intermediary component that selectively connects either the atomic oxygen sensor or the thermistor to the shared ADC and processing circuit. This intermediary allows a single circuit to reliably serve multiple sensor types without requiring complex dedicated pathways for each, simplifying the overall architecture while maintaining measurement reliability.
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 effectively reduces power, space, and cost by reusing sensor circuits for both types of sensors, while providing accurate measurements of AO fluence and temperature, enhancing spacecraft operational life and performance.
Implementation Method 1
atomic oxygen sensors including graphite strips to provide resistances that increase when exposed to atomic oxygen that erodes the graphite strips
Implementation Method 2
thermistors to generate second sensor signals indicative of temperature
Data Source
AI summary
A sensor system for a spacecraft comprising: atomic oxygen sensors including graphite strips to provide resistances that increase as the graphite strips ablate away when exposed to atomic oxygen, the atomic oxygen sensors configured to generate first sensor signals indicative of the resistances and, correspondingly, atomic oxygen fluence to which the atomic oxygen sensors are exposed; thermistors to generate second sensor signals indicative of temperature; sensor circuits that are identically configured to each other and that include first sensor circuits to convert the first sensor signals to digitized first signals and second sensor circuits to convert the second sensor signals to digitized second signals; and a controller to process the digitized first signals and the digitized second signals.