Particle and Smoke Detection on ISS for Next Generation Smoke Detectors
Urban, David L., Ruff, Gary, Yuan, Zeng-guang, Sheredy, William, Funk, Greg
Experiments: SAME
Rapid fire detection requires the ability to differentiate fire signatures from background conditions and nuisance sources. Proper design of a fire detector requires detailed knowledge of all of these signal sources so that a discriminating detector can be designed. Owing to the absence of microgravity smoke data, all current spacecraft smoke detectors were designed based upon normal-g conditions. The removal of buoyancy reduces the velocities in the high temperature zones in flames, increasing the residence time of smoke particles and consequently allowing longer growth time for the particles. Recent space shuttle experiments confirmed that, in some cases, increased particles sizes are seen in low-gravity and that the relative performance of the ISS (International Space Station) and space-shuttle smoke-detectors changes in low-gravity; however, sufficient particle size information to design new detectors was not obtained. To address this issue, the SAME (Smoke Aerosol Measurement Experiment) experiment is manifested to fly on the ISS in 2007. The SAME experiment will make measurements of the particle size distribution of the smoke particulate from several typical spacecraft materials providing quantitative design data for spacecraft smoke detectors. A precursor experiment (DAFT: Dust Aerosol measurement Feasibility Test) flew recently on the ISS and provided the first measurement of the background smoke particulate levels on the ISS. These background levels are critical to the design of future smoke detectors. The ISS cabin was found to be a very clean environment with particulate levels substantially below the space shuttle and typical ground-based environments.
Test conditions.
Extracted from the paper by AI · “Verified” means a person checked it
| Fuel | O₂ | Pressure | Airflow | Sensors | Source | AI conf. | Status |
|---|---|---|---|---|---|---|---|
| Kapton | — | — | — | ISS detector, STS detector, Thermophoretic particle capture, Light extinction | p. 16 | 95% | Pending |
| Silicone Rubber | — | — | — | ISS detector, STS detector, Thermophoretic particle capture, Light extinction | p. 16 | 95% | Pending |
| Teflon | — | — | — | ISS detector, STS detector, Thermophoretic particle capture, Light extinction | p. 16 | 95% | Pending |
| Candle | — | — | — | ISS detector, STS detector, Thermophoretic particle capture, Light extinction | p. 16 | 95% | Pending |
| Paper | — | — | — | ISS detector, STS detector, Thermophoretic particle capture, Light extinction | p. 17 | 95% | Pending |
| Velcro | — | — | — | P-Trak, Dust Trak | — | 90% | Pending |
Findings.
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01
Current spacecraft smoke detectors were designed based on normal-gravity conditions due to a lack of microgravity smoke data.
Other · p. 1 · AI confidence 95% · Reported · Pending
“Owing to the absence of microgravity smoke data, all current spacecraft smoke detectors were designed based upon normal-g conditions.”
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02
In microgravity, increased particle sizes are observed in some cases, and the relative performance of ISS and space-shuttle smoke detectors changes.
Other · p. 1 · AI confidence 95% · Reported · Pending
“Recent space shuttle experiments confirmed that, in some cases, increased particles sizes are seen in low-gravity and that the relative performance of the ISS (International Space Station) and space-shuttle smoke-detectors changes in low-gravity”
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03
The ISS cabin environment has particulate levels substantially below those of the space shuttle and typical ground-based environments.
Other · p. 1 · AI confidence 95% · Reported · Pending
“The ISS cabin was found to be a very clean environment with particulate levels substantially below the space shuttle and typical ground-based environments.”
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04
Well-ventilated flames and established fires emit smaller particulates that are readily detected by ionization detectors.
Detection · p. 7 · AI confidence 95% · Reported · Pending
“Well ventilated flames and established fires emit smaller particulate with sizes readily detected by ionization detectors”
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05
Smoldering fires and overheated (pyrolyzing) materials produce larger particulates that favor scattering detectors.
Detection · p. 7 · AI confidence 95% · Reported · Pending
“Smoldering fires and over-hea ted (pyrolyzing) materials produce larger particulate favoring scattering detectors.”
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06
Improvements in LED and diode laser technology have reduced the cost and increased the stability of photoelectric fire detectors.
Detection · p. 7 · AI confidence 95% · Reported · Pending
“The advent of improvements in light emitting diode and diode laser technology has reduced the cost and increased the stability of photoelectric fire detectors.”
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07
Smoke detector design must be based on low-gravity data because liquid smoke aerosols require on-orbit measurement of smoke particulate size distribution.
Prevention · p. 18 · AI confidence 95% · Reported · Pending
“CSD demonstrated–Smoke detector design must be based on low-g data–Liquid smoke aerosols require on-orbit measurement of smoke particulate size distribution”
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08
The modified P-Trak demonstrated functionality in low-gravity during the DAFT experiment.
Detection · AI confidence 95% · Reported · Pending
“Demonstrated the functionality of the modified P-Trak in low-g”