The Spacecraft Fire Experiment (Saffire) - Objectives, Development and Status
Schoren, William, Ruff, Gary A., Urban, David L.
Experiments: SAFFIRE I, SAFFIRE III
Since 2012, the Spacecraft Fire Experiment (Saffire) has been under development by the Spacecraft Fire Safety Demonstration (SFS Demo) project that is funded by NASA's Advanced Exploration Systems Division in the Human Exploration and Operations Mission Directorate. The overall objective of this project is to reduce the uncertainty and risk associated with the design of spacecraft fire safety systems for NASA's exploration missions. This is accomplished by defining, developing, and conducting experiments that address gaps in spacecraft fire safety knowledge and capabilities identified by NASA's Fire Safety System Maturation Team. This paper describes the three Spacecraft Fire Experiments (Saffire-I, -II, and -III) that were developed at NASA-GRC and that will conduct a series of material flammability tests in low-gravity and at length scales that are realistic for a spacecraft fire. The experiments will be conducted in Orbital ATK's Cygnus vehicle after it has unberthed from the International Space Station. The tests will be fully automated with the data downlinked at the conclusion of the test and before the Cygnus vehicle reenters the atmosphere. The objectives of these experiments are to (1) determine how rapidly a large scale fire grows in low-gravity and (2) investigate the low-g flammability limits compared to those obtained in NASA's normal gravity material flammability screening test. The hardware for these experiments has been completed and is awaiting their respective launches, all planned for 2016. This paper will review the objectives of these experiments and how they address several of the knowledge gaps for NASA's exploration missions. The hardware development will be discussed including several novel approaches that were taken for testing and evaluation of these series payloads. The status of the missions and operational status will also be presented.
Test conditions.
Extracted from the paper by AI · “Verified” means a person checked it
| Fuel | O₂ | Pressure | Airflow | Sensors | Source | AI conf. | Status |
|---|---|---|---|---|---|---|---|
| SIBAL cloth (75% cotton, 25% fiberglass by weight) 0.94 meters long and 0.4 meters wide |
— | — | 20 cm/s | Cameras, Signal conditioning card | p. 2 | 95% | Pending |
| SIBAL cloth (75% cotton, 25% fiberglass by weight) 0.94 meters long and 0.4 meters wide |
— | — | 30 cm/s | Cameras, Signal conditioning card | p. 2 | 95% | Pending |
| PMMA, SIBAL, Nomex, Silicone, opposed Silicone 9 samples, each 5 cm x 29 cm |
21% O2 by volume (expected concentration) | — | — | Cameras, Signal conditioning card | p. 2 | 90% | Pending |
Findings.
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01
Prior microgravity combustion experiments were limited to samples no larger than 10 cm in length and width, whereas Saffire samples are approximately 0.94 m x 0.4 m.
Other · p. 1 · AI confidence 95% · Reported · Pending
“Prior experiments have been limited to samples no larger than 10 cm in length and width whereas a serious spacecraft fire would likely be much larger and consume much more material.”
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02
SIBAL cloth is a composite fabric consisting of cotton on a fiberglass substrate that burns like cotton but maintains structural integrity after the cotton is consumed.
Other · p. 2 · AI confidence 95% · Reported · Pending
“It is called SIBAL cloth because it was developed for the Solid Inflammability Boundary at Low-Speeds (SIBAL) spaceflight experiment and has been used in many space experiments because it burns like cotton but maintains structural integrity after the cotton is consumed.”
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03
The Saffire experiments are conducted in Orbital ATK’s Cygnus vehicle after unberthing from the ISS and before atmospheric reentry.
Other · p. 1 · AI confidence 95% · Reported · Pending
“The experiments will be conducted in Orbital ATK’s Cygnus vehicle after it has unberthed from the International Space Station.”
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04
The experiment module consists of a flow duct containing the sample card and an adjacent avionics bay, with air drawn through the duct by fans.
Other · p. 2 · AI confidence 95% · Reported · Pending
“The experiment package consists of a flow duct and an adjacent avionics bay... Air is drawn through the flow duct by fans located at the top of the duct with flow straighteners at the bottom of the experiment module.”
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05
Saffire-I, -II, and -III are the first experiments of their kind to evaluate low-g material flammability with direct implications for fire safety on future exploration vehicles.
Other · AI confidence 95% · Reported · Pending
“The experiments being developed for Saffire-I, -II, and –III will be the first of their kind to evaluate low-g material flammability with direct implications for fire safety on future exploration vehicles.”