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Paul Ferkul

Publications and source records attributed to Paul Ferkul.

9 records
All sourcesNASA NTRSDOE OSTI
NASA NTRSDate not supplied

Fire Safety Implications of Preliminary Results from Saffire IV and V Experiments on Large Scale Spacecraft Fires

The spread and growth of flames over large solid fuel samples and their effect on the pressurized spacecraft were studied inside the Cygnus spacecraft while in orbit after departing the International Space Station. These experiments were developed by NASA’s Advanced Exploration Systems Division in the Human Exploration and Operations Mission Directorate. The ignited materials consisted of poly-methyl methacrylate (PMMA), cotton fabric and a cotton/fiberglass fabric blend. The samples were all 40 cm wide and with various lengths ranging from 18 cm for the PMMA samples to 50 cm for the fabrics. The overall results from these tests and their impact on the spacecraft are presented with emphasis on the fire safety implications of the results. The experiments included, a post-fire cleanup system, vehicle internal volume measurements, and transport of acid gases (HCl and HF). Measurements included video images, flame spread rate, flame temperatures and radiant heat output; energy release through oxygen calorimetry; distributed measurements of CO2 concentration and temperature at six locations in the spacecraft; CO2, CO, O2, HF and HCl concentrations; vehicle pressurized volume; and aerosol concentrations. Details of the flame growth and spread are discussed in other papers as are details of the post-fire cleanup system performance. The fire events had a measurable impact on the vehicle pressure, temperature, and carbon dioxide concentration. However, despite having heat release rates up to 10 kW, the average vehicle conditions did not rise to unacceptable levels. The combined results of the experiments provide significant new understanding of the impact of sample and flow duct height on flame spread and growth in addition to an improved perspective of the impact of a fire event on a spacecraft.

micorgravity↗
NASA NTRSDate not supplied

Fire Safety Implications of Preliminary Results from Saffire IV and V Experiments on Large Scale Spacecraft Fires

The spread and growth of flames over large solid fuel samples and their effect on the pressurized spacecraft were studied inside the Cygnus spacecraft while in orbit after departing the International Space Station. These experiments were developed by NASA’s Advanced Exploration Systems Division in the Human Exploration and Operations Mission Directorate. The ignited materials consisted of poly-methyl methacrylate (PMMA), cotton fabric and a cotton/fiberglass fabric blend. The samples were all 40 cm wide and with various lengths ranging from 18 cm for the PMMA samples to 50 cm for the fabrics. The overall results from these tests and their impact on the spacecraft are presented with emphasis on the fire safety implications of the results. The experiments included, a post-fire cleanup system, vehicle internal volume measurements, and transport of acid gases (HCl and HF). Measurements included video images, flame spread rate, flame temperatures and radiant heat output; energy release through oxygen calorimetry; distributed measurements of CO2 concentration and temperature at six locations in the spacecraft; CO2, CO, O2, HF and HCl concentrations; vehicle pressurized volume; and aerosol concentrations. Details of the flame growth and spread are discussed in other papers as are details of the post-fire cleanup system performance. The fire events had a measurable impact on the vehicle pressure, temperature, and carbon dioxide concentration. However, despite having heat release rates up to 10 kW, the average vehicle conditions did not rise to unacceptable levels. The combined results of the experiments provide significant new understanding of the impact of sample and flow duct height on flame spread and growth in addition to an improved perspective of the impact of a fire event on a spacecraft.

microgravity fire safety↗
NASA NTRSDate not supplied

Fire on the Moon: Solid Fuel Combustion Experiments

As NASA plans to return people to the Moon for extended durations, we present an experiment concept to understand fire and material flammability there. A small combustion chamber would be used to conduct the first-ever combustion tests on another world. Multiple fuel samples are to be individually burned in Lunar gravity, with cameras and other sensors recording flame characteristics. The main hypothesis is that some materials burning in Lunar-g are more flammable than on Earth. The reason is that buoyant flow has two counteracting effects on material flammability. Increasing gravity level permits more fresh oxygen to be supplied to the flame, but if the buoyant speed is too high, combustion chemistry and increased cooling hinder combustion. This has important implications for the current 1-g material screening method used by NASA. Oxygen limits for upward and downward spread on the Moon will be compared to 1-g values. Earth-based partial gravity facilities (drop towers, aircraft, and sounding rockets) will be used to refine the experiment and provide some limited-duration data. Measured flame characteristics in 1-g and Lunar-g will be compared to a detailed model. These will refine pressure-gravity scaling relations that will then be applied to other g-levels. The work directly addresses knowledge gaps in flammability and crew safety as defined in several NASA strategic documents.

Fire↗
NASA NTRSDate not supplied

Preliminary Results from the Saffire VI Experiment

Preliminary results are presented for one test of the last flight of the Spacecraft Fire Experiment (Saffire VI) which was conducted on an orbiting Cygnus spacecraft. These experiments directly address the risks associated with our understanding of spacecraft fire behavior at practical length scales and geometries. The lack of this experimental data has forced spacecraft designers to base their designs and safety precautions on 1-g understanding of flame spread, flame self-extinguishment, fire detection, and suppression. The Saffire experiment was developed by an international team of investigators with the goal of addressing open issues in spacecraft fire safety. NASA’s Spacecraft Fire Safety Demonstration Project was formulated with the goal of conducting a series of large-scale experiments in spacecraft environments that represent practical spacecraft fires. These tests spanned 1.5 to 3.2 kW with free air volumes of 17 to 19 cubic meters. The final flight in the series of six experiments examined concurrent spread over large samples (all 41 cm wide) including a thin sheet of flammable fuel (cotton/fiberglass 50 cm long); 2-sided spread over 1 cm thick polymethyl methacrylate (PMMA) (18 cm long); 1-sided spread over 0.5 cm thick (18 cm long); and Nomex fabric (7 cm long). Results are presented for the PMMA samples, the SIBAL sample, and the thin cotton samples from Saffire IV and V. The flame heat release is determined and compared to the overall temperature rise in the spacecraft and the change in the concentration of carbon dioxide and carbon monoxide in the spacecraft. Overall, the temperature and pressure rise in the spacecraft were found to be less significant than the increase in carbon dioxide and carbon monoxide.

fire↗
NASA NTRSDate not supplied

Preliminary Results from the Saffire VI Experiment

The preliminary results are presented for one test of the last flight of the Spacecraft Fire Experiment (Saffire VI) which was conducted on an orbiting Cygnus spacecraft. These experiments directly address the risks associated with our understanding of spacecraft fire behavior at practical length scales and geometries. The lack of this experimental data has forced spacecraft designers to base their designs and safety precautions on 1-g understanding of flame spread, flame self-extinguishment, fire detection, and suppression. The Saffire experiment was developed by an international team of investigators with the goal of addressing open issues in spacecraft fire safety. NASA’s Spacecraft Fire Safety Demonstration Project was designed with the goal of conducting a series of large-scale experiments in spacecraft environments that represent practical spacecraft fires. The final flight examined concurrent spread over large samples (all 41 cm wide) including a thin sheet of flammable fuel (cotton/fiberglass 50 cm long); 2-sided spread over 1 cm thick polymethyl methacrylate (PMMA) (18 cm long) ; 1-sided spread over 0.5 cm thick (18 cm long); and Nomex fabric (7 cm long). This paper focusses on the two-sided PMMA sample. The flame heat release is determined and is compared to the overall temperature rise in the spacecraft and the change in the concentration of carbon dioxide and carbon monoxide in the spacecraft.

fire↗
NASA NTRSDate not supplied

Flammability of Materials on the Moon

Some materials have recently been found to exhibit increased flammability in Lunar gravity. The reduced buoyancy driven flow on the Moon may present a goldilocks region of decreased convective cooling, while still supplying adequate oxidizer to the flame zone. Combined with the desired elevated oxygen habitat of exploration architectures and the difficulty of rescue, the combination could present increased risk to crew. Flammability of Materials on the Moon will be delivered to the Lunar surface on an HLS lander, and will burn four samples; SIBAL fabric will be exposed to normal air while the PMMA rods will be exposed to the normoxic Space Exploration Atmospheres (SEA) with elevated oxygen in a small atmospheric chamber. Each fuel will have two tests each, one burning upward and one burning downward. The results of flame size, spread rate, atmosphere changes, and extinction oxygen concentration will then be analyzed and used to help quantify the risk and mitigation for future exploration missions.

flammability↗
NASA NTRSDate not supplied

Flammability of Materials on the Moon

Lunar gravity has been found to increase the limits of flammability for some materials compared to Earth gravity, presenting a goldilocks zone of reduced convective heat loss, while generating enough buoyant flow to replenish fresh oxygen into the flame zone. Combined with the elevated oxygen concentrations of planned Space Exploration Atmospheres (Sea), a long duration fire experiment in Lunar gravity is important to help understand and mitigate the increased risk. Flammability of Materials on the Moon (FM2) is a robotic, self-contained, combustion chamber which will be sent to the surface of the Moon on a Commercial Lunar Payload Services (CLPS) lander mission CP-21. The environmental control system can replicate and conduct fire experiments automatically in the expected atmospheres, specifically 21% oxygen at 14.7 psia, and 34% oxygen at 8.2 psia, which are of immediate interest to the Human Lander System (HLS) and Lunar Rover. The laboratory prototype became operational this summer. There are four samples currently planned; two SIBAL fabrics (cotton/fiberglass blend) which will be burned in air and two acrylic rods which will be burned in Normoxic Space Exploration Atmospheres (SEA). One of each fuel will be burned upward and downward. SIBAL fabric has been found to only burn downward in air in lunar gravity (via Lunar gravity centrifuge and parabolic flight) where on Earth’s gravity it extinguishes immediately after ignition.

Jennifer Zayac↗