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Proceedings ArticleDOI

Fire Safety in the Low-Gravity Spacecraft Environment

12 Jul 1999-
TL;DR: In this paper, material flammability and fire spread in microgravity are significantly affected by atmospheric flow rate, oxygen concentration, and diluent composition, which can lead to modifications and correlations to standard material assessment tests for prediction of fire resistance in space.
Abstract: Research in microgravity (low-gravity) combustion promises innovations and improvements in fire prevention and response for human-crew spacecraft. Findings indicate that material flammability and fire spread in microgravity are significantly affected by atmospheric flow rate, oxygen concentration, and diluent composition. This information can lead to modifications and correlations to standard material-assessment tests for prediction of fire resistance in space. Research on smoke-particle changes in microgravity promises future improvements and increased sensitivity of smoke detectors in spacecraft. Research on fire suppression by extinguishing agents and venting can yield new information on effective control of the rare, but serious fire events in spacecraft.

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Citations
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Journal ArticleDOI
01 Jan 2015
TL;DR: In this article, the flame spread rate (FSR) over polyethylene (PE) insulated copper (Cu) wires with inner core diameter (dc) of 0.30mm, 0.50mm 0.80mm and insulation thickness (δp) with inclination angles ranged from −90° to +90°.
Abstract: This paper reveals experimentally the flame spread rate (FSR) [both upward (concurrently) and downward (opposed)] over electric wire with high thermal conductivity metal core at different inclination angles, which is new in view of that previous works about such inclination effect are mainly focusing on the material (wood, PMMA……) where the conductivity through media itself is not so important. Polyethylene (PE) insulated copper (Cu) wires with inner core diameter (dc) of 0.30 mm, 0.50 mm 0.80 mm and insulation thickness (δp) of 0.15 mm, 0.30 mm are studied with inclination angles ranged from −90° to +90°. Their behaviors are examined in both naturally normal (Hefei city with altitude of 50 m; 100 kPa) and a reduced (Lhasa city with altitude of 3650 m; 64 kPa) ambient pressure atmosphere. Results show that with increase in inclination angles from −90° to 90°, the FSR first decreases and then increases (“U” trend) with its value being lowest at nearly horizontal condition (0°) in both pressures, which is quite different from what we normally know for other materials with low thermal conductivity. Two characteristic lengths, the flame base width (Wf) and the pyrolysis zone length (Lp), are found to account for this special variation behavior with their variation trend with inclination angle being consistent with that of FSR. A simplified heat balance analysis concerning core thermal conduction effect is performed to calculate the FSR in relation to these two characteristic lengths, thermal conductivity of the metal core as well as the effective convection heating of the wire by the flame base. The calculated FSR are shown to be in fairly good agreement with the measured values at different inclination angles for different inner core (wire) diameters in both ambient pressures.

78 citations

01 Jun 2005
TL;DR: The selection of spacecraft and space suit atmospheres for future human space exploration missions will play an important, if not critical, role in the ultimate safety, productivity, and cost of such missions as discussed by the authors.
Abstract: The selection of spacecraft and space suit atmospheres for future human space exploration missions will play an important, if not critical, role in the ultimate safety, productivity, and cost of such missions. Internal atmosphere pressure and composition (particularly oxygen concentration) influence many aspects of spacecraft and space suit design, operation, and technology development. Optimal atmosphere solutions must be determined by iterative process involving research, design, development, testing, and systems analysis. A necessary first step in this process is the establishment of working bounds on the atmosphere design space.

67 citations

Journal ArticleDOI
TL;DR: In this article, an international research team has been assembled to reduce the uncertainty and risk in the design of spacecraft fire safety systems by testing material samples in a series of flight experiments (Saffire 1, 2, and -3) to be conducted in an Orbital Science Corporation Cygnus vehicle after it has undocked from the International Space Station (ISS).

57 citations


Cites background from "Fire Safety in the Low-Gravity Spac..."

  • ...The microgravity combustion science research conducted since the mid-1980s has significantly expanded the knowledge of the behavior of and resultant risk of a fire in the reduced gravity environment of a spacecraft [4, 13, 17, 18]....

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Journal ArticleDOI
TL;DR: In this article, the influence of neighboring spread on the mass burning rate was assessed in microgravity, while it would not at normal gravity, or vice versa, and the experimental results are expected to deliver meaningful guidelines for future, planned experiments at a larger scale.

48 citations


Cites background from "Fire Safety in the Low-Gravity Spac..."

  • ...[1], the characterization of flame spread over the coating of a single wire in microgravity has been studied extensively in recent years [2-9]....

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Proceedings ArticleDOI
19 Sep 2006-Space
TL;DR: Orbital's Lunar Surface Infrastructure is comprised of five areas: Human Transport System, Cargo Transport System (CTS), Lunar Exploration Surface Infrastructure, Lunar InSpace Support Systems, and Lunar Precursor and Science System.
Abstract: Orbital’s Lunar Surface Infrastructure is comprised of five areas: Human Transport System, Cargo Transport System, Lunar Exploration Surface Infrastructure, Lunar InSpace Support Systems, and Lunar Precursor and Science System. This paper focuses on the Cargo Transport System and the Lunar Exploration Surface Infrastructure and discusses some of the critical challenges faced, alternatives considered, and Orbital’s solution for these challenges. In addition to presenting a Lunar Surface Exploration architecture that fits within program constraints and highlighting the architecture defining trade studies, e.g. habitat geometry, habitat radiation shielding, lunar surface power, and cargo delivery system, a launch manifest and strategy for lunar base expansion are also discussed.

32 citations

References
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Journal ArticleDOI
01 Jan 1989
TL;DR: In this article, the flame behavior is observed to depend strongly on the magnitude of the relative velocity between the flame and the atmosphere, and a low velocity quenching limit is found in low oxgen environments.
Abstract: Diffusion flame spread over a thin solid fuel in quiescent and slowly moving atmospheres is studied in microgravity. The flame behavior is observed to depend strongly on the magnitude of the relative velocity between the flame and the atmosphere. In particular, a low velocity quenching limit is found to exist in low oxgen environments. Using both the microgravity results and previously published data at high opposed-flow velocities, the flame spread behavior is examined over a wide velocity range. A flammability map using molar oxygen percentages and characteristic relative velocities as coordinates is constructed. Trends of flame spread rate are determined and mechanisms for flame extinction are discussed.

122 citations


"Fire Safety in the Low-Gravity Spac..." refers background in this paper

  • ...Equally important, the flammability range, defined by the limiting oxygen concentration for flame spread, with a slow, forced flow in microgravity is greater than that in corresponding downward spread [32] and approximately equal to that for upward spread in normal gravity [33]....

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01 Jul 2005
TL;DR: In this paper, the authors summarize the life support functions and processes used onboard U.S. and U.R/Russian space habitats and provide additional information on the ECLS systems.
Abstract: Human exploration and utilization of space requires habitats to provide appropriate conditions for working and living. These conditions are provided by environmental control and life support systems (ECLSS) that ensure appropriate atmosphere composition, pressure, and temperature; manage and distribute water, process waste matter, provide fire detection and suppression; and other functions as necessary. The tables in appendix I of NASA RP 1324 "Designing for Human Presence in Space" summarize the life support functions and processes used onboard U.S. and U.S.S.R/Russian space habitats. These tables have been updated to include information on thermal control methods and to provide additional information on the ECLS systems.

113 citations

Journal ArticleDOI
01 Jan 1998
TL;DR: In this article, an experimental study of flame spread over ETFE (ethylene-tetrafluoroethylene)-insulated wires has been performed in microgravity to obtain basic data on the fire safety of wire insulation.
Abstract: An experimental study of flame spread phenomena over ETFE (ethylene-tetrafluoroethylene)-insulated wires has been performed in microgravity to obtain basic data on the fire safety of wire insulation. Three samples with different wire diameters, d w (0.32–0.51 mm) and the same insulation thickness, δ (0.15 mm) were investigated. The effects of the parameters thought dominant for wire combustion in fires: the ambient oxygen concentration, wire initial temperature, T i , wire diameter, d w , pressure, and dilution gas were investigated in the microgravity experiments. A series of comparative experiments were also conducted at normal gravity. The results show that flame spread rates in microgravity are higher than vertically downward spread rates at normal gravity when oxygen concentration is greater than 30% O 2 . However, with wire preheating, the spread rate in microgravity is higher than the downward spread rate at normal gravity even at lower O 2 concentrations. The increase in flame spread rates in microgravity became larger with decreases in d w . The effect of pressure on the flame spreading appeared very small, and lower pressure caused extinction of the flames in microgravity. The increase in flame spread rates in microgravity was especially large with CO 2 dilution, and this must be taken into account when selecting extinguisher gas. The microgravity experiments with CO 2 dilution gave rise to a new unsteady flame spread phenomenon for flame spreading over the wire: this phenomenon involves discontinuous flames partly occurring ahead of the spreading flame front.

93 citations


"Fire Safety in the Low-Gravity Spac..." refers background in this paper

  • ...5 insulations, although the wires themselves may have served as a heat source or sink, complicating the interpretation of these results [31]....

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Journal ArticleDOI
TL;DR: In this paper, flame-retarded epoxy composites and phenolic composites containing fiberglass, aramid (Kevlar® 49), and graphite fiber-reinforcements were tested using the NASA upward flame propagation test, the controlled-atmosphere cone calorimeter test, and the liquid oxygen (LOX) mechanical impact test.
Abstract: Flame-retarded epoxy composites and phenolic composites containing fiberglass, aramid (Kevlar® 49), and graphite fiber-reinforcements were tested using the NASA upward flame propagation test, the controlled-atmosphere cone calorimeter test, and the liquid oxygen (LOX) mechanical impact test. The upward flame propagation test showed that phenolic/graphite had the highest flame resistance and epoxy/graphite had the lowest flame resistance. The controlled-atmosphere cone calorimeter was used to investigate the effect of oxygen concentration and fiber reinforcement on the burning behavior of composites. The LOX mechanical impact test showed that epoxy/fiberglass had the lowest ignition resistance and phenolic/aramid had the highest ignition resistance in LOX. The composites containing epoxy resin and/or aramid fiber reinforcement reacted very violently in LOX upon mechanical impact. © 1997 by John Wiley & Sons, Ltd.

91 citations


"Fire Safety in the Low-Gravity Spac..." refers methods in this paper

  • ...The NASA Test 1 simulates the beginning of a fire with an ignition flux of typically 75 kW/m(2) maintained for 25 sec [11]....

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01 Jan 1998
TL;DR: The International Space Station (ISS) incorporates elements designed and developed by an international consortium led by the United States (U.S.), and by Russia (R.S.). as discussed by the authors describes the design and operation of the ECLS Systems (ECLSS) on board the ISS.
Abstract: The International Space Station (ISS) incorporates elements designed and developed by an international consortium led by the United States (U.S.), and by Russia. For this cooperative effort to succeed, it is crucial that the designs and methods of design of the other partners are understood sufficiently to ensure compatibility. Environmental Control and Life Support (ECLS) is one system in which functions are performed independently on the Russian Segment (RS) and on the U.S./international segments. This document describes, in two volumes, the design and operation of the ECLS Systems (ECLSS) on board the ISS. This current volume, Volume 1, is divided into three chapters. Chapter 1 is a general overview of the ISS, describing the configuration, general requirements, and distribution of systems as related to the ECLSS, and includes discussion of the design philosophies of the partners and methods of verification of equipment. Chapter 2 describes the U.S. ECLSS and technologies in greater detail. Chapter 3 describes the ECLSS in the European Attached Pressurized Module (APM), Japanese Experiment Module (JEM), and Italian Mini-Pressurized Logistics Module (MPLM). Volume II describes the Russian ECLSS and technologies in greater detail. These documents present thorough, yet concise, descriptions of the ISS ECLSS.

77 citations


"Fire Safety in the Low-Gravity Spac..." refers background in this paper

  • ...Proposed venting capability is the attainment of a total pressure of 30 kPa or less within 10 minutes [52]....

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  • ...The ISS suppression system is designed to release sufficient agent to reduce the ambient oxygen in a local affected volume to half the original concentration within 60 seconds [52]....

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  • ..., European, Japanese, and Italian space agencies have identical fire prevention, detection, and suppression requirements and operations [52]....

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