Browsing by Author "Nagel, Christopher"
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Item Characterization of Laptop Fires in Spacecraft(49th International Conference on Environmental Systems, 2019-07-07) Padilla, Rosa; Dietrich, Daniel; Lynch, Kelly; Juarez, Alfredo; Harper, Susana; Nagel, Christopher; Ruff, Gary; Urban, DavidAn accidental fire involving the Lithium-Ion (Li-ion) battery in a laptop computer is one of the most likely fire scenarios on-board a spacecraft. These fires can occur from a defect in the battery that worsens with time, over-charging the battery and leading to failure or accidental damage caused by thermal runaway. While this is a relatively likely fire scenario, very little is known about the how a laptop computer fire would impact a sealed spacecraft. The heat release would likely cause a pressure rise, possibly exceeding the pressure limit of the vehicle and causing a relief valve to open. The combustion products from the fire could pose a short-term and long-term health hazard to the crew and the fire itself could cause injury to the crew and damage to the spacecraft. Despite the hazard posed by a laptop fire, there is little quantitative data on the fire size, heat release and toxic product formation. This paper presents the results of initial attempts to quantify the fire resulting from a failed laptop battery tested at the NASA White Sands Test Facility (WSTF). The fire size and characteristics such as maximum heat release rate, total heat release, maximum temperatures and fire duration are determined. Using existing models and correlations for fires, the measured fire characteristics are extrapolated to laptop fires on a vehicle the approximate size of the Orion spacecraft.Item Orion Portable Fire Extinguisher Performance Testing against a Laptop Lithiom-Ion Battery Stored Energy Fire - Method, Magnesium Fires, & Combustion By-product Toxicity(48th International Conference on Environmental Systems, 2018-07-08) Harper, Susana; Juarez, Alfredo; Woods, Brenton; Beeson, Harold; Coan-Skow, Mary Rachel; Nagel, Christopher; Casper, Stephanie; Tarver, SterlingAs part of the qualification of the International Space Station (ISS) Fine Water Mist (FWM) Portable Fire Extinguisher (PFE) several test methods were developed to determine against stored energy sources. The most challenging of these devised stored energy fire test methods proved to be the Li-Ion battery fire test scenario. The intended use of new water based PFE technology on the Orion Crew capsule spurred the need for the same type of evaluation focused on the sources of stored energy slated for use on Orion. Laptops were identified as a realistic potential source for potential stored energy fires requiring a modified li-ion battery fire test scenario. In addition to open test cell (ambient oxygen concentration) testing to evaluate new proposed PFE performance, sealed chamber (20.9 & elevated oxygen concentration) testing was also performed. Chamber testing included combustion product sampling at various fire progression points for analysis and application to Orion emergency equipment design and response planning. Fire extinguisher stored energy fire test methodology was modified and testing performed. Initial tests indicated ignition of the magnesium cases was possible and further testing was performed to assess the damage potential of the new risk as well as the use of new Water Spray PFE as a means to combat this type of fire. The new Water Spray PFE technology proved effective in extinguishing laptop stored energy fires and much was learned in the way these types of fires progressed., Findings indicate potential Mg ignition mitigation strategies to be further investigated.