Engineering PapersSearch

NASA NTRS · 20210020516

Fire on the Moon: Solid Fuel Combustion Experiments

Abstract

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.

Explore related subjects

Keep this discovery

Explore connections, maps & timelines

BibTeXRIS

Paul Ferkul, Ya-Ting Liao, Gary Ruff, Daniel Gotti, Jay Owens, Luke Ogorzaly. Fire on the Moon: Solid Fuel Combustion Experiments. https://ntrs.nasa.gov/citations/20210020516

Cite the original work for its findings. Save a collection to share your selection of sources.

KEEP EXPLORING

Related reports

Fire in the Arctic: Current Trends and Future Pathways

Wildland fires in the Arctic are expected to become more frequent and more severe. In recent years, extreme fire seasons have been documented across the Pan-Arctic and boreal in five of the last seven years – including large wildfires in Greenland in 2017 and 2019 over tundra and high carbon soil landscapes and an earlier start of extreme fire seasons in 2023. Future Arctic and boreal fire regimes will experience increased fire risk though the end of this century (McCarty et al., 2021, Senande-Rivera et al., 2022). The main factors affecting the severity and frequency of wildland fires are fuels (vegetated biomass and type of biomass) and fuel condition (dryness), fire weather conditions (relative humidity, drought, precipitation), and ignition (human-caused, lightning). Climate change directly influences all of these drivers, and indirectly also some human-caused ignitions.

Fire

Evaluation of Low-Gravity Smoke Particulate for Spacecraft Fire Detection

Tests were conducted on the International Space Station to evaluate the smoke particulate size from materials and conditions that are typical of those expected in spacecraft fires. Five different materials representative of those found in spacecraft (Teflon, Kapton, cotton, silicone rubber and Pyrell) were heated to temperatures below the ignition point with conditions controlled to provide repeatable sample surface temperatures and air flow. The air flow past the sample during the heating period ranged from quiescent to 8 cm/s. The effective transport time to the measurement instruments was varied from 11 to 800 seconds to simulate different smoke transport conditions in spacecraft. The resultant aerosol was evaluated by three instruments which measured different moments of the particle size distribution. These moment diagnostics were used to determine the particle number concentration (zeroth moment), the diameter concentration (first moment), and the mass concentration (third moment). These statistics were combined to determine the diameter of average mass and the count mean diameter and by assuming a log-normal distribution, the geometric mean diameter and the geometric standard deviations were also calculated. Smoke particle samples were collected on TEM grids using a thermal precipitator for post flight analysis. The TEM grids were analyzed to determine the particle morphology and shape parameters. The different materials produced particles with significantly different morphologies. Overall the majority of the average smoke particle sizes were found to be in the 200 to 400 nanometer range with the quiescent cases and the cases with increased transport time typically producing with substantially larger particles. The results varied between materials but the smoke particles produced in low gravity were typically twice the size of particles produced in normal gravity. These results can be used to establish design requirements for future spacecraft smoke detectors.

Fire