Hearth on a spacecraft might be catastrophic. It may unfold rapidly in a confined area, and for trapped astronauts, there could also be no escape. It’s fading in time now, however Apollo 1, which was to be the primary crewed Apollo mission, by no means bought off the bottom due to a fireplace that killed the crew. There’ve been different harmful spacecraft fires too, just like the one onboard the Russian Mir space station in 1997.
In an effort to grasp how hearth behaves in spacecraft, NASA started its Saffire (Spacecraft Hearth Security Experiment) in 2016. Saffire was an eight-year, six-mission effort to check how hearth behaves in area. The ultimate Saffire take a look at was accomplished on January ninth.
Hearth behaviour in buildings right here on Earth is well-studied and well-understood. Hearth prevention and suppression are essential parts in constructing design. It is sensible to convey that very same stage of understanding to area journey and even to surpass it.
“How huge a fireplace does it take for issues to get unhealthy for a crew?” requested Dr. David City, Saffire principal investigator at NASA’s Glenn Analysis Centre. “This sort of work is finished for each different inhabited construction right here on Earth – buildings, planes, trains, vehicles, mines, submarines, ships – however we hadn’t finished this analysis for spacecraft till Saffire.”
NASA has carried out six experiments below Saffire, and every one was carried out in an uncrewed Cygnus cargo automobile after it accomplished its provide mission to the ISS. The automobiles are despatched into the environment to fritter away, and the experiments are run previous to the automobile’s destruction. Saffire 1 ran in 2016 inside an avionics bay with an airflow duct. The bay contained a cotton and fibreglass burn mix, which was ignited remotely with a sizzling wire.
Subsequent Saffire experiments examined how completely different supplies burned, together with the fire-resistant material Nomex and even acrylic spacecraft home windows. Assessments additionally included diverse oxygen flows, completely different atmospheric pressures, and completely different oxygen ranges. Every Saffire take a look at generated essential information on how hearth behaves inside spacecraft.
The ultimate phase of the Saffire program, Saffire-VI, was carried out on January ninth, 2024, previous to the uncrewed Northrop Grumman Cygnus spacecraft carrying the experiment burning up throughout re-entry. Saffire-VI was completely different than its predecessors in this system as a result of the experiment had increased oxygen content material and decrease strain much like precise situations in spacecraft.
“The Saffire circulate unit is a wind tunnel,” mentioned Dr. Gary Ruff, Saffire challenge supervisor at NASA’s Glenn Analysis Middle. “We’re pushing air by it. As soon as take a look at situations are set, we run {an electrical} present by a skinny wire, and the supplies ignite.”
Hearth in a confined surroundings does extra than simply harm issues and burn individuals. It additionally generates dangerous combustion by-products. Alongside the predictable carbon monoxide and carbon dioxide, a fireplace onboard a spacecraft can generate hint quantities of hydrogen fluoride, hydrogen chloride, and hydrogen cyanide. Hydrogen fluoride is a really poisonous chemical, and publicity requires speedy medical consideration. Hydrogen chloride is an irritant that may turn out to be deadly, and hydrogen cyanide can harm the mind, coronary heart, and lungs and will also be deadly. A bit of apparatus known as the Combustion Product Monitor (CPM) instrument makes use of laser spectroscopy to investigate the contents of the smoke and detect these hazardous chemical compounds.
Cameras contained in the experiment file what occurs, whereas different devices outdoors accumulate information. After the experiments accumulate their information, it’s downloaded earlier than the Cygnus automobile is shipped plummeting towards its atmospheric destruction. By altering variables like oxygen content material and circulate and atmospheric strain, the experiments collect information that the researchers use to construct a predictive mannequin of fireside behaviour aboard a spacecraft.
“You’ve bought a warmth launch price and a price of launch of combustion merchandise,” Ruff mentioned. “You possibly can take these as mannequin enter and predict what’s going to occur in a automobile.”
At this time limit, people are poised for an enormous leap. We’re working in the direction of establishing a presence on the Moon. From there, future crewed missions to Mars beckon. Researchers are learning the way to shield astronauts’ well being throughout these flights by understanding how their our bodies reply to prolonged time in microgravity, publicity to radiation, and different hazards. Stopping fires and extinguishing them rapidly are crucial points in spaceflight and astronaut security, particularly when astronauts are so far-off there’s no probability of any help.
The fashions constructed on Saffire information will assist missions succeed and assist everybody get dwelling safely.
