Hey everyone, and thanks in advance for your thoughts. My ongoing project is a document to help authors who want to write some (just some!) realistic physics into their science fiction - think the kind of thing 'The Expanse' did. This is something I already do in-person for a few authors, since I've got good qualifications in physics (including one specifically in space technology), and my day-job is a physics and maths tutor. They've encouraged me to put this together but I've really struggled with finding a clear, accessible, structure: Some people I've run this past want just a very quick rundown of the facts, some want details of the science, some find humour more accessible/more annoying, and some want just pure description, or an example. Because of this the structure I've hit upon, finally, is five subsections per chapter: A fact sheet, a prose section explaining the science, a first person descriptive (almost flash fiction) of what it is / would be like in real life, a worksheet, and list of sources of information.
What I've put here is parts of chapter 5: The factsheet, a sample of the science-explaining prose, and a sample of the descriptive/flash fic. The actual sections are about 4 x as long as the chunks I've posted here. I've omitted the worksheet and list of sources to try and keep this post from being unreadably long. I'm looking for any and all feedback, and if anyone wants to see more of a section, or the worksheet or sources list (I have links to some astronauts describing real-life space near disasters, but have to be careful what I use directly due to copyright!) feel free to PM me.
5: How would astronauts fight fire in weightlessness?
Fact sheet:
Being stuck in a kitchen with a burning toaster is, I once discovered, fairly terrifying. Being in a burning building… well that’s why we have heroic people called ‘the fire service’ who do the ‘save you from a burning building’ thing. But imagine a situation where there’s no fire brigade, the burning building is hermetically sealed, and escaping outside will actually kill you faster than the fire will.
Welcome to firefighting in space. No-one being able to hear you scream is your smallest problem.
Astronaut crews have almost nowhere to run from a fire, and no-one to help them. Tackling a blaze means using whatever equipment they have to hand – on present day space stations that’s just fire extinguishers and ventilator masks. In some space capsules, like the Russian's Soyuz, it’s... well, nothing. But since headlines like ‘Right Stuff Astronauts Die in Space Fire’ don’t sit well with space agencies (and even less so with the right stuff astronauts), preventing and stopping fires in space has become the subject of specialised, very well sealed, in-space experiments. What they've shown is that microgravity fire is a different creature – less aggressive but deceptive, and more adaptable – thanks to the way gas flow changes in weightlessness: On Earth hot air rises in a quick moving column, pulling the flame into a relatively well confined, bright, cone. In weightlessness hot air spreads slowly and diffusely, so flame spreads diffusely, diluting the light it emits – it can become almost undetectable, except in near darkness. The lack of well defined air flow also changes how fast the heat in burning material dissipates, how waste products spread out, and how fires consume oxygen. As a result weightless fires use both less oxygen and less fuel, stay burning at lower temperatures, and are tougher to put out than their gravity bound kin. That lesser appetite can make them less aggressive - but they’re also less predictable: Terrestrial fire always spreads upward faster than any other direction, but when there’s no ‘up’ it spreads randomly....
The experience:
.....I tumble through a hatch and into the hazed air of the station’s core module, a water-foam fire extinguisher clutched in one hand - I barely recall tearing it free from it's wall mounting as I hurled myself through the station's structure. A few meters further along the roughly cuboid living space I spot mission commander Ivonova hovering in the physics lab hatchway, struggling with a small CO2 fire extinguisher’s release catch. An odd, orange-white, glow illuminates her face from inside the lab, and tendrils of more opaque smoke are already reaching out of the meter wide opening. Holding a paper towel from the cleaning kit over my nose and mouth, I pull myself along the off-white wall towards her via cable bundles and locker handles. She snags the bulkier water-foam extinguisher from me, floats it next to her in the hatch, and finally gets her CO2 extingiusher to fire into the burning lab. The snatching motion turns me in midair, and for a second I see:
...John Sheridan, half dressed and face pale, swearing as he flings any flammable objects away from the lab hatch...
...Payload specialist and pilot Ashifa Naseer pulling a ventilator over her head, grabbing onto a worksation with one leg and, incongrously, starting to print something - trajectory data for an emergency flight home I guess – even as sparks fly past her face....
....‘Mickey’ Garibaldi’s hanging in the hatch leading to the hydroponics lab, shouting to Ivanka Iordanaova behind him: “'Vanka grab the ventilators and bolt cutters; We gotta fire!“
My spin brings me back around and, as I grab one of the thick bundles of cable running through the hatch to steady myself I realise we’re going to need Ashifa’s re-entry trajectory: Ivonova’s struggling - in microgravity the extinguisher’s kick demands she use one had to grab the edge of the hatch, making aiming it almost impossible. It’s hard to track the diffuse flames that form in space, they could be...
What I've put here is parts of chapter 5: The factsheet, a sample of the science-explaining prose, and a sample of the descriptive/flash fic. The actual sections are about 4 x as long as the chunks I've posted here. I've omitted the worksheet and list of sources to try and keep this post from being unreadably long. I'm looking for any and all feedback, and if anyone wants to see more of a section, or the worksheet or sources list (I have links to some astronauts describing real-life space near disasters, but have to be careful what I use directly due to copyright!) feel free to PM me.
5: How would astronauts fight fire in weightlessness?
Fact sheet:
- Most fire in space is diffuse, less aggressive, but almost invisible.
- Some liquid fuels continue burning after flames are extinguished, via an unknown mechanism.
- Lithium perchlorate canisters - a common part of life support systems - burn with an intesne, bright flame.
- Weightless fires are tough:
- They needs less oxygen and fuel to survive, resisting smothering.
- If starved of oxygen or fuel they break into pinhead-like flamelets, which spread and replicate until they find a new supply.
- Smoke in spacecraft spreads and builds rapidly, blinding and suffocating even people far away.
- Venting atmosphere can put out fires, but this can mementarily whip a fire into a blowtorch like flame.
- Space stations and ships only carry light fire fighting equipment: Extinguishers and ventilator masks.
- In microgravity fire extinguishers throw the user around (cheers Newton).
- The recommended response to a fire is:
- All crew immediately put on oxygen masks.
- Shut down ventilation to reduce oxygen flow and contain smoke.
- Shut off electrical power to the burning region.
- Tackle the fire using appropriate extinguishers (CO2, water mist or foam).
- Close off the affected compartment if possible.
- Prep for evacuation
Being stuck in a kitchen with a burning toaster is, I once discovered, fairly terrifying. Being in a burning building… well that’s why we have heroic people called ‘the fire service’ who do the ‘save you from a burning building’ thing. But imagine a situation where there’s no fire brigade, the burning building is hermetically sealed, and escaping outside will actually kill you faster than the fire will.
Welcome to firefighting in space. No-one being able to hear you scream is your smallest problem.
Astronaut crews have almost nowhere to run from a fire, and no-one to help them. Tackling a blaze means using whatever equipment they have to hand – on present day space stations that’s just fire extinguishers and ventilator masks. In some space capsules, like the Russian's Soyuz, it’s... well, nothing. But since headlines like ‘Right Stuff Astronauts Die in Space Fire’ don’t sit well with space agencies (and even less so with the right stuff astronauts), preventing and stopping fires in space has become the subject of specialised, very well sealed, in-space experiments. What they've shown is that microgravity fire is a different creature – less aggressive but deceptive, and more adaptable – thanks to the way gas flow changes in weightlessness: On Earth hot air rises in a quick moving column, pulling the flame into a relatively well confined, bright, cone. In weightlessness hot air spreads slowly and diffusely, so flame spreads diffusely, diluting the light it emits – it can become almost undetectable, except in near darkness. The lack of well defined air flow also changes how fast the heat in burning material dissipates, how waste products spread out, and how fires consume oxygen. As a result weightless fires use both less oxygen and less fuel, stay burning at lower temperatures, and are tougher to put out than their gravity bound kin. That lesser appetite can make them less aggressive - but they’re also less predictable: Terrestrial fire always spreads upward faster than any other direction, but when there’s no ‘up’ it spreads randomly....
The experience:
.....I tumble through a hatch and into the hazed air of the station’s core module, a water-foam fire extinguisher clutched in one hand - I barely recall tearing it free from it's wall mounting as I hurled myself through the station's structure. A few meters further along the roughly cuboid living space I spot mission commander Ivonova hovering in the physics lab hatchway, struggling with a small CO2 fire extinguisher’s release catch. An odd, orange-white, glow illuminates her face from inside the lab, and tendrils of more opaque smoke are already reaching out of the meter wide opening. Holding a paper towel from the cleaning kit over my nose and mouth, I pull myself along the off-white wall towards her via cable bundles and locker handles. She snags the bulkier water-foam extinguisher from me, floats it next to her in the hatch, and finally gets her CO2 extingiusher to fire into the burning lab. The snatching motion turns me in midair, and for a second I see:
...John Sheridan, half dressed and face pale, swearing as he flings any flammable objects away from the lab hatch...
...Payload specialist and pilot Ashifa Naseer pulling a ventilator over her head, grabbing onto a worksation with one leg and, incongrously, starting to print something - trajectory data for an emergency flight home I guess – even as sparks fly past her face....
....‘Mickey’ Garibaldi’s hanging in the hatch leading to the hydroponics lab, shouting to Ivanka Iordanaova behind him: “'Vanka grab the ventilators and bolt cutters; We gotta fire!“
My spin brings me back around and, as I grab one of the thick bundles of cable running through the hatch to steady myself I realise we’re going to need Ashifa’s re-entry trajectory: Ivonova’s struggling - in microgravity the extinguisher’s kick demands she use one had to grab the edge of the hatch, making aiming it almost impossible. It’s hard to track the diffuse flames that form in space, they could be...