How to Handle a Fire Onboard a Generation Ship?

[DaveC426913]

so even if they failed completely, after having vaporised everything perfectly up to that point,

Um. Vaporizing everything doesn't make it disappear. The vaporized components contain the same kinetic energy as the unvaporized components (minus whatever the laser pulse imparted on them). Ideally, you'll want both the radiative energy and the physical components to disperse, out of the ship's path. Hopefully, what's left will be spread over a wider area of the ship's proximal defenses. Just one more headache for you.

 

[pinball1970]

Apologies if this has already been mentioned.

Another example of a fire on a space craft.

https://www.nasa.gov/history/25-years-ago-fire-aboard-space-station-mir/

This was a happy ending. Note how long it took to remove toxic fumes from the craft. The escape capsule Soyuz has no fire extinguishers apparently according to Tim Peake. They depressurize the vessel extinguishing the flames.

 

[Strato Incendus]

Um. Vaporizing everything doesn't make it disappear. The vaporized components contain the same kinetic energy as the unvaporized components (minus whatever the laser pulse imparted on them). Ideally, you'll want both the radiative energy and the physical components to disperse, out of the ship's path. Hopefully, what's left will be spread over a wider area of the ship's proximal defenses. Just one more headache for you.

Thanks for pointing this out! ;) On that note, let’s get back to the question of where the captain would send the crew members to be as safe as possible from the barrage, keeping the dumbbell-structure of the ship in mind: In case one or several dust speckles to pierce the ship hull, would citizens be safer in the central pipe, around which the rings rotate? Or would they be safer on the rings themselves?

The holes the speckles would punch into the ship hull are likely so small that they won’t allow a lot of air to escape into space that quickly, I assume? They would detect slowly dropping levels of air pressure, and would quickly send technicians to fix them.

If there are a bunch of speckles punching holes into the hull in different places, that would perhaps finally be one way of getting me to that “disaster which requires a lot of helping hands to fix, and is dangerous” scenario that I need, since it would incentivise the commander to send a lot of male officers “into battle against the universe”. Quite literally, in case some of them end up getting pierced by dust speckles themselves — getting hit by a bullet will seem harmless in comparison, given the speed of the speckles, and what they would do to the human body as a result (we’ve discussed that part before).

Apologies if this has already been mentioned.

Another example of a fire on a space craft.

https://www.nasa.gov/history/25-years-ago-fire-aboard-space-station-mir/

This was a happy ending. Note how long it took to remove toxic fumes from the craft. The escape capsule Soyuz has no fire extinguishers apparently according to Tim Peake. They depressurize the vessel extinguishing the flames.

In fact, it hasn’t! Thanks a lot for this real-world example! :) In particular, this is useful for thinking about “stuff that could ignite”.

The part about the route to the evacuation shuttle is not that useful in my setting, since getting to one of the generation ship’s landing shuttles is still a death sentence if you flee the ship while it’s still in the interstellar medium — you won’t arrive anywhere with those landing shuttles.

Even if the air inside them never ran out, you’d die of old age, much like the older generations on the generation ship itself — except you can’t raise your entire family inside such a shuttle. Even if several generations somehow could survive inside a shuttle, a single shuttle probably does not have enough fuel to decelerate it from the mothership’s 0.125 c coasting speed all by themselves, in order to eventually brake at the target star.

 

[DaveC426913]

...the question of where the captain would send the crew members to be as safe as possible from the barrage, keeping the dumbbell-structure of the ship in mind: In case one or several dust speckles to pierce the ship hull, would citizens be safer in the central pipe, around which the rings rotate? Or would they be safer on the rings themselves?

Def safer in the pipe.

The holes the speckles would punch into the ship hull are likely so small that they won’t allow a lot of air to escape into space that quickly, I assume?

At relativistic speeds, I'm not sure particles would drill holes so much as explode, vaporizing chunks of ablative shielding and leaving craters.

That is, after all, the point of shielding - to
1. absorb and spread the damage out laterally so it doesn't reach the inner hull
2. carry away the kinetic and heat energy with the ablated material.

 

[Strato Incendus]

Def safer in the pipe.

Perfect, thanks a lot! That allows me to keep my evacuation scene, where a security officer guides a bunch of school children away from the ring and to the elevators that lead to the central pipe.

At relativistic speeds, I'm not sure particles would drill holes so much as explode, vaporizing chunks of ablative shielding and leaving craters.

That is, after all, the point of shielding - to
1. absorb and spread the damage out laterally so it doesn't reach the inner hull
2. carry away the kinetic and heat energy with the ablated material.

Sure, and usually, the shielding works. The point is that the sudden increase in density at the outskirts of the star system becomes too much to handle for both the protective cloud in front of the ship (which is being depleted fast) and the deflector lasers, so something does get past.

"Craters", while more destructive than "tiny bullet holes", is still better than "micro-meteor", because the latter would probably be enough to destroy the entire ship. So perhaps, "craters" is exactly the level of destruction I need? How large exactly the craters would be will depend on the individual speckle, I assume - and since they're too small to be seen with the naked eye, the reader has no way of observing where the speckles are coming from.

Hence, I would conclude I can just place and shape my craters wherever I want on the ship, as long as the speckle trajectory makes sense? (Meaning, they should traverse the ship from aft sphere to fore sphere, since, as we established, the ship is already facing backwards at this point.)


Speaking of the ship's own protective dust cloud: How would this be used in conjunction with deflector lasers? Specifically, how can the ship stop its own deflector lasers from depleting its own gas cloud, rather than whatever natural interstellar dust is waiting beyond the ship's own protective dust cloud?