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poisonhemloc.bsky.social
@poisonhemloc.bsky.social
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jayeatonart.bsky.social
This week on #RunawayToTheStars: Fusion spaceships are a radioactive explosion generator with a tiny pressurized box of air on the other end.

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LOG 8: Z-Pinch Fusion The Runaway is a rapid transit vessel (colloquially, a "torchship"), designed to transport cargo and passengers as quickly as possible on intrasystem trips between wormholes. During the majority of a journey, the vessel acceleration is between 8 m/s² and 11 m/s², the comfort range of gravity for most sophonts. While this shaves days off of voyages and reduces crew time spent in microgravity, it requires a great deal of firepower. The Runaway's comparatively tiny habitat sits on top of a massive pair of fuel tanks and z-pinch fusion engines. As plasma fuel is injected into the fusion chamber, the engine’s capacitor banks deliver thousands of electrical pulses per second, creating magnetic fields strong enough to initiate nuclear fusion. This magnetic field “pinches” the plasma along the engine's z-axis into a blinding blue jet of super-heated gases, pushing the ship to its cruising acceleration. Engine Schematic: fuel tanks deuterium capacitor banks shadow shield outer electrode inner electrode plasma electric current The magnetic field follows the direction of the electrical current. magnetic nozzle helium, hydrogen, and neutrons FUSION Image: Bip grumpily holds up a sign in front of one of the deuterium fuel lines with “3He” written on it. Bip: Ideally, I'd have one tank of ³He and one tank of deuterium, that would be more efficient than reacting doot with itself... Talita: Beggars can't be choosers. Also, fusion engines aren't the only propulsion here! Image: She points at a small multi-nozzle rocket on the side of the Runaway’s habitat. Talita: On both ends of the vessel are rings of reaction control systems, aka RCS. These smaller chemical rockets are used for fine maneuvering and approaching dock, since fusion engines are illegal to operate too close to habitation. While fusion engines have less radioactive exhaust than fission engines (which use a process similar to a nuclear bomb for propulsion), they still emit deadly neutron radiation when operating. To protect the inhabitants from being fried by their own engine emissions, there is something called a "shadow shield" between them and the thrusters. This is a block of material that absorbs the thruster radiation and creates a cone of protective shadow around the body of the ship. Image: A diagram of the Runaway shows shape of the shadow cone, and the size of the habitable area of the ship (green) relative to the rest of the vessel. The main habitat is a four story structure under a 12th of the total length of the ship, with a short cargo bay hallway in the upper section of the spine. Most of the length of the vessel is occupied by fuel tanks, shielding, and the engines. Habitat (green) cargo bay (green) RCS (purple) shadow shield (dark blue) radiators (red) Neutron Radiation Zone (white with skulls and crossbones) Radiation Shadow Cone (light blue) This stellar flamethrower also creates a ton of waste heat, which in the insulating vacuum of space, dissipates very slowly. In order to prevent heat from traveling up the spine of the ship and turning the habitat capsule into a multi-story oven, heat from the propulsion system is diverted to the radiator wings. The radiators pump waste heat away from the engine and spine of the ship, giving it more time and space to dissipate, and can glow red-hot while the engine burns. Their triangular shape allows them hide within the shadow cone during burns, and extend to cool faster and provide maintenance access when the ship is coasting or docked.
December 16, 2025 at 11:53 PM
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slowedmountains.bsky.social
A beautiful vision at the pets at home car park
Comic text: I saw a man with two chow chows at the pets at home car park, and next to him his daughter with a chow chow puppy in a baby carrier. Its face was covered in whipped cream.
October 22, 2025 at 8:06 PM