The point defense cannons (PDC) on the ships are based on modern systems used on seagoing naval ships. Because ships in The Expanse do not have energy shields, they are the only defense against guided weapons like torpedoes.
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'Slingshotting' is an illegal extreme sport. The ships are homemade one-person craft that fly through space using only a single thrust of the engine and a carefully plotted course. They compete by 'slingshotting' around the gravity wells of planets and other celestial bodies. Glory awaits those who survive.
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In the novels, 'slingshotting' wasn't introduced until the third book, Abaddon's Gate.
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You may recognize Chad L. Coleman from his roles as Tyreese Williams on The Walking Dead and Dennis 'Cutty' Wise on The Wire.
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The railguns fired by the Donnager and its attackers use a charged plasma to extend the effective length of the gun, increasing projectile velocity.
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The Command Information Center (CIC) on the Donnager is a smaller compartment inside a much larger one. The idea is that critical ship functions are separated into self-sealing sections of the ship in case the ship is breached, allowing the ship to keep functioning even with large areas in vacuum.
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Actors for the two lookalike characters, Bizi Betiko and the Data Broker, were found entirely by chance: both men had come to the show as background actors, where they were spotted by executive producer Naren Shankar.