Regarding the Thermal Exhaust Port “Design Flaw”

Michael Cain

Michael is a systems analyst, with a taste for obscure applied math. He's interested in energy supplies, the urban/rural divide, regional political differences in the US, and map-like things. Bicycling, and fencing (with swords, that is) act as stress relief.

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118 Responses

  1. Don Zeko says:

    For some reason I assumed that the port wasn’t just a metal tube, but also a tube of shaped magnetic fields a la the torus in a fusion reactor (since presumebly thermal exhaust from a reactor that can power a planet killer is no joke). So the torpedo isn’t changing course on its own volition, but is instead being steered by the shape of the field inside the exhaust port.

    That said, the whole concept of a planet killer in a super base is dumb. Just build something with the planet killer, propulsion, shields and the necessary support systems, and then escort it with a fleet of starships. That’s far more flexible, easier to build, and if your defenses do fail you don’t lose everything to one lucky shot.Report

    • Oscar Gordon in reply to Don Zeko says:

      The magnetic fields is a good thought, given the torpedo had to travel to the core, or somehow detonate deep enough to muck things up, rather than just wrecking the port itself. However, the fields would probably be working to move heat out of the port, rather than into it, to the torpedo would have been turned away, not sucked in.

      Now, if said fields were moving heat out (and let’s save the discussion about the inefficiency of a thermal exhaust port in outer space), then wrecking the port itself and maybe damaging the magnetic fields could cause heat to build up, but to do so quick enough to nuke the station is hard to believe (at least, before the main gun fired – after it fires, there is probably lots of heat to bleed out very quickly).

      So my theory is that the exhaust port was not the weakness, but rather the path to the weakness.

      Let’s suppose the rebel leaders, during their briefing to the pilots, got confused on the details, and the port wasn’t for exhausting waste head, but existed as part of a magnetic gas collection system (think Bussard Ramjet). The equatorial trench was the magnetic field emitter and the port was a gas intake that happened to terminate near some kind of thermal control system. The torpedo rides the magnetic fields that are sucking in gas (e.g. Hydrogen) and goes kablooey in the gas collection tank. The resulting explosion, being next door to the reactor thermal management system deep in the belly of the beast, knocks out the ability of the reactor to manage it’s heat, and for some reason or another, secondary systems fail to engage (perhaps because the main gun is firing?) and the reactor fails to scram.

      Thus, Earth Shattering Kaboom!Report

      • Don Zeko in reply to Oscar Gordon says:

        Part of the fun here is that we can make whatever assumptions we want about the nature of the reactor, because the amount of energy it has to be generating is such complete fantasy that we just need go treat it as magic that will work however the story needs it to work.Report

        • Oscar Gordon in reply to Don Zeko says:

          The real problem here is the idea that a space ship/station would have a thermal exhaust port. Heat moves in one of three ways, conduction (movement through solids), convection (movement through fluids), and radiation. A thermal exhaust port implies that heat is moving out of the port, which implies that the port is ejecting some kind of fluid into space, which we see no evidence of. Which makes sense, because waste heat in space is radiated away, not convected or conducted. You would use convection or conduction to move heat to the radiators on the hull, but once that heat is at the radiators, it gets radiated into space. A station like that would have massive radiators all over it’s entire surface, so no single point of failure for that part of the system.

          Even if my original hypothesis was right, and the trench and port was part of a massive gas collection system, and all that gas was used to move waste heat, they’d have to park that thing next to a gas giant almost constantly in order to gather enough working fluid to bleed off the waste heat something that size would generate.

          So that port was never a thermal exhaust port, it was merely a pathway that got a large explosive close enough to whatever was important to destroy.

          And this is where it actually becomes plausible, because the key system was probably buried deep in the station, deep enough that the probability of a lucky strike damaging it long before the rest of the station was beaten to flaming wreckage means it could be placed where it was convenient, without thinking too much about potential battle damage. So Erso’s play was to place a key system next to spot no one really thought was vulnerable, and then just selling that location as convenient to the design (which, perhaps it was). Hell, the port itself was ray shielded, which might have been his way to placate anyone who was thinking that port led to a very sensitive spot.Report

          • DavidTC in reply to Oscar Gordon says:

            A thermal exhaust port implies that heat is moving out of the port, which implies that the port is ejecting some kind of fluid into space, which we see no evidence of.

            Maybe we can assume that the normal *station* heat gets bled away using radiators. (Or, like every sci-fi does, the problem of general waste heat is just completely ignored.)

            So maybe that’s just the thermal exhaust port *for the beam*.

            I.e., after the planet-killer shot is fired, the Death Star has to vent some super-heated gas immediately, or everyone nearby quickly gets cooked by the residue beam heat.

            This explains why that port is *open* at the time, too, because you’d open it before charging the laser. You wouldn’t want to suddenly learn that port has a *mechanical failure* and won’t open *after* you already built up the heat!

            This also explains why the Death Star doesn’t constantly have to keep collecting liquid to vent. It just collects it between firing, and maybe the tank holds enough that it can do a dozen shots without collecting any. I mean, the station has to be that big for *some* reason.

            Which obviously means it would have never needed to collect more in the movies, as they didn’t shoot that much.Report

            • Oscar Gordon in reply to DavidTC says:

              So maybe that’s just the thermal exhaust port *for the beam*.

              That’s a good thought, except for one quibble: If it’s a vent port for superheated gas (i.e. plasma), it’s going to have some kind of magnetic shielding protecting the walls of the vent, and that shielding is going to be working like a rail gun to rapidly eject the plasma into space. Now, if I was getting ready to fire my BFG (planet killer edition), and I had to vent some very dangerous high energy plasma immediately afterwards, I’d have the magnetic guides on the vents up and running before the shot, so as to verify operation and allow time to scrub the shot if one of them was down or wonky. So when Luke popped a couple of torpedoes down the chute, they should have been rapidly ejected, or at least never made it far enough to destroy whatever needed to be destroyed.

              Aside from that, it’s a very good hypothesis.Report

              • DavidTC in reply to Oscar Gordon says:

                So when Luke popped a couple of torpedoes down the chute, they should have been rapidly ejected, or at least never made it far enough to destroy whatever needed to be destroyed.

                Maybe the plasma is just contained in a force field as it exits, and it exits purely by the force of expansion of itself, not needing anything to push it out.

                That actually seems a lot safer (In-so-much as imaginary science can be considered) than trying some sort of magnetic containment to actively remove it.Report

              • Don Zeko in reply to DavidTC says:

                This raises another question: if you know you’re going to expel a jet of superheated plasma out of this port, why is it (and its promised giant blowtorch) pointed parallel to the surface of the station rather than up and out into space?Report

              • Michael Cain in reply to Don Zeko says:

                And at the bottom of a freaking trench.Report

              • Oscar Gordon in reply to DavidTC says:

                Eh, maybe. In my engineering judgement, I’d use whatever means were at my disposal to get that plasma into space as fast as possible*, rather than trusting to expansion to handle it, because as it expands, it will transfer heat to the surrounding space. If I use a force field to contain the plasma and the heat, it won’t expand, so I either have to let the heat transfer, or I have to just let it expand somewhere safe, where any heat transfer will happen away from sensitive things.

                *And since plasma is charged, magnetic fields work very well to move it about.Report

              • DavidTC in reply to Oscar Gordon says:

                I didn’t mean the plasma was contained within a force field like a blob.

                I meant the walls of the tunnel might be force fields, all the way down. I mean, they’re within real walls, obviously. But the walls have force-field emitters down the sides, and make a tube for plasma to flow through. The plasma expands and forces itself out the exhaust port, as that’s the only place it can go.

                This would mean the torpedo could have gone bouncing down the sides, contained within the same force-fields. (Presumably, it’s not set to trigger by hitting a force-field if that was the plan.)

                Hell, if you handwave a bit, you can even use this to explain the weird 90 degree turn…the force-fields keep things in, but not out, so the torpedo got ‘caught’ inside (The force-field tunnel stick out a bit past the hole itself) and ended up headed downward. (Because the torpedos were slightly angled that way.) Granted, it should have lost more momentum doing that, but it’s as good an explanation as anything.

                There is precedent for force-fields containing plasma in Star Wars, because that’s how *lightsabers* work. The force-field even contain the heat.

                Or alternately the vent tunnel could just be made of unobtainium that doesn’t melt under plasma, or doesn’t even have any real heat transfer. There are materials in Star Wars that can block lightsabers, I forget the name but everyone’s wearing some in KOTOR, and presumably they block other plasma.

                In fact, considering it’s the same *crystals* as in a lightsaber, perhaps we should be wondering if the beam itself is merely a gigantic lightsaber (Without an end-containment), and maybe the thermal exhaust port is only used to vent *if you don’t fire the thing*.Report

              • Oscar Gordon in reply to DavidTC says:

                I’d buy that explanation.Report

              • DavidTC in reply to Oscar Gordon says:

                The real problem with this explanation, of course, is that it logically means the other end of the vent should have been some sort of plasma chamber, or chamber-of-stuff-going-to-be-turned-to-plasma.

                So how the torpedo damaged the ‘generators’ (I think that’s what they said) is unknown. Even if we assume they meant *beam* generators, not electrical ones.

                It’s hard to see how a tiny torpedo could alter a gigantic plasma containment from the *inside* in any way that would cause it to escape confinement.

                …but maybe inability to see it is the point.

                Basically there’s some engineer saying: “If the plasma holding chamber over-pressurizes enough, the output backs up, which means the kyber crystals in the generators will misalign, which means everything immediately blows up as the energy recirculating systems continue to pump energy in. But 1) That’s impossible anyway, because the entire process is completely automated and sensors would detect that, and 2) even if that does, somehow, impossibly, happen, we’ve very cleverly built a dedicated vent that will release the pressure before that happens, so the worse case is we just can’t fire until we recharge everything. Duh. Problem solved forever.”

                And in some other part of engineering, the less exciting ‘We have to build the stupid exhaust port instead of the cool super-weapon’ section: ‘Well, yeah, I guess you *could* put stuff down the exhaust if you aimed right, but what the hell for? You can’t hurt the force-field, so whatever you did would just bounce around and get vaporized when it hit the plasma in the middle, or vaporized when it’s vented. There’s nothing you can put down the vent with more energy than the plasma itself!”

                And no one is in a position to put those two things together, and notice if you blew up a torpedo *at the vent connection*, it would both over-pressurize and not be able to vent, or notice that Galen Erso was the person who both invented and ‘solved’ the problem of the entirely hypothetical problem of over-pressure with a stupid vent.Report

              • Dark Matter in reply to Oscar Gordon says:

                The thermal exhaust port doesn’t need a real purpose or function.

                Say you’re an Imperial Engineer working on the project. If you try to research what that port is doing and why, you’ll find complicated technological speak and requirements which require a LOT more time to understand than you have.

                The port doesn’t impact any of the subsystems you do understand. A high level system architect thought it was a good idea and apparently put a lot of thought into it. He knows a lot more about this than you do, any confusion on the issue is probably your fault (note the word “fault” is important here).

                You’re a busy man, there are unrealistic deadlines, and Lord Vader shows up occasionally looking for inefficient people to serve as example(s). It’s a really bad idea to actively try to do things which waste time and draw attention to what can be viewed as your own incompetence.Report

    • Morat20 in reply to Don Zeko says:

      There’s an “engineer’s defense” of the exhaust port somewhere on the internet, which has the chief design engineer defend it.

      He points out that the thing has a reactor and is freakin’ huge, that exhaust is a real thing that has to happen, that apparently the main exhaust port was protected well enough that the Rebels didn’t even try, and in the end it took a space wizard to do it.

      And once you’ve got space wizards running around, the engineer is off the hook.Report

  2. Burt Likko says:

    As we learned in Rogue One, the weakness in the exhaust port was the result of design sabotage which sort of moots all sorts of very amusing internet essays offering various engineering apologia for the “design flaw” of the exhaust port.

    That said, I personally enjoyed Rogue One immensely. And it does not moot the now obvious deconstructions demonstrating that Jar Jar Binks was the true Sith Lord mastermind all along and R2-D2 was the true leader of the Rebellion.Report

    • DensityDuck in reply to Burt Likko says:

      I do like how the writers closed the granddaddy of all SF plot holes with the old “hang a lantern on it” trick.Report

    • It’s good that my father isn’t around to hear a “design sabotage” explanation. During Korea, he was a sonar man on one of the aircraft carriers. Due to the limitations of technology at the time, primary sonar positions were adjacent to the hull at the bottom of a shaft that ran a significant portion of the height of the ship. Said shaft violated every single rule about compartmentalization for limiting damage. To deal with that, when Dad went on duty, the armed guard at the top of the shaft undogged the hatch, and while Dad climbed the ladder to the bottom, closed and dogged the hatch. The man he was relieving climbed the ladder, banged on the hatch to indicate he was there, the armed guard undogged the hatch again, the man came out, the guard dogged the hatch. The hatch could not be opened from inside.

      Canon conflicts on the actual size of the Death Star, but the smallest figure given is a diameter of 120 kilometers. Dad would have laughed himself silly over the notion that someone could sneak in a 60-kilometer long straight-line unimpeded shaft that cut through all sorts of compartments that could otherwise be isolated.Report

  3. Kazzy says:


  4. Brent F says:

    As discussed in the Rebel pilot briefing, those laser gun defenses are geared to shoot at much bigger ships, further away than the 1 man craft the Rebels were using. “The Empire doesn’t consider a snubfighter to be a threat.” Its also implied by the film that one of the other Rebel pilots could have made a computer assisted shot to kill the thing, they were just getting gunned down by the Empire’s space wizard.

    This is the design flaw, not that there was a thermal exhaust port that was an engineering necessity, but that they didn’t notice that it was vulnerable to small attack craft not normally a threat to a moon sized space station and didn’t gear their screening defenses appropriately. To take your carrier analogy, its like a Niemitz class was particularly vulnerable to speed boats and the entire carrier group lack effective anti-speed boat weaponry.Report

    • Morat20 in reply to Brent F says:

      To take your carrier analogy, its like a Niemitz class was particularly vulnerable to speed boats and the entire carrier group lack effective anti-speed boat weaponry.

      Funny story there

      Red, commanded by retired Marine Corps Lieutenant General Paul K. Van Riper, adopted an asymmetric strategy, in particular, using old methods to evade Blue’s sophisticated electronic surveillance network. Van Riper used motorcycle messengers to transmit orders to front-line troops and World-War-II-style light signals to launch airplanes without radio communications.

      Red received an ultimatum from Blue, essentially a surrender document, demanding a response within 24 hours. Thus warned of Blue’s approach, Red used a fleet of small boats to determine the position of Blue’s fleet by the second day of the exercise. In a preemptive strike, Red launched a massive salvo of cruise missiles that overwhelmed the Blue forces’ electronic sensors and destroyed sixteen warships. This included one aircraft carrier, ten cruisers and five of six amphibious ships. An equivalent success in a real conflict would have resulted in the deaths of over 20,000 service personnel. Soon after the cruise missile offensive, another significant portion of Blue’s navy was “sunk” by an armada of small Red boats, which carried out both conventional and suicide attacks that capitalized on Blue’s inability to detect them as well as expected.[1]

      At this point, the exercise was suspended, Blue’s ships were “re-floated”, and the rules of engagement were changed; this was later justified by General Peter Pace as follows: “You kill me in the first day and I sit there for the next 13 days doing nothing, or you put me back to life and you get 13 more days’ worth of experiment out of me. Which is a better way to do it?”[2] After the reset, both sides were ordered to follow predetermined plans of action.

      After the war game was restarted, its participants were forced to follow a script drafted to ensure a Blue Force victory. Among other rules imposed by this script, Red Force was ordered to turn on their anti-aircraft radar in order for them to be destroyed, and was not allowed to shoot down any of the aircraft bringing Blue Force troops ashore.[3] Van Riper also claimed that exercise officials denied him the opportunity to use his own tactics and ideas against Blue Force, and that they also ordered Red Force not to use certain weapons systems against Blue Force and even ordered the location of Red Force units to be revealed.[4]

      Bolding mine….Report

      • Oscar Gordon in reply to Morat20 says:

        Oh, the flag rank butthurt that day must have been epic!Report

        • Morat20 in reply to Oscar Gordon says:

          There’s a reason I remembered it.

          And also, apparently Nimitz class aircraft carriers do have a surprising vulnerability to speedboats, as long as said boats are packed with explosives or carrying one-shot missiles.

          And probably infiltrated by Hydra to boot.Report

        • Morat20 in reply to Oscar Gordon says:

          The logic of “I just lost and we have two weeks worth of time here, let’s play a gain” would have been really compelling without the later massive restriction on Red force.

          I mean some restriction like — “Okay, take the suicide speedboats off the table — we’re gonna need a bit to come up with a counter doctrine, so let’s try this against something else” wouldn’t even have been so bad.

          But if your tactics require the enemy disarming, revealing their locations, and not fighting back….Report

          • Oscar Gordon in reply to Morat20 says:


            Feel the butthurt, let the butthurt flow through you…Report

          • Brent F in reply to Morat20 says:

            Most of the pro-van Ripper takes on the exercise neglect to mention that what he pulled on the computer simulations were probably impossible to do in real life (small craft are actually shit at sea-keeping and are terrible missile platforms, plus vulnerable to literally every type of small arms, his simulated force probably would have gotten swamped, machine-gunned or failed to successfully use their weapons) and he was pulling some seriously screwy stuff with his force being able to co-ordinate with itself. Basically he was playing by video game rules.

            Not that this excuses brass reactions to him, just that both sides were acting like children. van Riper’s serious point, that the American military has become excessively reliant on their overwhelmingly powerful toys and are bad at reacting to the unexpected, and need to train to be more adaptible and find different ways to win than the standard playbook ended up getting lost.Report

            • DensityDuck in reply to Brent F says:

              “van Riper’s serious point, that the American military has become excessively reliant on their overwhelmingly powerful toys and are bad at reacting to the unexpected”

              Except that they were specifically told “unexpected things are outside the parameters of this test”! This wasn’t about “train to be more adaptable”, this was “conduct a specific activity in a specific way so that we can see how it goes”.Report

              • Don Zeko in reply to DensityDuck says:

                If the military is conducting its wargames with the assumption that their adversary will behave in exactly the manner they expect him to and have exactly the capabilities they think he has, isn’t than even more of an indictment?Report

              • DensityDuck in reply to Don Zeko says:

                “If the military is conducting its wargames with the assumption that their adversary will behave in exactly the manner they expect him to and have exactly the capabilities they think he has”

                That’s what a wargame is, bro, in the context that we’re talking about. “an exercise where anything can happen” is not the same thing.

                If you’re playing Risk and the other guy sets the board on fire, do you glumly admit that you’re too inflexible to deal with total incineration of the playing surface?Report

      • Kim in reply to Morat20 says:

        Van Riper? Who comes up with these names?
        It’s almost as bad as the simpsons’ writer… Schvartzwielder…Report

        • Morat20 in reply to Kim says:

          I’m guessing one of his Dutch ancestors, who was undoubtedly from North Holland. (There’s a place called “Rijb”).

          The “van” there pretty much signifies a name taken from an area. You know “of” or “from”?

          So an Americanization of “From Rijp”.Report

          • Burt Likko in reply to Morat20 says:

            I thought that inclusion of the “van” implied some level of noble association with the place named. So, if I were “Burt von Likko,” then the patronym indicates something approximating “One of my ancestors was the Baron of Likko.”

            (N.b., there is no such place as “Likko” to my knowledge, but damnit, there ought to be.)Report

            • Don Zeko in reply to Burt Likko says:

              Is there a distinction here between van and von?Report

            • Morat20 in reply to Burt Likko says:

              Von is German, and came to mean nobility. Van is Dutch, and never did.

              And then “von” stopped being noble for Germany and Austria (when they, you know, got rid of the whole noble thing).

              Which I only know due to a D&D character I built like 15 years ago and wanted a realistic name for, and a suitable lineage.

              He came to a bad end, involving a Lich and Contingency.Report

              • Brent F in reply to Morat20 says:

                That’s the basic answer.

                The much more complicated answer is that “von” can occassionally be exactly the same thing as “van,” because the cultural border between Dutch and German is porous and most Germans in that region spoke a dialect closer to modern Luxembourgish than the relatively recently adopted Standard German. So plenty of von’s are decendants of northwestern Germans of non-noble origins.

                Incidently, my grandfather is from the area and the time when they were transitioning to a standardised universal language, so his native tongue is part the Deutch you’d learn in a classroom and part Mosel-area peasant gibberish.Report

      • Mo in reply to Morat20 says:

        That’s a pretty good metaphor for the 2016 presidential campaign.Report

      • Murali in reply to Morat20 says:

        In a similar vein, Singapore was supposed to be an impregnable fortress, all its guns were aimed towards the sea (south, east and west) and were supposed to be effective against ships. Do you know how the japanese invaded? From the north, on bicycles.Report

    • Michael Cain in reply to Brent F says:

      As discussed in the Rebel pilot briefing, those laser gun defenses are geared to shoot at much bigger ships, further away than the 1 man craft the Rebels were using.

      In the original there are a couple shots of guns mounted in the sides of the trench with an incredibly limited line of fire outside the trench proper. And they’re not lasers, they shoot green blobby things that are so slow you can see them coming. Some of the blobby things pass under the X-wings, clearly traveling parallel to the trench floor. As close as I can remember, they score exactly zero hits. They’d have done better throwing rocks — or at least, using cannons firing canister shot.

      I had an acquaintance who was in procurement and testing that verified a story about the Phalanx gun used by the US Navy. Helicopter pilots were nervous landing with the Phalanx tracking them, so a new software load restricted the guns from tracking targets that were both close and slow. Didn’t help with the helicopter problem — the guns’ radar happily tracked the outer portion of the rotor blades, which were traveling above the “speed limit”. If we can track that well, surely the Empire should have been able to.Report

    • Mike Schilling in reply to Brent F says:

      particularly vulnerable to speed boats

      “I am the Sith Lord now”.Report

  5. North says:

    Yeah official cannon was that the Death Star was strongly hardened against capital ship assault and fighters were simply not considered a concern. A more salient question would be to ask where the fish the Death Stars capital ship escorts were. An asset that big should have had a veritable cloud of smaller support and defense ships gathered about it. That the X-wings were able to put-put there way to the surface of the Death Star largely unmolested was itself silliness.Report

    • Brent F in reply to North says:

      Oh, they had them. They just didn’t bother to launch the horde of point defense craft they carried because the commander was so convinced of his personally designed superweapon’s invincibility.

      Hence Vader being the competent one and going out with a small group of fighters under his personal command to shoot down the enemy ship to ship. As Leia pointed out in their earlier escape, they had 1000s of those to send out, but Tarkin didn’t bother.

      Episode IV Vader was really good at his job. Unfortunately for the Empire, he wasn’t in charge of things on the scene.Report

      • Kolohe in reply to Brent F says:

        Brent F: Episode IV Vader was really good at his job.

        The idea to let Leia go, potentially still in posession of the Death Star plans, was Vader’s, not Tarkin’s.

        And before that, Vader had One Job – extract actionable intelligence from their POW. And he failed. Inexplicably. Despite supposedly being one of the most natural talents in using the Force that had ever lived, when the Gitmo Droid was activated and everyone’s emotions were peaking – Vader didn’t even realize that the detainee was his own daughter.Report

        • DensityDuck in reply to Kolohe says:

          Bah, just blame it on The Force. He was strong with the Force–but his daughter was stronger, as it turns out.Report

        • Dark Matter in reply to Kolohe says:

          And he failed. Inexplicably.

          It’s similar to how/why Ben could hide on Vader’s home planet for years.

          Vader/Anakin was emotionally a mess. Leia was his dead wife reborn, no way he was up for dealing with that.

          All of his dealings with her were affected by him needing to avoid that. So he couldn’t see clearly into her mind, and his plan *had* to let her escape so he wouldn’t be faced with thinking the unthinkable.

          He wasn’t able to admit she was his daughter until his confrontation with Luke, i.e. after Luke started breaking through his mental blocks.Report

      • Don Zeko in reply to Brent F says:

        I’m partial to the idea that the imperial fleet was reluctant to fly a half-decent CAP because they didn’t trust the loyalty of their pilots. And given that the rebellion seems to be particularly rich in well-trained fighter pilots (or that TIE doctrine seems to involve swarm assaults and neglects shields or life support), it’s hardly implausible that TIE pilots defect at the first opportunity.Report

        • Kolohe in reply to Don Zeko says:

          It was implied in Episode IV that Tie fighters don’t have much range. Thus, where would they defect to?Report

        • DavidTC in reply to Don Zeko says:

          it’s hardly implausible that TIE pilots defect at the first opportunity.

          *Everyone* defects at the first opportunity.

          At this point in canon, we know of *two* different people people who defected from the Empire…Biggs in a New Hope, and what’s-his-name in Rogue One.

          We also have Wedge Antilles defecting in Star Wars Rebels, which is canon-ish.

          And Finn defecting from not-the-Empire in The Force Awakens.

          And that’s just the soldiers. If we add in the non-soldiers, we have Leia, her father, Mon Mothma, all were Senators. And there’s Galen Erso, obviously. Even Anakin Skywalker got in the game.

          Defecting from and betraying the Empire is practically the national pasttime in the Star Wars universe.

          In fact, I’m not sure we know of *any* characters in the Rebel Alliance that originally *didn’t* work for the Empire, which is a weird thought. Saves on training costs, at least!

          Well, barring Han and Chewie and Lando, but they weren’t really in the Rebel Alliance. …actually, cancel that last one, Lando sorta *did* work for the Empire, too! And it is entirely possible we will find out that Han used to, also, in his upcoming film, until he stumbled across Chewie. Maybe Lando also. And it’s entirely possible Chewie worked for the Empire also…if you count ‘slave’ under ‘works for’.

          I think Jen Erso might literally be the only character that joined the Rebel Alliance that didn’t work for the Empire. And she only did it for one mission before she stole a ship and started her *own* Rebel Alliance, with hookers and blackjack. And that one mission was to save her *father*, so I’m not really sure that counts..Report

          • Don Zeko in reply to DavidTC says:

            If it’s a rebellion, doesn’t if make sense that people with combat-applicable skills would very frequently have been trained in the imperial military?Report

            • DensityDuck in reply to Don Zeko says:

              Heck, even Luke Skywalker was gonna go be a TIE fighter pilot–in Ep IV when he talks about “transmitting his application to the academy”, it’s the Imperial academy that he means.Report

          • Mo in reply to DavidTC says:

            Han was originally an Imperial officer, he saved the life of and rescued an enslaved Chewie and Chewie owes him a life debt. So even Han and Chewy have Imperial connections.Report

            • DavidTC in reply to Mo says:

              That is technically non-canon at the moment.

              It is, however, probably the story they’re going for in the young Han Solo movie.Report

    • Oscar Gordon in reply to North says:

      So why spend the money to install point defense turrets in the trench?Report

      • Even more to the point, why spend money to install ineffective point defense turrets in the trench? How much “design sabotage” am I supposed to believe in?Report

        • I have visions of a grizzled petty officer with who knows how many years in service growling, “Tell Lord Vader to get his sorry ass out of the trench, we’re cleaning house.”

          Is there any evidence that the Imperial Navy even has the equivalent of petty officers?Report

          • Oscar Gordon in reply to Michael Cain says:

            They do (all the guys sitting at the terminals on any bridge are likely enlisted), but IIRC the imperial military had a nasty case of classism infecting the officer ranks, so enlisted ranks were treated as little more than expendable cogs instead of professionals (if they were valuable, they’d be officers, wouldn’t they).

            A common malady in times past & present.Report

          • Oscar Gordon in reply to Michael Cain says:

            I can just picture an imperial navy Chief Petty officer:

            “It took a deliberate act of the Emperor to make me a Chief, it’ll take another one to bust me, so get Vader’s metal plated ass out of my trench!”Report

            • This. It may be Vader’s fleet, and it may be Tarkin’s Death Star, but there is some CPO who is the deity of that particular trench. And enlisted personnel assigned to those turrets, who if given the choice of the DS blowing up and them dying, or facing the CPO after they had missed every single shot at the rebel X-wings, would have chosen death. The brighter ones might have first asked, “There are no CPOs in the afterlife, right?”Report

              • Oscar Gordon in reply to Michael Cain says:

                There are no CPOs in the afterlife, right?

                Everyone knows Chiefs don’t have souls. They burned them in sacrifice in order to become a Chief.Report

              • DavidTC in reply to Michael Cain says:

                And enlisted personnel assigned to those turrets, who if given the choice of the DS blowing up and them dying, or facing the CPO after they had missed every single shot at the rebel X-wings, would have chosen death.

                Well, yeah, but that assumes they knew the DS could be blow up that way. I kinda doubt that.

                For all they knew, the Rebel pilots were just screwing around in the trenches so the larger ships couldn’t shoot them.Report

            • “It took a deliberate act of the Emperor to make me a Chief, it’ll take another one to bust me, so get Vader’s metal plated ass out of my trench!”

              I find your lack of faith disturbing.Report

      • Mo in reply to Oscar Gordon says:

        Those point defense turrets were built in Corulag and there was no way the Emperor was going to cut off that sweet sweet pork in advance of the Corulag Straw Poll.Report

      • North in reply to Oscar Gordon says:

        I’m no warsie (more of a trekkie nerd) but with how good those turrets on the trench were at shooting the fighters down (as in not good at all) I’d assume they were meant for shooting at smaller capital ships, corvettes or maybe Millennium Falcon sized ships rather than for plinking at x-wings.Report

        • Oscar Gordon in reply to North says:

          Perhaps, although flying a corvette down the trench would be tough. Tight clearances and all. But that still ignores the larger question of funding priorities. If you have a battlestation with thousands of fighters, you spend your money on maybe some automated point defense around sensitive areas, but the rest goes to guns for dropping actual threats (i.e. capital ships that get through the screening elements).

          But, of course, Lucas was looking for spectacle, not practical.Report

  6. Wookieleaks says:

    The thermal exhaust wasn’t a FLAW because the Death Star destruction was an INSIDE JOB. Lord VADER was the only survivor of the ‘attack’ – but several ASSOCIATES of Lord VADER were seen on the battlestation before its destruction.
    – Lord VADER’S former mentor (who VADER ‘killed’ – but where was the body?).
    – His personal robot.
    – Another robot that was the best man at VADER’s wedding.
    – And most damning of all, his SON and his DAUGHTER!


    • DavidTC in reply to Wookieleaks says:

      The person that was closest to Luke Skywalker before the rebellion?

      A man named Biggs Darklighter, who grew up as Luke’s neighbor, and became a defector from the Imperial Navy…or was he?

      Was he perhaps acting on the orders of Lord Vader to bring his son in as a hero of the rebellion?

      We could ask Biggs, of course, but he was PERSONALLY SHOT DOWN BY LORD VADER in that very same attack run.

      These questions need to be asked, people.

  7. Don Zeko says:

    While we’re nitpicking, I want to know why the design innovations of the HMS Dreadnaught (or the USS Monitor, for that matter) never made it into the Star Wars-verse. Every capital ship you see on screen in the real movies and the prequels seems to be armed with nothing but small-caliber guns arranged primarily along the broadsides of the ships that can’t fire beyond unaided visual range or so. If they can build moon-sized planet killers, why hasn’t the imperial navy figured out how to build large dorsal and ventral turrets with long-range anti-ship lasers?Report

    • Michael Cain in reply to Don Zeko says:

      The SF world over the last three-four decades has been infected by some loathsome disease that makes people write space warfare like it was Napoleonic age-of-sail sea battles. You’re lucky if the writers recall that they can maneuver in three dimensions.Report

      • Don Zeko in reply to Michael Cain says:

        Pretty much. Battlestar Galactica was pretty similar, although I think a touch better. Have you ever played Mass Effect? It’s an odd duck in that the descriptions of the tech that you encounter in both character conversations* and the in-game encyclopedia is very science-literate, but what you see in the cinematics of space battles is nothing of the sort.

        *There’s a delightful aside in the second game where you happen across an officer drilling into some cadets about how, thanks to Newton’s laws, whenever you fire the giant railgun mounted on a spaceship you are ruining the day of someone, somewhere, so make sure to check your damn firing solutions.Report

      • Oscar Gordon in reply to Michael Cain says:

        Or that visual range means way too fecking close!

        I give David Weber credit for remembering that space naval battles will be very different affairs.Report

        • Morat20 in reply to Oscar Gordon says:

          Hmm. Charles Stross in Eschaton basically poked fun at Weberesque space-battles (big ships and missiles and such).

          A very Weber-like Navy went up against a pair of ships belonging to what can be be described as an “invasive performance art group in the system to put on a show”.

          It turns out missiles are great, but tend to fail when running into a thin dusting of nanoscale Von Neumann machines.

          Then again, Weber’s most famous space naval battle series was him deliberately doing Horatio Hornblower in space, and designing the physics system to force age of sail tactics. (Well, they do stack their wall of battle vertically too).Report

    • Autolukos in reply to Don Zeko says:

      Star Destroyers, at least, seem vulnerable to accurate fire from fairly small weapons in both Return of the Jedi and Rogue One; the bigger failing in capital ship armament seems to once again be the terrible fire control systems that lead to slugfests at point blank range instead of sniping the shield generators and following up with a few concentrated volleys against critical sections of the ship.Report

  8. Stillwater says:

    So, how many things did it take for the port to be vulnerable?

    Just one: The Force.Report

  9. Dark Matter says:

    …the Death Star… It’s not supposed to defend itself very well.

    Several problems with this. First the Death Star could have defended itself against larger attack craft, even just waded through enemy fire (with it’s force fields and defensive weapons), blown up whatever planet they were defending, and then left.

    Second, the Death Star’s purpose was strategic, not tactical. Modern day Earth has the ability to kill all life on the planet with nukes. A single Star Destroyer could do the same thing, which raises the issue of why does the Empire need the Death Star at all?

    The answer is force fields. Planetary force fields are so good that it was possible for a planet to encase itself in force fields to the point where the rebels thought they could defend themselves from the empire. The Death Star’s purpose was to show them that they were mistaken, it’s primary weapon’s function was to destroy planets by cutting through the force field guarding them.

    Go re-watch the destruction of Alderaan. The beam hits the planet for several seconds, even makes the entire thing glow. That would be the forcefield resisting the beam. Then the force fields fail and boom it’s over. If memory serves Vader commented at the time that calling Alderann “helpless” wasn’t correct.

    Because of that, the Death Star (which was a prototype after all) may have actually been a failure. If Alderann’s forcefields had been stronger (which might have been possible), then it would have survived the Empire’s super weapon and it would have been another day before the Empire could fire it again. The next Death Star was built so it could repeated fire the main beam and overload even the best shields and also blow up capital ships.

    Trench-mounted weapons failed at their job.

    Even ignoring the DeathStar was fresh off the production line and clearly hadn’t had all the bugs worked out yet, it’s a hair awkward to claim both that this was easy and on the other that only Vader and Luke could do this and stay alive.

    Further without the vent issue it would have been pointless. It was assumed small craft could not be a threat. Without the vent the little guys just die, how long it takes almost doesn’t matter.

    Speaking broadly, they were less accurate than WWII anti-aircraft guns.

    WW2 anti-aircraft guns didn’t have to shoot at targets which can move faster than the speed of light and at distances which need to be measured in light seconds. Further those guns were for larger ships.

    How many hundred Gs did the “missile” pull when it made that right-angle turn into the thermal port opening?

    You’re assuming the “missile” was as fast as the ships. More likely it was (by their standards) pretty darn slow. Luke’s ship was able to fly multiple “size of the death star” lengths away from the DS in the time that the “missile” took to fly just it’s radius.

    A slow missile could also presumably be targeted a lot easier than a fast ship.Report

    • J_A in reply to Dark Matter says:


      You’re assuming the “missile” was as fast as the ships. More likely it was (by their standards) pretty darn slow. Luke’s ship was able to fly multiple “size of the death star” lengths away from the DS in the time that the “missile” took to fly just it’s radius.

      I’m not the greatest at mechanics, it’s been decades, but I don’t think this is right.

      In empty space, conservation of momentum would mean that, at a minimum, without independent propulsion the missile would be moving at the same speed as the ship at the time of disengaging (assuming a bomb like ammebly, as opposed to a gun assembly. In a gun configuration the missile will fly ahead of the ship, i.e. faster)

      Granted, the ship could accelerate after firing, explains how it would reach several DS diameters in the same time, but the only way the missile could move inside the trench at a lower speed than that the fighter ship was flying before shooting is by deliberately braking after release.

      Which in essence is the same as turning at high speed. You need massive acceleration.Report

      • Dark Matter in reply to J_A says:

        The fighter very clearly has a drive (multiple drives probably since it’s probably able to do translight), a missile probably also has a drive.

        Nothing on the screen is going to be using chemical propellants, whether or not anything experiences “acceleration” is also seriously questionable from a 21st century viewpoint, and I very much don’t trust that “conservation of momentum” applies.

        More importantly, Luke can only fire that thing when he’s right on top of the port, it’s possible he’s got a tail gun so its “launch” is only relative to himself and it comes out slower than he is.Report

        • J_A in reply to Dark Matter says:

          it’s possible he’s got a tail gun so its “launch” is only relative to himself and it comes out slower than he is.

          Duh, you are absolutely right about this possibility, which would explain a lot. I’m embarrassed I didn’t think of that on my own; bad J_A, no cookie.

          ….and I very much don’t trust that “conservation of momentum” applies.

          I think this is where I have to suspend my suspension of disbelief. The idea that individual missiles will be built with non-relativistic drives is not only an affront to the laws of physics, but also to basic economics. Even Civil Wars need to meet a budget.Report

          • Oscar Gordon in reply to J_A says:

            X-wings have two torpedo launchers, mounted port & starboard along the ventral fuselage, almost under the cockpit, facing forward.

            Ergo, unless the torps performed a braking maneuver, they left the ship with the ship’s velocity plus whatever their launching delta-V was.

            That said, their development involved a whole lot of handwavium (mined exclusively by Unicorns from the caves of bullshitistan), and apparently they could make a 90 degree turn in less than a meter at speed, because Lucas still thinks Newton was a handheld device that was kinda popular at one point.Report

          • Dark Matter in reply to J_A says:

            Even Civil Wars need to meet a budget.

            True, but this is Star Wars and it’s scale is absurd.

            It’s reasonable to walk into a random bar in a hick backwards town, on a hick backwards system, and find someone with a spaceship with transwarp drive. Transwarp drive means everything is within reach of everything. We’ve seen the equiv of taxis move halfway across the galaxy, we’ve seen ships lift off the surface of a planet and be in orbit a few seconds later.

            There’s no exploration in SW because the entire galaxy was fully mapped a long time ago. Similarly “new” technology is also something of a non-starter, technology is *old*.

            Private companies can have enough “security” droids to think they can take over planets. Criminal gangs actually do. These things are considered small enough that it’s not worth the attention of the authorities.

            The Empire tried to hide the building of the 2nd Death Star in the imperial budget by farming it out to some virtual organization. Construction of the Death Star has to involve stripping multiple systems of resources, absurd numbers of people and droids, and it’s such a small part of the Imperial budget that they think it’s possible to hide the money.

            Some fans pointed out that the destruction of the 2nd DS would bury the Ewoks home in many meters of steel and exterminate them all. Lucas pointed out that the rebels could (and did) bring in enough ships to tractor the debris elsewhere.

            Moving back to the missile; It has to function in space and have a range greater than the diameter of the moon, maybe much greater. I also suspect our missiles have “drives” better than our taxis.Report

        • …I very much don’t trust that “conservation of momentum” applies.

          This is actually a point I might be willing to concede. Given that tech to produce gravity without mass was clearly in wide use, I could accept that they had something that could modify inertia of a particular mass as well. Must have been limited to small things, though — a star destroyer is a pretty dumb design if you have those techs at hand.Report

          • Don Zeko in reply to Michael Cain says:

            I haven’t though that this through. What does massless gravity generation imply about ship design?Report

          • Morat20 in reply to Michael Cain says:

            Could be lots of limitations — power scaling with mass, that sort of thing.

            It might be really simply to, say, produce gravity between two parallel planes (say, the deck and ceiling) but not along the surface of something like a ship.

            Then again, former-cannon had the standard inertial compensators to protect pilots from G-forces, but it wasn’t really stated whether that protected the ship in question.

            A given fighter could as easy be rated for 20G turns, but a pilot isn’t. Or it could be volume had a factor — you could compensate for intertia in a tiny volume (like the cockpit) up to a very high factor, but the larger volume (the ship) a much smaller one.

            It’s pretty easy to handwave in an explanation backwards (“we want artificial gravity and dog-fights in space at speed, but with the standard ‘the bigger it is, the slower it turns’ vibe people are used to”) and fake up the tech limitations to fit.

            I find stories wherein the tech limitations are given first, then the engineering and tactics worked from there, to be more interesting at times.Report

            • Michael Cain in reply to Morat20 says:

              I find stories wherein the tech limitations are given first, then the engineering and tactics worked from there, to be more interesting at times.

              So do I. I vaguely recall at least one story where ships could jump instantaneously from one point to another by exiting standard space/time, but momentum was preserved across the jump. So, for example, a ship nearly at rest with respect to Sol could jump to Barnard’s Star, but would then have to make up the 143 km/sec (320,000 mi/hr) velocity difference in order to come to rest with respect to that system. Trade patterns were dictated by the amount of delta-v that could be achieved without refueling.Report

              • Don Zeko in reply to Michael Cain says:

                That’s how they’be balanced the warp drive in some kerbal space program, for what it’s worth. Iirc people that understand orbital mechanics better than I do can make that work by hopping g around within the gravity well of a planet and using elliptical orbits.Report

              • Morat20 in reply to Michael Cain says:

                That just reminds me of Portal. 🙂

                Charles Stross is, in general, a big fan of saying “Take thing X existed, how would it work?” and extrapolating.

                One of his novels (the sequel to Saturn’s Children, although I can’t recall the title) is basically “In a colonized galaxy (by robots though) without FTL, how would economics work? Banking? How would scams work?”Report

  10. The cause of the rebel alliance was an unjust war. We shouldn’t be celebrating their terrorist attacks.Report