In The Force Awakens Han Solo and Rey both

note that a compressor has been added to the fuel line and both agree that it puts too much stress on the hyperdrive. Rey even bypasses the compressor manually when they are not otherwise able to escape Han's freighter at light speed.

What is it about the compressor that would cause it to stress the hyperdrive? What happens when the compressor is removed? And why would someone add the compressor in the first place?

Perhaps the novelization sheds light on this.

  • 4
    I'm not sure if this is something that could be answered, it's about a very vague technology that can't exist in our universe and an answer would require an understanding of it.
    – user45549
    Commented Dec 24, 2015 at 3:13
  • 1
    @hatandboots Some SciFi publishers like Marvel post specs for all their technology. Other times such 'information' is in the novel associated with a movie. While you might be correct, I think that there is a good chance that some official source took the time to document some or all of this for the die hard fans.
    – CodeMed
    Commented Dec 24, 2015 at 3:31
  • @CodeMed: Even if that is documented, the essence of the answer is still "because the writers decided that's how it works". These engines are not physically proven to work by real world scientific standards.
    – Flater
    Commented Dec 1, 2017 at 13:30

4 Answers 4


I'm not a mechanic/engineer, so this is going to be light on specifics, but as an enthusiastic owner of turbocharged cars I interpreted the compressor in this scene as being something similar - something that obtains more power without increasing engine size or fuel use by increasing the "pressure" inside the system. With cars, greater pressure places extra stress on things like hoses and such, so you need to be more careful with those parts when running an older car at high boost. Since the Falcon has seen better days and probably has a lot of relatively minor "fix it later" problems like maybe seals, hoses, valves, etc, it probably isn't a prime candidate for a device that increases the stress on the system.

  • 1
    This. Further, it's likely that it's not even an issue with the Falcon itself - it was likely a third-rate job, using a compressor that's not designed to work with the hyperdrive itself (or, simply not modifying the hyperdrive accordingly). It's the equivalent of running nitrous through a top-fuel dragster without rebuilding and modifying the engine to make sure that it can take the added pressure. Simply, the engine can't handle the stress (regardless of the Falcon's running condition).
    – user14952
    Commented Jan 3, 2016 at 21:40

Unfortunately, novelization doesn't address your precise questions too much, but does help a bit. Basically:

  • they simply find out WHO did it, but both unanimously agree that it's so dumb they don't have a first clue WHY it was done

  • The compressor was on an ignition line, and stressed hyperdrive flow. Translating this technobabble to anything meaningful or logical is left as excercise for someone familiar with six million forms of communication, I don't speak random Lucasoidal technobabble.

    To take a random swing at it, ignition line injected something (fuel) into the hyperdrive, and it was supposed to flow smoothly. Putting compressor on it obviously turns smooth flow into a more disturbed flow, because it creates variable pressure.

Moving slightly to his right, he touched a couple of contacts and was rewarded with a readout that was anything but pleasing.
“Hey! Some moof-milker installed a compressor on the ignition line!”
Unkar Plutt did.” Rey saw Finn shoot her a look and she glanced away, abashed. “I’d spent some time poking around all the ships parked at the outpost. Mostly at night. It was a way to learn some things. I was careful, and nobody much cared anyway, since I never took anything or tried anything.” She brightened. “Made it a lot easier when we filched this one. Though it wasn’t my first choice.”
Han nodded knowingly. “I can relate to that. What halfwit puts a compressor on an ignition line?
She nodded in agreement. “I thought it was a mistake, too. Puts too much stress on the hyperdrive flow.
…Stress on the hyperdrive flow,” Han echoed, reaching the same conclusion at the same time. For an instant he looked puzzled and just a tad curious. Who was this girl, who spoke so knowledgeably of flow rates and ignition pressures?

  • I will also look for more technical stuff, but this should be enough to start sating your curiosity. Commented Dec 24, 2015 at 3:33
  • You are saying that turbulence in the flow of fuel might cause the engine (which we will call the hyperdrive) to become inefficient and thus under stress? That is a creative and educated guess with some attempt at documentation. Thank you and +1. Let's see what else gets posted.
    – CodeMed
    Commented Dec 24, 2015 at 3:43
  • @CodeMed - my random theory is that you inject ignition mass into the engine (hyperdrive), and it needs to be injected smoothly. Problem is, I don't even know how internal combustion engines work in good detail :) Commented Dec 24, 2015 at 3:55
  • @CodeMed - It wouldn't necessarily have to be turbulence. It sounds like a hyperdrive functions by igniting something, which we might call "fuel" and which is delivered by an "ignition line". A compressor sounds like it would deliver fuel at an increased rate, and perhaps it does this perfectly (so the fuel is still delivered smoothly, but at an increased rate/pressure). Now the drive has to deal with more fuel than it was designed to, which may cause excessive internal forces or be akin to 'flooding' an internal combustion engine.
    – aroth
    Commented Dec 24, 2015 at 4:18
  • I am so going to start calling people moof-milkers from now on...
    – Burgi
    Commented Dec 24, 2015 at 14:34

The hyperdrive appears to be capable of massive amounts of thrust to propel the Falcon or any other starship capable of lightspeed to unknown levels of speed or warp. I would suggest the compressor was probably capable of some moderate level of boost to assist initiation of the hyperdrive on older systems that has potentially lost ignition initiation start. However due to the huge amounts of potential the hyperdrive generates the compressor soon becomes a hindrance even before the hyperdrive has reached ignition dynamo optimum levels. Like trying to start a 13b turbo rotary using a motor from an angle grinder, not much love there. Then boosting a motor with 3 inch mandrel pipes but with a 1/2 restriction in the system somewhere. Just sayin...

  • Your analogy may be relevant, but I couldn't make heads or tails of it, do you have a source for your first claims?
    – Edlothiad
    Commented Dec 1, 2017 at 12:24
  • I interpret this to say that everything in the Millennium Falcon was jerry-rigged from non-compatible parts. For this, I give +1. However, your answer is kind of wandering in that it does not seem that it is certain what its point it, so it makes a few arbitrary stops along the way before ending.
    – CodeMed
    Commented Dec 1, 2017 at 18:15

this is an audio engineering joke. Pretty much all music these days has compression added (there is brief mention of a compressor being added to the ship on Jakku) even when it is not needed. Compressors can really compromise sound quality, especially when they are overused. I'm 99% sure this is poking fun at compression overuse.

  • Can you cite a source for this? It sounds very fan theory-like. (I'd like it if it were true, but without proof...) Commented May 29, 2016 at 16:22
  • I'm reasonably sure she's talking about a modification that literally compresses some kind of fuel supply, not a compression algorithm.
    – Valorum
    Commented Feb 15, 2017 at 21:53

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service and acknowledge you have read our privacy policy.

Not the answer you're looking for? Browse other questions tagged or ask your own question.