Do I realize I’m grumbling about a 40-year-old entertainment franchise? Yup. Do I know that no one cares in the slightest? Mhm. Do I understand the difference between science fiction and science fact? Sure. Am I going to publish this anyway? You betcha.
I’ve always loved Star Wars. I don’t know what it is, maybe it’s the long cuts of silvery ships snaking through the inky blackness of space, maybe it’s the ridiculously one-dimensional plot line; it’s just been a mainstay of my childhood, and I know that I’m not alone.
So, in order to make sure nobody gets to enjoy their beloved childhood franchise, I’ve resolved to take a quick look at some of the scientifically incongruous bits that build one of the most iconic settings in cinematic history. This article will revolve around my favourite bit:
Now I love a good old space battle as much as the next guy, but the fact of the matter is that if you get a lot of your interstellar physics knowledge from Star Wars, you probably aren’t exactly deeply vested in scientific accuracy. This piece is designed for those of you who, like myself, can’t resist pointing out inconsistencies in films, and boy oh boy is Star Wars a goldmine of this stuff.
I’m sure you all have wrong differing opinions, but my all-time favourite ship battle in the original trilogy (i.e. the good one) is the epic Death Star battle at the end of Episode IV. Since it contains a majority of the elements I’d like to discuss, I will be using this as an example. If this is not your favourite battle, please direct your alternative opinions to the comments section.
The first scene shows the X-wings approaching the Death Star, where the Red Leader instructs them to deploy “spoilers in attack position”. As an aviation geek this got on my nerves. Spoilers are aerodynamic devices designed to direct airflow to increase drag and slow down the ship. Not only do the ships speed up after deploying the “spoilers”, spoilers directing airflow would not work in space where, as many of you might know, there is no air. I’m also not sure what exactly the fighters are using as a propulsion mechanism, but I assume it’s rocket fuel. I pulled up some numbers for the F-22, which looks fairly analogous, with a mass of ~19.70 tonnes according to Lockheed Martin, assuming fairly uniform density, and with Randall Munroe’s estimate of the X-wing at 12.5 m, this gives us a mass of about 13 tonnes dry. Assuming Yavin 4 has the proportions and density of Earth, escape velocity is a number of about 11 km/s. Consequently Tsiolkovsky’s equation:
suggests that the X-wings each carry a mass of over 25 tonnes, simply to escape gravity. This itself is bad, but engines being left on takeoff power throughout climb and cruise gives us a figure of roughly 60 tonnes (scaling down from the F-1 engines used on Saturn 5) for the approximately 2 minutes of cruise time. NASA claims they use a 2.27:1 ratio of LOX (liquid oxygen for combustion) to propellant, which gives us a figure of 196 tonnes of material, or a ratio of more than 10:1 of fuel+oxygen to dry mass. Not only would such a ship need to produce a ridiculous amount of thrust to get off the ground, nowhere in all 6 of the good films do we see where all this is being stored! That’s inaccuracy #1. A lot of you may be thinking that it need not be rocket propulsion. However, given the volume of the X-wing fuselage, alternative means of propulsion such as nuclear fusion, hydrogen ramming, and laser sails would need fuselages upto 50 times the size, having accounted for advancement in technology. The only alternative is higher energy density fuel, but given the trend of rising ignition temperatures with rising density, I’d estimate that such fuel would need ignition temperatures above 4000º C. Not only is that greater than the melting point of titanium (which is what the ships look like they’re made of), but it would also cause the thin nacelles to simply melt and separate the engines. And given that they are operating in the vacuum of space, all this heat would simply be conducted into the poor pilot’s (bare metal) cockpit, frying him and making Rebel steak And don’t even get me started on the shape of all those ships. Sure, sleek tasty metal sharks are nice and all, but it’s hardly the most effective design. In space, aerodynamics are of course moot, so why one might design such (admittedly sweet) ships other than for audience pleasure, I cannot understand. I have a bunch of other things I’m quite upset about, but the publisher asked me to save them for later. Rest assured that I am still mildly annoyed about a vast host of things in the Star Wars universe. Honestly, Star Wars is admittedly a work of science fiction (and one that I love) but it’s so little science and so much fiction that, in my (esteemed) opinion, it hardly merits the storied label that the title holds. Dear Mr Lucas, love the films, love your work, but please, please rebrand. Do I realize I’m grumbling about a 40-year-old entertainment franchise? Yup. Do I know that no one cares in the slightest? Mhm. Do I understand the difference between science fiction and science fact? Sure. Am I going to publish this anyway? You betcha.