How possible is it to propel the Death Star?
Thanks to a teenage farmer flying a starship, it’s a known fact that the Death Star’s propulsion system was it’s Achilles’ heel. However, minus the 2 meter wide exhaust port leading directly to the volatile main reactor, how else is the Death Star’s movement a pain in the Emperor's ass?
What are we Dealing With?
So many people have over-analyzed the Death Star already. This video finally answeres the question we’ve all been asking: ‘how many twinkies would be required to run this battle station?’. It’s also a generally accepted the Death Star was expensive. Very expensive. 800 quadrillion USD, or 132,000 times Earth’s GDP according to Forbes.
It’s surprising that the most impressive feat of the station, moving close to 8,000 light years in a couple of days, has gone overlooked. The stats behind this feat are astounding, and make Vader mopping the whole Death Star seem like a walk in a park by comparison.
Formulas used to calculate a fictional battle station’s Faster Than Light capabilities
If you hate math, then look away now.
In order to wrap our heads around how a man-made (technically, wookie slaves and Geonosians built a large part of it) space station the size of a small moon is able to move, first we need to calculate F=ma, or how much force is required to move an object weighing m kg to a certain acceleration (a).
Using this formula, we can calculate the force required to leave the orbit of a planet. For calculating the energy required to get the Death Star into hyperspace, we will use the famous E=mc² equation.
Under the Hood
The Death Star is impressive. It boasts a mass of 134 quadrillion tons, which is equal to the mass of the three pyramids of Giza times 8 million. That’s heavy, doc. Equally impressive is the station’s diameter. The circumference along the equatorial trench is about 504 km, giving it a diameter the length of Long Island, New York.
A Plausible Theory for hyperspace Travel
In the world of general relativity, it takes an infinite amount of energy to move one molecule to 100% the speed of light. So is faster than light travel (FTL) even possible? Of course it is (theoretically)! In 1994, a Mexican theoretical physicist named Miguel Alcubierre published a paper that allows for FTL travel to be possible by messing around with space time.
I don’t want to get too much off on a tangent, so for more information about the Alcubierre drive, here is his paper on the subject. For the theoretical physicist sticklers out there, I will be assuming that the Empire has no problem with generating negative energy.
Escaping a planet’s orbit
Let’s start this nerdy deep dive off with the most basic starship maneuver: accelerate out of a planet’s orbit. Earth’s escape velocity in low orbit is 7km/s. In order to get the Death Star from 0 to 7km/s in 10 minutes would end up being around 402 quadrillion Newtons.
A Long Time ago, far, far Away…
To be fair, the Death Star didn’t really need to get to any escape velocity in A New Hope, since it blew up the planet it was orbiting. But in order to crush the rebellion, it would have to travel from the mid rim/core world area to the outer rim in a matter of days. The distance is hard to calculate, as the galactic maps are not to scale. Figuring out the distance proved to be a bit of an educated guess.
In our galaxy, I measured the distance from the outer edge of the core to the middle of the spirals. My estimate has the distance between the two systems being just under 8 thousand light years, or 7,821 to be exact. To put that distance in perspective, the light of Alderaan’s sun reaching the moon base on Yavin is 7,821 years old. If someone at the rebel base had a very powerful telescope, they would continue to see the planet Alderaan for another 8,000 years.
Making 0.5 Past Light Speed
Time to get into more math. the Death Star Now has to initiate an Alcubierre bubble. This is a pocket of spacetime that encompasses the spacecraft and moves through spacetime around the bubble. This is purely theoretical, but to move a small spacecraft the size of a space shuttle, it would take 700kg of mass. Yes, I said mass. Now we have to use that handy E=mc² formula Einstein came up with. In order to figure out how much energy it takes just to initialize FTL travel, take the weight of a space shuttle times the speed of light squared. E=700kg*C² = 629,128,625,115,772,348 Newtons. We aren’t done yet though. Now we need to multiply this with the mass of the Death Star divided by the mass of a space shuttle. This comes out to 1.12X10³³ Joules. This is 13,043,478,260,869,565,217 times the amount of energy the WWII atomic bombs gave off.
For the Death Star to get this kind of energy, it alone could be classified as a Type 2 civilization on the Kardashev scale. I’m getting real nerdy here. The Kardashev scale is a way to classify how much energy a civilization uses. A type 1 civilization uses all energy from its home planet, type 2 uses all the energy from their system’s star, and a type 3 uses all the energy in their galaxy. Suprisigly enough, this amount of energy is tiny compared to the energy needed to blow up a planet.
Are we There Yet?
Ok so if the Death Star can generate that amount of energy to initiate travel, how long would it take to reach its destination? In the movie, it appeared instantaneous, but to be generous, lets give it a week to get there. Current estimates of the Alcubierre drive suggest it could propel that spacetime bubble at eleven times the speed of light. With the Death Star is in it’s spacetime bubble heading to Yavin at 11 times C, it will take the Death Star crew a measly 711 YEARS to reach their destination.
The Universe is Depressingly Big
Star Wars makes the galaxy seem small, with characters flying in and out of systems in seemingly no time at all. Unfortunately when you look at the science of interstellar travel, you begin to realize that this is the most unrealistic part of the Star Wars story. Another example is this great article on how the Kessel run took Han 16 hours, but 40 years outside of the Falcon’s perspective.
The good news is Star Wars doesn’t pretend to be scientifically accurate. It’s a nice break from reality, and a great deal of its success was due to feeling of escapism invoked by the movies. The real genius of Star Wars was taking something that is as empty, void and dark such as the universe and giving it life.