You’re Beautiful, Death Star. Don’t Change a Thing.

In recent years, the Death Star, specifically the design of the exhaust port, has become a popular (and fun) target of derision. “Oh Gee, those stupid engineers! They’re so smart that some ignorant farm boy was able to blow up their toy! Death Star… more like Not Star! Haw Haw Haw.”

It’s hard to argue that the Galactic Empire Corps of Engineers couldn’t have taken addition steps to safeguard the exhaust port. A short wall a few meters in front of it, or even a steel net like they used in the mouth of harbors during WWII to protect ships at anchor from torpedo attacks would have done it.

So was it a major oversight? I don’t think so, and here are the reasons why.

The Elephant in the Exhaust Port

The number one slam is the design of the secondary exhaust port. Since it leads directly to the reactor, it’s an obvious flaw! But is it? Listen to what the architect has to say about it.  For certain types of power plants, you can’t not have an exhaust port, be it your car or a diesel powered ship. Also, you can’t obstruct an exhaust, as that rather defeats the purpose of having an exhaust.  But here’s the thing, compared to the overall size of the Death Star, its exhaust port is tiny. To put that into perspective, if your Honda Civic’s exhaust were proportional¹ to the Death Star’s, your tailpipe would be just 0.808mm in diameter. That’s some green engineering.

You know what other craft had exposed exhausts leading directly to the power plant? WWII surface ships. I do not wish to make light of real military losses, so let it suffice to say that the U.S. didn’t lose a single capital ship due to a bomb down a smokestack, and it’s not for a lack of trying.

The Rebels Were Practically Wiped Out

Of the original force of 30 fighters², only three survived. Of those three, one was partially disabled and another damaged. Everyone that attempted the trench run (with the exception of Luke and Wedge) were killed. The other losses were due to a combination of surface fire³ and tie-fighters. That’s a 90% success rate (and would have been 100% had it not been for Han), which is an “A” anywhere but the Star Wars universe. Even had more fighters survived to make additional trench runs, there wasn’t enough time. Luke destroyed the Death Star mere nanoseconds before the main laser fired. If only Luke had been killed…

Luke Should Have Been Killed

Let’s get this straight. Han didn’t save Luke. Darth Vader⁴ did⁵. If he had simply kept his finger on the trigger for a split second longer, Luke would have been blown up. But he didn’t, and he wasn’t.

Don’t blame the other tie-fighter pilot for running into him, either. All that did was save Vader’s life (Actually, why didn’t Chewie go for the lead ship in the formation? Yes, Chewie. Who do you think was in the turret? Dumb old Chewie. Vader should have been killed.). Vader lost focus. It’s all his fault. He should have been cleaning Imperial urinals after that blunder, not leading a task force.

The Shot Was Impossible

I’ve already touched on the surface area of the Death Star—45,238km²— which is a lot. Now can you imagine flying around at thousands of kilometers per hour and trying to spot a 2 meter hole in the surface—a very bumpy, turbo-laser studded surface? Of course not. Let’s put it into every-day scales. Think about how hard it would be to spot a manhole cover while driving down a city street at 190mph in a Lamborghini. Just scale that example up to “not a chance.”

“Okay,” you say, “all I have to do is find the trench. That sucker is miles and miles long.” As the saying goes, length doesn’t matter, but width. How close would you have to be to see the trench? Well, according to theForce.net, the trench is about 59m wide. The smallest thing someone with normal vision can see with the naked eye⁶ is about 0.1mm  at a distance of 15cm, which is the width of a human hair. For the trench to appear to be this size, you would have to be within  85.5km. Well, they clearly had the Death Star map loaded into their Garmin so I’ll give that to you.

So the next important question to ask is, how fast were they flying? We know that Luke & co. were going balls-to-the-walls full throttle. X-wings are given a top atmospheric speed of 1,050km/hr on Wookipedia…which is only slightly faster than the WWII Me262.  I think it’s fair to assume an X-wing is faster. But how much faster? We are never given speed figures, but we do know (roughly) how large the Death Star II⁷ is. We don’t see exactly when Wedge exits the core, but we do see the Millennium Falcon do so. Assuming the scene is shot in real-time, it took the Falcon 32 seconds to reach the surface, giving it a speed of approximately 9,600km/hr (or Mach 7.5), so it’s reasonable to assume an X-wing is somewhere in that ballpark⁷.

At that speed, the end of the trench would become visible (hair width) 32 seconds before you reached it, however, the port itself wouldn’t become visible until you were within 3km–if it were on the wall. But it wasn’t. It was on the floor some distance ahead of the wall, which means you would have to be significantly closer to see it. How much closer? I’m going to do some lazy math here. Sitting on my couch, with my eyes 3 feet above the floor, at a distance of 26 feet, a 8.5″x11″ piece of paper has a visual hight of 0.25 inches, at the same distance hanging at eye-level, it has a visual size of 0.875 inches, which gives us a ratio of 3.5:1. This figure is almost certainly wrong, but will get us into the ballpark. If anyone would care to to the math with an X-wing at a height of around 24m above the bottom of the trench, please post the correct answer in the comments below. So if the port on the back wall would be visible at 3km, on the floor you would need to be within 0.86km to see it. Let’s just round that up to 1km for the sake of easy math. Which means that if you waited until you saw the port to fire your torpedoes, you’d be slamming into the wall 0.37 seconds after seeing that hair-width sliver.

The human perception time is between 0.25 and 0.5 seconds  (the time it takes for you to even realize that you’ve seen anything), and the average reaction time is between 0.25 and 0.75 seconds. So even with optimal human reaction times and perfect eyesight, if you waited to fire until you saw the port, you would die 0.13 seconds before you could even hit the trigger.

All of this is immaterial because it took 1.15 seconds for the torpedoes Luke fired to enter the exhaust port, which means that Luke did fire before he could “see” it—at a minimum distance of 3km (that’s if the torpedoes were traveling the same speed as the X-wing, and they were clearly faster). That’s the Force for you.

Let’s look at Red Leader’s attack run. From the time he fired to the time he (barely) cleared the end of the trench, 3.2 seconds passed. For the sake of argument, let’s say he was flying at half throttle (though I think he’d be going faster than that). It would mean that he fired from a distance of about 4.3km. Considering an AIM-9 sidewinder missile has an operational range of about 22 miles, 4.3km is believable, if on the short end. This gives him a realistic amount of time to fire and pull out without becoming a splat-mark⁸.  So Red Leader, presumably the best, most experienced pilot in the Rebellion, with the benefits of a state-of-the-art targeting computer and guided munitions couldn’t make the shot. And that’s my point. The shot was nearly impossible, and minimizing risk down to nearly impossible is brilliant engineering.

Addendum

After posting the article, I realized that I forgot to mention how Luke was weaving around near the end of the trench run. Though he did straighten out at the end, I  still felt the need to add a note about an important aspect of gunnery: Small errors in aim (caused by, say, weaving around) translate to large errors down-range. The longer the shot, the more you’ll be off by. So if Luke’s aim had been off by, say, 1ᵒ, at a range of 6.13km, that translates to 107m downrange—which means the torpedoes would have hit the wall 4.47km before reaching the exhaust port. For comparison, Red Leader’s aim was off by a whopping 0.04ᵒ. Good luck doing better than that.

In Conclusion

So without the Force, Luke doesn’t make the shot, except through pure dumb luck. The odds are mind-numbing. Some might say, one in a million.→

We don’t live our lives on one-in-a-million odds (you have a better chance of being hit by lightning), and engineers don’t design for a one-in-a-million chance. So laugh all you want, furball, but the Death Star was pretty darn awesome.

 

Edit: Thanks to Iron Lord at the Force.Net who caught that I was using the diameter rather than the radius in my size calculations. I appreciate the feedback!

Edit: Thanks to Bellerophon at the Starship Modeller Forum for noticing that my decimal point was off on the surface area for a Civic (in the footnotes). You guys are really keeping me honest!

Bonus Round

While I’m at it, I’m going to go after all the people who say that putting the bridge on the top of the Enterprise is bad design. While it is true that a high vantage point is meaningless in space, so is putting it almost anywhere else when you have deflector beams and shields.

Let’s put aside combat for a moment. Space debris is dangerous. At sufficient speeds, a spec of dust will punch through every material known to man, and I don’t care what the name of your bullshit made-up material is. It doesn’t matter where you are in a ship if bits of cosmic debris go all the way through it. Sure it would be bad if a thumb sized meteor went through the bridge, but not nearly as bad as if it punctured the warp core or anti-matter containment. And it isn’t just dust and rocks, highly energetic subatomic particles (cosmic rays)  would totally wreck your day. And putting the bridge into the center of the ship wouldn’t mean it’s better protected. Just as most walls inside a building aren’t load-bearing, or the bulkheads of a modern warship aren’t armored, the interior walls of a starship wouldn’t be solid armor (and they aren’t as we see Scotty cut through the bulkhead outside of engineering with a hand-phaser). The only meaningful armor is on the exterior of the ship, which means it doesn’t matter where the bridge is, as long as it’s on the inside.

To be clear, deflectors and shields don’t provide more protection, they are the only protection that allows a starship to travel at relativistic or superluminal speeds (notice that the Enterprise’s main deflector is powering up as it’s leaving Earth’s orbit at the beginning of TMP, even at its leisurely pace of 40,000km/hr). Adding more physical protection to the bridge when you have deflector shields would be like having Captain America’s shield but using a Kleenex for additional padding. Logically, a Tritanium hull must be strong enough to withstand micro-meteor impacts and be hardened against cosmic radiation when in planetary orbit or when parked somewhere, but that is a far cry from the forces involved⁹ when traveling at, say, 0.5c (540,000,000km/hr).

Back to combat. I think that the recent television portrayals are beautiful, but not particularly realistic. In TOS, due to budget constraints, a great deal of the combat took place well outside of visual range. The original range of phasers or photon torpedoes was on the order of tens or hundreds of thousands of kilometers, while from Wrath of Khan on, it’s depicted as hundreds of meters—which is just plain silly. But taken as canon (and it kind of has to be), you’ll notice that even at those close ranges, they still miss… a lot. Just watch any of the battle sequences from DS9 to see what I mean. Aiming for the bridge isn’t just impractical, it’s not even the most effective way of disabling a ship.

This is why in the real world, in real combat situations, whether it’s handguns, tanks, aircraft, or surface ships, you aim for center of mass.

I think that’s enough geeking out for one day.

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1. Based on a diameter of 120km, the surface area of the Death Star I is 45,238km². A 2016 Honda Civic has a surface area of approximately 177,817m^2, and its tailpipe has a diameter of 44.45mm.  If the Death Star’s exhaust were proportional to the Civic, it would be wider than a football field. Or how about this example: let’s say you’re Achilles, but instead of your ankle, your vulnerable area would be less than than the width of a human hair.Based on the on-screen dialog of the ‘Despecialized’ version of Star Wars and Wookipedia.
2. Not bad, considering the Death Star’s defense system wasn’t designed with small fighters in mind…which means those gunners are firing at small, fast, maneuverable fighters with what amounts to as howitzers.
3. Vader does pretty much call it when he says the Death Star is nothing compared to the power of the Force; Luke+Force=blown up Death Star.
4. Okay, Wedge saved him a few minutes before as well. Luke needed regular saving.
5. How small your eye can see; another source.
6. 160km according to Wookipedia.
7. But still very slow… the space shuttle reached speeds of 28,000km/hr, but we can only go by what we see on screen. In “reality” the X-wings would have to have been much faster to reach the Death Star while it was still on the other side of Yavin. If the moon with the Rebel base had a similar orbital distance as, say, Europa from Jupiter, it  would have an orbital distance of 670,900 km. The Rebel tactical display showed the Death Star on the exact opposite side of Yavin at a similar orbital distance. If Yavin is approximately the same size as Jupiter(139,822km), the total distance would have been 1,481,622km, almost 4 times the distance from the Earth to the moon… For perspective, the fastest manned spacecraft, Apollo 10, reached 39,897km/hr and it took almost 76 hours to reach lunar orbit. Even if Yavin was a very small gas giant and the moon was very close, the distances are still huge. Or look at it this way, even if the trench went all the way around the Death Star, it would have taken the Apollo 10 39 seconds to traverse it.
8. Speaking of splat-marks, notice that of the two torpedoes fired, only one hit within two meters of the port—and it barely made a mark.

   

    

9. If a 1 gram object (for perspective, that’s about 10 peas) struck the Enterprise at 0.5c, it would result in a release of 3.725×10¹³J of energy or about 8.9 kilotons of TNT (approximately half the yield of Fat Man, the nuclear bomb that destroyed Nagasaki), which is kind of a lot. The math. To put that into perspective, a single shell from a WWII era 15” gun, firing a 879 Kg shell at 804 m/s strikes with a kinetic energy of 0.000067901 kilotons. Unfortunately, I couldn’t find figures on the explosive charge inside the armor-piercing shell, but it would be less than a ton. To further put this into perspective, this 15” gun was the type used on the HMS Hood and HMS Prince of Wales in the fight against the Bismarck. It was powerful enough to pierce Bismarck’s 12.6” of armor. The Iowa’s 16” guns could penetrate 20” armor. The point is that it doesn’t take kilotons of energy to pierce even very heavy armor.

   Addendum: While we’re on about the HMS Hood, a single shell from Bismarck pierced the deck of the Hood and hit the magazine, blowing the ship up with all hands lost.

10. From Star Trek: DS9, season 4, episode 01, Way of the Warrior, Part 2, my screencap.