Putting the science in fiction - Dan Koboldt, Chuck Wendig 2018
How to design a practical spaceship
Star wars and the far future
By Eric Primm
Science fiction loves a beautiful starship. From the Minbari Sharlin to the Empire’s Star Destroyers to the Borg Cube to the Heart of Gold, aesthetics rule. From a practical standpoint, most starships in science fiction are poorly designed. They’re made to elicit awe, but a ship designed from the viewpoint of economics and efficiency would be visually boring. Even in post-scarcity societies, engineers would still strive for efficient designs, which drive out wasteful extravagances.
Poor designs are costly in terms of downtime, maintenance, and resources. Most important, a bad design puts lives at risk. In the vacuum of space, even small design flaws will quickly escalate into life-threatening problems. While contemporary spaceships are often based on aircraft, the operating environment is drastically different, but safety would be the primary limitation. Engineering is the discipline of balancing functionality with risk to make the possible practical. To make functional spacecraft, engineers would study the failures of past and contemporary designs. Here we’ll focus on shape, windows, and manned fighters.
Ship shape
To support life within, a starship must contain atmosphere. Since outside of the ship is vacuum, the structure must be sealed tight. Another way to think about them is to consider spacecraft big balloons. Inside the ship, the atmosphere must operate at a pressure that supports life. Because of the differential pressure outside and inside, the atmosphere tries to equalize by pushing on the ship’s skin. Logically, the skin is pressing back on the atmosphere to contain it. This means that even when not moving, the ship’s structure has a force applied to it. In engineering terms, the structure is pressurized.
Airplanes and submarines are vehicles that undergo pressurization, and in general, these craft have a rounded shape because the best shape for pressurization is a sphere due to the pressure pushing equally in all directions. Practical starships would be either spherical or cylindrical.
Add in maneuvers, environmental changes, gravitational fluctuations, weight modifications, pressurization cycles, etc., and it’s easy to see that spaceships undergo a lot of force. The varying levels of force have an effect on structure, known as fatigue. Yes, structures get tired. Instead of getting irritable and needing a nap, structures tend to crack. The aerospace industry found this out with the de Havilland Comet, a commercial airplane that crashed due to catastrophic cracks. Cracks at square window cutouts grew large enough to cause problems. As the study of fracture progressed, engineers learned that sharp corners create stress concentrations, which is as bad as it sounds. The sharper the corner, the higher the stress concentration, the more likely the crack initiation.
Therefore, designs that have gentle curves have less cracks. Windows on aircraft minimize stress concentrations. Doors on submarines are rounded at the corner for this same reason. A civilization advanced enough to build spacecraft will understand fatigue and fracture, and while their technology would be much more advanced than the current understanding, they would implement these basic design touches to ensure the safest vehicle possible.
Rounded designs, like commercial aircraft and submarines, are good examples of efficient structure. The best science fiction example is the space station Babylon 5. It’s cylindrical, which is close enough to a sphere for a good engineering tradeoff. The worst science fiction example is the city ship from the TV series Firefly. It’s creative while being an engineering nightmare.
Windows
Space is huge with not much to see. Regardless, science fiction spacecraft tend to have windows, and even worse, they have windows so that the pilot can … erm, pilot. Sylvia Spruck Wrigley already talked about the dangers of visual piloting in chapter 51, “Realistic Space Flight.” Since she is correct that spacecraft would be piloted by instrument, the pilots don’t need windows, which are basically holes in the structure with something transparent filling them. In other words, windows are failure points.
Putting important functions of the ship near weak points is not a good design. Despite the mission, chances are good the ship will encounter debris in space. Whether environmental factors like micrometeoroids, debris from battle, or trash left behind by inconsiderate people who also probably talk during movies, the ship will take damage. Therefore, navigation and the rest of the command center would be located away from the outer surface and buried deep in the ship. As it takes damage, the critical functions can still operate.
In fighter craft, windows are especially useless. Science fiction is correct in that missiles would be guided by tracking software instead of by hand. In most science fiction stories, fighter pilots use their sight to target enemies with guns. But in space, combat between fighters would not be like aerial dogfights. Smart militaries would keep their attack craft black to match the background of space, making it difficult to find. When fighting in the depths of space, black ships would be difficult to spot visually. Even in a planetary system with a star, the counter tactics for visual targeting would be to position the ship against a background of black space.
Targeting software would be needed for all weapons. With screens being relatively cheap technology, it makes more sense to have a solid structure outside with a screen and targeting computers inside.
Since visual cues aren’t needed for daily operation, command and control can be located anywhere on the ship. Starships, especially battle craft, would bury their decision centers in the heart of the ship, where damage is unlikely. Battlestar Galactica does this well. Instead of operating like an aircraft, the Galactica bridge is reminiscent of a submarine.
Unfortunately, every ship in the Star Wars universe fails this one. The Millennium Falcon is cool but hangs the pilots out there to be targeted. Despite the prevalence of droids and artificial intelligence, the vehicles in Star Wars rely on visual ship-to-ship combat. While this is more exciting, it’s incredibly reckless. I should turn in my nerd card now. As much as I love the iconic Star Wars designs, those ships reflect that instead of science fiction, Star Wars is science fantasy.
Manned fighters
When the X-wing starfighters first appeared on screen during Rogue One: A Star Wars Story, an actual cheer went up in the theater where I saw the movie. The silhouette of that spacecraft evokes the feeling of the entire franchise. It represents hope. The X-wing starfighter is also an unnecessary risk of life. At the time of the franchise’s creation, drones were not war machines. Star Wars extrapolates its space battles from air combat. But as modern armies are finding out, the weakest part of a fighter is the human inside it.
This is a truth that will carry into the future, and a spacefaring civilization would advance drone technology to be its main fighter force. Instead of a carrier ship loaded with fighters, the practical starship would control unmanned craft. The pilots can be located safely within the depths of the command ship, each controlling a single craft or squadron of drones. Warfare already includes significant signal jamming efforts, known as electronic warfare. Modern militaries excel at this, and it is an easy assumption that advanced civilizations would understand and conduct electronic warfare much better. Battlestar Galactica demonstrates this as static in the communication between the colonial Vipers and the main ship’s crew.
As has already been established, visual flying and warfare are unnecessary, so why put a being in a craft separate from the big ship? If saving a life for the sake of life itself isn’t enough, think about the time and money needed to train a pilot. The skills necessary for flight take a long time to develop, and by putting a pilot in a fighter, a significant investment is risked. Advanced civilizations would not accept these risks, and unmanned attack craft would be easily in reach of a society with artificial intelligence.
By removing the pilot, drones lose unnecessary weight, such as life support equipment, and become more maneuverable. The structure can be designed for flight that would harm a pilot. As stated earlier, structure undergoes significant forces, including anything inside it. Biological bodies are weak, and despite mitigating factors such as crash couches, exercises, and drugs, the physical body limits the forces that can be placed on the structure. By removing the body, the fighter can be smaller, more maneuverable, and more effective.
Unmanned craft are the future. The Cylon Raider in Battlestar Galactica is a great example, but those craft were autonomous cyborgs instead of drones. In the recent show, they also contain biological circuits. This is a potential limiting but not fatal flaw. For a counter example, the fighters from Babylon 5 are beautiful but limited fighters.