I wasn’t always interested in outer space or other planets. I gravitated towards near-future dystopian themes. All my early experiments in writing occurred on Earth. Then one day I had the crazy idea, what if you transplant one of your survival themes to another planet?
That sounded simple enough. Create an isolated jungle on a randomly named planet. Give it Earth-similar characteristics, and call it a day.
But what happens if people are moving from one planet to another? Short of portal-hoping, said travels involve crossing the void. Meaning space. And space doesn’t play by the same rules as Earth. This is when I discovered how critical gravity would be to my future plotlines.
If you are trying to write Science Fiction that occurs in space, you have a few considerations for contending with gravity and its impact on your characters.
Star Wars Approach
You can choose the Star Wars approach, where the series essentially ignores the consequences of gravity altogether. Think about a time when their magic gravity fields failed and people began drifting in random directions. Can you think of a time? I can’t. All the spacecraft are designed to fly in atmosphere, with thrust oriented like modern jets, not rockets. You can choose to ignore gravity as a pesky nuisance, but I prefer to consider gravity a conflict–a problem to be solved. Conflict and problems tend to make for good stories. Why would you want to deprive your characters of a phenomenon so unique to the setting?
Star Trek Approach
Star Trek does tend to rely on some of that gravitational magic to keep things on board in place, but I appreciate the fact that it does sometimes malfunction or is disabled when a ship is badly damaged. I will forgive Star Trek’s airliner layout of their craft considering when it was first written in 1964, we humans were barely dipping our toes into the realm of outer space. Yuri Gagarin had only left Earth’s atmosphere three years earlier. John Glenn made his three orbits around the Earth two years prior to the writing. And Neil Armstrong wouldn’t take his small steps and giant leaps (1969) for three years AFTER Captain James T. Kirk was going where no man had gone before. Considering our limited knowledge of space, the Star Trek approach gets a pass because they truly were blazing new trails.
Big Masses Spinning
Use Earth as your example. When large masses spin, they generate gravitational force. The physics equation looks like this: F = GMm/R² but essentially it states that more mass and/or a closer distance between objects, equals more force. Less mass and or a further distance between objects will result in less force. No reader cares to hear about whether or not you crunched the numbers on your imaginary planet, but knowing that the planet your characters are from has more/less gravity than the one they are visiting, can definitely have an impact.
In James S.A. Corey’sThe Expanse, the Martian Marines train at higher gravity in case they have to invade Earth, because Mars has less gravity than Earth. In the same series, the Belter people living off-world in starships and space stations aren’t even able to visit Earth because they spent their whole lives in zero-g and the gravity would be too oppressive. These space people’s anatomy has evolved for their environment, with longer limbs and bigger heads. I also appreciate the fact that medicine would have complications, including blood pooling and impact on pregnancy. All things to keep in mind…
These phenomenon work hand in hand and have to deal with the frame of reference of inertia. Simplified, this is the phenomenon that keeps water in a bucket if you windmill it upside down in a big circle. Many circus attractions utilize the same principles to keep passengers contained within the seats of the ride. It doesn’t function exactly the same as gravity, but in the context of space, it comes close. Many sci-fi authors/creators, and even legitimate space organizations have devised spacecraft and stations reliant on spin gravity. Mass Effect’s Citadel comes to mind. As does the elite’s orbital city in the 2013 film, Elysium. James S.A. Corey uses it frequently in The Expanse, adding complexity based on the center of the axial spin. The list is extensive.
The Avalon from the 2016 movie Passengers.
Constant Acceleration Drives
Acceleration = the rate of change of velocity with respect to time. Not to be confused with speed. Acceleration is that sensation when you are pushed back in your seat from an airliner taking off, or from a quick car launching from a red light. Acceleration can serve as a useful substitute for gravity, with one catch–you can NOT stop accelerating. Once the vehicle stops accelerating, it doesn’t matter at what speed, that force goes to zero. Your fuel supply is your biggest restriction.
Acceleration = how quickly speed is achieved
Velocity (Speed)= distance traveled in a period of time
The other big catch is that you must orient thrust in a useful direction for fake gravity. A rocket is aligned in the correct direction, because thrust pushes from the rear, simulating gravity below a person’s feet. An airliner’s thrust is not useful in the gravitational sense, because the force would be perpendicular to the floor/ground/deck.
Aerodynamics
While we’re on the issue of gravity and fictional space environments, we should also remember that aerodynamics (the shape of aircraft) doesn’t apply to starships that will spend their lifetimes in space. I keep going back to The Expanse, but it was the first time these concepts clicked for me. Spacecraft could look like hodgepodges of random blocks and chaos. They don’t have to resemble anything sleek and smooth that has to fly in an atmosphere. Forget wings, stabilizers, or drag. Vacuum doesn’t care about svelte. The Rocinante isn’t winning any awards for the most beautiful ship, but it is functional with constant acceleration drives.
The Rocinante has a brickish appearance that works perfect in space.
The iconic Enterprise
Mass Effect’s Normandy
See, the International Space Station definitely doesn’t care about being aerodynamic or good looking. It’s design is purely functional…which I guess is beautiful in its own way.
Final Thoughts
In the end you are the creator of your fictional world. If your narratives are plot and character driven, you might not worry about the science behind being in space. Plenty of stories with far larger fanbases than I could ever capture in a lifetime have disregarded concepts like gravity altogether. Magic gravitational certainly have their advantages, especially if space is seen less as a setting, and more as a backdrop.
But for all those authors that have tried to incorporate some features of what space would be like, I commend you. You have challenged my mind to a new set of rules. If nothing else, I have a greater appreciation for the reality of space life and all its challenges.
