The Flipside of FTL Travel


Faster-than-light travel makes the science-fiction world go round. Especially space opera, with its galaxy wide empires, space wars and alien civilizations. FTL travel has many faces, though, depending on the technology of its world (and the writer’s creativity), and with those many faces come many perils. It has undoubtedly more advantages than disadvantages in fiction, but let’s talk about the flipside of it for a change.


Relativistic effects

The most common downside of FTL travel in fiction is caused by good old relativity. According to Einstein’s theory of relativity, any object flying at or above the speed of light suffers a time dilation proportional to its speed. That means that for people on a ship traveling faster than light, time flows “slower” than for the people on a planet. You can imagine it this way: the tremendous speed at which the space ship moves, rips the ship and those aboard it from the normal space-time continuum and ‘envelops’ them in a temporal bubble.

That means that for a ship traveling at FTL speeds, a trip from A to B might take a month, but when it arrives, the time that passed on A and B can be much greater, from a couple of years to decades and even centuries, depending on the distance between them and the speed of the ship.

This creates awesome story potential, of course. You couldn’t just visit your parents on another colony every month, or you’d see them age by decades every time. Or arrive to find their world already centuries ahead of yours.

The Forever WarThe most recent book I’ve read that played on time dilation for FTL travelers was Joe Haldeman’s Forever War.

A group of soldiers are sent out to fight a war against an alien force, flying from one stage of battle to the next, each time losing centuries in ‘normal time’. The story’s main conflict is based around the fact that time dilation causes these soldiers to be completely removed from human society, suffering of enormous cultural clashes each time they have “shore leave”. Also, the technological development that takes place while they are in transit to their destinations creates big differences between their weapons and defenses, and those of the aliens they clash with.


Physical damage

FTL travel mustn’t follow Einstein’s rule at all. That’s one of the awesome things about science-fiction. So if you ignore relativity and assume time always flows the same for everyone all the time (heh), there are still plenty of dangers you can envision for FTL travelers. One of these is physical damage.

The acceleration needed to propel a ship at faster-than-light speeds is enormous. Gigantic. Humongosaurian! The forces acting upon the tender flesh of the humans aboard such a ship are equally fantastic. Ever seen a pilot’s face in G training? Yeah. And that’s at 7 Gs. Imagine how the human body reacts to hundreds, even thousands of Gs. Welcome to hell.

FTL travelers need technology to prevent them from turning into pulp the instant someone says “Engage!”. In Haldeman’s Forever War, they had man-sized bubble-suits filled with a special gelatinous substance that flooded all their bodily cavities (even their lungs), and that prevented them from massive compression. These bubbles could, of course, malfunction. You can create awesome story conflicts around the technology necessary to keep FTL travelers intact, or at least alive.


But the most ingenious use of the physical damage potential in FTL travel I’ve read so far, was in Dan Simmons’ Hyperion Cantos.

FTL ships accelerated so fast, that light-year distances were covered almost instantaneously. The humans aboard these ships, however, were destroyed by the forces acting upon them. They died horribly, and upon arrival of the ship at destination and decelerating to normal speeds, they were reassembled and resurrected by a Resurrection Cache, in a long and painful process that diminished their physical and mental abilities with each time and left them deeply ‘scarred’. Also, to be eligible for resurrection, they had to be wearing a cruciform—a parasitic alien organism that attached itself permanently to their chests, copied their DNA, and granted them immortality by not allowing them to die. An apparent gift, but in fact a terrible curse.


Mental damage

Humans are fairly frail in terms of mental stability when they are exposed to situations of extreme physical strain, high risk and responsibility. FTL flight bears all of these, and then some. Just like airplane pilots are under a lot of stress (even despite automatic flight control), space ship pilots will be stressed too, even if their ships have AIs to help them fly.

But apart from stress—which is kiddie stuff, right?—FTL flight might harbor additional psychological dangers, depending on what type of FTL travel you develop for your storyworld. Maybe extreme acceleration causes hallucinations; maybe an artificial suspension during flight causes amnesia; maybe it even causes people to have dreams about past lives, or suffer outer body experiences; maybe the disintegration and reassembly involved in FTL travel changes their personality, or severely traumatizes them.

Actually, I’ve chosen the latter effect for my novel The Deeplink. In my version of FTL flight, ships and their crews are dissolved on a subatomic level and propagated through space in the form of information (quark spin), then reassembled upon arrival. Because this process is extremely fast, people’s brains are reassembled almost instantaneously and ‘fire up’ violently, resuming life. This causes the characters to suffer from traumatic seizures accompanied by fugue states and temporary insanity, in a calculated timeframe upon arrival. Time in which the ships are entirely under the control of AIs. I won’t say more, lest I spill out spoilers, but that’s the gist of it.


Fuel and material costs

Think our good old gasoline costs much? How about antimatter? Zero-point modules? Tylium ore? Infinite improbability drive batteries (or whatever the hell that contraption works with)?

Fictional fuels for fictional drives are pretty damn expensive, as they should be. Characters might have to do a lot of dangerous things to get them. Risk their ships and their lives. Fight wars. Destroy entire worlds, or suffer from destruction.

Also, you probably can’t roam the heavens in a tin can. The materials needed to construct ship hulls that can withstand FTL flight, radiation, and stardust with speeds that render it deadly, won’t be easy to get by. Expensive, rare materials may be needed to construct FTL engines, shields, life support, recycling units, computer systems and AI cores, etc.


And last but not least, strategic meaning

FTL capacity can make THE difference for a civilization’s survival and thriving in the future. Thus, if there are means to strangle the access to FTL for your competitors, you have yourself an awesome story conflict potential right there.

You can fight over fuel, or special materials needed to build ships, or alien parasites that resurrect you. Or you can fight over particular territories, Mass Relays, or access to wormholes as they do in Lois McMaster Bujold’s The Vor Game.

The strategic position or possession of a means of FTL travel will be very coveted, and thus it can mean competition and war, betrayal and death. Plenty conflict potential!

* * *

          This post is part of the A to Z Blogging Challenge, April 2014.          

   In 2012, my F post was — Feasibility Matters

Published by Veronica Sicoe

Science Fiction Author — I deliver the aliens.

29 thoughts on “The Flipside of FTL Travel

  1. That’s one thing I enjoy about science fiction especially speculative scifi, because everyone could be a potential conflict. Yay aliens, oh they want to eat our brain stems. We can travel to distant places, and now we have plenty of resources. Oh, those distant places are full of bacteria that slowly warps our minds and turns us into zombies. Earth is running out of space we have to leave, but only mode of transportation crushes our bones to a pulp.

    You could even do all three things, cause why not? When the solution is as much as threat as the original problem that’s kind of cool.


  2. Awesome post. It’s not too often authors are willing to look at the costs of their technological magic, especially when it’s something like FTL that’s just become an accepted sort of plot device. Peter Watts has some interesting things to say about the cost in his Beyond the Rift collection.

    My A to Z Challenge


  3. You’re awesome for mentioning mass relays. Mass Effect is a favorite of mine. The Forever War is also a favorite. I learned a lot about FTL from that book, and it’s a really influential scifi story for me, next to Dune.

    I haven’t seen a post of yours in a while, but man they’re always so good. You really know your stuff. 🙂


    1. Thanks, Elisa! I’ve been more or less on hiatus due to pregnancy and childbirth. But I’m back now, and using the A to Z challenge to somewhat jumpstart my blog again. Good to see you again. 🙂


  4. Einstein’s theory only applies as you approach the speed of light, not if you go beyond it; he said faster than light travel is impossible. That’s part of the reliance on things like worm holes in sci-fi, they approximate FTL travel without actually doing it. Warping space, which we’re doing, is another way of creating the effect of travelling faster than light without actually doing it.


    1. Einstein might not have discussed objects actually flying faster than light, but science-fiction has. There’s not only space warping and wormholes out there. They’re definitely the most common ones, especially in TV sci-fi, but they’re not the sole means of FTL travel. Various, conveniently unexplained technologies are found in novels which succeed to propel ships to faster than light speeds without doing anything to the environment of the galaxy (or “space-time”, or whatever is chosen as the backdrop, depending on the theory).


  5. Very interesting, Veronica. I like science fiction — last I read was Wool — and all this makes a lot of sense. Thanks for braking it down for us, or me, with such expertise. I see you have ten chs. edited. Nice work. Hope to take a look at it soon.


    1. Thanks, Silvia! I’m glad you’re having fun here. It’s what I’m blogging for. 🙂

      Wool was a fun read. I enjoyed it, despite the occasional scientific blunder.


  6. I wish that you could have been my tutor as I floundered helplessly in Astronomy and Physics class. I’m only now beginning to loosely grasp such things as time dilation, anti-matter and string theory.


  7. In Battletech/Mechwarrior, there was a condition called Transit Disorientation Syndrome, which seems universal in many sci-fi, but in MW, it appeared that some felt sick after traveling through hyperspace. Similar to getting sea sick on a boat.


  8. Hmm… to me it the method of FTL matters little. Since the author can make up whatever he/she wishes. What I am interested in is the method of navigation. For example, if one wanted a very realistic form of navigation, you could use lightspeed sensors (no FTL,sensors sorry Star Trek fans). In so doing, the moment your ship popped out of hyperspace/FTL, it could only rely on astrometrics (measuring distance by viewing stellar bodies) to figure out the ship’s location. Due to light lag, the stellar images are old, which means that the farther one travels, the MORE course adjustments one will have to make if they are going to uncharted territory like Star Trek. The best navigators would be adept at using the FTL/hyperdrive LESS to reach destinations, while less skilled pilots would have to use it more, which might lower FTL engine life expectancy. For well traveled routes, computers would already know the orbital paths of planets and could warp right to them.


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