Thursday, 21 July 2016

Creating SF: Depicting Space Battles in Visual Science Fiction


All that Glitters is not Gold

    One of the biggest problems in creating a SF story in any medium is the concessions that have to be made to the medium in which the story is told.  This is especially prevalent in visual media such as movies, games, and comics/animation.  The problem is acerbated for those how prefer SF that falls onto the 'harder' end of the spectrum, as they lose many inaccuracies usually used because they make the telling of the story easier.  While someone unconcerned with how a space battle might actually look given the technology concerned it is a simple matter to add some glory lasers and explosions, copying what has worked in other franchises like Star Wars or Star Trek.  For those of you that do worry over these details, read on..

   I'm going to discuss some of the more common elements of space battles in visual SF, although by no means all of them.  For each I'll try to look at why they are shown the way they are, why they are inaccurate, and how they can be changed for greater realism.  A lost of this sort of thing comes down to the exact details of the setting so I will focus on fairly broad issues, things that are unlikely or impossible given our current understanding of physics.



 Who, What, When, Where, Why?

   While you might think that a discussion of physics or technology would be the most important part of this blogpost, there are other aspects to creating a space battle equally important.  If the battle is part of a story then it has to show the story or it is ultimately pointless.

   Say you are producing something along the lines of Star Wars or Battlestar Galactica with main characters who fly fighters, and with a story that focuses on the personal element that they bring into the tale, rather than the grand strategy of admirals and kings.  In this situation frantic dogfights with wheeling fighters, explosions, and hair-raising manoeuvres will probably serve the story quite well.

   If, on the other hand, your story is about a nation, a war, or a leader rather than a simple soldier it has different requirements.  Tactics will let you explore the leader's abilities, strategy will convey the importance of certain actions or individuals in the grand scheme of things.  In this case your might want to set your scene on the bridge of a starship, with huge tactical displays, and hasty conferences between the officers.

   The answers to the above questions will help you to decide on the details of your setting that facilitate the decision; things like the technology used, the strategies and goals, etc.  Only then can you begin to work on the visual aspects of the space battle and know that it will support and compliment the story you are trying to tell, rather than distracting the viewer from it.

   The two examples I gave are by no means the only choices, and you can even switch between the two within the course of a single battle.  There are also other similar considerations; the design or a ship can be used to reflect on the nature of those who built them.  Dull colours and blocky shapes can suggest lower level technology when contrasted with organic curves and polished metal.  The scenario can also be expanded visually; chaotic formations during an ambush, or elegant fleet manoeuvres during the siege of a planet.



Space is Big

   Space is called Space for a reason, mostly because there is a lot of it.  Yet in a almost any work of visual SF - Star Wars, Star Trek, Farscape, Babylon 5, etc. - ships huddle together as though running out of space; as they are, in a way.  The situation is even more ludicrous when you delve into the lore of the various settings and find out that the weapons involved are apparently capable of engaging the enemy at beyond visual rages.  In anything remotely 'realistic' this is an almost inexcusable error.  The reason it is so widespread is quite simple; screens have only so much space.  To show a fleet or a battle in as exciting a way as possible, or to convey the course of a battle, the artist needs to crowd the spacecraft together.

   Fortunately the cure is almost as simple as the explanation.  The first is a technique occasionally used in Babylon 5; it involves showing one ship firing, and then cutting to its target and showing the impact of its weapons.  Having a planet or other large astronomical feature in the background can help to give a sense of the distance between the opposing spacecraft, and if visible energy weapons are being used colour can differentiate between enemy and friendly fire.  The second technique, and the one that better conveys a fleet, is to frequently show the tactical displays being used by the officers directing the battle.  Since such a display should be designed to provide information in a clear manner it should not be too hard to make it legible to the audience.  It also has the advantage that the display can be used to show planned manoeuvres before they are carried out.



Visible Drive Trails & Weapons Fire

   Whenever missiles are used in visual media they are almost always have a neat trail of smoke or vapour to mark their progress, something occasionally produced by manned craft as well.  Likewise energy weapons will glow brightly in all the colours of the rainbow, and even kinetic rounds will glow brightly.  Once again the reasoning behind this is simple, it makes it easy to see what is happening and it looks cool.  Movies and games both use this tactic, games often going on to give fighters long exhaust trails that make their trajectory say to determine visually.  The Homeworld strategy games are notable in this regard with most small ships producing visible trails.

   Glowing kinetic rounds, while they may seem the most unlikely, are in fact the most realistic - to an extent.  Gauss cannon or railguns could heat up the projectile they are firing; simple iron shots might be glowing red or white hot by the time they leave the barrel.  But while they might emit some light it is likely to be so little that combined with the small size and high speed of the projectiles they would be invisible to the human eye.

   Missiles with smoke trails also seem to be quite plausible at first.  Aircraft can leave contrails behind them, and chemical fuelled rockets will most likely produce some smoke, although it is minimised in missiles to make them harder to spot with the Mk.1 Eyeball.  In space however a vapour or smoke trail will never form; with no air to slow and support particulate matter from the rocket engine the trail will disperse far to fast for the human eye to catch.

   Energy weapons glowing seems like a pretty rational thing.  They are after all composed of energy and in the case of plasma weapons are utilising a state of matter that does usually glow.  Lasers will not be visible without particles to scatter the beam, the only reason that we can see them on Earth.  The component particles of a particle beam do not emit energy unless they are slowed or deflected, and when this does occur the radiation emitted is probably not going to be visible given the energies involved.  Plasma weapons might be visible as glowing projectiles, if they ever prove to be feasible in the first place; but given the tennis nature of fusion plasmas, and the relatively small volume of a plasma bolt, they might be very hard to see even then.  The weapons that will be very visible would be things like nuclear shaped charges, although they would also be very brief.

   Aside from the fact that this means space battles will never look like how Hollywood thinks they will there are a few other result of this.  You will almost never see incoming fire.  In the case of particle beams and lasers even sensors will not, in the first case because there is no radiation emitted, in the latter because the beam is travelling at the speed of light.  Missiles and projectiles might be seen, but not by the human eye due to their probable velocities.  In a written work this is easy to accommodate and while a visual work might have more trouble many weapons can be given a muzzle flash or other effect to show that they have fired, and energy weapons can have radiators that begin to glow(although visible glowing radiators are in themselves unrealistic).  The bigger problem is that without visible weapons fire it may be difficult to convey to the viewer what the individual spacecraft are shooting at.



Explosions & Damage

   One of the most dramatic moments in a space battle is when a spaceship with 'the good guys' aboard takes a hit.  In most franchises this results in a big gout of orange fire and then, if we're lucky, a shot of the hull plating torn away from the support structure underneath, preferably glowing from the energy of the shot.  This same ball of improbable fire makes its appearance when a spaceship, missile, or asteroid is blown up, and often on the detonation of nuclear weapons.

   The problem with this is that high energy explosives use in warheads do not produce an orange fireball like an exploding car.  Normal high explosives usually produce a nearly invisible blast since it is thermal energy that creates the visible fireball, and most explosive warheads are optimised to produce mechanical damage.  A thermobaric warhead would create a nice gout of flame, but they are fundamentally unless in space.  The explosion of fuel stores, the ignition of leaking atmosphere, and the release of superheated coolant can be used to explain these gouts of flame to some extent, but even then the effect will be far more rapid than inside an atmosphere, becoming more of a flash than a ball of fire.  And even if something aboard the targeted vessel is ignited there will be no billowing smoke clouds, since these too will expand extremely rapidly in the vacuum of space.

   High energy weapons such as lasers, particle beams, nuclear warheads, and possible plasma cannon, might leave glowing areas on the armour of a spaceship.  I don't have the knowledge to judge on that.  I do know that they will not produce big orange fireballs, though.  High powered weapons strikes are going to be a bright flash of light, potentially coloured depending on the materials and weapons involved, with mechanical deformation affecting the surrounding area to some extent.  The extent of the damage and its appearance is quite a complex question, and the best place to get answers is over on Atomic Rockets.

   Related to this is the explosive end of every ship damaged in battle, usually with a nice fireball.  Given the penetrative qualities of kinetic weapons, and the soft kill potential of radiation based weapons, it seems likely that many ships could be put out of action with very little exterior damage, at least in the case of larger ships.  Given that real fusion and fission reactors are likely to explode the only explanation is that it is a result of high energy reactors of other kinds loosing containment.  Certainly in Star Trek with their antimatter warp cores even an small but penetrating hit could cause a massive explosion.  From a historical perspective it was easier to add a fireball back when CGI was in its infancy that it was to do complex battle damage, so that is the reason why it is so common in older works; newer works just continuing the trend for the most part.

   Anything nuclear is usually surrounded by a lot of inaccuracies in any fiction, so it is no surprise that many works do not show nuclear explosions the way they should.  In space, without an atmosphere to produce a fireball nuclear explosions will be very very brief, albeit of great intensity.  Of course the afterimage would last much longer if you did see it in person.  Often in movies and games nuclear explosions, even when they do not produce fireballs, persist for quite a while; in the real world you would blink and miss it.

   The final inaccuracy commonly found alongside dramatic explosions is that nearby spacecraft will shudder as though hit by a blast wave; yet this is impossible without an atmosphere.  The total mass left behind by an exploding missile, or even a ship, is insignificant compared to the volume of space, and unless the other spacecraft is ridiculously close, or shrapnel is involved, this is not going to happen.



   None of the above are significant problems.  They are mostly matters of convenience, of limitations in the medium used to depict that battle, or of convention.  There is no particular trick to incorporating the 'correct' version of space battle visuals, but it does seem to be somewhat uncommon.  I suspect that it is largely a result of the saturation of Star Wars and Star Trek; people are inspired by these franchises to create their own SF but often end up with a variation, rather than something that makes more sense on the world-building side.  This is kind of like the ridiculous size of many spacecraft in SF, everyone else is doing it, so there is a temptation to use the exist metric rather than try to make the viewer use your universes internal scale or logic.

14 comments:

  1. Sean Robert Meaney21 July 2016 at 05:50

    Given a microwave carrier can deliver a sound wave a nuclear explodion in space should deliver the 'sound' of the explosion on whatever little microwave exists in the explosion.

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  2. Hi Moran, great post! I been waiting for that
    A question - why "visible glowing radiators" are unrealistic?

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    1. It is something I'm going to take a look at in a further post about designing a hard SF spaceship. Basically though in most cases if the radiator is hot enough to glow visibly it is probably dangerously close to melting. Also in the case of weapons radiators, and temperature high enough to make it glow is probably damaging to the components that they are supposed to be cooling. Main drive or reactor radiators might glow, especially if they are solid state devices, but apart from that it is impractical and unlikely. Of course, in thermal vision they will be highly visible, and one of the best 'lock-on' places for heat seeking missiles.

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    2. About glowing radiators, the creator of the upcoming Children of a Dead Earth disagrees.
      Many of the practical designs use nuclear engines and/or reactors (those are near-future tech warships, after all), requiring glowing radiators. High temperature (1200°K) is worked with higher-melting point materials, like silicon carbide (3000°K).
      https://childrenofadeadearth.wordpress.com/2016/04/25/why-does-it-look-like-that-part-3/

      Interestingly, different systems require different radiators (for vastly different temperatures), so crafts with life support system also have heat radiators, which are non-glowing due to the lower temperature.

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    3. Well drive radiators are the exception to the rule, especially if you factor in any kind of fusion. Children of a Dead Earth looks interesting, the first serious attempt at a space battle simulator - as opposed to simple a space battle game - that I have come across recently.

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    4. In a sense glowing drive radiators are something we already have - many rockets use radiatively cooled nozzles in space and they do get rather glowy:
      F9 second stage

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  3. An interesting blog entry, not to mention insightful in how the common tropes of space battles handle against the realism of physics.

    I do recall a few moments of Babylon 5 that use the same setup, though if I also recall such segments correctly, the ships of the opposing parties are always grouped together in the same general frame of reference rather than shown to be distant at best. Though I guess it would be an issue for the suspension of disbelief if there's no other indication that there were other spacecraft in the vicinity to show that they are on the same side.

    Though it is surprising that the contrails of missiles would not be visible in space, though considering the arguments against fireballs from impacts, I guess it should have been expected. Though in the defense of detecting incomming fire, I think it wouldn't be out of place that the sensors of the targeted ships were not detect the DEW bolts and KEW rounds (arguably) themselves, but the targeting sensors of said weapon systems used to calculate a firing solution. A spike in electromagnetic radiation consistent with targeting scanners if you will. And, arguably, would give just enough critical time for the spacecraft to counter the attack in some fashion.

    It's also interesting in how one can approach how a space battle is presented based upon the POV of the character in question and the general overarching..... motif for lack of a better phrase, of the narrative before and after the encounter. Not to mention the design and deployment of the spacecraft and associated task constellation itselves can give additional worldbulding hints and flavors about those who utilize such weapon platforms.

    A though had occured to me as I read the various points of the blog entry on how one could visualize a large scale space battle. A scene opens with a lone combat spacecraft enering the battle, but in subsequent interior shots of the CIC there are GUI representations of other spacecraft in the contellation along with the hostile force in the opposition vector. This could lead into an interesting mix of isolation and suspention when the audience could liken the drama to a submarine movie where the enemy targets are little more than graphic icons that may also give a kind of subtle commontary to automatic modern war. Then the radiation of active targeting scanners are detected and evasive maneuvers are ordered to avoid the incomming rounds. Exterior shots show a few shots impact the hull in flashes of light and the audience is unsure of what was hit or what was damaged until a succeeding interior CIC shots have reports and visual graphical representation of the area damaged and what was hit, adding to it the ever present chaos of combat which is in stark contrast to the apparent isolation of the lone space craft. Return fire can also be tension filled suspence when the only indication that the rounds reached their intended target is only through the monitor of sensor and weapons operators. It could really drive into the point that space combat is not elegant, but chaotic and largely isolated for each spacecraft involved due to the vast distances of space and that there is no certainty that weapons fire will impact their target or if the next moment is their last. Chances are such an execution would be less on the heroism of war and more towards the uncertanty that is the modern fog of war.

    Still, it gives me plenty of thought for my own setting that would breath even more life into it and offer different approaches to it. Thanks once again Moran!

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  4. Sean Robert Meaney14 August 2016 at 23:32

    Frankly I think it would more likely look like lightning discharging down an otherwise invisible uv laser across the target ship surface and up a second uv beam allowing a massive electron glow to melt the target hull.

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  5. The visibility of drive trails is something I've given some thought to. Something as low power as a chemical rocket might not have much of a visible plume, but typically we choose to have ships that can get places in a timely manner, preferably at a high thrust. That implies high drive powers, and depending on just how high power you go, you're basically expelling plasma with the energy content of a nuclear bomb per second. For my part, my spaceships have thrust powers in the low petawatts. They fire NSWR missiles that put out hundreds of terawatts. As far as scifi goes, this still delivers relatively modest performance.

    What would an extremely hot, extremely high speed plasma trail look like? I don't really know. It'd dissipate very quickly, but it's going fast enough it'll still probably cross a significant distance. Initially the plasma would radiate in low wavelengths not visible to the human eye, which the plasma itself is opaque to, which I suppose would contribute to it holding on to its heat for a bit longer. (this is apparently a key reason why Orion's pusher plate wouldn't melt) Past that point, you might get something rather glowy. Maybe. I know nothing about plasma physics, and in particular I can't estimate how fast it would expand or for how long it would remain incandescent and dense enough to be visible.

    Paging plasma physicists. :P

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    1. I suspect that it will not be visible. If you look at photos of plasma drives test that NASA and others have done the plasma becomes invisible very quickly, with a much shorter plume than the almost invisible one from a hydrogen thermal drive. A advanced fusion drive, or a STL starship's drive, would have a bigger plume, but still not what they show in games and movies.

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    2. I'm not sure how much of a comparison real plasma rockets make to high thrust, high isp engines. There's going to be orders of magnitude more mass coming out of the nozzle. One way I thought of it is that if the extremely tenuous plume of something like VASIMR is visibly incandescent, surely a much more denser plume should be more visible, and remain visible for longer - at the very least until the point where it reaches the very low density of the VASIMR plume.

      The illustrations I've seen of the plumes of fusion rockets and such tend to range from a wide, diffuse plume like VASIMR to what seems like a very highly collimated beam. I imagine the former is more accurate since there's nothing containing the hot plasma from promptly expanding once it leaves the nozzle. I'm guessing to some extent it would depend on the relationship between speed of expansion of the plasma and exhaust velocity.

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    3. I suspect that most illustrations are the result of the artist going with what they though looks best. Until NASA or someone actually makes an fusion drive I suspect the question is moot, since the math involved is nontrivial, and not something artist are likely to bother with.
      Another aspect of the question is that a collimated drive plume will be far more dangerous than a diffuse one, so it doesn't only have a cosmetic impact on a 'Verse.

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  6. On the note of massive clumps of ships huddled close together, Legend of Galactic Heroes is, most of the time, a nice aversion. See for example this or this. Realism aside, it's more attractive to me just composition-wise. It's just so much more interesting and readable than a messy blob of ships - that first ship there is coming up against a goddamn wall!

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