Spaceship Shields in Science Fiction

The Necessity of Shields in Space


In so many science fiction stories involving spaceships, they almost always include shields on the vessels. Even in a real world scenario they’re important to have. Outside the protective magnetosphere and atmosphere of our planet, cosmic rays lurk. If a spaceship’s crew is exposed to them long enough, more than a few weeks, they will sicken and die. And let’s face it, a trip to Mars is going to take more than a few weeks. Then there are those pesky micrometeorites. Depending on the speed of your ship and the speed of the meteorite, something the size of a sand grain can hit with the power of a bullet, or a howitzer shell. So, whether considering science fiction or real spaceships, it’s good to have shields.

Spaceship Shields in Science Fiction

Often, in a scifi show, we hear a phrase like, “Shields at 42%!” I’ve been wondering about that and why it would work that way. Obviously, it adds dramatic tension, but would it really work that way when spaceships and their shields become a reality? I tend to think not. I’m not an engineer, so anyone who is out there can correct me, but I believe shields would either be working or not, operating at 100% or not at all. I understand that you could shift energy from one shield to the other in the trope, but why build in that capability? While in a battle, why not just run the whole thing at max capacity? Then you could focus on maneuvering and not bother with that detail. If your power plant could not run all shields at max, that would suggest you need a bigger power plant.

If we consider electronic components that we have now like the diode, for instance, they work at spec until they burn out and don’t work at all. Same for capacitors, resistors, etc. When the power supply on my computer died, I didn’t get a message saying, “Power at 42%, Captain.” It operated at its rated power level until something, perhaps a diode, stopped working and the power supply croaked. Shouldn’t shields operate similarly?

Plausible Spaceship Shields

When I wrote, The Huralon Incident, I imagined shields that were directed by a number of emitters. The devices project a small shield each until they absorbed more energy from a weapon than they could handle, and burn out. That’s it. Either it’s working or it’s not. These emitters would cover a ship, so even when you lost one, only a small portion of total shield protection went down. In such a case the report wouldn’t be, “Shields at 90%, Captain,” because that wouldn’t be very informative. The report would be like, “Emitter down on the ventral port quarter, Captain.” This would work better because the Captain now knows not to present the ventral port quarter to the enemy’s weapons.

So, what do you think? Does the idea of shields, that when hit, decrease in strength by degree make sense or not? How would you imagine a shield working? Let me know in the comments.

If you’re interested in a different way to see how shields might work in the future, check out my book, The Huralon Incident. It’s a military space opera with detailed space battles, a superspy, nanites, humor, sociopolitical world-building, and plenty of descriptions of food. You can find it below:

About EagleAye

I like looking at the serious subjects in the news and seeking the lighter side of the issue. I love satire and spoofs. I see the ridiculous side of things all the time, and my goal is to share that light-hearted view.
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3 Responses to Spaceship Shields in Science Fiction

  1. On my spaceships, the shields are not designed to defend against space weapons, but against space debris. The biggest hazard is what’s out in front of you, as your vessel accelerates through space. It isn’t shield shaped–more like a lance, a jousting pole, that extends out many miles. It nudges space crap aside, so it doesn’t come in contact with the vessel.
    It’s not meant for space battles, but once when it was being attacked by laser beams, the spaceship changed trajectory and headed directly for the laser platform. Using its energy beam, it nudged the platform aside just hard enough so that it broke apart. Defense becomes offense.

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  2. As an Electrical Engineer, I can see several ways that shields would degrade gradually. Shields against energy weapons would likely have something akin to surge protectors, and emitters and receivers for the field itself. As you point out, it would likely make sense to build multiple redundant systems rather than one greatbigasaurus, although as I recall the Enterprise did have that one big dish up front. So in battle, you would have emitters, receivers, and surge protectors burning out. To try to itemize those to the Captain in the midst of battle would be like reading a damage control report. It would be far too much info. Which brings us to … the Captain or any other human is not going to be in control during a space battle with energy weapons at close range beyond doing what they do on the Enterprise and that is specifying an evasion or attack pattern to the computer, which then ties that in with the weapons, shield, and drive information to create an optimal offense/defense.

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  3. The thing for me about shields and defensive force fields in sci-fi is they must by nature involve a reasonable amount of hand-waving. Real-world physics doesn’t exactly lend itself to the concept. The problem is that they’re often presented as a kind of of armour plate equivalent, being chipped away (the ‘shields down to 90 percent’ trope), whereas in real-world physics they can only be a field, and the behaviour of such fields is well understood. As you say – either on or off. Earth’s magnetic field shows the principle up: it traps charged particles up to a point.

    Doc Smith tried to rationalise it another way back in 1930 in ‘Spacehounds of IPC’ by suggesting shields were actually electromagnetic energy projectors that matched the power and frequency of incoming energy, but on opposite phase, thus neutralising it (remarkably for Smith’s usual galaxy-smashing hand-waving, this was genuine physics – it’s how jamming works). Miss the frequency or the phase and you’re in trouble, of course. Niven and Pournelle’s Langston Field explored it in the ‘field’ sense: it took energy to create a space inside the field for the ship. If the energy failed, the shield collapsed into the ship, vapourising it.

    The thing is that, as usual, real-world physics doesn’t lend itself easily to a dramatic or interesting story. So it seems to me that for a compelling shield system the author has to suspend disbelief in an interesting way – which also means something that doesn’t repeat the usual ‘shields down to 75’ trope. I particularly liked your idea in ‘The Huralon Incident’, including the way the propulsion system could assist (I won’t add a spoiler here – it’s a brilliant concept for your readers to discover!).

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