Sci-Fi Weaponry: Laser Guns to Planet Busters—How do they measure up?

As long as there has been science fiction, there have been science fiction weapons.

People need defense, others want offensive capability. From vaguely described “blaster” pistols and rifles that shoot energy, to planet-destroying behemoths like the Death Star, and sophisticated devices like Robert A. Heinlein’s Nova Bomb and L. Ron Hubbard’s unique method of destroying the Psychlo homeworld. (If you have not yet read Battlefield Earth, you can read the first 13 chapters or listen to the first hour of the audiobook for free.)

As technology develops, so has, and will, our ability to dish out damage.

The Sci-Fi Blaster

The obvious assumption early on was that bullets would become outdated, as would inconveniences like magazine capacity, time-to-target, and ballistic trajectories. “Blasters” became lasers and then blasters again, as our grasp of energy density and release increased. Asimov, Heinlein, Hubbard, Smith, and Rodenberry all had energy pistols in their fiction, often supplemented with bullets or rocket-powered projectiles.

However, there are practical limits to laser weapon efficiency, and the more powerful the device, the more those limits come into play, often with the lasing materials having a mismatch in frequency or resonance with the energy source. An efficiency of 75% isn’t currently achievable beyond some very small solid state diode lasers. That 25% or more waste energy is heat that will cook the operator. Needless to say, we’re not quite ready to make laser guns real.

Sci-Fi Shotguns and Projectile Weapons

There are also physical limits to how fast a projectile can be accelerated in atmosphere. Above a certain velocity, drag quickly slows the bullet. You can fire two bullets, one at 4000 feet per second, one at 3000. Within a hundred yards, they’ll both be slowed to the same velocity anyway. You’ve wasted propellant energy, and gained little.

David Drake created line of sight “powerguns” using energy-releasing cartridges that solved the line of sight and ballistic issues, while avoiding the energy overload and dispersal problems of a laser. Of course, no one has yet devised those cartridges; that’s why it’s science fiction, the genre of “what if?”

But these are just small arms, shooting either mass or photons.

Sci-Fi Melee Weapons

What about melee weapons? There’s the classic lightsaber, based on the even more classic vibroblade—a resonating molecular wire supported by a force field. There are sonic weapons—fiction 60 years ago, now a reality.

The old “set for stun” trope is becoming real with a weapon that uses a laser to ionize the air, and shoots electrical current through it, no wires needed. It’s not fielded yet, but it’s valid theory with some experimental support.

Battle Bot Weapons and Mech Suits

For getting around the battlefield in style there’s the favorite of the giant battle bot robot, which fails conceptually based on being blatantly visible standing above the horizon, to a huge mass to footprint ratio, and a terrible weakness of having joints just like an animal that can be injured with the same application of force and direction. Kneecap the battle bot, and it’s done. It’s much easier to fix a track block on a tank. But bots look amazing, and have an entire genre of their own.

Bring it down to powered armor, though, and it has some potential. Heinlein detailed the concept at length in Starship Troopers. Craig Alanson’s Expeditionary Forces has several for different alien races. And many others have used them. A powered suit does require more support and maintenance than leg infantry, but it increases their combat footprint. The trick is to make sure the increase in damage dealt is greater than the increase in the tail of fuel or batteries, maintenance, transport, and supply. A science fiction soldier with a powered exoskeleton can carry a lot more food, water, ammo, and potentially move a lot faster, over rougher terrain. If the suit is armored, he can handle more damage than a man with a couple of  bulletproof plates, that don’t hinder explosive damage enough to matter.

Weapons of Mass Destruction

Moving into a larger arena, we come back to orbital bombardment. Any mass at sufficient velocity can wipe out entire areas, cities, even planets. Nuclear warheads can be made into the hundreds of megatons, and then there’s antimatter-matter reactions. We mentioned atmospheric limits for projectile velocity.

Something massive and gravity powered—an impactor—isn’t as limited due to sheer inertia. Whether an asteroid or a chunk of metal, such a weapon can wreak more havoc than a nuclear bomb. Asteroid sized masses will have lingering effects on the atmosphere of dust and debris. Those have been used as weapons by Jerry Pournelle, and others. That’s a much larger scale device, with theoretically no upper limit. Fred Saberhagen’s Berserkers destroyed multiple planets that way. The alien in The Expanse took over the asteroid Eros and hurtled it toward Earth—making it an alien weapon with many layers of potential mass destruction.

If we can think of ways to kill entire populations and ecosystems, it’s certain other species could too. And perhaps they have. Other possible civilizations are not answering our messages to space, after all. Do they not exist? Or did they wipe out each other and themselves?

Military Sci-Fi and Futuristic Weapons

In all of these pursuits, there’s the conflict between offense and defense. Body armor has evolved from animal hide or wood, to bronze, steel, and modern composites. Bulletproof vests have gone from heavy jackets that would barely stop a small pistol, once, to much lighter plate carriers that can stop multiple hits of armor piercing rifle rounds. So perhaps those energy pistols will be necessary.

At a bigger level, air defense versus aircraft continues to be a struggle after a century, as does anti-armor capability versus tanks. Experts keep predicting the end of tanks and aircraft as weapons improve. It hasn’t happened yet, because defense and countermeasures also improve.

In space, orbital bombardment or runaway asteroids will be countered by interception techniques. Nudge an asteroid with a nuke and it misses. Throw enough energy at an impact weapon and it either breaks up in atmosphere or at least misses its target. It may still throw up enough dust to be an environmental concern, though. It would be interesting to see if any contemporary militaries are working on this.

Some of the classic space opera shows and computer games miss the mark with their weapon technology. Star Trek and others have energy beams and perhaps torpedoes or missiles, but these are not the only technologies that can be used offensively.

A matter transporter can be used to transport antimatter aboard an enemy ship, for example, or to cut chunks out of it. And in fact, L. Ron Hubbard got this right, in using a transshipment rig (a matter teleporter) to send bombs to the Psychlo homeworld.

A tractor beam can be used to crush, grip, drag, throw, or shake a vessel and its occupants. Or it can throw asteroids. Think of this as a bar brawl in space, not a duel with seconds and polite rules. With a good enough computer, you can literally play billiards, striking an enemy ship with rocks until you send it away, or into a star or black hole. Problem solved.

Science Fiction Battleships

As far as spaceship combat, fighter ships are so cool, though unlikely. Getting enough motive energy into a package that small isn’t really workable in any universe. There’s its lack of offensive capability vs. energy screens, or against the sheer mass of a large ship. Then, any ship with that kind of energy usage can be seen light years away. In fact, speed of light lag is about their only defense. No matter how good their screens are, a sufficient impact will either destroy them or knock them away from the fight, like a croquet ball hit with a mallet.

So what if you move to bigger ships? Well, then so does the enemy, and you waste a lot of power building an even bigger ship that is also a bigger target, as the Empire in Star Wars was taught repeatedly and never learned.

This was the basis of the Battle of Midway—the island was effectively an unsinkable aircraft carrier. The ships were far easier to disable by comparison. Planets can’t easily be attacked by ships, unless those ships are dropping mass or weapons on very selected targets. But you don’t need manned ships for this.

The Winning Strategy is More Important than Weapons—Logistics

However, the routes that provide trade to a planet or system can be controlled. This is where so many stories fall short. It’s not courage or technology that win wars, though they can certainly help. It’s logistics. Cut off the trade to a system, besiege it, and its economy shrinks to be self-supporting only. If there’s anything it needs from outside, and you control it, you now control the system, whether it’s an entire star system, a habitat, or a planetary surface. Though it might take months or years to accomplish this. In the meantime, they have the resources of a planet to throw at you. And they’ll be desperate.

It’s strange to think “subtlety” in these types of total war, but we should. One can pile on more mass and energy until one outdoes the other, at huge expense and terrible cost in other resources.

Or one can pursue less blunt approaches. There’s the ugly concept of tailored diseases (bio weapons), or mass chemical adjustment of an atmosphere. These will wipe out a species, or an entire ecosystem, and leave the planet relatively undamaged. If you make it slow-enough acting, the survivors will even take care of most of the cleanup for you, burying the bodies and shutting things down in an organized fashion. It’s brutal, but effective.

That’s more of an offensive act.

It’s a bit weird to think of destroying a planet or system as a defensive posture, but it might be. Consider the Psychlos in Battlefield Earth, looting our planet for a millennium, and then determined to destroy us once done. L. Ron Hubbard had Jonnie Goodboy Tyler and his rebels use the enemy’s own matter transporter to send them not only bombs, but bombs that reacted with the entire chemistry and structure of their planet to totally slag it. It’s not subtle, but it is devious, and when the survival of your species and planet is on the line, all bets are off and anything goes. (Read the first 13 chapters or listen to the first hour of the audiobook for free.)

Conclusion: Sci-Fi Weaponry

In the end, most weapons come down to the application of force to a person or object. Force that can be applied efficiently, effectively, and safely by the user makes a weapon that much more potent. Fine-controllable force that avoids collateral damage is a popular subject in the best sci-fi books and speculative development, and explores options from stunning a person unconscious to vaporizing a planet.

Other resources you may be interested in:

10 Sci-Fi Weapons that Should Never be Invented

Science Fiction Futures

Star Wars and Battlefield Earth: Classic Science Fiction at Its Best

List of L. Ron Hubbard fiction books

Military science fiction resources: Fandom Military History and Sci-Fi Weapons Coming to Life

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