How can I explain a one-shot, slow-to-reload laser sidearm?

Question

I'm writing a semi-realistic science fiction story set, let's say, 500 years in the future, where humanity has colonized some of the solar system. For combat purposes, I've been playing with the idea of two common weapon types:

1. a semi-automatic ballistic weapon with frangible rounds, for defense onboard a spacecraft (you don't want to cause a hull breach!)
2. the weapon I'd like to discuss: a laser sidearm.

I don't want these laser weapons to have a rapid fire rate or a continuous beam. I'd prefer if they functioned like a musket, with one shot and then a long "reload". My current idea is that each shot uses one capacitor as ammunition; when drained, the capacitor must be removed, then another is snapped in place. Even then, this process would take a skilled user 3 to 5 seconds. I'd like it to be somewhere between ten and thirty seconds. This weapon would mainly be used to take down criminals in heavy anti-ballistic armor, which the frangible rounds cannot penetrate.

How can I explain a laser sidearm that has one shot, then a 10 to 30 second reload time?

Answer 1

Lasers need a lot of energy to be used as weapons. Even with a high-density battery (better than our current Li-ion batteries), it's going to be a large and heavy battery, so it's the equivalent of a one-shot cartridge. Every time you shoot, you discharge the whole battery, and you have to insert a new one.

Another possibility is cooling time. Even if you have batteries or generators able to provide the power the laser needs, it's a lot of heat to deal with, so you have to wait 20-30 seconds before you can shoot again.

Answer 2

You could have your power supply as 2 parts:

A super-capacitor that, once fully charged, can power one shot from the pistol.

A battery. The battery provides a slow trickle of power to the super-capacitor that takes however long you want to want it to to power up the next shot. Say, 30 seconds.

Your battery pack can supply 1, 6 or more shots depending on how you want the mechanics to work.

One important question you'll need to answer is, if you need to change clips as often as with a normal pistol why they don't just use normal gunpowder pistols. Perhaps the advantages of being able to recharge ammo for free back at base is a big enough advantage.

You'd also expect someone who can hook their weapon into a more powerful power supply to be able to fire a lot more shots per minute unless you want to make the weapon prone to overheating.

Answer 3

You can use a chemical laser

A chemical laser is a laser that obtains its energy from a chemical reaction. Chemical lasers can reach continuous wave output with power reaching to megawatt levels. They are used in industry for cutting and drilling.

Incidentally, the output power make them suited for weapon use...

If your laser is designed in such a way that a cartridge with the reactants has to be loaded before use, this can easily explain why between various shots one has to pause:

• reloading the cartridge
• allow cooling down of the equipment
• require finite time to allow the system to neutralise the HF gas before loading the next charge or choke to death

An added benefit is that you can set it to free purge when fighting in vacuum and fire as fast as you can reload (pump action shotgun style).

The reason for laser over more powerful balistic sidearms is the damage they would do to the ships hull is less likely to result in an explosive decompression of the craft, however a hole cauterised through a pirates helmet and head is likely to give him pause.

Third party edits added

Answer 4

Having actually built a laser in the past, I think this might be a smaller problem than you realize.

Modern lasers aren't a burn risk until they reach around the 3 Watt range. (Yes, only three Watts, but concentrated in a single direction; pen lasers are more like a milliwatt device.) At that point, not only is the beam plainly visible in the air, it will cook flesh by both radiation and induction.

However, such beams usually take around half an hour to heat up and provide sufficient light. It involves reaching a state called a "population inversion", meaning that more than 50% of the active medium is in an excited state. Afterward, pulsating lasers generally have a reflective block on them; energy gathers while the beam is contained. Well, that's one way, there are a bunch of odd ways to do it.

The other thing to consider is that these lasers, like dye lasers, are generally the size of an entire table, and cost around US$100K. The rationale behind the military not using them for infantry weaponry yet should be overt.

500 years in the future, it's likely that we'll have made a few discoveries which will make them a lot smaller. However, as historical precedent shows, there is no guarantee that we'll have made equal progress on warm-up time. Perhaps the beam takes a full five seconds to reach population inversion?

Another thing I would like to point out to you, on the side, is that light does actually carry momentum; and while it's usually insubstantial to massive creatures like people, it is quite tangible for a focused beam. That's part of how one can get burned by a high-wattage laser. It's also why, under the wrong circumstances, a laser might do little to protect the hull. (It's also why dumb mirrors are completely useless against weaponized lasers.) Look up the "Mössbauer Effect" for further details; it might even give you some ideas for your writing.

Answer 5

Don't make them literal lasers. Make them plasma weapons instead.

In a plasma weapon, a small piece of ammo is heated to the plasma state, and then the plasma is fired at the target using a magnetic field. The target is damaged by the heat of the plasma, and plausibly by the plasma's kinetic energy or electrical charge as well.

A plasma weapon might have these characteristics:

• Typical rifle or pistol shape. The part you hold in your hand contains ammo storage and the heating chamber. The barrel contains the magnetic coils for launching the plasma.

• Simple weapons would use a supply of pellets, which have to be heated to be fired. This would take time. Larger weapons with bigger power supplies might have a storage tank for plasma, allowing rapid fire. The barrel would also build up heat and need time for cooling.

• Shots would emit visible light and heat in all directions. Notably, they'd be visible from the side, unlike a laser.

• Shots could be different colors depending on what is in the ammo. The evil Coppertonians might use weapons that fired a green beam, for example.

• Shots might "only" travel at several hundred to a few thousand feet per second, instead of traveling at the speed of light. Under the right conditions, someone could hypothetically see a shot coming and dodge or otherwise react to it.

Answer 6

A charge storage device (capacitor, battery, etc.) that can give you the fast discharge you need for a laser shot has to be heavily optimised in that direction - and so will be poor on things like overall power storage, leakage rate when charged, etc.

Therefore you may well find you have the laser being fed by something like a flywheel+dynamo; the flywheel is then spun up by a power source (such as a more conventional battery) that can store more power over a longer term, but takes a while to deliver a shot's worth of power.

Answer 7

Hand cranked capacitor.

This would be similar to a crossbow which one must crank up with a handle between shots. Here, the crank flexes a piezoelectric crystal, accumulating charge in a capacitor. At full load the capacitor discharges into the laser generator and fires. Then get cranking!

Artistes and creatifs: I tried hard to find an image of a steampunk weapon with a handle and bike gears mounted on the side. No luck; I had to halfassedly MS Paint my own. But this would be a fine project for Dragoncon or some similar venue where there is a forum for steampunk creations.

gun from https://i.pinimg.com/736x/37/23/c2/3723c21ad87c2785a64268ac889ded31--arms-race-steampunk-weapons.jpg modified by me with crank from https://www.picclickimg.com/d/l400/pict/263133537680_/Antique-Victorian-Eastlake-Style-Brass-Doorbell-Hand-Crank.jpg

Answer 8

Do they need to have to take it out? Capacitors, like the ones in flash photography, take a while to charge a lot of energy from a low amp, low voltage battery. This could explain the wait time. If you want them to have to remove the battery, you could have single use battery technology.

One way to figure this out is to estimate how much energy light would need to burn through fabric, metal, plastics, etc, or just look up ballpark estimates, then reverse engineer battery technology to match that.

Another reason you could use would be single use, nuclear batteries. It fires, but you have to open the chamber to vent the radiation or risk being burned, then eject the battery once it's cooled or no longer high radioactivity. Then, the user replaces the battery with a new one.

Changing the caps themselves don't really make sense as caps are not an energy source, but an energy storage device.

Answer 9

The Springfield MMMXI muzzleloading carbine/revolver is your choice!

This carbe is the combination of state-of-the-art plasma technology ( most Scifi lasers in our beloved movies actually act like plasma!).

How does it work?

The carbine consists of three main parts. The muzzle, that has a plasma-push stick attached. The cartridge vessel, that loads the energy cell. The trigger, state of the art sensitive hammerhead engine.

How it might look according to our engineers: (copyrigh -> someone, somewhere).

Carbine Revolver Steps to use it:

First, take a Plasma cell from your space cartridge box. They're round, expell a radioactive shiny color, and are shock resistant as they don't have any catalizer installed. You can play tennis with them! (2-8s)

Second, put the plasma cell with the + side pointing outwards from the muzzle, into the muzzle. push it hard, it's made to fit in void without holes. (4-8s)

Third, push it down with the plasma-push stick. (4-8s)

Fourth, open the breechloading energy compartment. (2-4s)

Fifth, introduce the unstable Unobtamium energy cell, the catalizer that will transform the glowing plasma in a all-environement super fast, glowing projectile. (4-8s)

Sixth, close the catalizer and pull the activation lever. (2-4s)

Seventh, aim and shoot.(Ns)

approximate 1-shot time length with no skills:

40s to 1 minute.

Power output: that of a small artillery piece.

Disclaimer: Mimetic Radioactive plasma cells that mimetize with the nevironement they're shot are on sale. It's like an invisible shot (that irradiates a lot of heat and shows on infrared or with spray/dust).

Answer 10

A ruby laser is a pulsed type laser that uses a Lab grown Ruby doped with Cadmium and some rare earth minerals. You excite it with a Flash tube. Depending on which flash tube you use and how much power you put through it, they will burn out after only a single pulse. Still powerful enough to punch a hole in thin gauge, mild sheet steel.

Answer 11

Instead of using batteries use a generator (something like a Fuel Cell, but enhanced) that cannot give enough power to keep the laser on continuously, but will need to recharge (possibly ramping up voltage) a condenser which will provide the energy for the shot, but will need time to recharge.

A mechanism similar to old battery-capacitor flashes.

Answer 12

I really like the idea of weapon style 1. 1 way 2 explain your laser pistol would be that instead of firing from the changing the capacitor, the pistol itself contains a capacitor, and to reload you instead add batteries, it takes 10-30 seconds for the batteries to charge the capacitor. I'd love to read your story at some point.

Answer 13

Maybe Mass Effect (the video game series) can give hints here? In Mass Effect 1, continuous fire would overheat a weapon, after which there'd be a cooldown of 5 seconds or so until you could shoot again. Some overpowering weapon mods would make sniper rifles overheat from a single shot, so there'd be a cooldown timer after each shot. To me, that sounds similar to what you're getting at.

Mass Effect 2 then introduced a thinly-veiled ammunition system: your weapon builds up thermal heat until it's overheated, at which point you'd throw away the "thermal clip" (=emptied magazine) and insert a new one.

Answer 14

You can use an Explosively pumped flux compression generator to power a laser or other energy weapon, it uses explosives to create a very short, very strong current.

Each generator would come in a nice disposable cartridge that you can spend several seconds reloading. It also has other nice aesthetic benefits, such as causing a nice bang sound, and possibly a flash from venting the exhaust.