Space Warfare, Weapons

If you read these blog posts, then you are probably some fan of science fiction or science fantasy. Personally I have always loved the sweeping space operas like Star wars and Battle Star Galactica. And with these stories comes the backdrop of space for any grand battles. Recently I have started consuming newer genera of sci-fi, near future sci-fi, which uses existing theoretical concepts to create a believable world with defined limits, which are severely lacking in stories like Star Trek and Star Wars. (if you would be interested in some of these stories, I would personally suggest you watch The Expanse and read The Three Body Problem trilogy).

For today's piece I will explore some of the weapons talked about frequently in these stories.

A scene of the Battlestar Galactica bombarding a base star with missiles

Before conversing about these topics there are several things you should understand about space warfare. Number one and most important: Space is big. I can't overstate how big space is, the distances that are used are so big as to be imperceptible to us. If I said, the furthest planet from the sun (Neptune) marks the outer limit of our solar system defining the diameter of Sol to be 8.8 billion kilometers across it would mean nothing to you. Instead, time is more understandable so this is quick frame of reference. It would take us 31 years for our fastest ship to travel from one end of the solar system to the other at maximum burn with the earths current fastest rocket. Most scientist predict that in the future our fastest Ion engines will be able to traverse the solar system in 3.1 years. Keep in mind that any travel you are going to do requires acceleration and deceleration. These factors mean that space combat is two things, slow, and at very long distances. In space warfare it is predicted that you should never be able to see your target. The second notable thing is that space, being as open and cold as it is, has no hiding places. Engines, life signs, weapons cooling, all leave a heat signature. In the near absolute zero temperatures of space any of these signs would be visible for a long distance, and as such hiding or running away is almost an impossibility.

A diagram of our solar system (not to scale) which is measured in AU (approximately 149,600,000 kilometers to 1 AU)

Two more points before we start. Plasma, and Nuclear Missiles. Both of these weapons have limited applicability in space. Plasma weapons essentially super heat an object until it is plasma then fling it at a target through some means of propulsion. As cold as space is, the plasma used would cool quite quickly unless used at fairly close ranges or if it is stored in a device and triggered upon detonation. Nuclear missiles are also not very effective because of the lack of medium in space. The devastating shock waves produced by atomic bombs here on earth do not occur in space because there is nothing to create the shock waves. And as big as space is, the initial explosion probably wont hit the target unless it is a direct hit. If it is a direct hit, the explosion would most likely vaporize the target, however, the use of nukes in this circumstance would be almost overkill in anything except for planetary bombardment as conventional missiles would achieve the same end with much less cost.

Rail guns:

Rail guns, or coil guns, or gauss cannons are similar to conventional projectile in that the fire a slug, or metal bullet at a target at high speeds. However rail guns differ from ballistic weapons in their firing mechanism. A rail gun uses its name sake rails to magnetically propel the bullet out of the chamber at high speeds. This has several advantages over conventional ballistics. One, the price of each individual bullet is decrease, we would no longer have to pay for each shell casing and pack of gunpowder. And two, there is almost no interference as seen from gunpowder shock waves, this makes the bullets faster and more accurate. While there is no predicated speed for space based rail guns, the US navy currently employs several large mounted rail guns on they destroyers. These guns can fire slugs up to 720m/s, the destructive force of these modern guns is purely kinetic but yields an equal or greater result then some missiles. One final point, one of the major downsides of rail guns is overheating, but in space the guns would cool instantly. In use these guns would probably be medium to close range (less than 1000km and more that 5km). The unchangeable direction would mean that ships at a longer range could simply get out of the way, but the accuracy means that it would still be efficient against large targets for some distance.

The new Chinese, ship mounted rail gun

PDCs:

Point Defense Cannons are rapid fire weapons that can cover a large area at close range for long periods of time. There are a wide range of PDCs such as laser based weapons or heavy mounted machine guns (auto cannons). The idea of a PDC would be to disable missiles and small strike craft, destroy oncoming debris such as ship scrap and asteroids, and present a rapid form of destruction at close ranges l. Because of the role in shooting down small fast moving targets PDCs would most likely have to be programmed as opposed to being controlled by humans. Right now humanity has a type of PDC in the laser PDC. The US navy has several of their battleships carrying experimental laser PDCs, however the design is not fool proof and the lasers consume large amounts of energy and frequently need to cool down.

Laser cannons:

Laser cannons are fairly simple, focused light and radiation become a long range beam that fires at the speed of light. This beam can melt structures and is incredibly accurate. However, heat dissipation and energy radiation over time place the weapon in a similar range category to rail guns. The only issue is that atmosphere dissipates the focus of the beam very quickly, meaning that orbital bombardment is not that likely of an option. However, these weapons are still theoretically extremely powerful.

The famous Starship Enterprise firing two phaser arrays (similar to lasers)

LRM systems:

Long range missile systems would be the simplest of weapon systems, although they would also have changed from what we know today. Understanding PDCs as seen above, missile systems would need to be incredibly advanced and able to detect lasers and nearby batteries that it would need to avoid before striking its target. However LRM's self propelled nature means that they are the best for long range engagements of over 1000 kilometers as they can perform course corrections and can avoid any obstacles in the way. There are several types of payloads in LRMs, EMPs can short out any technical equipment they come in contact with which means death for a lot of space ships if they rely on a AI system, or an automated life support system, or are trying to escape using ion engines. There can also be plasma payloads which will vaporize most anything is detonates on similar to nuclear payloads. One uncommon concept which I have only read about once is a medium payload, which fills space with a dense cloud or shoots our scraps like a flak cannon. This could supplement the lack of a medium for the shockwave of a nuke if the nuke was detonated immediately after, or it could be used to intercept incoming missiles.

PDSs

Planetary Defense Systems are weapons that can fire out of the gravitational field of a planet and are stationed on a planet or some similar celestial body such as a moon or asteroid. These are fairly simple and are basically just very powerful versions of the weapons talked about above. These can be used to lock down regions of space or protect civilian crafts that fleets don't have time to protect themselves. While I say that these weapons are more powerful, keep in mind that most of the weapons talked about above could destroy any reasonably sized ship (if based on modern standards of ships) in one or two shots. PDSs would just completely annihilate them.

So now whenever you see some kind of media talk about sci-fi battles like in the battle of the MCRN Donnager in the Expanse you will know what certain weapons do and why the captains are acting like they are.