Standard Sci-Fi Army

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Never bring infantry to a walker battle.

"The scale of the Imperial war machine is unprecedented. Never before in the history of the galaxy has such a fighting force been assembled. Never in such numbers, never with so much variety, and never on so many worlds. There is little in the galaxy that is not under the Empire's control, and it is but a trivial act for the Empire to annex a new world when the Emperor wills it."

— Admiral Wullf Yularen, Imperial Handbook: A Commander's Guide

The planetary cousin to the Standard Sci-Fi Fleet. While the Space Navy dominates the sky, it's up to the grunts to take the ground.

It is sometimes claimed that the use of militarized spaceships will make planetary forces obsolete. After all, why waste men and vehicles on the ground if you can just blast them from orbit with lasers, missiles, plasma bombs, or huge rocks?

The answer is simple: Unless you're going for genocide, you will need to be able to hold your new territory after you've blasted the defenders to ashes. If nothing else the invader needs a base to build supplies for his next glorious conquest. And of course he will want some subjects from which to collect the oppressive taxes needed to pay for his mighty fleet. Not to mention mopping up enemies not concentrated enough to warrant turning starship-grade weaponry on, pacifying local populations, and probably defending ground infrastructure or even taking targets that are too close to places you don't want blown up, or that are somehow protected against orbital attacks. (This is also the reason modern countries still have armies in the face of modern air power and nuclear weapons.)

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Army Arrangement and Balance

Standard SF forces tend to follow the same lines as real world armies. If aliens are using said forces, there are going to be analogs to human ones. After all, Most Writers Are Human.

Force composition varies, depending on the technology level and setting. Armies from 20 Minutes into the Future still tend to be armed with kinetic weapons(i.e.: bullets), with the occasional energy weapons restricted to heavy weapons and/or prototypes. Far Future armies tend to be armed with high tech gear and energy weapons. Post-apocalyptic works have a mix of preserved or decaying modern technology and improvised weaponry. Steampunk will go for steam-powered tech with a Victorian aesthetic. Alien forces tend to use energy weapons almost exclusively. Of course, the writer's skill, knowledge and interests will also influence an army's depiction.

The most common models are:

Televised or animated programs: Rarely goes beyond basic infantry, tanks/APCs, and usually some kind of aircraft (unless there's the possibility of merchandising). Animated shows tend to go farther, but live-action programs have budgets to think about. It's a lot easier to draw/model a half dozen different land vehicles than it is for the Special EX team to mock them up, and cheaper to put a dozen of them on the screen at a time.
Tabletop and video games: Will have all of the below and then some, if they can fit.

Each army branch (Infantry, ships, armor, etc.) helps each other, balancing out any weakness. For example, Tanks have great protection and are well-armed, but have poor visibility. Infantry are far less protected than tanks, but are smaller and can take advantage of the tank's blindness. Thus, the tanks need soldiers to protect against infantry, and the foot soldiers need the tank to deal with any enemy panzers.

See Common Military Units for more information on how armed forces are organized.

For the major SF Army types, check out the Analysis section.

Units

The Standard SF Army are divided into several groups: Infantry (Standard and Irregular), Armor, Oceanic Ships, Aircraft, Support Units, and Allies.

Standard Infantry

Soldiers trained to fight on foot (or whatever limb used for locomotion). Since the beginning of warfare, infantry have been in combat. The most common unit used, often for storytelling purposes or they're cheaper due to logistical limitations (both in reality and in-universe.) Most characters in the Sci-Fi army will likely be one of these.

General Infantry (Grunts)

The basic trooper who does most of the fighting, engaging with the foe directly. As such, when they go into battle they should be well armed (either energy or projectile weaponry), armored, and prepared.

Of course, it depends on the setting what they have for equipment. In standard Sci-fi settings, most regular troops could also be carrying portable scanners to help detect the enemy, though oddly lacking nanite or cybernetic enhancements, cloaking/thermal camouflage, or other "high tech". Such advanced equipment was reserved for the Elite or Supersoldiers. Sometimes the grunts would wear spacesuits for unearthly worlds, but often a trooper had just his helmet, armor, and uniform. General Infantry comes in many different forms:

Light
Used in skirmishes, scouting, pursuit, raids etc. Lacking heavy weapons and vehicles, they're far more mobile than other infantry. Can operate in rough terrain such as mountains or swamps. In addition, they can be strategically deployed faster than most other units.
Line
The standard grunt, armed with a primary weapon, a secondary weapon (generally a sidearm), and perhaps grenades/scanners/medical packs/whatever they're assigned. If a series has nothing else, it will have these.
Heavy
Armed with heavier equipment like crew serviced weapons (like Mortars), Squad Automatic Weapons, Missile Launchers, or other BFGs. These troopers can take down tanks and over heavily protected units. Like modern soldiers, these are typically found as part of a squad, rather than grouped separately.
Another variation is heavily armored infantry. They will be very well shielded, and difficult to take out by other infantry. However, such Heavy Infantry will be much less mobile and less likely to survive (especially if the enemy are armed with anti-armor weapons).
Mechanized
Travel via APC/IFV but disembark when needed, thus greater mobility on the battlefield. Occasionally supported by their armed transport, which provides heavy firepower. However, they require more resources for their vehicles (parts, fuel, ammo) as well as support troops on hand to crew the APC.
Elite
Renowned infantry, equipped with better equipment and enhanced training. Sometimes known for fighting prowess, being able to operate with few resources and support. Generally also dress better and hog all the attention.

What makes an Elite force, well, elite varies. Sometimes the unit is the first to use newly developed weapons - for example, the British Rifle Regiments were the first to get rifled weapons, when everyone else was using muskets. Or it just means the unit has a longer battle history than others. Another reason is that the unit is created is to employ newly developed combat doctrines, or they are specially trained for specific environments. Or for those showing enough skill and bravery, being transferred to the Elite as a reward. The last reason has drawbacks, namely it can create discipline and morale problems for the other regular forces.
- Shock Trooper
  Also called Assault Troops or Stormtroopers, these are the first troops into a heavily defended area. In a large-enough campaign, they serve as the vanguard for an entire offensive. While often considered elite infantry, their primary strength often relies on their sheer numbers and their fanaticism or determination. Usually based on the Real Life shock troops of the Soviet Army during World War II, or the pioneering German stormtrooper units of World War I.
- Super Soldiers
  Vastly stronger, faster, and smarter than typical troopers. Sometimes a result of genetic engineering, cybernetic enhancement, or other influences. Such enhancements allow them to operate in dangerous terrain(such as the vacuum of space) without extra equipment. It may also provide resistance to chemical weapons, diseases, and radiation. They tend to outperform standard infantry by a large ratio. However, they are fewer due to their training or creation.
- Drop Troops
  Airborne infantry writ large. They deploy into the combat zone directly from the ship or from a moving transport in the upper atmosphere, fully expecting to engage the enemy as soon as their boots touch the ground. Usually tasked to clear and secure landing zones ahead of the main force; as such, their role often overlaps with that of the Marines (which may be a source of Interservice Rivalry). Often overlaps with Super Soldiers - even if they pull from the same pool of recruits as regular infantry, they're expected to be a cut above the rest (largely because they have to be to survive the drop).
- Praetorian Guard
  The best of the best of the best. They serve as guards for royalty, high-ranking officers, and other VIPs. Typically, they will not be in the thick of it with the rest of the army, staying at headquarters or residences, but if someone attempts to attack a location protected by them, the Praetorian Guard should prove to be swift and merciless. Typically limited to a handful of soldiers, some rulers see their Praetorian Guard comprising of multiple divisions that serve on the frontlines, displaying ruthless tactics in the field. May or may not overlap with State Sec Troops.
Power Armored
Troopers wearing Power Suits - having improved protection, firepower, and capabilities. The proliferation of Power Armor will determine the role it plays in battle. Some settings have it common as dirt, and utilized by even the Grunts. Others reserve it for their Elite units, to give them an additional edge. In the middle, they may form an independent corps that takes the role of scouts, air support (if equipped with Jet Packs), light armor/fire support, and other specialized roles.
Marine
Traditionally marines (or naval infantry) fall under the command of the navy, but often find themselves in the same fights as the army. Here, as in the past, the role of marines will be to gain initial ground in invasions and create a sizable perimeter to allow the larger and more mobile army to assemble before moving out. They will also serve as guards aboard fleet ships and installations that escort the army to their combat zone, along with serving as EVA troopers and performing boarding actions against enemy ships. In a show which focuses almost exclusively on the fleet, any infantry will likely fall under this category. People who object to the word "marine" as smacking too much of Space Is an Ocean might choose to call them something different, like espatier, while still giving them the same basic job.

Support Infantry

Provide specialized aid to regular grunts. Some are deployed in the rear lines providing maintenance, and others serve on the front lines. These infantry will typically have some sort of weapon or defense, just in case. Generally not in armor, unless operating under combat conditions.

Headquarters
The Commander, his personal staff, and their support. The Commander, of course, commands the army. His staff provides him with everything he needs to command effectively, from situation and intelligence reports to his morning coffee. Supporting troops usually include logistical staff and pilots specifically tasked to get the commander what he needs and where he needs to be, as well as a security detail (which, if the commander is royalty or otherwise Very Important, may include the Praetorian Guard). Usually kept well behind the front lines and not featured beyond establishing who's in charge, but if given any real screen time, there's likely going to be at least one scene where the enemy makes a direct attack on the command post, giving the commander a Rank Scales with Asskicking moment to show that he's more than just Armchair Military. If the commander is a Frontline General, expect the headquarters to be an assortment of trucks and armored vehicles fairly close to the fighting.
Logistical
Clerks, supply officers, chaplains, lawyers, cargo handlers, etc. who fulfill the physical, mental, and spiritual needs of the soldiers. They make sure the troops are well armed, supplied, and ready to fight.

While not the most glamorous of infantry, their role is vital to victory. Logistics determines how long the troops can fight, how well their vehicles can operate, when and how battles are fought, how well everyone is fed and cared for, how to transport all those supplies, and, well, just pretty much everything. Which is why in stories, a good connection with logistics could get the heroes a vital device or transport that would be otherwise unavailable. Better yet, a good connection can get the heroes good grub. Alas, most stories tend to forget about these support troops.
- Contractors/Camp Followers
  Often a force on the move collects an assembly of civilian hangers-on to see to the various needs of the troops. While civilians are not technically part of the unit in question, they typically follow them from base to base (hence the name). Between civilian and military support, expect a force to carry around nearly as many civilian staff as soldiers. Or possibly far, far more (the modern US Army has 10 support staff for every soldier actually in combat). Contractors officially work for the military. Informal followers can include refugees, scavengers (and looters), new-found loves, merchants, "escorts", and sometimes the occasional strange alien or eccentric scientist.
Engineers
Technicians, armorers, mechanics, Sappers, Seabees, anyone who is trained in repair and maintenance of technology and equipment. Sappers (combat engineers) and Seabees in particular actually see combat, as they either demolish enemy emplacements or build front line bases. Due to their intense combat experience and access to specialized equipment, these Combat Engineers often fall under the elite category.
Intelligence
Collects and studies information on the enemy. They also make sure the enemy can't collect accurate data on your forces. In the field, they may be interrogators who question prisoners, intercept enemy communications, infiltrate databases, or go in disguise to contact the locals.
Medical
Doctors, Nurses, and Medics that save other grunts' lives. Their main equipment is their healing technology, often more compact and fantasic than current day medicine. Perhaps due to the Hippocratic Oath, some medics are totally unarmed, or at least have difficulty firing their weapons. This will of course not be an issue if the enemy makes it a policy to Shoot the Medic First.
Pilots
Whether its aircraft or tanks, vehicle operators are needed to move people around. Aerospace pilots are the elite of this lot, as there are few who are capable of operating high-speed, high-tech warplanes. Although valuable, there is a trend in SF in which aircraft pilots do Special Forces or even grunt work. Presumably so the writer(s) can have both ground and air/space action without having to double the cast. (The reverse — spec-ops soldiers that can also fly — is somewhat more believable but strangely rare.)
Training and Doctrine
Barring the odd special snowflake who's both immortal and nigh-indestructible, even the best of the best aren't going to be around forever. Somebody has to ensure that the next generation of soldiers has the same skills, quality, and esprit de corps as the last one by taking green, fresh-faced boys who have likely never known real hardship and molding them into the meanest, toughest, most resourceful killing machines that have ever walked the face of the Earth (or local equivalent planet). From a narrative perspective, the Boot Camp Episode often serves as a way to foreshadow both the nature of the military itself and the overall tone of the work before the cast ever so much as fires their first proper shot in anger. This is the Drill Sergeant Nasty's natural habitat; the recruit rumor mill often even speculates that he spawned from some unholy mixture of local pond scum, the festering remnants of uneaten (and inedible) mess hall slop, and pure undistilled hate.^note

Security

Used for providing security, force protection or law enforcement. Thanks to Star Trek, these are the second most commonly seen infantry. Often sent on away teams, guarding installations, or serving aboard ships, plus a favorite of megacorporations. As such, Security units tend not to fare very well and often considered expendable. Probably trained to deal with civilians more than other infantry. They can range from simple guards to gendarmerie units, having some sort of distinguishing uniform.

Typically not as equipped as Grunts, and usually not as effective in combat. (In fiction, Security personnel often carry a single sidearm, and maybe some light armor if they're lucky.) That said, these troops are generally not meant to be used on the battlefield. In most cases Security is already working in well defended areas, and considered the last line of defense. In addition they are cheaper, plentiful, and useful in peacekeeping and diplomatic functions. Having Power Armored super-soldiers as guards can be quite unnerving during a nice dinner between ambassadors.

Robot

Any machine that supports or even takes the role of an infantryman, and at most the size of a grunt. Sometimes humanoid in shape, but not always. Robots are used by today's militaries, often for scouting, bomb disposal, and fire support. Because of their nature, these units don't need food or water, don't get tired, and can be fixed easier than a wounded trooper. However such units have technological requirements to keep operating (for example, a portable, efficient power source), as well as economic cost. On the bright side, a robot being lost is far more preferable over the lost of a living trooper (well, unless they're self-aware and have rights, too; it may be desirable too keep them nonsentient so this won't be an issue).

How well these units operate depends on the technology being used. Sometimes they're dumb, weak and useful only as cannon fodder for being so cheap. Other times they're unstoppable and highly intelligent, but harder to build and thus fewer available. Regardless, one should be cautious of the enemy trying to hack the robot's programing or an AI going rogue.

Artificial Monsters

Why stick to standard troopers, when you can create your own from scratch? Basically, any creature created through genetic engineering that is radically different from anything seen before. It can range from human variants to alien horrors. Sometimes, Artificial Biologicals can be even sized up, creating organic tanks, aircraft, or even ships. The drawback is that this requires high tech or powerful magic to do. Not to mention the creations could turn on their masters.

In many space operas, Artificial Creatures are more often used by the bad guys, or go rogue. In any case, the heroes avoid using them at all.

Exotic

Sometimes the military will develop an interest into fringe ideas, like psychic phenomenon. In SF, this occasionally pays off, because there would be little point to mentioning it if it didn't. Could range from a person with ESP who can provide intelligence, to a psychic super being, or even a Squishy Wizard with power armor.

Effectiveness varies greatly. Sometimes the Exotic is a great asset. Or the supposed "psion" is really a loon that somehow convinced the top brass thinks he has powers. Or that the Extoic goes insane and becomes a danger to everyone.

Racial Specialists
In a group made up of several different races, the physical makeup of some species', for good or ill may set them apart from the other members of their coalition. They may be assigned special equipment that plays to their strengths or compensates for their failings. Alternately, they may be placed in their own special units to allow them to fight as their physiology best suits them.

Special Ops

Operators who deal with specific missions that regular General Infantry (even Elites) are unable to. These troopers may deal with rescue, counterterrorism, assassination, sniping, guerrilla warfare, training indigs, etc., all depending on their purpose. Often consisting of small teams (though not always), they are well trained, armed with the highest technology, and can operate autonomously. Selection for these troopers is rigorous and few candidates able to pass. These Operators tend to be at the peak of physical and mental perfection, making them supersoldiers in their own right.

In general, it is unwise to use such forces in conventional operations. They may be the elite of the elite, but that doesn't mean they can take out another army alone. Not to mention it would be poor resource management - using SpecOps in regular combat would be like using a scalpel to cut down a tree.

Commandos
Special operatives who are sent out alone, using stealth to achieve their missions. Lethal and very versatile, they move without detection, able to make weapons out of anything, and able to swim and climb over everything. Has a reputation of being a One-Man Army, though this tends to be an exaggeration. While able to take out scores of troops, they're easy prey for vehicles or if they are out in the open. As such, cunning and sneaking is their way.
In real life, the term generally refers to units or commands of Elite infantry (such as the U.S. Army Rangers) or Special Ops (like the Para Commando of the Indian Army). Though renowned, they don't operate on missions as single individuals.

Special Warfare

Not to be confused with the above category, these are soldiers trained for the handling and delivery of chemical, biological, nuclear, and radiological weapons, or their SF equivalents. Using specialized biohazard suits, or possibly even immunities to these agents, they are the first ones into a zone after their weapons' use, to ensure they were completely effective and to determine it is safe for the rest of the army to move in. Because these weapons are indiscriminate on who they target, they tend to be used by less honorable militaries, or only as a last resort. As delivery troops, they usually overlap with Artillery.

Cavalry

Although not as common today or in SF, cavalry units do show up. Like their ancient counterparts, Cavalry are soldiers riding an animal. Unlike their ancient counterparts, they're limited to scouting or ceremonial roles. One advantage is that certain animals can go where vehicles can't and can cover more ground. In places where high technology is rare, it makes more sense to use horses or mules - they don't require any high tech equipment to keep running. If Cavalry is used in frontline combat, this means the army has technologically regressed, the commander is a bit wacky, or they're riding something so dangerous it could tear a tank to pieces.

Vehicle Cavalry

Infantry using vehicles other than personnel transports to rapidly deploy and fight, replacing mounted infantry in their roles as shock troops or locating/holding down the enemy. Comes in several varieties:

Air Cavalry
Close-knit helicopter/shuttle/dropship/hovercraft and infantry unit performing recon and short raids. Developed during the The Vietnam War.
Armoured Cavalry
Units that use ACV’s instead of warhorses. King's Royal Hussars of the British Army is one example.
Motorcycle Cavalry
Same principle, only with bikes. Typically such "motorcycles" can hover and are armed to some extent.

Irregular Infantry

Non-standard military forces such as militias, guerrillas, or paramilitary organizations. Typically these forces are not part of the main military, but can be used in combat operations. More than often they're the antagonists of many of a Standard Sci-fi Army, wither through force or mere bureaucracy.

Black Ops

Covert units deployed by a nominally civilian group, such as a Spy Agency or a Megacorp. Like Spec Ops, they conduct secret, specialized missions. However, Black Ops are so clandestine that it's done outside of official and military channels. Such missions tend to be questionable, even outright illegal; if caught, they can usually expect little to no chance of rescue, as the government responsible will invariably deny any involvement or connection to what's going on. Black unmarked uniforms and vehicles are typical, with advanced equipment to boot. Can be assigned to regular military as support.

Indigs

When operating on a faraway planet (or other foreign soils), sometimes the Army will be backed by local ("indigenous") forces, often in a temporary arrangement to accomplish the same goals. They can be militia, guerrillas, resistance fighters, or friendly aliens. Despite lacking regular equipment or training, they make up for it by having a better understanding of the locale. They're also more motivated to fight, having much more personally at stake. In addition, they can tie down enemy troops which would otherwise be better used elsewhere. Sometimes, particularly when defending, this group includes local quasi-military forces like police.

Usually work as light infantry and scouts/guides, often with some light (easily portable) support weapons and perhaps cavalry thrown in. Heavier equipment is rare, and will usually consist of a few captured vehicles or guns, plus any equipment provided by a "patron" Army. With time, a well-led and organized resistance movement may grow into an army in its own right.

Political

Whereas Special Ops and Supersoldiers excel in combat, Political troops are the ideological elite. Whether being the personal guard of a dictator or improving the troops morale, they are often loyal to a regime. Fighting ability of said troops varies, since authority doesn't necessarily mean being combat savvy. For their services, Political troops are well paid, and have the best weapons and equipment. May be attached to regular armies providing support, but commonly used to keep the regular army in check.

State Sec Troops
Combining Political, Security and Terror into one mean package. Often based on the Real Life Waffen-SS Troops of Nazi Germany. These can often be quite formidable on the battlefield, but their main strength is their ruthlessness towards both enemies and allies who show subpar fighting zeal. Often clad in heavy, stylized armor, and generally armed with powerful weaponry. Very often an elite cadre within the Political troops - a State Sec for State Sec.

Terror

Any infantry whose purpose is to accomplish their goals by targeting non-combatants and engaging in illegal activities that violates Interstellar law (i.e. rape, pillaging, murder, etc). They tend to be poorly prepared against conventional military. As such, they use deception and try to blend in with the locals (often a violation with the laws of war). Not utilized by honorable or good guy militaries, such units are used by less scrupulous forces.

Civilians

Any non-military that are sent out for various reasons. Often, these tend to be either:

Scientists
Whose knowledge is useful, especially when exploring or dealing with the unknown. Often in the rear, probably in some super-secret military base doing research. Other times they're out in the field to test new technology, study alien stuff, or scanning the area. In battle, they may be in uniform and armed for defense. But more often they're defenseless and wear lab coats.
Observers
Typically a journalist or some politician, who joins the unit to investigate what is going on the battle field. Occasionally, it's some whiny kid who tags along for no clear purpose. Unused to weapons, expect them to go in with little equipment let alone any weaponry. Often, they explicitly won't be allowed to touch anything because they aren't trusted to use it safely.
Political Officers
Government agents who are given authority over the military. They may be civilians or belong to some separate paramilitary service. If armed, they tend to be carrying a pistol - not for defense, but to enforce their will.

Whatever the case, it can run one of two ways:
1. The unit is made up of recurring characters, and the civilian is new. In this case, they become a problem for the soldiers. They have to watch out for the civilian who is typically unarmed, inexperienced, and unable to find their way out of a paper bag.
2. The civilian is the main character, a recurring character, or having A Day in the Limelight. Expect their non-military perspective and/or specialized knowledge to save the day, over the objections of the troops.

Armored Combat Vehicles (Armor)

The other major component to a fighting force. Faster, stronger and carrying heavier weaponry most infantry or aircraft can't. However, Armor requires more maintenance and resources - they need support personnel, ammo, spare parts, and fuel to keep on going. It also requires the nation running the army to have the infrastructure and knowledge to build these weapons.

Some Armor can be specialized for different roles - some tanks that can shoot fire, others that turn invisible, and occasionally some that can time travel. Others could be for more mundane but vital support missions, such as setting up or taking down bridges or structures. It does depend on what technology is available.

Scouts

Commonly a dune buggy or motorcycle (or a similar analog). Notable for their quick speed and cheapness, but lack any armor or firepower, and used for reconnaissance.

Armored Cars

Think Jeeps or Humvees, a fast but lightly armed vehicle that can be used in a number of versatile roles for support (recon, transport of troops, etc.). In Real-Time Strategy (RTS) games, they're limited to scouting or anti-infantry roles. They may be given anti-armor weapons in order to make fast flanking or harassment attacks in support of Armor. While their armor is light, their defenses can protect from small arms.

Armored Personnel Transports

Vehicles designed to carry infantry speedily and safely from Point A to Point B, on the off chance somebody tries shooting at them on the way there. Faster and have stronger armor than Combat Cars or Scouts, but less armored than Tanks. Unlike their real world counterparts, such transports would be truly all terrain. There are two major types:

Armored Personnel Carriers (APC)
Designed to transport troops safely, APC's are not meant for direct combat. It has no heavy weaponry, though it is lightly armed for defense.
Infantry Fighting Vehicles (IFV)
Can carry infantry, but also provide direct fire support. It may also allow infantry to fight from inside the unit. Can be armed with an autocannon (or sci-fi equivalent) as well as anti-armor rockets. However, IFV are not meant to take on Tanks alone.

Tanks

Heavily armored and armed all terrain units that are designed for frontline combat. The current kings of the battlefield, but not invincible. One of the biggest disadvantages is that tanks have poor visibility. The other is that tanks tend to require a lot of maintenance. In some settings, Tanks may become obsolete due to technological developments. Infantry may be armed with Power Suits and Armor-killing rockets. Dropships become faster and can hit first. Mecha are so super, they outclass tanks.

Usually armed with a large gun, which depending on the setting could fire kinetic rounds or energy beams. The main cannon can take out another Tank of its type. It also has secondary weapons, such as a smaller gun (often a miniature version of the main weapon) and anti-personnel mines. In SF, tanks tend to hover (but not always), and sometimes have a special ability (such as cloaking). Tanks often come in several varieties:

Tankettes
Rare, but occasionally seen (especially if toys are involved). About the size of a small car, and typically used for infantry support or recon. It lacks the large tank guns, though is equipped with machine guns and grenade launchers. Think Tachikomas: fast and well armed, but against heavier tanks or even Power Suits they were outclassed.
Light Tanks
Used for recon. They’re fast, cheap to produce and maintain, and usually can still pack a bit of a punch. Because of its lightness, these tanks could also be deployed with airborne troops. In games, they tend to be underpowered, and as a result need numbers to take on heavier tanks.
Main Battle Tanks (aka Medium Tanks)
Have a successful balance of firepower, mobility and protection.
Heavy Tanks
Heavier and larger due to their greater armor and firepower, often serving as command vehicles for larger units. Their biggest disadvantage is trying to produce them in great numbers, and their larger size and heavier weight often makes them slower than MBTs. In Science Fiction, a surprising amount of these will have double-barreled turrets, despite the redundancy and problems of using them in real life.
Supertanks
The careful application of Phlebotinum has allowed military designers to create tanks that can go above and beyond the limitations of regular armored vehicles. These are high-tech wonders, enhanced by Artificial Intelligence, powered by nuclear (or even more amazing) engines, bristling with awesome firepower and has nearly perfect protection. Of course because these are so advanced, Superpanzers tend to be far more expensive to make than Heavy Tanks. And because of the high technology, it would require specialized and highly skilled support.
- Land Battleship
  A tank the size of a naval vessel, usually bristling with many guns, and/or one huge one. Often used as a kind of mobile command unit, and can carry and maintain smaller units. The weakness of this unit is that its much slower than smaller tanks and are huge targets.
- Mobile Armor
  For all intents and purposes, a flying tank. All the protection and firepower of a Main Battle Tank, with the speed and maneuverability of an attack helicopter.

Tank Destroyers

Defensive vehicle designed to take down tanks. Tend to be less flexible than tanks (often lacking a turret), but are cheaper to maintain and build. Some are open-topped, which allows them to carry a larger gun, and helps the crew reload it more quickly. However, it also makes them a lot more vulnerable.

Assault Guns
These look very similar to Tank Destroyers, but their main gun tends to fire large calibre, low velocity shells that are best used against bunkers, strongpoints etc. Extremely useful in urban battles, where their heavier firepower makes it easier to level buildings filled with enemy troops. They differ from Self-Propelled Artillery in that their gun fires directly at a target, and they tend to have heavier armour.

Mecha

Any legged ACV, often bipedal, with typically more armor, weaponry, and/or mobility than Tanks. Although not making sense from a military standpoint (having a high profile means it's a larger target), mecha are very cool. Most are Real Robots, but using a Super Robot is not unheard of. It should be noted that in Eastern (especially Japanese) Sci-Fi, mecha are more likely to be of the "Giant Armored Soldier" type, while Western Sci-Fi seems to prefer the Walking Tank. Much like supertanks, Mecha are expensive for being not just advanced technology, but that the maintenance is probably higher. A mecha has much more parts needed to function than a tank, and has more joints for wear.

Spider Tanks
Hybrid of a mecha and a standard tank, spider tanks provide the best of both worlds: the coolness of a mech and the practicability of a tank.
Mini-Mecha
Either a one or two person cockpit on a pair of legs that typically has light weapons and armor and is used as a scout (which actually makes some sense); or a larger version of Powered Armor.

Technical

Any civilian vehicle modified for military use, most of the time a sci-fi car with a weapon attached to it. Often used by Indigs/resistance forces, technicals are typically weak against military units. However, it does provide mobility and firepower when there is nothing else available.

Oceanic Ships

Out of the major branches, Oceanic ships appear the least in a standard Sci-Fi force. Outside of video games, one rarely encounters a wet navy in other genres. And even then, they don't play a major role. There's no definite explanation why this is the case. Perhaps due to the audience thinking space navies operate on the same principles of its blue-water counterparts, writers believe ocean navies would be redundant. Of course, a great number of worlds are likely to have significant oceans, not to mention worlds covered entirely with water.

If any wet navies are present, in all likelihood most (if not all) are submersible craft. Whether it's a carrier, battleship, torpedo boat, or destroyer, it can become submerged and still fulfill its duties below the surface, because if you want to design maritime equipment for those planets that need them, might as well go all the way and cover all needs in one chasis. Common in which the ocean is the main setting or a post-apocalyptic world. Often mirror their space-borne counterparts in function. Space-borne ships under a certain size may possibly double as these, complete with going underwater, thus rendering dedicated maritime ships obsolete. Another variation notably seen in [1] is the use of underwater troopers fighting around underwater cities rather than vehicle based combat, largely inspired by [[Film/Thunderball]].

For a full list of different types of naval craft see Types of Naval Ships.

Aircraft

Science fiction is apt to have Space Navies fulfill most roles the Air Force or Wet Navy would in modern combat. Space ships are in a good position to rain death from above and provide intelligence. However, a space force isn't always available, and thus aircraft must fulfill those roles when needed.

Common in video games (especially Real Time Strategy), where the setting/genre limits space craft. Most (if not all) of these craft have VTOL capabilities. Outside of games, dedicated aircraft are often replaced by either Dropships, a Swiss army weapon (like a Mecha), or made obsolete due to some technological development that perfects Anti-Air defense. If they are around, they tend to be pricy - requiring resources, a lot of support to operate, and the technological know how to build them.

Attack Drone

Small unmanned unit that provides intelligence, maintenance, or firing support. Probably the most common airborne units after fighters. Drones can cover more ground, are automated, and can save lives instead of risking people. In SF, Drones tend to be much smaller than their modern day counterparts, using some sort of anti-gravity, and much more capable. The downside is the low durability (a single bullet could take one down), plus the need for clear communications and technological requirements. May or may not have an AI controlling it.

Fighters

Small craft that deals with air superiority. Can be the same as a space fighter, but not necessary. It's main purpose is to attack other airborne craft. Often armed with some sort of energy weapon, though having a space fighter armed with some missiles could help.

Interceptors
Lighter, fast craft designed to catch up with incoming targets. In Real Life, these craft sacrifice maneuverability for performance (such as speed and armament). However, this meant against regular Fighters, Interceptors had a disadvantage being unable to maneuver. In SF this isn't always the case - since shields or new technology could provide improved protection than a typical fighter.

Recon Aircraft

Provides battlefield intelligence, usually equipped with sensors and communications. Also used to provide early warning from incoming attacks. The more sensors, typically the larger and less maneuverable the craft becomes.

Electronic Warfare

Designed to jam or confuse enemy communications and sensors, and protect allies from electronic attack. Much like Recon, the more equipment mean less maneuverability and more mass.

Carryall

Aerial transport that can rapidly deploy and pick up vehicles without the need to land. Like other Utility craft, they have no weapons.

Close Air Support

Designed to provide fire support for ground forces in coordinated strikes. Durable and armed with precision weapons. Typically, these craft lack any anti-aircraft weaponry and require fighter escort.

Armed Utility
Basically a modified version of a Cargo craft, only carrying heavy armor and weapons instead of supplies. Often used for supporting ground forces when they need a lot of firepower.

Bombers

Deploys high explosives or strategic weapons on installations and other targets. Unlike Fighters, they have a greater range without refueling, and capable of attacking deep in enemy territory. Though they could be used for tactical strikes, Bombers are valued in the modern day for their strategic importance. Because of their armament they have little in anti-air weapons. May require Fighter escort, but it could rely on stealth for defenses.

Fighter-Bomber/Strike Fighter/Multirole Fighters

Can both strike at ground targets and attack airborne targets. Cheaper to maintain, build, and equip than dedicated craft, and avoids being too specialized. There are trade offs, giving up advantage in some areas (such as the long range of a bomber) for generalized performance.

Helicopters

Sometimes, Dropships or transporters are not available, so these tend to show up. Versatile, they can be used for a number of purposes. Commonly used in transport and gunship roles.

Sometimes there are other air-support vehicles that aren't technically helicopters - turbofan vehicles are a popular choice for some reason - that show up in this role. Generally speaking though, they fly like helis, they fight like helis, and they'll probably get an Apocalypse Now Shout-Out like helis.

Strategic Missiles

Unmanned guided rockets capable of delivering a payload (often something very explosive) to a target. While smaller craft and artillery are armed with smaller missiles, Strategic Missiles tend to be massive and can travel great distances. They can hit a target on the other side of the world, or perhaps on another planet altogether. Of course this is a one-way trip: the destruction caused by the warhead means the engine can not be retrieved. In addition, a facility or launch platform is required to deploy this unit.

In Science Fiction, Strategic Missiles are rarely seen deployed. Often they're used to take out orbiting craft or to deploy a really dangerous weapon. In other cases the politicians and generals are talking about the potential dangers of using such weapons, and if it is worth the cost. The moral and political considerations have to be made, and treaties often prohibit the use of such weapons except in certain cases. In addition, these weapons often end up in the hands of bad guys. As such, the heroes are often trying to re-take or stop the bad guys from using them.

While Nuclear, Anti-matter, or newly discovered weapons are common warheads, SF had other creative uses for Missiles. Sometimes they can be loaded up with a passenger, allowing them to be rapidly deployed to any place on a planet. Of course, there must be a reason why the passenger could survive the stresses of such a trip. Other payloads can include sensors or other science equipment. More exotic warheads include dropping a device to terraform a specific area.

Flying Fortress

The mid-point between a Bomber and the Airborne Warship below. The Flying Fortress is a large aircraft armed with a large array of guns, missiles, and/or bombs. Many are used as command vessels and may be capable of carrying troops on their own.

Airborne Warship

Large craft the size of naval ships, but capable of flight. Extremely well armed and armored, but tend to be slow and vulnerable to small craft. Popular in Steampunk settings, where they look like naval warships but with propellers or balloons. Futuristic works tend to go for a starship-like aesthetic, or simply have an actual spaceship fulfill this role. While Carriers are popular, Battlecruisers are also common.

Defensive and Command Support

Any units or structures not meant for direct combat, but can aid in defense or back up other units.

Air Defense

Any unit or structure designed to take down aircraft, and sometimes even orbiting units. Energy weapons or rapid-fire kinetic cannons are common - able to fill the sky with beams/rounds to hit any incoming units. Missiles or large rockets are also used, their main benefit of homing on its target. In some instances their weapons can be used on ground forces to great effect.

Outside of RTS, it's rare to see a dedicated anti-air unit on the front line. Most SF tanks or infantry have some sort of anti-air weapon (or may have a variant armed with them). Such units are the reason why aircraft my be obsolete in a future war. For orbital defense, expect very large weapons or missiles to take out spacecraft.

Artillery

Capable of firing large projectiles or energy weapons for indirect fire support. Often seen when Air or Space forces are unavailable. Munitions could be rockets, shell-firing cannons/mortars/howitzers/guns, or beam weapons. In SF, these tend to be Self Propelled Guns, with light armor and treads/legs/hovercraft for movement. Unlike a tank, Artillery is usually not designed for direct fire or taking hits.

Each type of artillery has it's own advantages. Missiles can either carry bigger single payloads, or be fired in rapid succession, as well as carry all sorts of special ammunition like incendiaries, chemicals, mines, or even particularly hardy drones, but are slow to reload and vulnerable to point defenses. Directed Energy Beams tend to be very destructive, and highly precise, but requires a direct hit to be effective and can only fire on line of sight, limiting their range, while they're by nature unable to carry special payloads, various wavelengths can have special effects of their own, Ion weapons that disable ships without damaging them being one popular example. Ballistic Shells are a mix, being able to arc over obstacles and carry a variety of payloads like missiles, but also have a more steady rate of fire, while being harder to interdict like Beams. Unique to them however, is their relatively low profile, energy weapons are very bright and often draw a direct line from the gun to the target. Missiles are slower and leave obvious smoke trails. But the path of an artillery shell is nearly invisible. Science fiction and fantasy tales can have all sorts of fun with these thanks to advanced technology or magic.

Command

Any vehicle dedicated for officers to coordinate missions. Often filled with communications equipment and advanced computers to assist the General Staff. They often vary in size, from the size of a bus (serving as a mobile command tent) to little more than a jeep (carrying officers between command posts). Other times, they can be a modified tank or APC, especially if the commander likes to get up front and fight alongside his troops.

Communications

Personnel, vehicles, and structures that allows information to be transmitted between units. Without them, the ground pounders have no way or coordinating their operations. Often technological, more fantastical means (such as modified animals or psychic powers) could be used. In addition, comm links may be connected to ships in orbit, or even bases light-years away. As such, one of the goals of the bad guys are to destroy or limit the ability to contact other units.

Despite fictional portrayals, communicating between troops can be difficult - the enemy is trying to listen in, confuse the signals, or tracking them to find out where the you are. And part of the Commuinication's job is to make sure that doesn't happen.

Even taking into account something which would make eavesdropping impossible (like Quantum teleportation), there's still problems. Signals have to be decoded, authenticated, and sent to the proper officer. The sheer amount of talking that's being done during a battle can lead to confusion. Some units are not linked up to another unit because of some reason. Messages could be misunderstood or are outdated. All this must be taken into account and dealt with.

Passive Defenses and Countermeasures

Installations / units that provide protection for the ground pounders and whatever they are defending. Often used to prevent the enemy from dropping explosives or teleporting troops right on top of them. Also a good way to prevent a battle from being very short - after all, a nuke or high explosive could end one in seconds. The range of these defenses vary - from protecting a single unit to a whole planet - depending on the technology and energy requirements. Also a neat way for writers to justify having low-tech fights in their works.

In fiction, the Deflector Shield is a common passive defense - able to stop strategic and orbital weaponry, can be used to cover a wide range, while having some drawback that allows conventional forces/weapons to pass through. Cloaking is another popular choice, able to hide units from the enemy. Jamming communications is pretty typical. More fantastic are Countermeasures that prevent certain technologies from working, such as radar and nukes.

Because of the advantages, the main goal of the offensive forces will be to neutralize these protections. Once a shield/countermeasure is gone, the battle becomes a quick victory for the attacker.

Mobile Base

A movable and versatile base, often a very large vehicle capable of transforming from a stationary complex into a transport. It may also provide fire support in battle. Mobility has several advantages, such as moving to another spot if the enemy decides to bombard the area. However, because of their size they remain vulnerable to smaller units. It makes for a big (if moving) target. Such a role may be served by a space ship.

Mobile Factory
A common Real-Time Strategy fixture, where the base can also produce vehicles and weapons. A large ocean or spaceship is ideal - enough space to hold materials and machinery. Unusually, giant ground vehicles often fulfill this role - hauling not only itself but the heavy manufacturing equipment and materials. One can only imagine how expensive this can cost, with fuel and maintenance for such a large land vehicle.

Mobile Demolition

Any unit that is designed to transport explosives close enough to the enemy, then detonate. Generally unarmed, weak, and relies on speed or stealth to bridge the distance. For high-tech forces, a drone or a tank-like robot is ideal - well protected or mobile enough to avoid getting damaged, could be controlled remotely, and the controller is safely away from the destruction.

For low technology or resource strapped forces, less advanced robots or even animals could do the job. Though using animals tends to be questionable, both for ethics and the difficulty of training. For less scrupulous or outright evil factions, a living intelligent being could be used. Highly unethical to say the least. If there are volunteers, they tend to be fanatics.

Recon/Mobile Sensors

Any vehicle or structure with sensors to gather battlefield data, and notably looking for dangerous weapons. Some Recon vehicles are protected against most threats, including Nuclear, Biological, and Chemical weapons. In RTS games, such units are often used to detect stealth units but are generally unarmed.

Satellites

Orbiting unmanned craft designed to facilitate communications or gather intelligence. While generally safe in orbit, satellites can still be shot down by anti-orbital or spacecraft fire, or hacked by the enemy. More advanced forces could launch and deploy their own satellites using mobile launchers and small, powerful rockets.

Kill Sat
Can rain down destruction from orbit. It could be considered a superweapon, but not always. May be armed with an energy weapon, or it can drop a kinetic payload on top of a target.

Utility/Cargo

Carry out specialized roles, such as transport, training, repair, and fueling. These can be ground, air, or sea vehicles of varying sizes. In RTS games, these vehicles are unarmed for game balance. Much like Support troops, Utility craft are vital for an force to operate, and are the workhorses of a supply chain. One of the goals of droptroops are to destroy these to slow or cut off supply lines.

Harvester
Utility craft used to gather raw resources. Common in RTS games, where harvesting is the main way to expand ones forces. As such the priority is to take these out. This is not the case in non-RTS stories, so Harvesters are rare outside of games. If they are seen, they are operated by Contractors and usually far from any fighting. The more important the stuff being gathered, the more it makes Harvesters a target. As such, they require escorts.

Allies

Some people in the military may stand out more by their relationship to the main force than they do for the specific role they play in the fight. These include:

Hired Guns/Mercenaries

Free agents or units hired by the host nation to augment their own strength. Can be found in just about any role on the battlefield and at any skill level, from security forces to elite shock troops, although most portrayals lean towards the latter. If they're the good guys, they'll usually be highly professional (though they have an odd way of showing it) and follow a code of professional ethics that tells them to stick with a contract until it expires, unless their employer tries to screw them over. Villainous examples tend to be Only in It for the Money at best and Psychoes for Hire at worst, heedless of collateral damage and jumping at the chance to betray their employer for someone who pays better. Occasionally you'll get the odd band of Former Regime Personnel who are (generally) more ideologically committed, but even these guys are often more concerned about their own agenda than their host's well-being.

Advisors

Professionals brought in from a third party to provide training and guidance. They can be contracted by the state (like Hired Guns, and often drawing from the same sources) or provided by an allied power which can't or doesn't want to make their involvement more overt. Baron von Steuben and Lawrence of Arabia are famous examples from real life. May end up Going Native.

"Advisors"
Sometimes, the advisor is not really there to offer advice. An influential foreign power may want to safeguard its own interests by forcing its partner to include its own personnel in the ranks. In this way, these "advisors" are a cross between actual advisors and political officers, exact proportions varying. A Real Life example would be the Soviet officers embedded in the military of Soviet Bloc countries during Stalin's reign, ostensibly only there to help make up for the lack of experienced officer corps.
"Advisors"
Another form of so-called advisors simply using the title as a fig leaf, are "trainers" or "advisors" that actively fight the enemy instead of, or in addition to providing training, mixing the roles of actual advisors and auxillary forces. One notable example in Real Life are the Soviet pilots ostenably sent to Vietnam or Korea to "train" the local air force in their use of the various mig fighters the Soviets sent their communist proxies, but in reality often took those same planes to the skies themselves against the West.

Allied Auxiliary Forces

Soldiers from an allied military who fight alongside the main forces. In fiction, largely exist to create Jurisdiction Friction, since they often belong to another chain of command entirely and have different objectives, even when both forces are fighting for the same cause.

Conscripts

People who are drafted into the military, being forced to fight or provide services. These pressed men are reluctant to fight, and often questioning why the war is fought. Typically disinterested in military protocol and more interested in escaping the war.

Examples