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)
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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.
Force composition varies, depending on the technology level and setting. Future armies tend to be armed with high tech gear and energy weapons. Post-apocalyptic works have a mix of decaying modern technology and improvised weaponry. Steampunk will go for steam-powered tech with a Victorian aesthetic. Of course, the writer's skill, knowledge and interest 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).
Tabletop and video games: Will have all of the below and then some, if they can fit.
Each army branch (Infantry, ships, armour, etc.) helps each other, balancing out any weakness. For example, Tanks have great protection and 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.
For the major SF Army types, check out the Analysis section.
The Standard SF Army came be divided into several groups: Infantry (Standard and Irregular), Armored Combat Vehicles, Oceanic Ships, Aircraft, and Support.
Soldiers trained to fight on foot (or whatever limb used for locomotion), and has been used since the beginning of warfare. 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 infantryman 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. They 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. Other times, Heavy troops 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.
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 where 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 do employ newly developed combat doctrines, or specially trained for specific environments. Or for those showing enough skill and bravery, being transferred to the Elite is a reward. The last reason has drawbacks, namely it can create discipline and morale problems for the other regular forces.
Super Soldiers Vastly stronger, faster, and smarter than typical troopers. Sometimes a result of genetic engineering, cybernetic enhancement, or otherinfluences. Such enhancements allow them to operate in dangerous terrain (such as the vacuum of space). 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 infantrywrit 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).
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.
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 on the actual battlefield.
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. The 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 an Authority Equals 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. 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.)
Used for providing security or police work. Typically not as equipped as Grunts, and usually not as effective. (In fiction, Security personnel often carry a single sidearm, and maybe some light armor if they're lucky.) However, they are cheaper, plentiful, and useful in peacekeeping.
Commonly sent with away teams or serving aboard ships, and a favorite of megacorporations. Probably trained to deal with civilians more than other infantry. They can range from simple guards to gendarmerie units.
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.
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 rouge.
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 rouge. In any case, the heroes avoid using them at all.
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.
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, 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.
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.
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.
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.
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.
Covert units deployed by a nominally civilian group, such as an Spy Agency or a Megacorp. Like Spec Ops, they conduct secret and 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. Black unmarked uniforms and vehicles are typical, with advanced equipment to boot. Can be assigned to regular military as support.
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.
State SecTroops Combining Political, Security and Terror into one mean package. Often based on the Real Life SS Waffen 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.
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.
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.
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.
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.
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.
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. Often 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.
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 obsoletedue 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. The greatest 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.
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.
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.
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.
Out of the major branches, Oceanic ships appear the least in a standard Sci-Fi force. Such ships are only seen in video games, and rarely in other genres. There's no definite explanation why this is the case. Perhaps due to people thinking space navies operate on the same principles of its blue-water counterparts, writers believe ocean navies would be redundant.
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. Common in which the ocean is the main setting or a post-apocalyptic world. Often mirror their space-borne counterparts in function.
For a full list of different types of naval craft see Types of Naval Ships.
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.
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 the modern day, 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.
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.
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.
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.
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.
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.
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 NowShout-Out like helis.
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.
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.
Any units or structures not meant for direct combat, but can aid in defense or back up other units.
Any unit or structure designed to take down aircraft, and sometimes even orbiting craft. Often some sort of energy weapon or rapid-fire kinetic weapon is used. Missiles or large rockets are also used. 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.
Any unit capable of firing large projectiles or energy weapons for indirect fire support. Could be rockets, shell-firing cannons, or beam weapons. In SF, these tend to be Self Propelled Guns, with light armor and treads/legs/hovercraft for movement. However, unlike a tank, Artillery is usually not designed for direct fire or taking hits. Often seen when Air or Space forces are too expensive to use or not around.
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.
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.
Serves as a base for its forces, but is far more mobile and versatile. It may also provide fire support in battle. However, because of their size, they remain vulnerable to smaller units. It makes for a large (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.
Basically 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 idea - well protected or mobile enough to avoid getting damaged, could be controlled remotely, and the controller was well safely away from any destruction.
For forces with less technology or resources, 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 criminal organizations or factions were the "individual" doesn't matter (such as Hive Mind aliens), a living being could be used. Highly unethical to say the least.
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 generally unarmed.
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.
Defenses and Countermeasures
Installations or units that are used to provide active defenses for the ground pounders and whatever they're protecting. The most common defense is some sort of Deflector Shield able to protect the troops from orbital strikes or nuclear weapons. Other defenses include cloaking (to hide the location of where the troops are at) and countermeasures that make certain weapons unusable. One example is a device that makes nuclear weapons unable to operate, or to take it further, makes any nuclear fission impossible.
If the Shields / Countermeasures are really effective and can protect strategic targets, the main goal of the opposition is to take it out.
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. 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, were 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. As such Harvesters are rare. If they are seen, they are operated by Contractors and usually far from any fighting.
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:
Free agents 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.
Mercenaries As above, but hired by the unit rather than on an individual basis.
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.
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.
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.
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Anime and Manga
The Big O: Paradigm City Military Police, which consist of Security forces armed with IFVsand heavy artillery. Should they fail, at least a giant Mech shows up to save the day.
Blue Submarine No. 6: Considering most of the world is flooded, navies are the primary fighting force. The bad guys use biologically derived ships and infantry.
Dominion Tank Police: Focuses on a division of Police who drive around Tankettes. They're more dangerous to the city than the criminals.
Fullmetal Alchemist: Amestris' forces are dominated by infantry, with some primitive tanks, and the State Alchemists in the role of Exotic soldiers.
Full Metal Panic!: Mithril employs Special Forces that center around Mecha, which a submersible Carrier as a Command vehicle. Gauron and his forces are often Terrorists.
Ghost in the Shell and Ghost in the Shell: Stand Alone Complex: Focuses largely on a Cyborg Security/Special Operations group. In the anime, they have support from intelligent Tankettes. Regular military forces are armed with Spider Tanks and Power Armor (which make short work of the Cyborg Special Ops and Tankette group in open combat).
Gundam: Most of the attention is on the Mechs, but they're often supported by Armored Vehicles, Infantry, and other craft (Including Land Battleships, Mobile Armors, and Airborne Spaceships). Newtypes would be an example of Extoic Infantry/Pilots.
Neon Genesis Evangelion: NERV's primary offensive units are Exotic Mecha piloted by disturbed kids. The agency also employs a large amount of Support, Civilian, and Security personnel as well has its own aircraft and a wet-navy ship.
Robotech: In the Macross saga, the SDF-1 forces include an Aircraft and Troop Carrier (both submersible until the space fold, then they're just welded onto the ship, a number of atmospheric Aircraft, and non-transforming Mecha. The bad guys wear Power Armor, but are huge enough to take on mecha. The Masters saga featured Tank-transforming-Mecha, Anti-air batteries, and a Security branch for humanity. In New Generation, the Scott Bernard had to rely on a group of Indigs armed with Power Armor that could transform into Scouts.
To the Stars, a fic set in the far future of the Puella Magi Madoka Magica universe, has a fair few of these. The standard human infantry is a Super Soldier in Powered Armor, with extensive implants so they can be as effective as possible. They are accompanied by clouds of drones for deflecting incoming fire and improving firepower. The main character's grandfather is a medic, and the tech level is such that as long as the brain is intact, the soldier can probably be saved if they are recovered in time. Even with all of this, they're outclassed by the alien forces... except for the Magical Girl corps, who are all even more super than the Super Soldiers, and use magic to fill a huge range of roles, including air combat, space combat, black ops, stealth enhancement, and the like. The main character uses teleportation to turn her squad into hyper-mobile drop troops.
Aliens: The Colonial Marines are mostly Line Infantry, with Heavy infantry armed with smart guns. They also have transportation such as APC's and Drop Ships. The film also provides an example of Civilians: Burke plays the role of the Observer, Ripley as a consultant.
Avatar: The RDA has a personal army on Pandora, including tubrofan aircraft, Mecha, as well as regular infantry. The Indigs are the Na'vi, who rely on local animals to serve as Cavalry, both land and air.
The Matrix: In reality, the Machines have large armies of Robots, with special programs in the Matrix to serve as Security. Humanity relies on Special Forces that infiltrate the Matrix, since their only real weapons in the real world is poorly armored Mecha and hovercraft.
The 1980's movie Megaforce featured the titular mercenaries being armed with weapons "the most powerful science can devise". Using light vehicles like flying motorcycles and dune buggies, Megaforce's lasers and small missiles could destroy modern Main Battle Tanks.
Star Wars: The Empire relies heavily on giant, high tech Mecha, Elite soldiers and State Sec Troops. The Rebels rely heavily on Special Forces, with their necks being saved by the Indigs. The Jedi and Sith are Exotic infantry. The Prequels and Expanded Universe involves a large variety of combat vehicles.
In the prequels, the Separatist Confederacy and its precursor the Trade Federation relies on Robots as its main grunts. The Republic uses Super Soldiers (the regular clones) and Special Forces (the ARC troopers). The Jedi and Sith, again, are used as Exotic infantry and double as officers (the Jedi), civilian politicians (Palpatine and Dooku) and political officers (Maul, Ventress etc).
There's a few examples of atmospheric aircraft in Star Wars. The T-47 Snowspeeder seen in Empire Strikes Back is a civilian airspeeder converted to fulfill combat purposes by the Rebels. Another example is the V-wing, an atmospheric fighter-bomber used by the New Republic.
Star Trek V: The Final Frontier: With the transporters malfunctioning, Kirk attempts a rescue with a platoon of Starfleet troops. The Indigs still managed to overwhelm them.
Star Trek Into Darkness: When John Harrison attacks a high-level meeting of Starfleet's leadership, Admiral Pike calls for an air defense team. While Kirk is trying to shoot him down with a rifle, we get quick shots of a group of Starfleet soldiers with a turret trying to do so as well.
Transformers: Like the series, giant Mecha with Civilians. Unlike the series, the Mecha get support from Special Forces Indigs with close air support (plus Armor support in the sequel).
Terminator: Until Terminator Salvation, we only get to see brief glimpses of the war. Skynet relies on robotic aircraft, infantry, and even treaded Mecha. The Humans rely on infantry, in at least one time in the first movie, the use of Technicals.
The film version of the Mobile Infantry in Starship Troopers seems to consist solely of basic troopers and drop ships (compare to the other versions listed below). The Bugs have castes that act as tanks and aircraft and others though.
The Bolo series by Keith Laumer, later by David Weber, largely focuses on the AI-controlled Supertanks.
CoDominium: During the CD era on the colony worlds, Infantry was king, aircraft gone due to technological developments, artillery valuable, and a single tank could decide a war.
The Childe Cycle of Gordon Dickson: Largely focuses on infantry, but Armor does exist.
Dune: Because of the existence of effective force field tech, infantry is king. This changes on Arrakis, where the use of shields attracts the dangerous native lifeforms. The Baron Harkonnen uses this to his advantage by using Artillery, considered obsolete thanks to the shields. Super Soldiers like the Sardaukar and the Fedaykin of the Fremen dominate warfare. The Fremen are also Cavalry, using the giant Sand Worms as their steeds. APCs, Drop Ships and various military aircraft also exist, at least judging by the first novel. No mention of tanks or mechas. Firearms vary wildly, lasguns are often Cool, but Inefficient due to the aforementioned force fields (a laser hitting a field would cause a nuclear explosion). Melee weapons see much more prominent use than in most sci-fi settings. Mentats, Face Dancers and the Bene Gesserit can be considered Exotics.
Hammers Slammers: The titular mercenaries largely employ tanks, supported by Artillery and infantry. Instead of using APCs for transport, the Slammers use open-topped armored cars. Although the Indigs and assorted mercenaries they face are not as well equipped, they still can pose enough a threat to Hammer's men.
Honor Harrington: Although most of the focus is on space combat, ground combat also appears. The major sides typically employs marines in Powered Armor, and separate armies. During the Committee of Public Safety, Haven's armed forces included an increase of political units. Tanks exist in the setting, but are considered largely obsolete due to the mobility that the Power Armored troops have combined with some of the more powerful weapons they carry, and thus are seen very rarely. Occasionally, we see the Space Marines of various powers (Manticore, Haven, and the Solarian League Navy) used against unarmored enemy infantry, terrorists, or indigs. The resulting battles are brief.
Legacy of the Aldenata: Dominated by Infantry (especially Powered Armor) and Artillery, since the Posleen anti-air shoots down any aircraft very effectively and many Posleen weapons trivialize Earth-built armor. Oceanic navies also play a role. The one instance of a Civilian going along with some Generals to prepare Earth for the Posleen ends horribly.
Starship Troopers: An example in which Powered Armor is in common use, and their support comes largely from orbiting craft. For the Bugs, the Warrior Caste serve as their Infantry. A supposed psychic (officially called a "gifted", and the narrator suspects he just has very good hearing) is an example of a Exotic soldier.
The War of the Worlds: The Martians use Mecha, and their technology is so advanced that the Indigs (19th Century British army) are barely a match for them. Artillery and Warships take down a few Tripods.
In addition to Mecha, the Martians are said to have used 'Flying Machines'. Exactly what Aircraft category they would fit under is unclear, since the protagonist does not see them during the course of the novel (they're a rumour, albeit one that is said to have been confirmed after the War) and the Indigs lack any real airpower, but they are indicated to have bombing capabilities.
Bill the Galactic Hero has served in a number of different military roles, including Security, Special Ops, and (of course) a plain old grunt.
The Confederation of Valor series mostly deals with line infantry who wear low-key Powered Armor, understandable since the main character is a sergeant in such a unit. They're generally transported to the battlefront by air. The series also has aerial fighters, tanks, and artillery, as seen during the full-scale battle in book four.
The Hunger Games: Panem Peacekeepers serve as State Sec Troops, guarding the Tributes and enforcing order in the districts, and utilize hovercraft for aerial roles (from combat to transport to patrols).
Andrey Livadny's The History of the Galaxy series are mostly focused on ground combat (despite being a typical Space Opera), so this trope is present. Since the setting spans over 1000 years, the realities of ground combat change. At first, standard mechanized infantry and tanks are the norm for the Earth Alliance. Then their attempt to their the Dabog colony with this type of army utterly fails when the colonists use their serv-machines developed from studying the local dinosaur-like predators. After the Earth Alliance develops their own walkers, and the Free Colonies start to copy those developed by Dabogans, infantry becomes pretty much useless, and all ground combat is done by mechs. Since the Earth Alliance is much more advanced in the fields of AI and mind-machine interface, resulting in very effective serv-machines of the dreaded Hoplite and Phalanxer designs, the colonists decide to try a new approach and start mass-producing fairly primitive and cheap (smaller) computer-controlled drones called LDL-55 (walkers armed with a 200-megawatt laser) and MX-300 (treaded RPG launchers), whose primitive AIs are at their best when networking together. Later on, the Earth Alliance also develops combat androids. After the war, the victorious colonists form the Confederacy of Suns, and retire most wartime weapons, including the mass-produced drones. They do keep some serv-machines but choose to adopt the more effective Earth Alliance designs rather than their own Golden Eagles. Mechanized infantry is once again used for small-scale conflicts, and some later start wearing Powered Armor. There are no dedicated atmospheric fighters. All fighters are of the aerospace variety and are, thus, part of the Standard Sci-Fi Fleet. However, most serv-machines are equipped with short-range boosters allowing for limited flight.
The author has made a clear distinction between the various types of serv-machines. Only four are ever named: Hoplite, Phalanxer, Raven, and Golden Eagle. The latter is a Free Colonies design retired after the First Galactic War. The Hoplite is a relatively light model (about 20 metric tons) and is primarily used for scouting and close-range combat. The Phalanxer is a Mighty Glacier (about 60 metric tons) and is mainly designed for long-range bombardment of targets pinpointed by a Hoplite (they often form combat pairs). After firing, the Phalanxer can drop its back-mounted heavy missile launchers and act in a more combat-heavy role. The Raven is only really used in a few novels. Sometimes, it's portrayed as a third, medium type (40 metric tons) complementing the Hoplite and the Phalanxer, while other times it's portrayed as a unique model incorporating the best of both designs. All three models have advanced AI and mind-machine interfaces, allowing the pilot to "meld" with the AI and control the mech without using any controls, with the AI eventually learning from the pilot and improving. Standard serv-machine weapons include Magnetic Weapons, Frickin' Laser Beams, and missile launchers. Point Defenseless is averted, as they're also equipped with laser defense grids. Advanced AI also allows for Magnetic Weapons to fire Pinball Projectiles, especially if another serv-machine has pinpointed the target.
Babylon 5: The Earthforces we see in most episodes are from the Navy and Security branches. Regular Army are informally known as GROPOs (a contraction of "Ground Pounders") and seem to have the standard mix of personal arms & body armor with squad support weapons. Close Support Aircraft are seen in battles that are stated to be pure Army.
seaQuest DSV: Considering the oceanic setting, it's no surprise that advanced submarines are the main focus. The good guys also deploy Kill Sats, and psychics and dolphins for experimental use. The main ship got stuck with civilian Teen Genius. The UEO experimented with Super Soldiers, which didn't go so well.
Space: Above and Beyond: Both Humans and Chigs seem to rely heavily on infantry for ground combat. Pilots are also used for grunt work, although justified within the show. Armored vehicles are used occasionally by both sides.
Stargate SG-1: Because the Stargate is only 20ft across, infantry dominates interstellar warfare. The U.S. Air Forces does use robots for drones, scouts, and logistics. Cruise Missiles and Drone Attack aircraft are often launched through the Gate to soften up hardened targets. Scientists are sent along to provide advice and support during exploration. The actions by the rogue NID and the Trust are examples of Terror units.
O'Neill: What kind of archaeologist carries a gun? Jackson: *Raises hand* Uh, I do. O'Neill:Bad example.
Starfleet typically sends down Security force with away teams or on certain missions. It's not until Deep Space Nine that we see any ground warfare. Everyone appears to rely largely on Infantry. To make sure their own Supersoldiers stay loyal, the Dominion addicts all their troops to a chemical agent and sends a civilian to act as a drug pusher. An episode of the original series had Starfleet personnel using a photon mortar, but the weapon never appeared again afterwards. The heroes were once on the receiving end of a Klingon mortar in DS9, but the rounds were so laughably weak (and seemingly completely lacked shrapnel) that they had to land directly on someone to do more than annoy them.
Star Trek: Enterprise finally shows dedicated Space Marine-like troops. The MACOs operate in small squads and are usually seen on ship boarding actions, although a few episodes show them deployed on planets. They receive special training and carry rifles with custom mods, while any fleet officer usually carries a phase-pistol.
BattleTech: Mecha dominate the battlefield, but infantry, tanks, and aircraft are still around. The Clans manage to develop Powered Armor (Elementals) and Mini Mechas (Protomechs) that can take on full-sized mecha.
Warhammer 40,000: Another example in which almost every single unit type is included. It is also notable for popularizing:
Political units, notably the infamous Commissars.
Elites/Supersoldiers: The Space Marines, Eldar Aspect Warriors and several Imperial Guard Units
Exotics: Space Marine Librarians, Pskyers
Logistical Support: Techpriests, Priests
Mecha: Titans, Tau Crisis and Riptide battlesuits, Eldar War Walkers, Wraithlords and Wraithknights, Ork Killa Kans
In Rifts, where small arms are capable of slagging a 20th-century Main Battle Tank or vaporize a human, tough armor is a necessity. Also, Armored vehicles (from bikes to tanks), aircraft, Powered Armor and Humongous Mecha of many different types and configurations are available to mercenaries and independent adventurers, to say nothing of official military forces. Exotic troopers can include cyborgs, chemically-augmented super-soldiers, psychics, and depending on the individual force, even magic-users, mutants, and Dragons.
In Traveller the state-of-the-art armies use Powered Armor for a good chunk of their infantry and grav vehicles for cavalry/armor. Rapid-interface units (Space Marines, though only some of these are actually called marines) and the like, have suits that allow them to jump directly from orbit like paratroopers. Artillery is provided by missile launchers and in the case of the Third Imperium, meson guns. The army of the earlier Terran Confederation also contained a number of security divisions specially trained in hearts-and-minds work among conquered Vilani. The Zhodani had specialist commando units with psionic abilities and used Robot troops.
Star Grunt II is a miniatures game that focuses on the infantry, especially the grunts. However, Powered Armor, AP Cs, air transport and gunships, and artillery are common elements. Tanks are less common, but are supported by the rules. This inlcudes a sample scenario which provides an object lesson in what happens to tanks without infantry support.
Tomorrow's War has rules for everything except Humongous Mecha and Land Ships. As well as for "Irregular" troops such as insurgents.
Advanced Wars: For the most part, the military units in the games are nothing fancy until AWII. Then the game introduces quasi-Spider Tanks, giant lasers, and the Black Hole forces look high tech. By Dual Strike, they've added Supertanks to their arsenals.
Battalion Wars features Grunts and Heavy Weapons specialists of various types for infantry, and recon, Light and Heavy Tanks, specialized vehicles such as Anti-Air and Artillery, and Multipurpose Fighters and Bombers. It also includes a Supertank in the Battlestation and a Flying Fortress for many factions. The sequel adds naval craft as well.
Sid Meier’s Alpha Centauri: The games has a number of chassis types, including Infantry, Aircraft (mid-game "Needlejet"—i.e. fixed-wing aircraft—and "Copters", and late-game "Gravships"—basically fan-propelled zeppelins lifted by Anti Gravity instead of gas), Oceanic Craft (early-game "Foil"—i.e. hydrofoil—and mid-game "Cruiser"—i.e. keeled ship), Speeders, Hovertanks, etc. In addition, the local Mindworms play the role of Exotic Indigs.
The Expansion Pack introduces two alien factions, who have the same types of chassis as humans. They actually start the game with an Ogre-class Spider Tank/Humongous Mecha, however, they lack the tools to repair or make more of them.
Command & Conquer: Almost every single infantry and vehicle could be found in these games. Although Tiberian Dawn and Red Alert armies are largely conventional, even they have vehicles that are fantastic (Turbofan Orcas, Chronotanks, Mammoth Tanks, and Stealth Tanks just to name a few). As both the Tiberium and Red Alert series' progressed, they got more and more sci-fi-ish, with Tiberium going futuristic and Red Alert going more Pulp-fantastic.
This, while Generals on the other hand mostly remained realistic, with only very few true Sci-Fi units. Examples are mobile Cruise Missile Platforms, anti-missile lasers and laser cannons, missile jammers, HollywoodHackers, and the occasional GLA stealth unit, who are World War II tech-using vaguely-Islamistish terrorists.
Dune II: Unlike the books, the Dune RTS games have a wide range of infantry and vehicles. Emperor: The Battle For Dune had the Tleilaxu provide Biological monstrosities as units. Many armored units are now Mecha. The Sardaukar and Fremen subfactions count as Supersoldiers, while the Guild ground forces are considered Exotic.
Halo: Dominated largely by infantry (from Light to Elite, and of course the Super Soldiers), although both sides use field aircraft and at least one Armored vehicle. Halo Wars expands on this, giving the UNSC Heavy and Elite infantry (the Hellbringers and Helljumpers respectively), APC's, and Anti-aircraft units. Several of the Covenant vehicles are effectively Technicals, being repurposed mining equipment.
Metal Gear Solid: Since Metal Gear, the series has involved the titular Mecha or mentions the machines. MGS introduces genetically engineered Special Ops, as well as truly Exotic troops. As the series progresses (save MGS3), the more Sci-fi elements begin to emerge. And even then, Metal Gear Solid 3 involves psychics, a hundred year old sniper with photosynthetic moss in his skin, a jet pack-wearing insane cosmonaut, a guy with superman speed, someone who could control hornets, and a supertank.
Military Madness (aka Nectaris) follows the basic setup for their armies. Since its set on the Moon, the infantry are naturally wearing power armor. In the Playstation 3 remake, the Buggies are renamed Technicals.
Starcraft: Powered Armor, Mecha, and Supersoldiers are common. Terrans have Moblie Bases and their "Ghost" units are Exotic Special Ops. The Protoss are Exotic by nature, and most of their vehicles are Technicals (being reprogrammed maintenance machinery) . Although most Zerg are technically infantry, they have different breeds that fulfill the various roles in a Sci-Fi Army.
Tanarus: Tanks are the primary focus of the game, mostly of the Main Battle Tank and Hover Tank variety.
Total Annihilation: Infantry roles are replaced by Mecha. The game is also notable for the its Commander unit. Should the Commander be destroyed, often it's game over. This is carried over to its Spiritual SuccessorSupreme Commander, which includes tanks, mechs, aircraft, and naval units. It also has the Commander unit, along with powerful Experimental Units.
X-COM:The Humans fight with advanced Aircraft and Special forces w/Tankettes. The aliens deploy a wide range of Infantry, including Exotic psychic forces, and literal Terror units. Some player guides encourage players to develop their ground forces along these lines as well, with specialists and roles.
In UFO: Enemy Unknown (or XCOM: UFO Defence, if you like) and XCOM: Terror From The Deep the best (and only sensible) tactic was to make everyone wear Flight Suits or Magnetic Ion Armor and train hard in psionics or MC control and wield BFGs. No need to specialise, just make everyone unstoppable psychic flying deathmongers.
The Firaxis remake diversifies X-COM soldiers into various classes, including Assault, Sniper, Support, and Heavy, and develop abilities along those trees as they level up. Those who are discovered to have the Gift become Exotic forces in addition to their combat class (they can also wear a special armor that boosts their abilities). In addition to Cyberdiscs, the aliens now employ small Attack Drones that repair nearby friendly (mechanical) units and fire a small particle cannon. With some research, X-COM soldiers can capture them to use them for the mission.
The Bureau: XCOM Declassified has Outsiders also using gunships in some missions. Initially, they're a big threat, as they make cover useless. Later, though, with the use of more powerful weapons and abilities, they become fairly easy to kill. The Outsiders themselves have many different classes within the same race, including common soldiers, commanders, tech-commanders (i.e. shield-enhancers), psionic commanders, snipers, scouts, etc. Your own agents can be chosen from one of four classes: Commando, Engineer, Recon, and Support. Your Player Character is a unique Squad Leader class with separate abilities.
Rebelstar: Tactical Command, a spiritual successor to X-Com: UFO Defense, focused mostly on Infantry. Each side had their own special units: The Humans had weak robots, the Arelians had flying saucers, the Zorn had either giant green alien dogs or dinosaurs, and the Frylar had flying bugs and flame tossing giant beetles.
The Expansion Pack adds the Phoenix Mercenaries, a breakaway group made up of former Crayven mercs who have decided to strike out on their own. Their tech is similar to Crayven, for the most part, with a few additions.
The sequel takes place 300 years later, although the units of the two human sides are suspiciously similar to the first game, with the Terran Empire using energy weapons and hoverdynes and the Northern Star Alliance using ballistic weapons and terradynes. This is justified in-story, as the Terran Empire was prospering for nearly two centuries, while the outer colonies were isolated and suffered regression before forming the NSA. Also, many of the NSA planets were colonized by the Crayven Corporation, justifying the tech. The game also adds walkers for the Empire, and helicopters ("helidynes") replace aerodynes as air support. The dropships are no longer the bulky kind and can be turned into the most powerful unit in the game with upgrades. The Virons are similar in terms of ground troops, except for their ability to merge and "un-merge" into new units. Their ground vehicles hover but are called "centruroids".
FEAR has a general mixture of various infantry types in the form of the Replica soldiers, who are vat-grown clone troopers who respond to the commands pf psychic commanders (simultaneously fusing Biological, Exotic, and Super Soldier in one package). Within the Replica are specialists; Elite Replica troops in heavy armor, enormous Heavies that are bigger and better armed and wearing oversized armor suits, Spec Ops units in the form of the Assassins, and mechanized support piloting REV Mini-Mecha suits or Elite Powered Armor suits that essentially serve as walking light tanks. Finally, there's robotic units in the form of light "Mech" units which are small bipedal walkers about as tall as a human.
Jeff Wayne's War Of The Worlds: Similar to the Literature example above, but humans are on an even war footing with the Martians. The Human arsenal has been expaned with tanks, armored cars, self-Propelled artillery/anti-air, and a balloon. The Martians forces now have Recon, Exotic telepathic, and various construction units.
MechWarrior Living Legends, unlike previous MechWarrior games note which only had mechs for the players, as other assets were just Cannon Fodder in the singleplayer mode, is a combined arms game (similar to the Battlefield series). The standard warfare unit is the BattleMechwalker, which varies between 20 to 100 tons. The mechs are the most adaptable asset, occupying almost any role, depending on the chassis and its loadout. Aerospace fighters occupy the Dogfighter, interceptor, bombing, recon, close air support, and the VTOL assets function like helicopters and are used primarily for harassment and scouting. Tanks vary from 20 to 95 tons, and come in several flavors; treaded, wheeled, and hover (as in hovercraft with skirts and fans). Tanks are more durable than mechs, but slower, and generally very specialized, such as only equipping Anti-Air weapons. APCs work as resupply points for ammo, and as a spawnpoint for infantry. The game lacks standard infantry, and instead has Powered Armor, which has a jump pack, missile launchers, a big load of grenades in several flavors, and can carry two weapons, such as lasers or autocannons.
The Voth in Star Trek Online's Dyson Battlezone have a mix of various types of infantry (everything from line infantry to special forces) and mecha. They also use genetically engineered dinosaurs as everything from supply runners to the equivalent of main battle tanks.
In Schlock Mercenary, mercenaries and what we've seen of military forces use various flavors of infantry and armor. They seem specialized for enclosed spaces and other situations where calling down death from orbit isn't an option, so there's not a lot of variety - no indirect fire's been shown. Everyone gets Power Armor. The setting's Deflector Shields are based on gravity control, so most things fly, and the line between armor and close air support is blurry. The closest thing to other aircraft roles is a spaceship with a crew that's been annoyed enough to come down there.
Exo Squad: Both sides rely on Exosuits (a cross between a Mecha and Power Suit). The human ExoSquads are supported by jet-pack powered light infantry. Human resistance forces play the role of Indigs (some of them have jetpacks too). The Neosapiens develop Supersoldiers, some focusing on brute strength, others on mental capabilities.
G.I. Joe: Special forces versus Terrorists, usually with lots of vehicles for just about every niche listed above that could sell as a cool toy (and often did, usually with a certain bit of overlap when you line them up all together).
Roughnecks: Starship Troopers Chronicles: the CGI series actually have Power Armor for the humans. Like the Zerg, the Bugs rely on Infantry variants to act as artillery and other units (including spaceships).
Sonic Sat AM: The Saturday morning cartoon had Robotnik run a force composed of Robotic Grunts, Mini-mecha, Attack Drones, and Bombers. The Freedom Fighters have to make due with simple Infantry.
Transformers: The series focuses on sapient alien Mecha, with the good guys often dragging along Civilians (which even worse in the Anime Unicron Trilogy). There is basically no division between infantry and mechanized vehicles, air support, or technical and support functions. The skill and power of individuals generally trump any organized battle plan.