Among science fiction stories with space flight, the overwhelming majority are about combat, both between spacecraft and between futuristic ground troops. Not to mention the occasional starship marine assault trying to board a hostile ship while in flight. Yes, there are a few non-combat stories, mostly about exploration, but space combat is here to stay.
This is just the natural continuation of the process of militarisation of space
Which naturally leads to questions about the space branch of the military of various nations. The "astro-military" in other words. Some may start out as a subdivision of an existing branch and eventually grow large enough to split off (such as how the US Army Air Corps spit off to become the US Air Force in 1947 ). Some may grow large enough to absorb other branches of the military, others may be reabsorbed into other branches. In William Keith's Galactic Marines series one of the themes of the early novels is how the US Marines fight being absorbed or eliminated. Their solution is diversifying their mission to include performing assaults on Luna and Mars.
There will generally be something like a "space navy" who deal in combat spacecraft (with a sub-branch for space fighters, even though those are unlikely). There will be "space marines", who generally are found on board combat spacecraft. They are generally elite fighters, since spacecraft usually can only carry a limited number of them. There will be a "space army", which are usually just the old ground army troops ferried to combat zones on other planets on huge lightly armed troop carriers. Finally there might be a Spaceguard.
Two on-line resources I recommend are William S. Frisbee Jr.'s Tips on Writing Military SF and William's Future War Stories. Both are almost the equivalent of college-level courses in the subject. It will take you a long time to read through the many essays and entries, but it will be worth it.
Specifically for the topic of astromilitiares, you should look over Mr. Frisbee's essay on Designing Militaries, Future War Stories essay on things that military science fiction are constantly getting wrong, and Thomas Evans' The Problem with Military Science Fiction Part 1 and Part 2
In the game SPI's Universe, there are some colorful names for various professions.
|Astroguard||Member of a planet's or star system's local military spacecraft force.|
|Star Sailor||Member of the federal spacecraft navy.|
|Freefaller||Soldier in the zero-gravity branch of the federal armed forces.|
|Ranger||Soldier in the standard ground branch of the federal armed forces.|
|Spacetrooper||Soldier in the assault force branch of the federal armed forces.|
|Scout||Member of the exploration branch of the federal armed forces.|
Tyge Sjostrand suggest the term Espatiers for space marines, since after all the term "marine" implies the ocean (French marine, from Latin marinus, derived from mare "sea"). The best guess I have at how it is pronounced is "Ess pa tee yea". Rick Robinson really likes Mr. Sjostrand suggestion:
Frederik Vezina disagrees about the pronunciation.
Another term for ground troops is "Gropo". A contraction of "ground-pounder", as opposed to sailor. Term coined by British Navy, popularized by J. Michael Strazynski in an episode of Babylon 5.
And in the anime Macross, the (Japanese) writers noted that the military on the ground is called the "Army" and the military on the ocean is called the "Navy", so logically the military in space would be called the "Spacy" (alternatively it could be a contraction of "Space Navy"). Since the release of Macross, the term has been used in other works: Martian Successor Nadesico, Voices of a Distant Star, and Mobile Suit Gundam.
Alas, "Spacy" is a little too similar to "Spacey", which in the slang of the United States means "vague and dreamy, as if under the influence of drugs".
Historically this was a project created by the US military in 1957. Officially cancelled in 1962, it apparently is still undergoing some top-secret development as late as 2018. From a science fiction standpoint this would only make sense on a balkanized planet (i.e., more than one soveregn nation), not on a planet totally controlled by a single government. The project was called SAtellite INTerceptor or SAINT.
The idea seems to be to deal with the threat of Soviet satellites. On the one hand they might be orbital nuclear warheads. On the other hand if the US just preemptively destroyed out of hand any satellites the Soviets launched, the international political situation would deteriorate rapidly. So it would be well if the US could send up at an hours notice a crewed spacecraft to inspect the new Soviet satellite. If it turns out to be a nuke, then you can destroy it.
One of the proposed missions for the Boeing X-20 Dyna Soar was satellite inspector.
Pye Wacket was an apparent re-fit of a flying saucer shaped missile project that was in danger of being cancelled. They tried to apply it to the Blue SAINT program, making it a crewed satellite interceptor. Sadly it was in direct competition with the X-20 Dyna Soar project, so Py Wacket got axed by McNamara in 1962.
The Convair Space Shuttle was not an official part of SAINT. But it was intended to deliver repair crews to satellites for fixing malfunctions and maintenance. I'm sure it could be adapted to SAINT with little trouble.
First off, you should read Future War Stories in-depth analysis of space marines. For some of the standard features of space marines in media science fiction, there is the incredible time-sink of the TV Tropes Space Marines entry. And SF master William Keith has done a remarkable job with the creation of space marines in his Galactic Marines Series. Read a few of those novels to see it done right.
Remember that a better term for marine is "Espatier". After all, the term "marine" orginally came about because the fighters were deployed on sea going vessels. Espatier sounds better than "space-ine".
And if your science fiction universe contains space pirates, they are the natural prey of espatiers.
As previously mentioned, espatiers will tend to be elite units, compared to ordinary ground troops. This is because most combat spacecraft do not have much capacity to spare to carry espatiers, so the number of espatiers will be limited. Therefore with espatiers you will be relying upon quality over quantity. Since espatiers are usually based on board spacecraft instead of in ground bases, espatiers can be deployed much more rapidly than army troops. Unfortunately this means the espatiers will also be stuck with the job of trying to hold the ground taken for however long it takes the space army to get its act together and transport battalions of troops to the combat zone.
Since espatiers will generally be deployed in smaller numbers than ordinary troops, they have more options for insertion and extraction. To make up for their smaller numbers, they probably will have access to force multipliers, such as powered armor suits. Usually, the more elite a unit is, the more specialists it has.
Espatiers will be highly trained in hand-to-hand martial arts, though these will have to be modified for microgravity use. Espatiers will also be skilled in how to fight while wearing a space suit, and how to defend against your opponent's attempts to puncture your suit skin. Dougherty and Frier call troops with this training "protected forces" (Profors) meaning how to fight while wearing gear that protects you from a vacuum or other hostile environments. Espatiers space suits will probably be armored.
While military troops generally use firearms, eventually your Espatiers and Freefallers are going to find themselves floating in microgravity locked in mortal hand to hand combat. Naturally this takes a much different skill set from fighting on a planetary surface where gravity holds everything down.
Joshua Whalen is of the opinion that when it comes to microgravity hand-to-hand combat, punching your opponent is worse than useless. While floating in mid air, as you throw a punch your body will tend to move backward as your fist moves forward. This robs the blow of much of its power. And when your punch connects, both of you go sailing off in opposite directions. Newton's third law strikes again. A hook or roundhouse punch will also start you rotating around your long axis. You can only punch or kick with real damage if you are braced on a wall or other massive object. Bracing yourself might not be a problem, since spacecraft habitat modules tend to be cramped.
Mr. Whalen goes on to say that the techniques derived from JuJitsu or Tai Chi/Pa Qua will work. A gentleman who goes by the handle Marsbug notes that Judo Ne-waza techniques might also work, since those are based on when you and your opponent are lying on the ground and grappling. Choke holds and joint locks are also effective in microgravity, especially if the lock breaks a bone in your opponent's limb.
Dirk Bruere has a nice article about unarmed combat in zero g here. Highlights: Thai Boxing comes into its own since grabbing your adversary while kicking them works perfectly in free fall, many joint locks do not work with the exception of the Back Hammer and Judo Arm Bar, and pressure points are still effective.
Keep in mind of course that microgravity unarmed combat techniques that work when you and your opponent are dressed in shirt sleeves inside a shirt sleeve environment might be difficult or impossible to perform when you are dressed in a pressurized space suit. Imagine fighting when both of you are wearing inflated fat-suits. With padding.
However vacuum combat adds that added dimension of killing your assailant by puncturing their space suit. This might be difficult to do with your bare gloved hands, but it is not that hard to find something sharp and pointed. A gentleman named Mangetout pointed out that if you can get behind your space suited foe they are at a severe disadvantage. It is almost impossible for them to reach behind themselves while you can tinker with their life support back pack or the latch on their space helment. You'd want some sort of short spear or sword to defend yourself.
You might want to do some research on the hand-to-hand combat techniques used by Navy Seals when both they and their opponent are underwater in SCUBA gear. Obviously cutting your opponent's air hose works just as well in space as it does underwater.
Noted SF author Harry Harrison had some musings about microgravity weapons that were not firearms, written up in the October 1967 issue of Amra in an article titled Take That, You Alpha Centaurian Swine!. He later used some of the weapons in a short story called "No War, Or Battle’s Sound".
The general level of weaponry in hand-to-hand space battling is very depressing. All of the invention seems to have been done by E.E. Smith a few generations back, and the authors who came along later have been happy to use Doc’s armory without modification. The names may be changed, but call it what you will — it is still Van Buskirk’s space axe that crunches through the helmet.
And what about that space axe? As described by the immortal Doc even the iron-thewed Van couldn’t have done much damage with it in a null-G situation. You only have to think of all the complex tools that have been designed to turn nuts and bolts in space — without having the operator turn in the opposite direction — to realize what would happen when that mighty axe was swung.
I have brooded on this problem, and the possibilities of new weaponry in space, and present the results here. They are free for all to use, I ask only that authors retain the names I have assigned so I can enjoy a bit of egoboo.
Firstly that axe. It will have to become a Power Axe that will operate independently of gravity. To all appearances a normal axe, it has a power source concealed in the haft and four small jets located in the tip beyond the blade. The only pressure required to swing it is the pressure of a fingertip on a switch.
Admittedly a great deal of practice in free fall will be required to master this device — but time is one thing that the military has in sufficient quantity and a daily drill with the Power Axe will be a welcome addition to the schedule of activities. Once mastered the axe can be used as a second source of propulsion in space as well as being a deadly weapon to be used to hack through space armor. — Harry Harrision
So much for the normal. What about the original weapons, the devices that grow out of need, that are adapted only for use in space, against space-suited opponents. The possibilities are wonderful.
Consider the situation. You are faced with an opponent in a spacesuit, armored perhaps, though weight and the resulting inertia might prove to be a handicap. In any case the problem to be solved is the same one that has faced every soldier since the beginning of time. Kill the opponent. In space this can be done two ways — by killing the individual, or by destroying the integrity of his protecting suit so that the conditions of space kill him.
First the opponent. A device that will not work against an armored opponent but which will be just dandy against a fabric-swathed enemy is the Lightning Prod.
A light weight hand-held device that can be easily maneuvered into position, it has a single operating button that triggers a jet from the rear of the handle (A). The jet drives the Lightning Prod forward at a speed great enough to force the sharp spikes (B) through the layers of cloth and rubberized fabric so that they bite into the flesh of the luckless occupant of the suit. Upon complete penetration the triggers (C) are closed and a death-dealing shock from compact accumulators is sent through the conducting spikes. End of enemy — Harry Harrision
The Drillger may be used against armor or fabric, and is a powered weapon with driving jet in the hilt (A). The blade is a tapered drill, something like a rock drill, that turns at great speed and that can easily penetrate most materials. If a deadly wound is not inflicted the removal of the Drillger will leave a nice vent for the suit’s atmosphere. — Harry Harrision
More useful against full space armor is the Gropener. Held in one hand it is activated by a single button (A). This turns on jet (B) that pushes the weapon against the opponent with great force allowing the oscillating blade (C) to saw a slot, hack off a limb or a head or generally cause enough damage to win the encounter. — Harry Harrision
The Nipoff utilizes the ancient principle of the geared down worm screw, the same simple mechanical device that enables a 100 pound woman to lift a two ton car. Held in one hand it need only be pushed gently against the enemy’ s arm or leg to become effective. At that moment the battle is over and the victor can go on to more important duties. Contact closes button (A) which causes the two blades to close on the chosen limb. Once locked in place it cannot be removed and the unlucky victim can only look on in horror as the geared down electric motor slowly closes the blade and severs the member. Very nasty. — Harry Harrision
I think it fair to assume that technology will have advanced a bit by the time hand-to-hand space battles will be needed — if they ever will be needed — and it is not unfair to assume that a reversible adhesive will be developed. We are learning a lot about surface films these days and a film whose character can be changed electronically to be alternately adhesive and neutral seems a logical outcome. This film coats the feet of the Pryder (a prying spider if the derivation appears dubious) and enables it to walk on any space suit surface.
The Pryder can be hand launched or scattered mechanically in a mass barrage. When one of these little devices touches a surface it begins a spiral search pattern over the surface, with sensitive extensions of the prying-jaws (A) searching for any cracks or openings. As soon as a joint or wrinkle is detected the Pryder stops and squats and turns on full adhesion. The prying-jaws are inserted, the motor started and whatever crack they are jammed into is widened. The result is obvious. — Harry Harrision
A nasty bit of business is the Slaphole. This has an armored back that is held in the palm — and a contact fuse operated shaped charge on the inner face. In use it is a deadly slap, on the back, since contact explodes the charge which punches most of its energy straight down, blowing a neat hole through whatever material the space suit is made of. — Harry Harrision
A final, and not so deadly, weapon is the Soot-shoot, a hand held device to be used for taking opponents out of operation, perhaps when prisoners are needed. It has a charge of compressed gas that expels positively charged particles of carbon black. Aimed at a helmet it would blanket it and render the occupant blind. Very neat. Truss him up and bring him home. — Harry Harrision
|US Army Units|
|Ø||2||Senior soldier||Two foot soldiers who cover each other|
|Fireteam||Ø||4—5||Lance corporal to Sergeant||Maximum tactical flexibility with the minimal size|
|Squad, Patrol||•||8—16||Corporal to Staff Sergeant||2 or more fireteams|
|Platoon||•••||15—60||Warrant officer to 2nd Lieutenant||2 or more squads|
|Company||I||70—250||Chief warrant officer to Major||2 to 8 platoons|
|Battalion||II||300—1000||Lieutenant colonel||2 to 6 companies|
|Regiment||III||2000—3000||Colonel||2 or more battalions|
|Brigade||X||2000—5000||Colonel to Brigadier general||2 or more regiments or 3 to 6 battalions|
|Division||XX||10,000—20,000||Major general||2 to four brigades or regiments|
|Corps||XXX||30,000—80,000||Lieutenant General||2 or more divisions|
|Army||XXXX||60,000—100,000+||General||2 to 4 corps|
|Army group||XXXXX||250,000+||General to Field marshal||2 or more armies|
|XXXXXX||1,000,000+||General to Field marshal||4 or more army groups|
There are some who say that in a universe full of combat starships capable of obliteraing a planet, ground troops are obsolete. William Frisbee explains why this is not the case. There are plenty of tasks that troops can perform which are not possible to do with strategic weapons.
Troopers may be much like real-world soldiers, except they will probabably have much more advanced equipment. Including advanced armored fighting vehicles. Troops will also be trained to fight alongside armored vehicles, combat aircraft, and artillery (both ground based and orbital). This is called Combined Arms.
Another piece of advanced equipment science fiction writers like to equip their troopers with is directed energy weapons instead of conventional slug-throwers. Usually laser rifles. As a general rule though laser weapons are more trouble than they are worth.
In addition to engaging in fluid battles, the army may also have to deal with planetary fortresses, either manning them or assaulting them.
Compared to space marines, space army troops will be relatively unskilled and non-elite. Quantity over quality in other words. This means specialized spacecraft will be needed specfically designed to ferry large numbers of troops to battle fronts on other planets.
Transporting battalions of ground troops to other planets will be a major headache. The troop transports will be huge, probably easy targets for hostile ships, lightly armed (if at all), and not very maneuverable. They will need escort ships for protection. Another thing needed are fleets of logistic ships to transport all the food and ammo the battalions are going to need. Finally there must be a way to insert the troops into the combat zone, and get them out if need be.
A related spin-off is one very near and dear to my heart, that of the cyclopean artificially intelligent supertank. This was invented by Keith Laumer in 1960 in a story called Combat Unit. The gargantuan tanks are called Bolos and are described as being "continental siege units", that is, instead of only being able to lay siege to a fortress Bolos can lay siege to an entire continent. With firepower rated in megatons-per-second, Bolos have a computer intelligence far higher than any human. In most of Laumer's Bolo stories, the Bolos are majestically honorable and loyal. Which provides great contrast to the slimy opportunistic cowardly human politicians and rigidly dogmatic conservative human generals who are also common to the Bolo stories. Many of the stories end with the Bolo nobly sacrificing their lives defending the humans, which is a downer since the Bolo is often the most likable characters in the story (example: A Relic of War). The Bolo series of science fiction has become a franchise, with quite a few short stories and novels written by other authorized authors. William Keith not only has written a few Bolo novels, he did some artwork as well.
The Bolo's main weapon is a "hellbore", which is a gigantic plasma weapon of a size usually only found on dreadnought starships. Often it has several slightly smaller hellbores as auxiliary weapons. The secondary weapons are batteries of something called "infinite repeaters", a named used for several different weapon types at the whim of various authors. Usually they are some species of railgun. I would assume the name comes from the the huge size of their ammo magazines. The Bolo's armor is composed of various types of handwavium with names such as durachrome. flintsteel, duralloy, and endurachrome. They also are defended by magic force fields known as "battlescreens", later versions not only defend but can actually convert hostile weapons fire into energy to recharge the Bolo's power systems.
Bolos have sophisticated communication systems, and can rapidly hack enemy computers and control systems given even the most constricted access. Bolos are also programmed with all military strategy and tactics from up-to-the-minute theories to historical records dating back to ancient Egypt. Bolos have artificial intelligence and are fully self-aware, using something called "psychotronic computers". Bolos can operate autonomously, but a Bolo with a human commander riding inside is a more effective combination. This is yet another example of the tired old trope that the intuition of a human being will somehow never be simulated by a computer, thus providing the humans with job security.
Bolos are organized in an elite unit called the Dinochrome Brigade. Humans generally trust and like Bolos, unless they are military leaders who feel that their job is being threatened.
Inspired by Laumer's Bolo stories, and by Colin Kapp's short story "Gottlos", Steve Jackson created a table-top boardgame called Ogre. First released in 1977, it has been released and re-released in one form or another up until 2013. In the classic scenario, the Defender player is guarding their command-post with an entire army composed of huge tanks, assault hovercraft, howitzers firing nuclear shells, and troops in powered armor. The attacker has one Ogre. And the Ogre wins more often than not. The major appeal to playing the Ogre side is the feeling of power, as the Ogre inexorably advances to kill the command-post through everything the defender can throw at it, leaving a trail of dead and burning AFV. Which probably explains why the game is so perennially popular, a feeling of power never goes out of style.
The balance is maintained by the game's rule structure. When the defender scores a hit on an Ogre, it just damages an Ogre component (like one of the many guns or a bit of a tank tread). When the Ogre scores a hit on a defender tank, the tank explodes into radioactive fragments. So the Ogre gradually gets whittle away while the defender's army melts like frost in the hot sun. It is a race towards total destruction.
In 2012 Steve Jackson games released a huge Designers Edition of Ogre, unfortunately already out of print. There is an inexpensive recreation of the original pocked game, a version to play with miniatures, a strategy manual, and a role playing game. The role playing game would probably be the most useful to a science fiction author.
Ogres are also artificially intelligent like Bolos. However they are not particularly noble, unlike Bolos. They are just massive invulnerable unstoppable killing machines. Even the troops friendly to the Ogres were a little frightened of them. The standard Ogre Mark V was armed with two main battery cannon, six secondary cannons, twelve anti-personnel weapons, and six long range missiles.
As an illustrator, I had the honor of creating the original artwork for the Ogre game.
From a military standpoint, Bolos and Ogres are nuke-bait. Such a concentrated piece of hostile military assets would be a prime target for, say, a 25 megaton city-killer nuclear warhead. In the Bolo novels they have magic anti-nuclear-explosion force fields to protect their "iodine colored flint-steel" armored skins. In Ogre, the defensive technology centers around some handwavium called "Biphase Carbide Armor", which can shrug off damage from tactical nuclear weapons. Without such defensive measures, continental siege units make no military sense.
A battle station, mobile assault platform, or orbital fortress is basically a huge warship armed to the teeth that has no engine. It has lots of offensive weapons. Much like the Death Star from Star Wars, but used more to defend planets instead of blowing them up.
A military space station is a military base that just happens to be in orbit instead of on the ground. It is used to support troops, house spacecraft, administer logistical aid, and the like. Generally it only has defensive weapons, but may be protected by a space navy task force. They are much like the U.S. military bases located in the continental United States.
See also Space Outposts.
If your government is in a war, and your army is too small, too unskilled, or otherwise inadequate, you have a problem. And the various mercenary legions will be quick to point out that they have the solution. For a price.
On the one hand mercenaries could ensure that your government wins the war. On the other hand, there are many risks involved. Mercenaries might be tempted by the fact that they are stronger than the government's army: turning on the people who hired them, smashing the state, and running off with the money. The enemy might bribe the mercenaries to switch sides. Not to mention all the dire things that can happen because the hiring government and the mercenaries are not on the same page with respect to the objective, allowable tactics, and/or collateral damage.
On the flip side, the mercenaries are running risks as well. The hiring government might not pay the agreed on fees. The government might run out of money. The government might figure that the sneaky way to avoid paying is to send the mercenaries into a suicidal battle (the Uriah Gambit). Or upon the winning of the war, the government might lead the mercenaries into a trap and use the government's soldiers to slaughter them all. Finally they could merely be on the losing side, the government who hired them could be no more, and they are suddenly all alone on a hostile planet with no way off.
Pay for the mercenaries can be "up-front" or "upon success only".
Up-front means the mercs get paid regardless of success. Generally it is paid half at start and the balance upon completion. Sometimes the contract specifies that part of the balance can be lost due to failure to achieve certain objectives.
Mercs can also be on retainer. This means a potential client pays the mercs money with the understanding that if the client decides to hire the mercs, the client has priority over other clients. The client also has veto power over contracts the mercs can accept while under retainer. Retainers can be secret, to give the client plausible deniability.
Mercs can require that the client post "repatriation bond." This is a sum of money the client places in an escrow account sufficient to ship the mercs off-planet. When the bond is invoked, the mercs become legal non-combatants and are given safe passage to the nearest starport. This can be used to ship mercs who are prisoners of war off planet. It can also be used by mercs if their client is a government which was overthrown.
Citizens and soldiers belonging to governments tend to despise mercenaries because they are, well mercenary. The Mercs are not fighting for reasons of patriotism, they are just in it for the money. Mercs can be fighting another mercenary legion in one war, and be fighting alongside the same legion in a different war. They are soldiers of negotiable loyalty. Although when you get down to the mercenary individual trooper level, their immediate loyalty is to their fellow comrades-in-arms.
Large mercenary organizations tend to refrain from treacherous conduct, since getting a reputation for being untrustworthy will cause a rapid drop in the number of job offers. Mercenaries are averse to strategies and tactics that inflict high casualties, since the soldiers are basically their stock in trade. When a unit from one mercenary legion surrenders to another legion, the capturing legion treats the unit fairly. After all, not only is it not personal (it's just money), but the tables might be turned one fine day. Again it is reputation, a reputation for massacring surrendering units will ensure that your troops receive the same treatment.
But in addition, if you start killing mercenaries who surrender, you working against your own self-interest. Mercenaries will surrender when there is nothing to be gained by further fighting. If you start killing surrenderees, the mercs will come to the conclusion there is nothing to be gained by surrender. They will then fight to the last, which is the functional equivalent of shoving your own troops into a meat-grinder. You will then have first hand experience with a "Pyrrhic Victory."
Currently here on present-day Terra, "mercenaries" are not legal. Under international treaties they are neither lawful combatants, nor non-combatants. Which means mercenaries have no protection under the Geneva convention, and any government or corporation who employs them are breaking the law. To do an end-run around this, governments use the transparent fiction of "private military contractors" (PMC). Legally PMCs are glorified shopping mall guards, pay no attention to the fact that they possess armored fighting vehicles, helicopters and warships (you know how mean those mall-rat teenagers can be). Legally PMCs are forbidden to shoot at the enemy, but they can do so if forced (wink-wink, nudge-nudge). So the government will tell the heavily-armed PMCs go to hill Whiskey-Tango but don't shoot at the enemy, unless, you know, they fire at you or if you see anything that might remotely be considered a threat.
Some mercenary legions are privately owned, others are actually parts of a government's army hired out for training and profit (or to avoid them being a drain on the military budget).
Mercenaries generally have no "home planet", they are migratory workers. This means they also have to transport their administrative structure, military dependents (families of the soldiers), and any other infrastructure. Threatening the merc's dependents is an extraordinarily bad idea. The mercs will drop whatever they are doing, locate the organization responsible, kill every man, woman and child associated, burn the buildings to the ground, and sow salt into the earth.
To a mercenary, their best friend in the entire universe is their personal weapon. Their second best friend is all the other members of their mercenary unit. Mercenaries are always drastically outnumbered by the combination of enemy troops and disdainful "friendly" troops, so mercs have to help their buddies and watch each others back. Their third best friend is their communication equipment. When you are outnumbered, you want to be able to call for help. And to know exactly where your fellow mercs are located. You also want them to know where you are located, so your artillery does not inadvertently shell you and so the medic know where to find your wounded body.
Mercenary leaders put a priority on having the best medical technology they can possible afford. The mercenary soldiers are the the stock-in-trade of the mercenary band. Each merc who is medically saved from dying or becoming so disabled they have to be discharged will save the band the large cost of training a new recruit. The mercs will also fight harder, knowing that advanced medical facilities are close at hand.
Another mission for mercenaries is "cadre." The client nation hires a small team of mercenaries as trainers for their national armies. Boot-camp for hire.
Some mercenary units specialize. There might be one that is mostly artillery or air defense. Others are more general purpose, with a balanced mix of all branches.
Mercenaries in science fiction include Jerry Pornelle's Falkenberg's Legion, David Drake's Hammer's Slammers, Gordon Dickson's Dorsai series, Glen Cook's Shadowline (which is an SF retelling of the Norse myth of Ragnarok), Andre Norton's Star Guard, John Dalmas' The Regiment, a few novels in the BattleTech series, and the webcomic Schlock Mercenary.
In David Drake's Hammer's Slammers universe, the hiring government and the mercs are kept honest by the Bonding Authority. This is run by an interstellar consortium of bankers who have the power to utterly destroy the economy of a planet or financially ruin a mercenary legion. The Bonding Authority is non-partisan, but when they enforce the rules, they are holding a huge club.
Military Intelligence gathers information, does analysis, and uses this to provide guidance and direction to commanders in support of their decisions.
Traditionally each branch of the military has their own intelligence departments, with the exception of espionage. James Bond does not work for the British army, he is with MI5. But all the British naval warships have on-board Navy radar operators.
The three levels of intelligence are
- Strategic Intelligence: focus on broad issues such as economics, politics, military capabilities, and intentions of foreign nations.
- Operational Intelligence: focus on supporting an expeditionary force commander (intelligence for a military campaign).
- Tactical Intelligence: focus on supporting forces in a battle and patrolling units (and debriefing the patrols to obtain information). Where are the enemy combat units, where are they going, are there any advantageous terrain features that can be used, those sort of questions.
The intelligence department is tasked with responding to the needs of the commander, keeping in mind the military objective and the overall plan for the campaign. The commander has information requirements. The intelligence analysis staff surveys existing information, identifies gaps in the knowledge, sends collection assets to fill in the gaps (for example Reconnaissance). The staff then produce analysis reports for the commander. This process is called Collection Co-ordination and Intelligence Requirement Management (CCIRM).
The four phases of the intelligence process are
- Collection: information is gathered from public sources, spyplane flyovers and spy satellites, internal or external map makers, published journals of various nations, spies posing as diplomats, spies posing as journalists, eavesdropping on radio and satellite transmissions, and decryption.
- Analysis: assessing adversary's capabilities and vulnerabilities (threats and opportunities), identifying the least defended or most fragile enemy resources (critical vulnerabilities).
- Packaging: Critical vulnerabilities are indexed for easy access by advisers and line intelligence personnel who aid the commander. Vulnerabilities are indexed by nation and military unit, along with a list of possible attack methods. Critical threats are maintained in a prioritized file. Important enemy capabilities are analyzed periodically, with the period length set by enemy's preparation time (time varies from monthly to in-real-time). Critical vulnerabilities and critical threats are given to the commander as lists of threats and opportunities.
- Dissemination: the analysis is sent out through databases, intel bulletins, and briefings.
In the Traveller role playing game, espionage is a part of the Imperial Interstellar Scout Service. Who originally only had the job of exploring newly discovered planets with an eye towards colonization.
Logistics is the art and science of moving ones military units to the battlefield and keeping them supplied with ammunition, food, propellant, plutonium, antimatter, and other necessary items. The old bromide is that amateurs talk about battle tactics while professionals talk about logistics. The sad fact of the matter is that logistics is about ten times more difficult than tactics, but a lot less glamorous. Far too many science fiction novels and games totally ignore logistics. Armies are always trying to increase its tooth-to-tail ratio, that is, the ratio of "tooth" troops whose job is neutralizing the enemy to the number of "tail" troops whose job is giving logistical support to the tooth troops. Another term for this is "reducing the length of the logistical tail". The idea is to make the number of "tail" troops as small as possible.
Space logistics include many more items than conventional ground army logistics. For instance, as a general rule a modern-day real-world ground army can count on a breathable atmosphere being locally available, but rocket troops on Luna cannot. The MIT Space Logistics Center identified the following (non-combat) supply classes: Propellants and Fuels, Crew Provisions and Operations, Maintenance and Upkeep, Stowage and Restraint, Waste and Disposal, Habitation and Infrastructure, Transportation and Carriers, Miscellaneous.
Space army units are kept supplied by convoys of cargo spacecraft. The cargo ships should be protected by escort groups if the enemy has convoy raiders engaged in commerce raiding using wolfpack tactics. Unlike wet navy ships, the space convoy ships have a difficult task in delivering the supplies from orbit down to the space army troops, running the gauntlet of hostile weapons fire while simultaneously preventing the supplies from burning up in reentry. Whether uncrewed canisters or crewed orbit-to-surface craft will be used is up to you.
How much tonnage would a troop-carrier spacecraft have? Hard to say. Isaac Kuo suggested that one could get a ballpark estimate by looking at USN amphibious assault ships. LHA and LHD amphibious assault ships are carriers which deliver a couple thousand marines and everything necessary to support them. They have a displacement of about 40,000 tons per 2,000 troops or about 20 tons per trooper.
Space navy ships are kept supplied by auxiliary units. These include Destroyer Tenders, Sub Tenders, Mine Sweepers, Aircraft Tenders, Fuel Ships (Oilers and Tankers), Supply Ships, Transports, Repair Ships, Hospital Ships, Colliers (missile supply ships), and Ammo ships. Those are wet navy ships, you'll have to adapt this to your space fleet.
This is one factor that makes a planetary invasion such a challenge. Presumably the local armed forces on the planet get their logistical ammo, food, and other supplies from the same planet. The invaders, on the other hand, have to rely upon logistical convoy fleets making the long journey from the invader's staging base. If the locals can get their convoy raiders in position to cut the invader's logistical tail, the invader is in real trouble.
In some science fiction universes, space task forces try to shorten the logistical tail by bringing along "factory ships" that can manufacture items such as ammunition on the spot, given raw materials from the local asteroid belt. Factory ships will be mother-ships to small fleets of rapid mining vessels, and ships designed to scoop deuterium and other useful elements from local gas giants. You can find this in William Keith's Galactic Marines series, Steve Gallacci's Albedo Anthropomorphics, and the anime GunBuster.
The military units being supplied by the logistics tail will often attract "camp followers." These are civilian hangers-on who officially or unofficially see to needs of the troops. Official camp followers could be civilian contractors supplying official items like fuel, signal flares, and fragmentation grenades. Unofficial camp followers supply services like cooking, laundering, liquor, nursing, sexual services, and sutlery. For a price. Unofficial camp followers are notorious for after-battle scavenging and looting.