As you probably already know, "strategy" refers to the science of successfully fighting an entire campaign or war, while "tactics" refers to the science of successfully fighting a single battle. Predictably some military strategy and tactics are general enough to apply to interplanetary combat, while others do not work at all in the space environment. Sun Tzu's The Art of War, for instance, is general enough to work splendidly. Others will fall afoul of unique features of spatial combat, like the lack of stealth, and the mathematical predictabilty of launch windows and arrival times.
There is a good discussion on orbital tactics at the Rocketpunk Manifesto.
There is a good list of unscientific hackneyed tropes with respect to starship combat in the TV Tropes listing Standard Starship Scuffle.
A basic but often overlooked feature of interplanetary combat is the fact that it is in three dimensions, not two. Think "airplane dogfighting", not "wet-navy battleship duel".
Actually it is even more extreme than airplane dogfighting, since airplanes have a strict limit of how far up or down they can go. Spacecraft have no limit.
Orientation has no limit as well. In Star Trek you never see one ship approach another with one ship flying "upside down", but in reality there is no reason not to. In many SF space combat games, one can change the ship's orientation in order to allow different sets of weapon turrets to bear on the enemy.
Things become even more complicated if you are an admiral or sky marshal who is responsible for all the ships in a battle, as opposed to a captain who just commands their own ship. Admirals generally control the battle from a room equipped with a Big Board, called an Operations Room or a Combat Information Center (which is NOT the bridge). If you are a lucky admiral the battle occurs near a well defended planetary base or orbital fortress. This allows you to dictate tactics to your task force without having to worry about being personally attacked by rude enemy ships. But if the battle happens out of communication range of a cozy fortress, you will have to risk your pink hide in the battle. You will be in a "flagship", a well defended and strongly armed warship carrying an operations room. This is for C2, C3, C2I, or one of the other C4ISTAR military functions. The flagship captain will take care of running the flagship while the admiral concentrates on running the battle.
Naturally the battle will take a catastrophic turn for the worse if the admiral is killed and/or the flagship is destroyed. You should locate the operations room deep in the armored core of the spacecraft. That absurd exposed bridge on the top of the Starship Enterprise would have been shot off a long time ago. The same goes for the bridge on Space Battleship Yamato.
For more information refer to The Great Heinlein Mystery: Science Fiction, Innovation and Naval Technology by Edward M. Wysocki Jr. If you want the real inside dope, refer to 1945 US Navy CIC manual.
The Combat Information Center is a little difficult to understand if you are not a member of a military wet navy.
It is NOT the ship's bridge, even though they are commonly arranged much the same as the fictitious "bridge" of Star Trek's Starship Enterprise (this is because real-world CICs were inspired by Matt Jeffries's design, see below). In the real world a wet navy ship's bridge only has a couple of stations. The Starship Enterprise has its bridge located in its CIC for dramatic reasons (the "bridge" is the navigation and helmsman stations, that red console Sulu and Chekov sit at).
It is NOT the fleet command room, though it is often used for one. In reality, non-flagship vessels have their own CICs.
As Christopher Weuve puts it:
All vital "intelligence" (data) from sensors, scouts, intelligence agencies, central command, other ships, etc. pours into the CIC. The Evaluator's duty is to analyze and evaluate all combat information. They filter the information, deciding what is important and what is noise. They pass the filtered information with suggestions on tactical situations to the Captain and the Flag. The information also goes on the Big Board tactical display.
In a stunning example of science fiction innovation, the very concept of an CIC came from a science fiction novel. In his novel Gray Lensman, legendary author E. E. "Doc" Smith postulated a huge flagship called the Directrix. It contained a monster operations room centered around a seven hundred foot "tank" 3D display, capable of tracking several billion warships on a map of the galaxy. At the Technovology website, Mark Charters mentions a letter to Astounding magazine. Editor John W. Campbell stated the acknowledgement of Captain Cal Lanning that Smith's ideas were used extensively in the design of US Navy warship's Combat Information Centers. At the TV Tropes website, they allege that the Directrix was the inspiration for Chester A. Nimitz to use a similar system for directing fleet operations during the Battle of Midway. After that, everybody started using them, which is how it became a troupe in the first place.
The bridge of the classic Star Trek Enterprise was designed by Matt Jeffries. In a second stunning example of science fiction innovation it influenced the design of the U.S. Navy master communications center at NAS San Diego. On US naval vessels, their bridge design does not look anything like the bridge of the Starship Enterprise, but the Combat Information Center in a navy vessel does have some resemblances (mostly the Captain's chair in the center of the room). Again, refer to The Great Heinlein Mystery: Science Fiction, Innovation and Naval Technology by Edward M. Wysocki Jr.
A ship's bridge is just a two-station place (navigation and helm) mainly meant to control the movement of the ship. Usually the captain is not even present, unless some critical maneuver is underway. Back in the age of steam, the bridge did not even have any controls. They would instead give commands to the engine room where the physical controls are located. They'd either use speaking tubes for verbal commands, or use a ship's wheel and a engine order telegraph. Later the power of electricity allowed the actual controls to be located in the bridge. However, even to this day warships tend to have the physical controls for the weapons to be located deep in a protected area of the ship, not on the exposed. bridge. This allows the weapons to keep on fighting if the bridge is destroyed. Since a spacecraft does not need the visibility of an exposed bridge, it too can locate the bridge in a protected position.
As previously mentioned, Matt Jeffries designed such a logical arrangement for the bridge of the Starship Enterprise that the US Navy studied it when they were designing their command centers. The main idea they favored was the captain/evaluator in the center, where they can turn to look over the shoulder of any of the work stations, plus the idea of a Big Board where currently critical information can be displayed.
Combat Information Center from a U.S. Navy Guided Missile Destroyer DDG51 class, courtesy of Christopher Weuve.
Blue are chairs. Yellow are desks. Red are CRT/Flatscreen monitors. Magenta are rear-projection monitors ("e" and "f"). Lower case letters "a" through "h" are to allow one to match up the deck plans with the photograph. In the photo, right above "e" is the red display showing ships course, speed, and screw (propeller) revolutions. The backs of the chairs have pouches containing manuals for that control station. Note that chairs are bolted to the floor.
Bridge of the starship Enterprise, designed by Matt Jeffries. This is a combination of a bridge (helm/navigation) and a CIC. Captain/Evaluator is in the command swivel chair in the center. All station are arranged so captain can look over the sholders of each operator and examine their displays. In the front is the big board viewscreen.
Operations rooms are centered around some sort of tactical display, the aforementioned Big Board. In World War 2, you had huge tables with models of soldiers, tanks and aircraft, being moved about by military women using croupier sticks. You can see this in almost any movie about the Battle of Britain, depictions of the famous Battle of Britain Bunker. Another classic item is the grease-pencil annotated polar plot on an edge-lighted transparent plotting board. You can see that one in places ranging from old Voyage to the Bottom of the Sea episodes all the way up to Star Wars A New Hope and The Empire Strikes Back. Still later a Radar or Sonar cathode ray tube with the sweeping line became popular. Those are still used with air-traffic controllers, with aircraft annotation and everything. Then came NASA mission control and quite a few James Bond villains who were fond of video walls composed of multiple monitors displaying all kinds of different data. The Starship Enterprise had a classic Big Board display in the front. Finally, science fiction has postulated that futuristic combat spacecraft will have some species of holographic display (generally spherical) showing the location and vector of all friendly and hostile spacecraft in the battle. The display will probably have additional information, see Long Scan
For more information refer to The Great Heinlein Mystery: Science Fiction, Innovation and Naval Technology by Edward M. Wysocki Jr. If you want the real inside dope, refer to 1945 US Navy CIC manual.
Keep in mind that when Gray Lensman was written, computers were little more than electronic abacuses, there was no such thing as "computer graphics". The described tank was all analog, with physical lights for all the ships.
In warfare, a Combat Theaters is an area or place in which important military events occur or are progressing.
What we are mainly interested in here is the classification of such theaters. This determines the design of the military assets and the strategies & tactics used, e.g., you ain't gonna be using a sea-going naval battleship in the Battle of the Bulge to crawl through the densely forested Ardennes region of Belgium in order to cross the T with the US infantry line. You use ground units and ground tactics in a ground theater, and naval units and naval tactics in a sea theater.
Ray McVay points out that the US Navy uses color names for the theaters they operate in.
- Brown Water Naval Ops are conducted in rivers
- Green Water Naval Ops are conducted along shores and coastlines
- Blue Water Naval Ops are conducted in the high seas
Orbits around Terra (geocentric) are sometimes classified by altitude above Terra's surface:
- Low Earth Orbit (LEO): 160 kilometers to 2,000 kilometers. At 160 km one revolution takes about 90 minutes and circular orbital speed is 8 km/s. Affected by inner Van Allen radiation belt.
- Medium Earth Orbit (MEO): 2,000 kilometers to 35,786 kilometers. Also known as "intermediate circular orbit." Commonly used by satellites that are for navigation (such as Global Positioning System aka GPS), communication, and geodetic/space environment science. The most common altitude is 20,200 km which gives an orbital period of 12 hours.
- Geosynchronous Orbit (GEO): exactly 35,786 kilometers from surface of Terra (42,164 km from center of Terra). One revolution takes one sidereal day, coinciding with the rotational period of Terra (on other planets the altitude depends upon that planet's particular rotational period). Circular orbital speed for Terra is about 3 km/s. It is jam-packed with communication satellites like sardines in a can. This orbit is affected by the outer Van Allen radiation belt.
- High Earth Orbit (HEO): anything with an apogee higher than 35,786 kilometers. If the perigee is less than 2,000 km it is called a "highly elliptical orbit."
- Lunar Orbit: Luna's orbit around Terra has a pericenter of 363,300 kilometers and a apocenter of 405,500 kilometers.
Geosynchronous Orbits (aka "Clarke orbits", named after Sir Arthur C. Clarke) are desirable orbits for communication and spy satellites because they return to the same position over the planet after a period of one sidereal day (for Terra that is about four minutes short of one ordinary day).
A Geostationary Orbit is a special kind of geosynchronous orbit that is even more desirable for such satellites. In those orbits, the satellite always stays put over one spot on Terra like it was welded atop a 35,786 kilometer pole stuck in the ground. For complicated reasons all geostationary orbits have to be over the equator of the planet. In theory you'd need only three communication satellites in geostationary orbit and separated by 120° to provide coverage over all of Terra.
All telecommunication companies want their satellites in geostationary orbit, but there are a limited number of "satellite slots" available due to radio frequency interference. Things get ugly when you have, for instance, two nations at the same longitude but at different latitudes: both want the same slot. The International Telecommunication Union does its best to fairly divide up the slots.
The collection of artificial satellites in geostationary orbit is called the Clarke Belt, again named after Sir Arthur C. Clarke.
Note that geostationary communication satellites are marvelous for talking to positions on Terra at latitude zero (equator) to latitude plus or minus 70°. For latitudes from ±70° to ±90° (north and south pole) you will need a communication satellite in a polar orbit, a highly elliptical orbit , or a statite. Russia uses highly eccentric orbits since those latitudes more or less define Russia. Russian communication satellites commonly use Molniya orbits and Tundra orbits.
About 300 kilometers above geosynchronous orbit is the "graveyard orbit" (aka "disposal orbit" and "junk orbit"). This is where geosynchronous satellites are moved at the end of their operational life, in order to free up a slot. It would take about 1,500 m/s of delta V to de-orbit an old satellite, but only 11 m/s to move it into graveyard orbit. Most satellites have nowhere near enough propellant to deorbit.
Lagrangian points are special points were a space station can sit in a sort-of orbit. Lagrange point 1, 2, and 3 are sort of worthless, since objects there are only in a semi-stable position. The ones you always hear about are L4 and L5, because they have been popularized as the ideal spots to locate giant space colonies. Especially since the plan was to construct such colonies from Lunar materials to save on boost delta V costs. The important thing to remember is that the distance between L4 — Terra, L4 — Luna, and Terra — Luna are all the same (about 384,400 kilometers). Meaning it will take just as long to travel from Terra to L4 as to travel from Terra to Luna.
Having said that, Earth-Luna L2 (EML2) is often suggested as a place to park lunar ice and other resources boosted into Lunar orbit.
If the planet the station orbits has a magnetic field, the planet probably has a radiation belt. Needless to say this is a very bad place to have your orbit located, unless you don't mind little things like a radiation dosage of 25 Severts per year. And that is for Terra, Jupiter's radiation belts are a thousand times worse. In 1973 Pioneer 11 was surprised by radiation levels around Jupiter ten times greater than NASA had predicted. This is why Pioneer did not send back photos of the moon Io since the radiation belt had fried its imaging photo polarimeter. Work on the Voyager space probe came to a screeching halt as they frantically redesigned it to cope with the radiation, but still be assembled in time for the launch window.
Terra's zone of glowing blue death is called the Van Allen radiation belts.
The Inner Belt starts at an altitude from 400 km to 1,200 km, depending on latitude, and ends at an altitude of about 6,000 km, with its most lethal area 3,500 km out. The South Atlantic Anomaly can potentially disrupt satellites in polar orbits, but usually does not pose a problem for manned spaceflights. Except for the ISS. The radiation is high-energy protons (400 MeV).
The Outer Belt ranges from 13,000 km to 60,000 km, with its most lethal area 27,000 km out. The Outer Belt is affected by solar winds, and is thus flattened to 59,500 km in the area directly between the Earth and the Sun, and extends to its maximum distance in the shadow of the Earth. The radiation is high-energy electrons (7 MeV).
A safe channel exists between the belts from 9,000 km to 11,000 km.
Hostile space forces intent on invading or investing a planet will wish to use the planet's orbital space for dropping invading troopers onto the planet, and softening up the planet (and supporting said invading troopers) with orbital bombardment. The planet will be resisting with defending fleets in orbit, orbital fortresses and planetary fortresses.
But as you can see above, orbital space over an industrialized planet is going to be crowded with civilians and commercial space stations. Some of which will be military in disguise.
Also keep in mind that orbital communication and spaceport civilian assets are a substantial part of what makes an industrialized planet valuable. Think about the drastic hit the economy of Terra would suffer if telecommunication satellites were destroyed. Invaders who want to seize a planet because it is valuable would do well to avoid damaging what makes the planet valuable.
As Rick Robinson observes above: Ships in orbital space do not encounter each other as ships on crossing orbits in deep space do, one flash-past and off they go into the void on their separate paths, needing dozens of km/s of delta v to reverse track and re-engage. Not quite like jousting, but there are some similarities.
In deep space there generally is no terrain, no forest or hill to anchor your flank so to speak. In Ken Burnside's Attack Vector: Tactical players can use buckshot-like kinetic energy weapons to create their own terrain. In effect, the buckshot is used to herd your opponenet into vectors advantageous to you. Your weapon fire creates "terrain" by rendering certain vectors dangerous to your opponent. Your opponent will be faced with you saying "Heads - I win, Tails - You lose", as they decide if they'd rather suffer the buckshot damage or take a chance on whatever fiendish trap you have laid in the clear vector.
"Wet-navy" tactics on the ocean are not interplanetary-navy tactics, but some principles still apply. Christopher Weuve has a "must read" list for anyone who wants to understand strategy and tactics as applied to science fiction.
Some Principles of Maritime Strategy by Sir Julian Corbett. Go to the appendix and read the "Green Pamphlet". As Mr. Weuve says "...which shows you how to think about using a navy. Everything you need to know about Maritime Strategy, in about 30 pages. VERY good stuff."
Edward Luttwak's The Grand Strategy of the Roman Empire. "...which shows you how to think about borders. (Stephen Donaldson's Gap series would have been a lot better had he read this book.)" This book is also very useful if you are writing a science fictional future history. Just read through it, replace "planet" for "city-state", "starship" for "naval vessel", and "stargate" for "road", and your future history writes itself.
Wayne Hughes's Fleet Tactics. "...which shows you how to think about attrition and analyzing tactics."
Frank Uhlig's How Navies Fight. "...which is a book of examples of how different navies have been used."
James George's History of Warships. "...for discussion of why naval vessels are they way they are."
Ken Burnside notes how capabilities drive tactics:
Ken goes on to note that a more realistic set of technologies would have ship drives that were much weaker and laser weapons that had greater ranges. Unfortunately this results in very boring interplanetary combat.
On rec.arts.sf.science James Nicoll started the following interesting dialog: