Space Combat in Conjunction: Basic Assumptions

This is sort of a digression from our Building a Space Navy series, but a necessary one.  In order to finish filling out the Building a Space Navy chart, we will eventually have to add in some actual ships and rockets and stuff.  For their capabilities and armaments and other particulars to make even a lick of sense, we must establish what design assumptions are in place in the Conjunction setting.  That's what this post is about.

Dis iz Doin it Rong.

As always, special thanks to Rick Robinson for waxing lyrical on these topics on his Rocketpunk Manifesto blog, and Winchell Chung Jr. for his indispensable Atomic Rockets website.  I will be referencing their work throughout.

Assumption #1: Purple vs Green is a Draw

For those of you not familiar (lucky!) with "Purple vs Green", it refers to the debate among Hard SF fans about which type of weapon system is better: Lasers or Kinetics?  The subject is passionately discussed in a variety of places.  This blog is not one of them.  For an in depth analysis, Rick Robinson has a couple of posts that Atomic Rockets already linked to, so that's where you should start, with further discussion here.

In the Conjunction universe, a laser capable of destroying any and all kinetics attacks is too expensive to build, especially in terms of power.  While a big laser Combat Mirror would have the power to vape anything massing less than a small asteroid, the thing is impossible to aim fast enough to do the job, so there you go.  Contra wise, with enough small lasers massed on a single side, there is no amount of kinetics capable of overwhelming a determined defense.  The cost in delta-V is to high to move that much mass.


This is how you do it.

This is important to the setting for two reasons:  First, having only one type of weapon system dominate is kinda boring.   By having both swarms of Kinetic Kill Vehicles and eye-burning lasers, you get variety to spice up your setting.  Two, by making both banks of lasers and swarms of kinetics just about even, things like maneuvering, tactics, fire discipline and other stuff you can lump under "human factors" become important.  After all, it it's just a matter of "whoever has the most lasers/missiles wins", then why write about it?  With beams and kinetics evenly matched, the choice of which one to use, under which circumstance, can be critical.

Assumption #3: The Light-Second Limit

This isn't a real limit, but a practical consideration that comes from the first assumption.  Basically, in the Conjunction universe, you can't effectively remote control something more than a light-second away.  By "effectively control" we mean, things like evasive maneuvers, coordinated fleet movements, synchronized fire from lasers, and the direction of flights of missiles.  What this means is that even the largest, most sophisticated swarm of missiles and autonomous combat craft will have a control ship with real people somewhere within three hundred thousand kilometers.    The Light-Second Limit also refers to the fact that the closest distance you can get to an attacker and still reasonably dodge a laser is a light-second, because it gives you (duh) a second's time to move.  You cannot, of course, actively dodge, because by the time you see the laser, it's cooking you.  But if you stay moving around, the laser's targeting system can only see where you were a second ago, due and then guess where you'll be by the time the laser actually gets there.  So, the goal of the attackers is to get inside the light-second range, while the defender will want to keep the attackers at least a light-second out.

Assumption#3: Most Combat Takes Place in Orbital Space

Beware smiling patrol craft...

In a realistic setting, where's all the interesting stuff going to be?  In orbit, of course.  That's where ninety percent of all live fire incidents in the Conjunction universe have taken place.  This type of environment is a loathsome cross between brutal house-to-house urban fighting and dreadnaughts in the open ocean, only at 7 km/s in free fall.  I chose those two examples most deliberately;  In orbital space, you can fight over the horizon, and you can hide in a crowd.  There is a horizon in orbital space for the simple and unavoidable reason that there is some planetary body in the way.  because of this, unless there is an existing satellite network you can use, you will need scouts to check out the opposite side of the planet and probably a relay craft as well to insure communication.   Or you can use smaller, more maneuverable Patrol Craft that have the crew - and the authority - to make command-level decisions.  You really need that level of authority because of the other consideration, where a baddie can hide in the debris, the sovereign orbits of another nation, or even hide on or in space stations and spacecraft that are otherwise kosher.  In order to prevent a diplomatic incident, you would need an organization with broad powers to stop and search and international oversight.  An organization like the UN&C Space Force and Espatier Corps, for example. 

Aassumption #4: The Staring Contest - Lasers Against Lasers

Again, thanks to Rick Robinson for pointing this out.  You can armor a spacecraft, obviously, you can even armor radiators, if you make them out of the right stuff.  But you can't armor the lenses of your own lasers, therefore, the lasers themselves are the best target on a spacecraft.  The thing is, both sides know this.  This is why those nifty swarms of KKVs also pack a handful of laser tipped missiles that home in on the defenders lenses when they light up to break up the swarm.  Given a close enough range, a disposable pulse laser can in fact burn a hole in those nice, heavy lasers on our space warrior's bad-ass battlestars that will have to be put out of action and repaired.  Assuming, of course, that you get the chance.

Let us remember, however, that only the mirror will be kaput.  The laser generator, which is the heart of the system, will probably not be damaged.  Spacecraft will probably have multiple emitters for a single laser generator, so they can remain combat effective even with the loss of a mirror or two.  This is also a plus in that larger mirrors can be fixed-mounted in multiple places for a given generator, while a turret is unavoidably smaller - and therefore of shorter effective range - than a fixed mount of the same length.

Because of the cost of a laser system of this type, most lasers are mounted on non-disposable spacecraft.  Manned spacecraft have the opportunity to perform damage control and replace burned-out mirrors.  But probably not during a battle - it will all be over quickly, one way or another.

You may have other things to think about.

There will be a couple other posts in this category as we continue with the main series of articles.  Now that we've established our basic assumptions, we can discuss the types of spacecraft that our "space navy" will need to deploy.  We can then discuss some of the combat doctrines that will be in force in Conjunction.  But before all that, we will discuss fleet posture in our next Building a Space Navy post, in order to establish the final group of criteria we need to know before we design a fleet.

See you then!