Wednesday, March 11, 2015

Space Combat in Conjunction: Design Considerations

We've come a long way in our discussions about building a space navy forces and the combat considerations thereof.  At this point, we can start actually designing some spacecraft, or at least start focusing in on the specific needs our space forces will have to address when designing spacecraft.

First off, and remember that in the case of Conjunction, this is the most important, is the fact that the UN Space Force is not a military in the conventional sense.  It is a law-enforcement body primarily and a search and rescue service secondarily.  Military action, as will occur in the dark years of the Great Conjunction War (or whatever they decide to call it) are all new and uncomfortable roles forced onto the majority of the commanders, mission planners and spacecraft designers of the future.

That last part brings up an interesting point, however:  Spacecraft have a horrendous amount design time, and spacecraft as big and complex as the ones in  Conjunction can easily take years to develop and build.  This fact, along with the multi-year travel times from the Inner System to the combat theater, will make it all to likely that the spacecraft developed for the Conjunction War will not be available until the war is over.  This leads to our first design consideration, one mentioned by Heinlein in the past: The weapons of this war were designed to win the last war.

Specific to Conjunction, the weapons of this war weren't made for war at all, but police actions and purely theoretical combat scenarios that our ornery Jovians have no moral requirement to follow.  Hilarity ensues.
For a given value of "Hilarity"
So, what would the UNSF have available, at the start of the war, and what would they have in the slips or on the drawing board?  As far as what the UN have available, it's mostly Patrol Rockets like the Class-A, little utility rockets like the Cygnus, and the big, trans-Chronian transports.  The Class-A and the Cygnus have been mentioned before - just click on the link for a reminder.  The big transports need a few words, as these classes of spacecraft will have been well established prior to the war and really are the backbone of not only the UNSF, but of all space travel in Conjunction.

 Annie and Chris mention the Mekong in the comic strip, as the ship the two will have share for the two year trip to Saturn.  This is a River-class logistical ship, of a kind similar to the ones Rick Robinson describes in his Rocketpunk Manifesto.  However, the Mekong is not a military ship; it is a civilian-run transport that is heavily subsidized by the UN in exchange for ferrying personnel and patrol craft across the black.  This kind of compromise is to be expected, given that the UNSF is not a military, is not at war, and is only mandated to keep the peace.  It also has to do this in a sphere of operations roughly a billion kilometers in diameter, They can't have a large number of purely peacekeeper spacecraft of this size,  It isn't cost effective. 

That being said, there are a lot of convoys moving between Titan and Terra in a constant stream of methane, and you can't just station a fleet in the shipping lanes, so each convoy needs some escort, and that escort needs the delta-v and the life support to move across a large chunk of interplanetary space.  Therefore, I postulate the creation of a logistical carrier and a stripped-down variant made for civilian use.  The UN Carrier - call it the Gagarin class and name it after astronauts, will be armored and armed with large defensive lasers, carry a half-dozen patrol rockets  a dozen or so Cygnus rockets, and two crews for itself and each rocket it carries.  That's a lot of people, but a spacecraft of this type is more starbase than spaceship anyway.   In addition, the Gagarins will need large repair spaces for the patrol craft, a fleet reserve of propellant, and space to carry any kinetic vehicles that will be used in combat.

The civilian version - our River-class - will only carry a pair of patrol rockets, maybe for utility craft, a correspondingly smaller propellant reserve, and most likely no kinetics for deployment during travel.  weather or not they carry kinetics as cargo depends on how easy it is to manufacture KKVs at Saturn and weather or not the UN wants it's colony to make its own WMDs or not.

How do these behemoths move between the worlds?  Chemical rockets - or even nuclear ones - are right out as they are too inefficient.  A nuclear electric drive, delivering constant boost at minimal acceleration, is the best option.  The disadvantage to such a drive is that minimal acceleration thing.  To alleviate this, the logistical craft could have NTRs - after all, they got the reactors anyway - and thus be able to hit the gas when needed.  In fact, there is even a way, albeit a very expensive and inefficient one, for our logistical craft to move from the inner system to a hot spot in the outer worlds much faster than normal.  This involves the technique upon which naval legend Chester Nimitz credits the American victory over the Japanese in the Pacific - underway replenishment.

To perform underway replenishment, we need another class of spacecraft: The Tanker.  This need not be too complicated, as ice is a more effective medium for transporting hydrogen than hydrogen is.  As a purely practical matter, the propellant tanks of the interplanetary ships will have to be full of water anyway, as you can't expect to carry cryogenic hydrogen under pressure for two years.  So our tanker will basically be a gigantic plug of water ice with a nuke at one end and an electrolyzer at the other.  The heat from the nuke serves to melt the ice for conversion into propellant.  The logistical craft and the tanker will have to dock nose-to-nose in order to prevent irradiating one another, and will spin around their common access to make enough force to let the propellant pump in between the two.  I'm not a hundred percent on this, but I don't think the pair of craft could dock nose-to-nose under acceleration, seeing as their rumps would be at cross-purposes.
Two words: High Maintenance.

It goes without saying that the logistical craft have spin gravity.  This is in the form of two rings, spinning in opposite directions to cancel the gyroscopic effect.  I imagine that the rings will sit inside a huge, globular water tank - that fleet reserve I mentioned - as a way of making the propellant do double duty as cosmic radiation shielding.  Because the ship will sometimes spin end-over-end while taking on reaction mass, the logistical craft must either halt spin on the gravity rings - a pain in the butt - or use a species of Winchell Chung's Ezekiel's Wheel.   If this looks like it could be a maintenance nightmare, let me reassure you - yes, yes it is.  Any spin-gravity system is high maintenance, and one that must spin along two axes is high maintenance squared.   However, with a large number of crew, literally half of which will be out rotated out at a time, lengthy and complex maintenance cycles are a feature, not a bug.

 So, we have patrol rockets, utility craft, logistical carriers, and tanker already available for the UNSF at to play around with.  What about what is on drawing board?  Mission planners and saber-rattlers are all too aware that the Great Conjunction will come and put the UN&Cs most troubling possession in between the oil-hungry masses of the inner system and the oil-rich oceans of Saturn's moon, Titan.  They must have made some plans ahead for the eventuality that Jupiter, which in our scenario is self-sufficient in terms of power and many other commodities, is ready to go its own way.  What have the UN developed to counter this?

Enter the Laserstar.

Even for Conjuction, my Laserstar concept is an oddity in the annals of space combat.  Usually the biggest, most heavily armed and armored ship is the "battleship" right?  In this case our basic assumptions about combat and the tactical considerations thereof make the Laserstar the opposite of that: The ultimate defensive system in our arsenal.  It boasts a Violet wavelength laser with a twenty meter mirror on the nose and six ten-meter mirrors on its flanks.  These monsters are uncrewed, controlled by on-board AI, and nuclear powered.  They are named after the native countries of the first astronauts and cosmonauts, with The Union of Soviet Socialist Republics being the flag ship.  The Laserstar's purpose is to provide cover fire for the logistical craft it is assigned to defend.   With the number of lasers on these leviathans, the goal is to make a successful kinetic attack impossible.
It's the CCCP for short.  Her friends call her Cee-Cee.

That's a lot of ships.  A lot of different ships.  And given the nature of space and its peculiarities, how they come together as a cohesive fighting unit will be equally peculiar.  It is also the topic of our next post.

A few announcements:  I will not be posting the week of the twenty-second.  It's the week of my wife's annual vacation and our fifteenth wedding anniversary is the 25th and I don't wanna work on stuff.  Also, there will be a moratorium on Conjunction based articles and comics throughout the month of April, as I will be participating in the A-to-Z Blog Challenge.  Our offerings for the Challenge will be an alphabetical series of Star Morph maps.