Welcome back to my Aurora Tutorial. We're currently discussing combat, specifically warship design. Last time, I covered missile defense with beam weapons, but now it's time to shift to the system I usually base my defenses around: anti-missile missiles (AMMs). AMMs have benefits and drawbacks relative to beam defenses. On one hand, I've generally found them to perform better than beams and to be more effective, particularly in the face of a massed attack. They're also much easier to upgrade, as you can just swap in a new missile with improved performance. On the other hand, AMMs can get expensive, and the ships firing them have limited ammo capacity. If they run through their magazines before the enemy does, you're dead.

So what is an AMM? Like beam defense, AMM defense is a numbers game. You need the smallest feasible missile, fired at the highest possible rate, so the obvious result is a size-1 missile¹ with a strength 1 warhead,² optimized for the highest hit probability possible and with sufficient range to match the sensor/fire control combination you have planned. As such, you should probably design the electronics first. Missile fire controls are built in the same tab as active sensors, and have the same range characteristics. On average, a typical MFC has about the same range as a search sensor 3 times its size. I usually try for a size 3-4 sensor, and an MFC that either matches it in range or is a little bit better. I do this because I expect later missile defense ships to have better sensors, and a slightly oversized MFC lets the older ship take advantage of the extra range. So going back to the AMMs, a missile's hit probability is equal to (missile speed*maneuverability*0.1)/target speed. Maneuverability is based on how much space you've put into agility³ so you need to find a balance between spending space on the engine and spending it on agility. Read more...

Today marks the 104th anniversary of the Battle of Jutland, the climactic naval clash of the First World War. This is a topic I've discussed at some length already, so it's worth turning our attention to the background the battle was fought against, the British blockade of Germany.

The headquarters of the Northern Patrol, who enforced the blockade

While most think of globalization as an inherently modern phenomenon, it was almost as prevalent in the first decade of the 20th century as it was in the first decade of the 21st. Britain and Germany were two of the leading players in the new global economy, deeply tied into international trade. Britain got over half of its food from overseas, while Germany imported a quarter, to say nothing of the essentials necessary to sustain an industrial economy. Each rightly deduced that the other was vulnerable to attacks on its commerce, although they set about it in very different ways. Germany, knowing that it was outmatched at sea, planned a classic guerre de course based on commerce raiding by converted merchant ships and cruisers. This ultimately failed in the face of British innovations in Command and Control, forcing them to switch to submarines for their attacks on British commerce. Read more...

It's time once again for the Naval Gazing open thread. Talk about whatever you want, even if it's not military/naval.

Amazon Prime seems to be the service for naval/military movies. (I promise I am not getting paid by Jeff Bezos.) Recent ones I've watched include Run Silent, Run Deep, the Final Countdown and Strategic Air Command. The first is based on the novel of the same name, and is decent, if not quite as good. The Final Countdown is conceptually extremely silly, but has lots of very cool 1980-era carrier ops footage. The only thing that really annoyed me was in the scene where they're launching the strike against the Japanese fleet. Why did you fly off three Prowlers? They won't get their first air-search radar for another 6 months! And Strategic Air Command is extremely mediocre of plot, but has a ton of extremely nice aerial and ground footage of B-36s and B-47s.

2018 overhauls are There Seems to be Something Wrong with Our Bloody Ships Today, Millennium Challenge 2002, Auxiliaries Part 1, Falklands Part 2, my review of The New Maginot Line and the first three parts of my Jutland series. 2019 overhauls are the pictures of my early visits to museum ships, the Falklands glossary, the Montana class, So You Want to Build a Modern Navy - Aviation Part 4, Battleship Aviation Part 2 and Shells at Jutland.

Last time in my Aurora tutorial series, we looked at the basics of beam weapons and warship design. But beams are not the only threat out there, and the hardest thing for new players to get is usually missile defense. I once ran a multi-player game where several of my friends (unfamiliar with Aurora) were each given a race and turned loose. I also ran my own power, which I attempted to nerf to keep things relatively even, and use as a wildcard. As it turned out, I significantly underestimated how much nerfing I needed. When one of them tried to attack me, I managed to destroy his fleet with essentially zero difficulty despite a significant technological disadvantage. I knew missile combat and he didn't, so his defenses were ineffective.⁴

Despite this, building an effective missile defense isn't particularly difficult. It just needs to be taken seriously, because the AI opponents can throw a lot of missiles. For beam defenses, this basically means that you need to optimize for the maximum number of hits (of any damage, because missiles are killed by 1 damage) at point-blank range against fast-moving targets. The math on all of this is made easier by the fact that pretty much everything scales linearly. In particular, if a target is moving faster than the attack's tracking speed,⁵ the chance to hit is equal to the chance for that range times (tracking speed/target speed). At any given tech level, it's easy to build effective missiles that are faster than 4x racial tracking tech,⁶ so it's best to just treat the turreted weapons as 4X more likely to hit for analytical purposes. There's a box on the right side of the ship-design window that lets you set the speed and range the FC to-hit values will display for. Read more...

The Tomahawk missile has been one of the most influential developments in naval warfare over the past half-century. While it began as a nuclear missile, and was soon developed for anti-ship roles, the most famous version of the Tomahawk, and the only one to remain in inventory today, is the conventional TLAM (Tomahawk Land Attack Missile). The TLAM gives conventional surface ships and submarines the sort of inland reach and firepower that was previously only available to carriers.

Iowa launching a Tomahawk

Developing the TLAM wasn't as simple as mating the guidance system from the nuclear version with the warhead of the anti-ship Tomahawk. While the TERCOM⁷ guidance system was perfectly adequate for a missile with a nuclear warhead, it couldn't get the missile close enough for the 1,000 lb warhead to be effective. Another, similar technique known as DSMAC (Digital Scene Matching Area Correlator) was used to bridge the gap. This was essentially a camera on the missile that would provide an image to be compared to a stored file of processed satellite imagery. By matching the two, the missile could figure out where it was with even greater precision, and the technique is fairly robust against changes within the image. This is possible because the missile isn't looking for the target directly, but is instead using the data to update its estimated position, and then flying to the pre-planned target coordinates. To make sure that DSMAC could still work at night, the missile was fitted with a strobe light. Read more...

We've come through a lot of Aurora's economics/colonization gameplay, and it's finally time to talk about the really cool bit: warfare. This is an extremely complex part of the game, and while there are multiple feasible playstyles, it's also an area where it's easy to get things wrong and end up with a useless fleet. So before we start actually playing with the wonderful shipbuilding system, let's take a look at the broad overview of combat, which we will then flow down into how to build not just ships, but an integrated fleet.⁸

There are two types of weapons in Aurora: beam weapons and missiles. Beam weapons come in a number of different varieties. All have essentially infinite ammo (with a few restrictions) and are only useful at short ranges (~100kkm for beams, ~50mkm for missiles), meaning your fleet needs to be able to close with the enemy (this usually means higher speed than a missile fleet) and survive any missiles they can throw your way. Missiles have to be researched, built and transported separately, but offer you the opportunity to avoid beam combat. On the whole, I tend to prefer missiles, although this is as much an aesthetic as a practical choice, and many other options can be made to work. Read more...

The US Navy's Tomahawk cruise missile has revolutionized naval warfare over the last four decades. It has given surface ships and submarines the ability to reach targets far inland, the sort of firepower that was previously limited to aircraft carriers. Tomahawk was originally developed in the late 70s as a nuclear cruise missile, although it quickly spawned a number of variants with conventional warheads. The most famous are the land-attack versions used in numerous conflicts since 1991, but the first conventional Tomahawk was intended for a very different target.

A TASM is tested on the retired destroyer Agerholm

The growth of the Soviet Navy inspired the USN to look into ways of increasing the anti-ship firepower of the surface fleet, and the nascent Tomahawk missile provided the perfect platform. By replacing the W80 with a 1,000 lb conventional warhead taken from the AGM-12B Bullpup, and fitting a guidance system derived from the Harpoon missile, the USN could produce a long-range anti-ship missile at a low cost, which became known as TASM (Tomahawk Anti-Ship Missile). The problem was targeting. Ranges of 250 nm or more were being discussed, and no shipboard sensor was capable of actually finding and identifying targets at that range, or of updating the missile in flight. The Soviets had solved the problem by using aircraft to spot the targets and pass updates to the missile after launch, but American submarine doctrine ruled this out. Read more...

Welcome back to my walkthrough of Aurora, a rather unique 4X game. Now that we have our initial colonization well underway, it's time to turn our attention to the stars. Aurora's interstellar travel model is built around Jump Points, essentially wormholes that link star systems. Any ship with a jump drive can transit a known jump point or escort other ships through, and jump points can be stabilized to allow all ships to pass freely. But before you can make use of a jump point, you first have to find it.

This is the job of grav survey ships. These work pretty much like geological survey ships, only they go to survey locations in deep space. Each system has 30, and some number of jump points. A few systems have only one, while 2 is typical and 5 or 6 isn't unknown. This obviously requires ships, but before you rush off and build a version of your geosurvey ship with grav sensors, it's worth taking a deeper look at the jump point mechanics. Read more...

Of all the weapons that have entered service over the last 50 years, none have had a greater impact on naval warfare than the Tomahawk cruise missile. This weapon has given destroyers and submarines the ability to strike targets far inland, a capability that was previously the exclusive preserve of the carriers. This dispersion of strike power has proved vital to the surface and subsurface navies in the post-Cold War world, and has given the President new tools for projecting American power.

Iowa launches a Tomahawk

Tomahawk originated in the early 1970s, shortly after the signing of the Strategic Arms Limitation Treaty (SALT I), which didn't cover submarine-launched cruise missiles. The basic idea of such a missile wasn't new. The JB-2 Loon had been test-fired from a couple of submarines in the years after WWII, and the US had followed it with Regulus, which was fitted to five submarines, which conducted deterrent patrols in the Pacific from 1959 to 1964. However, Regulus was large enough that even its specialized submarines could only carry 2-5 missiles and it had to be launched from the surface, so it was rapidly phased out and replaced by Polaris. But in the aftermath of SALT I, the time seemed ripe to try again. The new weapon would have to fit into a standard 21" torpedo tube and be launched from underwater, giving the fleet's attack submarines a strategic strike capability against the Soviet Union. Read more...

Welcome back to my look at Aurora. Picking up from where we left off last time, it's time to look more at colonization, including terraforming, as well as to discuss civilian shipping lines and how they can benefit you.

Now that you've got a colony on Luna, and a geosurvey underway, let it run for a month or two so stuff has time to build. When you have 100 infrastructure on Earth, create a colony on Mars and order your cargo ships to take it there. This will take a couple of weeks, but you'll end up with two extraplanetary populations. At some point in this, you should get a notification that a shipping line has commissioned a ship of some sort. Shipping lines are semi-autonomous civilian ships that automatically move things around for you. The first vessel is almost certainly either a freighter or a colony ship, both of which you should be familiar with, at least in concept.⁹ Colony ships simply pick up colonists from source worlds (in this case Earth) and drop them off anywhere that's a destination with enough space. Anywhere with 10 million people or less is automatically a destination, while populations with more can be set to be a source, a destination, or stable. Freighters will attempt to carry trade goods from places that have surpluses to places with demand. Particularly when first colonizing, the majority of the demand will be for infrastructure, which populations automatically produce. As your colonies grow, they will produce and demand other trade goods, too, and might set up two-way trade. You get tax revenue from all of this, while the lines get money that lets them buy more ships. Read more...