Heavy Cavalry Redux

“Drive me closer! I want to hit them with my sword!”

no-one with a tank, ever

This is a recreation/reformulation/retcon of the original description of the Empire’s heavy cavalry legions, in light of both criticism received – and assistance to resolve it – and rethinking of my own. It should be considered as a replacement for the original post here, et. seq.

Let us proceed.

Making up the remaining one of every sixteen legions (i.e., one per three light cavalry or heavy infantry, and one per nine light infantry), we have the heavy cavalry. Direct-fire death on very large treads, which is to say, main battle tanks. The biggest of all the big sticks. Putting the “brute” into “brute force”.

For additional flexibility, the majority of Imperial MBTs are built off a common base platform, with a selection of swappable modules to provide specific functionality for specific cases. (Unlike many modular vehicle systems in this ‘verse, however, these aren’t hot-swappable; the need to remove and replace and integrate large and complex chunks of armor plate, etc., when doing it means that this requires some pretty major machine-shop type facilities. It’s not something you can do in the field, and indeed something only seen at the most well-developed remote operating bases.) Due to these functionality differences, MBTs are usually classified by the module.

So first we’ll talk about the capabilities of the base platform, and then we’ll talk about some of the more commonly seen modules:

Base Platform

The base platform of the Imperial MBT is a low-slung vehicle with all-around glacis design, designed to minimize its target profile and give it a low center of gravity. In dimensions, it is approximately 12 m (39 ft) long, 4 m (13 ft) wide, and 3 m (10 ft) high; its total mass (varying, of course, by module), however, is of the order of 60 short tons, due to the extensive use of lightweight composites.

8 m of the length and 3.5 m of the width at the front is the module socket; height of modules varies, but none take it much above the basic 3 m height. At the rear of the platform, an externally-opening compartment can be used to hold resupply, infantry needing transport, or a “hot soup” fuel pod to increase vehicle endurance.


The armament of the base platform (effectively the secondary weapons systems common to all tank classes) is fitted in four altazimuth ball mounts, located on either side of the vehicle, towards the front and rear.

These mounts’ field of fire extends 180 degrees vertically, and approximately 160 degrees horizontally at zero vertical, i.e., limited only by the occlusion of that side’s other mount. In effect, they maintain full coverage to the side, front, and rear of the tank, with only a small gap in coverage to the front for the rear mounts, and to the rear for the front mounts.

The front mounts include coaxial ortillery target designators and heavy (72 mm) mass drivers/micromissile launchers; the rear mounts only include medium (36 mm) mass drivers.

(While the latter do spend much of their time firing forward and to the flank, their special purpose in being mounted where they are is to give you something to pop the drone lining up to shoot you in the ass with so you don’t have to stop engaging your main target while you do it. In their battlefield environment, micro-AKVs are cheap and plentiful, so this happens a lot. If you had to slew the main gun around every time, you’d be taking your eye off the ball way too much – even if you could get it to reliably track something that small and fast-moving.)

See also Point Defense, below.


The armor of Imperial MBTs is relatively standard for Imperial armored units; there’s just a lot of it. The core structural frame is honeycomb-patterned diamondoid composite, covered with multiple slabs of interlinked refractory cerametal (i.e., a ceramic-metal composite formulated for both great physical strength and resistance to heat), electrical and thermal superconductor meshes, more cerametal, reactive-armor sections, and an outer anti-energetic ablative coating to sprayed on top of it all. Additional side plating shields the rollagons. A nanopaste-based self-healing system runs through channels in the armor, keeping damage patched up in the field.

The survivability specifications on all this armor is that the vehicle should be able to survive a near-miss with a tactical-range nuclear weapon or equivalent orbital kinetic strike.

Command and Control

An Imperial MBT nominally crews three: semi-specialized commander, driver, and gunner positions; in practice, this is rendered a mite fuzzy inasmuch as they’re both ably assisted by the vehicle’s internal synnoetic (i.e., designed to function integrated with another sophont mind) AI, and linked to each other by internal conflux hardware (i.e., functioning as a loose, mesh-topology temporary group mind for maximal efficiency, enabling coordination and multitasking by splitting off semi-autonomous agents).

Primary control is routed through the AI and direct neural links – the vehicle seats are virtuality chairs, connecting to the crew’s implanted laser-ports – but auxiliary/backup manual controls are also available.

Core sensors and communications include all the standard options: radio and whisker laser communications, access to the OTP-encrypted tactical mesh, threat identification systems, teamware and C3I systems integration, thermal imaging, remote sensor access, and all-around local sensors including pulsed-usage radar and lidar, T-ray high frequency snoopers, ground-penetrating radar, target-painter detection – and, of course, plain old electronic visual and sound transmission, since the interior of the MBT is fully sealed and includes no direct visual paths.

The MBT also includes a battle computer capable of functioning as a major node in the tactical mesh, and a full ECM suite.


As with all other units of the Imperial Legions, the heavy cavalry too has its drone accompaniments, with each MBT having a pair of WMH-12 Skyorca drones attached to it for close air support, along with a pair of heavy ground drones matching its own tactical function.

Internal Environment

To the delight of those legionaries who like a little comfort in their soldiering, the internal spaces of an Imperial MBT are a comfortable – albeit confined – shirt-sleeve environment. (Climate control, leather seats, the works…)

This is partially because given the expense of building one of these anyway, throwing in a few civilized comforts is barely a blip on the budget, and partially because – well, anything that successfully penetrates the armor tends to leave the crew as a hundred-yard-long red/blue/silver-white/etc. smear on the ground behind the exit hole anyway, so there’s no point in having them sit around in full combat armor. A padded jacket and helmet are sufficient to prevent accidents from concussion and rough terrain.

The interior is also a fully sealed and controlled life support environment for NBCN protection and exotic atmosphere/vacuum use. This also renders all tanks amphibious tanks by default: once you’ve covered all the various atmospheric compositions and pressures you might need to operate in and discarded thereby air-breathing engines and other systems, you’ve built a vehicle that can shrug off submergence, too.You could drive a modern Imperial MBT from continent to continent across the ocean floor, given a case of rat bars and a good reason to try it.

Point Defense

The MBT is equipped, as all else is, with a military-grade kinetic barrier system.

For active point defense, the base platform is equipped with a mix of mini-autocannons (in altazimuth ball mounts) and laser emitters, laid out to ensure all-around coverage, and capable of independently and automatically targeting all incoming fire and close-in soft units, subject to target identification and prioritization routines set by the crew.


It seems a little inappropriate to say that the MBT is also powered by a micro-fission “hot soup” reactor, inasmuch as, well, it ain’t that micro. It is “mini”, perhaps, compared to standard-sized fission reactors, but it’s as large as the thorium molten-salt kind gets. The bigger ones all tend to be the safer “pebble-bed” design.

Naturally, this is buffered through a large set of superconducting-loop accumulators to handle immediate power draws and provide backup power in the event that you lose the power reactor – enough to make a fighting withdraw, anyway, although not enough to continue an engagement with.


The Imperial MBT moves on neither wheels nor treads; rather, it sits atop eight semi-squishy rollagons, near-spheres of a “smart fluid” rotated electromagnetically from within the sealed main hull, enabling it to move with equal facility in any direction, at speeds of up to 150 mph on a good, flat roadbed. Note that this is not a drivetrain developed specifically for military purposes: modern civilian ground-cars use similar technology.

The propulsion system also has considerable electromagnetic control over the shape of the rollagons; while they don’t have them normally, if you need spiked wheels or some other shape-variation to cross some tricky terrain, it can provide them on demand; if need be, they can even form “paddle-propellers” for amphibious operation.

A limited vector-control/impeller system permits the tank to apply vertical thrust to itself; this is used primarily downwards on light-gravity worlds to keep ground pressure high enough for the rollagons to be effective, occasionally upwards to reduce ground pressure where the ground is soft, and even more occasionally to lessen the severity of falls, ground collapses, or deliberate drops from low-flying transport aircraft.

(It would theoretically be possible, on light-gravity worlds, to use it to make “skips” over obstacles or other short vertical jumps, but this is generally considered an excellent way to become skeet.)

Stealth and Masquerade

The Imperial MBT, much like the heavy infantry, supports only the most basic chameleonic coating and signature reduction features; the nature of the battlefield environment of the time is such that any heavy unit has a signature (in terms of heat, reactor neutrinos, and the EM pulse accompanying weapons firing) that can’t be baffled worth a damn. As such, designers concentrated on designing a vehicle that could “tank” (sic) incoming fire in the process of executing shock and awesome.

It should however be noted that this does not preclude the use of external decoys, or the use of signature modification systems to confuse terminal guidance of incoming weapons, or indeed to masquerade as something else — but these systems have to work with the platform’s high signature, not try to conceal it.

Module: Tactical Assault Tank (HV-10 Basher-class)

As close as it comes to a “standard” MBT design, the HV-10 Basher-class module loadout is similar to the V40 Ralihú IFV, scaled up; the Basher-class comes with a turreted super-heavy (144 mm) mass driver, but substitutes a bilateral quadbarrels with limited independent training for the Ralihú’s single coaxial quadbarrel.

(The heavy mass driver is also designed to function as a heavy micromissile launcher, if required, and as such is entirely capable of delivering large-diameter canister shot for anti-infantry work.)

Module: Long-Range Assault Tank (HV-12 Stormfall-class; also HV-12i Longeye-class)

The HV-12 Stormfall-class LRAT module is equipped with a turreted super-heavy (144 mm) mass driver intended to be capable of long-range indirect as well as direct fire, but substitutes the quadbarrels for bilateral “pop-out” missile pods, each capable of doing a simultaneous launch of up to 16 minimissiles, reloadable with a short cycle time from internal magazines. Just perfect for those days when you want to fight in the shade.

By changing the minimissile loadout of the Stormfall, it can also serve as an active air-defense platform.

Rarely seen is the HV-12i Longeye variant, which trades in both super-heavy mass driver and missile pods for a graser installation, suitable for direct fire only but capable of punching out even more heavily protected targets. Also, notably, the Longeye graser is often capable of penetrating the atmosphere and reaching targets in low planetary orbit.

Module: Drone Tank (HVC-14h Thunderbolt-class; also HVC-14l Stinger-class)

A drone tank, in legionary parlance, is the land-based miniature equivalent of an aircraft carrier. The HVC-14h Thunderbolt module contains nanoslurry and miniature drone components, which it uses to construct and deploy ad-hoc micro-AKVs to suit the requirements of the current battlespace, launching them into action as a centrally coordinated wing, for defense, reconnaissance, attack, or other functions.

(Or, to put it another way, it’s a self-propelled field factory that spews out custom drones and minimissiles on demand, simplifying your logistics and multiplying your options.)

The HVC-14l Stinger functions similarly, but substitutes swarm hives for the micro-AKV factory, and is thus able to saturate the local battlespace with microbot/nanobot swarms, be they the standard eyeballs, shrikes, gremlins, or balefire, or more specialized models.

Module: Tactical Arsonier (HV-10a Flammifer-class)

Used for cleaning up or eliminating nanoswarms (highly vulnerable to thermal overloading), area denial, reducing bunkers and dug-outs, and spreading pure terror, the Flammifer-class replaces the heavy mass driver of the Basher-class with a scaled-up nuclear-thermal flamer, while retaining the quadbarrels as-is.

Module: Command Tank (HV-10c Strategos-class)

The Strategos-class is a specialized vehicle for coordinating tank-squadron activities and close air support. The Strategos module doesn’t add any weapons systems; rather, it adds two more crew positions for squadron command, a specialized tactical/logistics C3I AI, and a nodal communications suite and its antennae.

A pair or triplet of Strategoi are usually assigned to a tank squadron made up of other classes for command/control functions.

Module: Pummel (HV-11 Pugnacious-class)

The pummel tank is a highly specialized variant, designed to rip apart buildings and fortifications. It carries sappers in its rear compartment, and is equipped with specialized demolitions equipment up front.

Module: Wrecker (HV-10w Trison-class)

Another highly specialized variant, the HW-10W Trison and other wreckers are logistics units, used to recover wrecked tanks and other heavy equipment off the battlefield for repair or for scrap.


The Flapjack-class cavalry dropship was made specifically for this; apart from that, they mostly drive to wherever they’re needed, because only the biggest transport aircraft can carry them in useful numbers.

A Sticky Solution




A prohibitive constraint on the use of conventional weapons in the anti-satellite (ASAT) role is their tendency to create debris through a variety of paths: direct ablation, spallation or fragmentation debris, warhead shrapnel, non-intercepting ordnance, and so forth.

The accumulation of such debris beyond a chaotically variable critical point – easily surpassed during military escalation, per Orbital Hazards in Simulated Great Power Escalation Scenarios (Oricalcios, Efiathe, and Cylassé, 2074) – poses a long-term hazard to civilization by inducing a cascade catastrophe, a rapid chain multiplication in debris count likely to render the orbital bands involved non-viable in the long term.

TAR BABY attempts to avert this by developing a specialized non-fragmentation ASAT weapon.

Specifically, we propose a dedicated ASAT warhead designed for compatibility with the Firehawk surface-to-orbit missile system (selected for its multiple-burn capability). Upon closing with the target satellite, this warhead deploys a sphere of viscous adhesive at its nose, formulated to remain effective in vacuum conditions for the duration of the impact event and to retain its shape via surface tension.

It is believed that this mechanism should allow a TAR BABY warhead to achieve a hard connect with the target satellite with minimal uncaptured fragmentation. Embedding within the adhesive body should in itself cause significant disruption to the operation of the target, but for maximal effect, after the adhesive sphere has set (either by passage of time or injection of a catalyst), the multiple-burn capability of the Firehawk can be used to perform a controlled deorbit and destruction of the captured satellite.

For further details of our proposal, please see the enclosed technical documentation.

Submitted for your consideration,

Vidal Amnestrianos

for and on behalf of

Firefly Aerospace, ICC

On AKVs and Survivability

From the questions box:

Dear Gentlesoph,
Having been reading your posts, I have a question about AKVs such as the ‘Daggerfan’ and ‘Slasher’ classes. With high-powered lasers capable of doing damage at one light second, how do AKVs survive the 300,000km journey into single kilometer range? As stated in your ‘Nonstandard Starship Scuffles’ post, military vessels use armor woven through with thermal superconductors dumping heat into ‘thermal goo’. I assume this armor/thermal management system applies to AKVs as well, although you also state that point-defense lasers will shred a vessel unfortunate enough to get into very close range. How can an AKV survive at single kilometer ranges long enough to inflict damage on the target? Thank you for your time, I look forward to more posts!

Well, there are two parts to this: how do AKVs close to skin-dancing range, and how do they survive when they get there? I’ll take ’em one at a time.

On the first point: with great difficulty.

If you take a wing of AKVs and throw them at a fresh battleship, all you’re doing is providing its point-defense computers with skeet; they’ll be chaff and charnel before they get anywhere near the inside of the BB’s point-defense zone.

What you have to do is wear it down first. That’s is the job of the non-carriers on your side of the fight: throw a lot of kinetics at the enemy to make their PD work hard. That does three jobs: one, it keeps the PD grid busy in itself; two, any of it that gets through may just take out a chunk of the PD grid; but most importantly, three, by making them run their point-defenses, you’re building up heat in their ship. Your non-carriers also have the job of pumping heat into their ship directly with the big lasers.

That heat, in turn, is going to eat away at their PD efficiency in a variety of ways. Most simply, it’s going to have to cut back on its firing rate once the heat sinks start filling, because otherwise the crew will cook, but also the hardware becomes less efficient, processor error rates go up, and similar badness ensues.

That’s when you send in the AKVs, and you send in a lot of AKVs mingled with a lot of chaff and decoys, swamping the capabilities of the now-degraded PD grid. They won’t all get through – you plan for a lot of them not to – but once the grid’s sufficiently degraded, enough will to ruin the BB’s day.

As for when they’re there? Remember, they’re described as operating within the point-defense envelope, which is to say, inside its inner boundary, which is defined by the minimum effective range of the PD – set by a variety of factors, such as the range at which firing the PD will seriously damage your own ship, but of which probably the most important is the ability of the PD to track the target and slew to fire on it. At the sort of hug-the-hull sub-km range AKVs like to operate at, it doesn’t take much velocity to generate a huge traversal angle, and what you can’t track, you can’t reliably hit.

(And it’s hard for your screen to fire effectively at the AKVs ruining your day, ’cause even discounting the effects of the AKV exploding at point-blank range, every miss will hit you.)

All of which is to say: While there are some subtleties and complexities to the tactics (defense AKVs, screening vessels sharing PD, etc., etc.), the short answer is it takes a lot of work and losses to get an AKV force within range of a target, but once you do, that target is dead meat.

The Counterrevolution Will Be Televised

combat instrumentation and logging module (CILM): Part of the standard military-basic biomod package, the combat instrumentation and logging module is an enhanced lifelogger, recording tagged sensory recordings as well as physiological information, armor, weapon, and equipment telemetry, and tactical mesh status. The data recorded by the CILM is used to provide contextual data in after-action reports, for targeted improvement of individual performance and fireteam coordination, and in the development of future training scenarios.

Given the Legions’ institutional sense of humor, the CILM is commonly if unfortunately referred to as the “fight data recorder”.

Blackjacket’s Dictionary


shrieker: (also ping-pedo) a single-shot directional EM pulse generator mounted in a capsule suitable for mass driver deployment.

It is a truism of tactics that active sensors, while much more effective than passive sensors, can rarely be used since they are even more effective at disclosing the user’s position to other vessels. The shrieker represents a compromise with this truism; given effective localization and a little mathematics, there is no necessity for the sensor emitter and the sensor receiver to be in the same location. Thus, it provides the means to implement this by emitting the radar/lidar pulse from a point distant from the launching vessel.

The shrieker is far from a perfect solution. It provides partial information on the location of its launcher, especially if the pre-pulse run is short, or the opposition’s sensors are sufficiently sensitive to pick up Doppler distortion in the emitted pulse; and deployments are limited inasmuch as, although directional, a shrieker can only be used in situations in which its pulse will not illuminate the launching vessel or other friendlies to the passive sensors of the opposition. Nonetheless, the additional information provided by even limited active sensor capability can make all the difference in a tactical situation.

– Blackjacket’s Dictionary

How I Wonder What You Aargh

Cirys superzorcher (n.): A hypothetical weapons system in which the various elements of a Cirys swarm (q.v.) are equipped to function as the radiative elements of a phased-array laser. Such an array, with an effective aperture equal to the diameter of the swarm, would theoretically be able to deliver a substantial portion of the total solar output of the contained star in a single beam against targets located at interstellar distances.

Occasional peaceful uses for such beams have been mooted, including laser sail propulsion (although it should be noted that there is little call for such craft on a larger scale than existing propulsion arrays – which have the advantage of being mobile – can handle, and the ability to build a laser-sail craft capable of surviving such propulsion is questionable), long-distance, including extragalactic, communications (a matter of great interest to the Elsewhere Society), and even remote power generation and delivery.

However, while condemned by Cirys Aendyr himself – who is said to have wept when this application of his concept was brought to his attention – the most common proposal is to use the Cirys superzorcher as the weapons system implied by its name. The ability to place so much power on target (a figure of the order of 108 exawatts for a Hearth-class star) across interstellar distances, capable of vaporizing lithic worlds and severely damaging gas giants and stars, is peculiarly attractive to certain types of mentality, especially when it is considered that the purely photonic beam of a superzorcher is substantially more difficult to detect than a typical RKV, and cannot be practically intercepted or recalled.

As such, while the Cirys superzorcher requires a high degree of technological advancement and autoindustrialism to produce (a potential currently limited to the Empire and certain other Core Markets) and is in any case a prohibited weapons system (classified as a Tier I star-killer under the Ley Accords), an informal consensus exists among the Presidium powers that the construction of such a device by any polity, within or without the Worlds, may be reasonably interpreted as notice of intent to commit gigacide, and as such is a legitimate cause for preemptive defense of the highest order.

– A Star Traveler’s Dictionary

Things You Are No Longer Allowed To Do In The Imperial Military Service

This one goes out to all my readers who have spent time deployed somewhere really, really, exquisitely tedious…

From: Master-at-Arms, CS Ablator
To: All Personnel, Task Group SPIKY POTATO
Subject: Prohibitions That Should Not Have To Be Explicit

It has come to my attention that due to the less than challenging nature of our current duty station, certain behaviors qualifying as discipline problems have become alarmingly common throughout this Task Group. Worse, it has come to the Admiral’s attention, and the Admiral, permit me to assure you, is even less amused by them than I am.

From the date of posting this notice, therefore, the following are now explicitly prohibited, and violations will attract the full weight of Article Three to the violator and anyone else involved.

  1. The chief reason for the unchallenging nature of our present duty station is the technical advantage we enjoy over the enemy. The correct military terminology for this, however, is battlespace supremacy. Under no circumstances is it to be referred to in after-action reports as god mode. Good grief, people, you all know that our AARs are matters of public record. Try to show a little professionalism.
  2. Local allies are technically referred to as colonial troops, and not as ablative meat, however lacking their TO&E might be. At least where they can hear you.
  3. Even if the locals have no missiles capable of doing more than bouncing off our ships’ hulls, the tactical tank is for monitoring local-space activity. Not for playing Galaxy of Conquest in super-high-res. (And if you’re the officer Captain Oricalcios walked in on mid-game, your tactics were terrible and you just failed this year’s promotion board.)
  4. The official motto of the Imperial Military Service is “Between the Flame and the Fire”. Unofficially, the paraphrase “civilization has enemies; we kill the bastards” has been usually tolerated. All of the following, however, are to be avoided: “Your sexy new war gods”, “because nuclear ain’t enough”, “death death death death death”, and any references to squid.
  5. Yes, the paderi are a quadrupedal species. This does not mean that our local allies can be used as cavalry mounts.
  6. Even, and I wish to emphasize this in particular, if it was their idea. Even assuming that it is a good idea, the optics are terrible.
  7. Nor are any of our current variety of combat drones suitable for use in this role. You’ll just have to live without valiantly charging down the enemy so you can hit them with your sword.
  8. Even if you have a cavalry sword. Why do you have a cavalry sword?
  9. Your fellow legionaries are not to be used as projectile weapons.
  10. Betting on arm-wrestling with civilians while wearing power-assisted armor is forbidden, even if they are drunk and spoiling for trouble. The local hospitals have started to complain.
  11. Combat stimulators are not to be considered a substitute for esklav, no matter what you think of the mess brew.
  12. Nor, although the Imperial Military Service is relatively permissive where fraternization is concerned, are they to be used to spice up your love life. Surgeon-Lieutenant Aendyr has been issued a blanket authorization to post pictures.
  13. While chameleon coatings can be set to any color and pattern, flames, hot pink, your favorite painting, or last week’s episode of Battle Beyond the Brane are not approved for field use.
  14. Aftermarket speaker systems are not to be fitted to combat exoskeletons. Your AI already provides a perfectly adequate soundtrack.
  15. …even if you did require them to “challenge the enemy to a dance-off”, we have a requisitions procedure for a reason.
  16. No military equipment is to be used for recreational purposes. If whatever you thought of makes you smile, giggle, or laugh, you are to assume that it constitutes recreational purposes until advised otherwise.
  17. Especially if it involves any intersection of stealth hardware with practical jokes.
  18. Yes, cook-outs are recreational. Besides, no heat-generating weapons in inventory can be turned down far enough to leave the meat even slightly edible. Yes, we checked.
  19. So is requisitioning drop shuttles for booze runs or ‘surprise rapid insertion liberty’.
  20. While the IMS recognizes that explosives can be used to solve a remarkable number of classes of problems, and while formal research into expanding this list is usually done by the Office of Military Research and Development it is nonetheless happy to add field improvisations to its official repertoire, this applies to field improvisations. It is not a blanket authorization for unofficial explosives research.
  21. While the Imperial Military Service also has no fan-fiction policy, largely due to no-one ever imagining that it might need a fan-fiction policy, would-be authors are reminded that it still needs to be cleared through all the normal channels before you post it publicly. Especially if you want to illustrate it with staged or real combat videos.
  22. …and if you’re writing that kind of fan-fiction, be aware that at least some of your characters can have you spaced for mutiny.
  23. While your efforts to challenge yourselves are admirable, save it for actual exercises. Pretending you’ve forgotten to bring bullets to the battle so you’ll be forced to improvise may be a challenge, but it’s also a mockery of the rules of war, and just begging for an unpleasant surprise.
  24. Especially if by “improvise” you mean “punch, a lot”.
  25. It’s still a bad idea to play Ancyr roulette even if it’s mathematically impossible for the bullets to penetrate N45 Garrex field combat armor.
  26. …especially if whoever you’re playing it with isn’t wearing N45 Garrex field combat armor.
  27. Unless you’re a psychological warfare specialist, you are not authorized to conduct psychological warfare.
  28. Against either side.

That is all. Or rather, that had better be all, because Ablator has an awful lot of hull that could stand a good cleaning. Six by six?