Outsize

“Finally, let us turn to the biggest megaships of them all, the fleet carriers. Including them in this work is a choice which I expect to be somewhat controversial – many would argue that a fleet carrier is a formation, not a vessel – but with respect to those readers who may hold that position, since the Imperial Navy treats fleet carriers as a single vessel for asset accounting and command designation purposes, so in turn shall I.

“Let us begin with a look at the history of the type. Fleet carriers were not known before the Exterminomachy (5782-5901). While before that time lighthuggers had met with occasional hostility, they had proven more than capable of defending themselves against local system defense forces, in particular with the Perreinar Wheel1 – and in those cases where they were not, it was because they had encountered a Power not readily opposed by pure military force. This changed with the arrival of the skrandar berserker probes, whose numbers and willingness to embrace suicide tactics made them a serious threat to even well-defended vessels, and eliminating breeding site for which required the transport of full task forces to their host systems.

“The first fleet carriers, then, were improvisations; lighthuggers pressed into service under the right of angary. Stripped down by removing all cargo capacity, much crew space, and all other less-than-essential facilities, and enhancing their fuel capacity with multiple drop tanks, it became possible to clamp a small number of light units – overstocked with fuel and supplies – to the spine of such a vessel, and have it haul them slowly and painfully to a target system.

“Such crude improvisations were fraught with problems, from wear and tear on ships and crew during the slow transit, to the risk of interception before the transported units could free themselves from the carrier – both due to the inefficiency of the mechanical clamps, and the need to cut clamps frozen in transit or actual hard welds used where clamps would not suffice, to even entire vessels lost from the carrier in transit. (The last of these to be recovered, CS Bloodwashed3, was salvaged with all hands in 6722.)

“Fortunately, by the third year of the Exterminomachy, new designs were emerging from the cageworks at Ashen Planitia and Armory. The second-generation fleet carriers were custom-built starships, or rather, the specialized elements (the “propulsion head” and “collier module”) were, since the second generation eschewed the rigid designs of the first in exchange for dispersed tensegrity structures.

“In effect, the starships transported by the fleet carrier, along with the specialized elements, formed the floating compression struts of the overall structure, while being linked by braided cables (derived from orbital elevator technology) into a unified structure. The majority of the propulsive thrust is provided by the dedicated propulsion heads, while specialized fleet mediator software enables the use of the drives of the various carried ships to balance the structure and correct attitude. Meanwhile, supplies carried in the collier modules, distributed by rigged flexpipe and by cable-crawling logistics robots, eliminated the need to overload any individual ship with supplies, and indeed enabled the transportation of greater volumes of fuel and replenishment. Moreover, such fleet carriers could separate instantly if intercepted by simply blowing the explosive cable-couplers and engaging their drives independently, the dispersed tensegrity structure providing adequate safety separation for this.

“Such dispersed-design fleet carriers served with distinction throughout the remainder of the Exterminomachy, and have remained a key element of IN subluminal doctrine since. While there exist a third generation of fleet carrier designs, these merely reflect the evolution in technological reliability that allows the physical cables of the second generation to be replaced with vector-control tractor-pressor beams, and does not reflect any change in fundamental design or doctrine.

“As ad hoc structures, of course, it would be incorrect to say that fleet carriers have classes, in the strictest sense. However, the individual propulsion heads and collier modules, the former full starships in themselves, do. Thus, we shall begin our examination of fleet carriers with a look at the most common propulsion head in Imperial service, the Legends-class…”

– Megaships of the Imperium, Lorvis Maric, pub. 7290


  1. Perreinar2 Wheel: a fight-and-flight maneuver in which a lighthugger puts its stern towards the battle and engages its interstellar drive, thus retreating from the engagement while simultaneously treating the enemy to the close-range efflux of a pion drive – a situation which is very rarely survivable for anything larger than a baryon.
  2. From the eponymous horse archers who had perfected the “Perreinar shot” centuries before.
  3. Lost in the wreck of CS Cúlíän Daphnotarthius, which suffered a structural collapse of the spine while outward bound to IGS 31238 in the second year of the war.

Initiation

functional lightspeed (n.): A curious quirk of relativistics; thanks to time dilation and distance foreshortening, when a lighthugger on a sufficiently lengthy voyage achieves 0.707 lights, the wall-clock time experienced by the crew exactly matches the length of the voyage in the empire-time frame, thus creating the mathematical illusion that the starship is travelling at the speed of light.

While meaningless in practical terms, this has not stopped lighthugger crewers from using it as an excuse to throw a party and hold a “light-barrier crossing ceremony” to initiate those who have never done so before into the Right Honorable and Inebriated Order of the Improbably Celeritous. Such ceremonies include initiation into the “mysteries of the deep black” by the gods of space and stars and their court (played by the oldest Improbables aboard), much drunken horseplay, and the traditional final rite of standing on the foreshield of the lighthugger until one’s nerve cracks, followed by the equally traditional treatment for radiation exposure.

– A Star Traveler’s Dictionary

Trope-a-Day: Year Outside, Hour Inside

Year Outside, Hour Inside: Thanks to relativity, truth in television for lighthugger crews, who slowly build up a hefty time differential (and cultural delta) with the parts of the universe operating on the empire-time frame.

(Hint: if there’s a family member or social grouping you just can’t live without, make sure you all sign up together.

…also, give up on playing MMOs or multiplayer games with anyone off the ship, no matter how much tangle you brought. Timeslip is much worse than netlag.)

Trope-a-Day: You Can’t Go Home Again

You Cant Go Home Again: A consequence of lighthugger travel and the ensuing time dilation for ephemerals; or people from ephemeral societies, rather, since its the high cultural delta of the society you left that causes the problem.

Also, more rarely, what happens to people left off-world at the time of an Apocalypse How or Gone Horribly Right.

Trope-a-Day: Subspace Ansible

Subspace Ansible: The tangle channel, which involves manufactured entangled (not in the standard quantum sense, note, because we know that doesn’t work; these are ontotechnological devices using the “privileged channels” a long way behind those) particle-pairs.  This makes them quite expensive (since they are a consumable resource, one particle per bit transmitted, and have to be shipped there the long way once you separate the ends; if you don’t have one or a stargate, your best option is a lighthugging communications torpedo) at least relative to using light-speed EM communications and relaying them through the stargates, the way most of the non-priority extranet works, but they’re invaluable for priority communications and beyond the reach of the stargate plexus.  (They are, for example, the only means of ready communication available to lighthuggers.)  And yes, they do work for mindcasting.

(And, yes, they can also let you play interesting games with causality. Just as expected.)

That said, extensive use of caching, prefetching, and AI traffic prognostication makes the extranet delays mostly invisible in practice, as does the ability to engage in pseudo-real-time communication by sending a partial copy of you along with, or as, your message to be able to have a real discussion with the recipient, then reabsorb it when it returns.

Trope-a-Day: Streaming Stars

Streaming Stars: Averted.  However incomprehensible the speeds lighthuggers move at, they’re not nearly fast enough – and can’t be, courtesy of the luminal limit – to create noticeable motion parallax.  Some blue- and red-shifting and relativistic distortion, yes, once they’re cruising along at the full 0.9c; but no motion parallax.

Xenognosis

Xxenognosis (n.): (also “the Big Hello”) The knowledge that sophont species other than one’s own exist; also, the discovery by an individual or species that they exist.

In popular mythology, this is usually conflated with first contact, or at least with the establishment of genuine communications between the species in question – which portrayal, unfortunately, is almost pure nonsense.

Interstellar civilization just isn’t that subtle.

Space is cold and dark. Interstellar life is the exact opposite. Between the EM penumbra, starship drive flares, the gravity-wave ripples of stargates in operation, and even some few modified stellar spectra, anyone within a couple of thousand light-orbits of the Periphery with any astronomical competence at all can have no doubt that there’s exotic life out there – with the only possible exception being those on the wrong side of the Shadow Veil.

If you’re actually trying to make contact, you can’t avoid giving advance notice. In the first first contact on record, the galari identified Extropy Rising – a slowship, not even a lighthugger – light-months out of their system, even before the inbound ship spotted the radio emissions of galari civilization. The deceleration burn of a modern lighthugger is easily visible from the next star over, and highly distinctive to boot; an optimized fusion torch or the double-peaked signature of a pion drive look like nothing else in space. As for starwisps – how many stars do you think there are that shine monochromatic green?

(And if the lighthugger in question is a linelayer, it’s going to leave a stargate megastructure orbiting in their outer system for them to look at for months, maybe even years, before a scoutship gets there. Conveniently engraved with instructions for use, even.)

This does have its disadvantages, triggering social unrest, cultural shifts, bursts of technological development, and the like, or on less developed worlds – the kind whose occupants may go unnoticed until your arrival – sometimes even religious movements. In the case of psychotics-in-waiting like the skrandar, it may well have converted them into the berserkers they ended as.

But if you want to explore the galaxy at all – well, what can you do? Even the Voniensa Republic, who are remarkably prissy about this sort of thing, have had to reconcile themselves to that.

– A Star Traveler’s Dictionary

Oceans

ODeepHab Eleven
Eastern Abyssal
Gulf of Antareä
Eliéra

The incoming voice rattled scratchily from the speaker. “Benthic Needle, we have you on our magnetograph now. Confirm your position.”

“Inertial guidance shows us eight-eleven porisedt from sonar target, relative bearing zero-eight-five, station-keeping against current. Request calibration reading on relative depth, DeepHab.”

Ping! Ping! Ping! Ping! Ping!

“Benthic Needle, we show your relative depth as two porisedt above our datum, with a three degree for’ard pitch.”

“Thanks, DeepHab. Retrimming.”

Water gurgled into the trim tanks as the pilot adjusted the controls.

Ping! Ping! Ping! Ping! Ping!

“We’re ready for terminal guidance, DeepHab. Advisory: we have negative, repeat negative, visual capability.”

“Proceed on heading zero-six-zero for eleven-one porisedt to intercept final vector, Benthic Needle, activate high-resolution targeting sonar, and hold; descend six porisedt to four below datum relative for moon pool access. Map follows.”

A burst of data-noise later, the proposed course mapped itself out in blue-green trigraphics on the inside of the minisub’s blank steel cupola.

“Executing, DeepHab.”

Ping! Ping! Ping! Ping! Ping!

“Say, Benthic Needle, out of curiosity, why does the Spaceflight Initiative want you guys to practice blind docking anyway?”

“No mystery, DeepHab. The Needle’s shipping out to Isimír next year. There’s no light down in its subcrustal ocean, so we’re learning to operate without it.”

“There’s no light down here, either, Needle, but we do have lights.”

“Yeah, but there’s never been any light down in Isimír’s ocean. If there’s any life down there, it’d be rude to go lightin’ the place up before we find out if it’ll poison the locals.”

Trope-a-Day: Mile-Long Starship

Mile-Long Starship: Some bigger classes easily fall into this category or above: dreadnoughts and superdreadnoughts, grapeship megafreighters, the top end of highliners, colony seedships, mobile factories, that sort of thing, and – of course – city-ships.

Special note here to most lighthuggers, which have to accommodate vast quantities of deuterium and antideuterium and whose antimatter-pion-torch engines are so ridiculously lethal to be near that you want them on the end of a very long spine indeed.

Trope-a-Day: Made of Indestructium

Made of Indestructium: … alas, the universe is hard on indestructium.

About as close as nature gets is probably neutronium – and whatever even more degenerate forms of quark matter, etc., you can get beyond it. Sadly for engineers everywhere, neutronium is rather hard to work at the best of times, behaving essentially like a fluid, and having a really nasty habit of evaporating in a giant whuff of neutron radiation the moment you remove it from the deep, deep gravity well necessary to make the stuff. Metastable neutronium would be nice, and there are people working on that…

In somewhat more practical terms, muon metals, which is what you get when you strip all the electrons out of metal and replace them with muons, their leptonic cousins. Since muons have the same charge as the electron but greater mass, they have much smaller ground-state waveforms than electrons in the atoms thus formed, resulting in matter than has similar chemistry – albeit rather more endothermic – to the original, but whose density and physical properties in re energy-resistance are pushed way, way, way up as the atomic spacing shrinks way down. It would make good armor, if the mass penalty wasn’t, inevitably, quite so harsh. On the other hand, it’s one of the things that makes torch drives practical (being so incredibly refractory, and thus letting you push the drive output/waste heat/resulting radiation rather further than you otherwise could), and also is invaluable to coat lighthugger wake shields with, being able to easily shrug off the sort of dust-particle impacts you get when plowing through interstellar space at 0.9c.

But neither of these is actual indestructium, ’cause, well, antimatter. Neutronium and antineutronium will annihilate quite nicely, and while regular antimatter isn’t quite as corrosive to muon matter as it is to everything else – an antimuon is not a positron – the proton-antiproton annihilation will proceed as normal and will make the whole thing come apart just fine.

Alas, indestructium, we barely knew ye.

(There’s also singularity-locking, the handwavium I promised to explain last time. That’s actually a simple reuse of existing handwavium – vector control – in this case being used to grab and redirect, while conserving, the momentum of things that would otherwise impact the surface of the singularity-locked thing into a giant kinetic energy sink.

The reason it’s called singularity-locking is because the sort of giant kinetic energy sink you want for this is a modestly-sized black hole. This is why stargates use it, because they already have a modestly-sized entangled kernel sitting in there to make their primary function work, so you might as well get the extra use out of it. It’s also why nothing else does, because if you think muon metals have a harsh mass penalty, they’ve got nothing on dragging millions of tons of hole around with you to make your armor work. A mass ratio of what, again?

[Also, people – with fairly good reason – don’t exactly want one in their back yard anyway, on general principles.]

Sadly, this isn’t pure-quill indestructium either, technically – while it would require a ridiculous amount of energy, it is theoretically possible to overload either the singularity-locking systems or the K-sink itself, and boom. Fortunately, it would be so much boom that so far no-one’s seemed inclined to hit a stargate with a small moon and see what happens…)

Trope-a-Day: Stealth in Space

Stealth in Space: There ain’t no stealth in space.

This applies especially to lighthuggers, inasmuch as an antimatter torch at high burn can be detected for light years even if you’re not the star system that it’s pointed at.  If you are, all the more so.  Much the same goes, at least for the destination system, for even the best-collimated of the launch lasers starwisps use.  Any way you look at it, there’s no way to be subtle when engaging in near-luminal travel.

But it applies to everyone else, too.  Even small reaction-drive burns – and vector-control drives of similar energy consumption – are bright enough to be seen most of the way across the system, and more to the point, the heat of operating life-support systems for biosapiences – or even the waste heat for the minimum technology needed to support digisapiences – stands out like a searchlight against the 3K sky background.

It’s not impossible to manage a degree of sneakiness.  It involves making use of thermal superconductors to capture your emissions in most or even all directions, and heat pumps (which, let us not forget, generate even more heat which you have to then capture) to capture them in heat sinks – which will fill up and roast you if you keep it up for very long, so be careful about how long you need to use them.  It involves making maximum use of cover – cold objects in space to hide behind, and hot objects to hide in front of, while being careful not to visibly occult anything, and always pointing the right bits of your ship in the right direction (observer-dependent, so best hope the system’s not busy).  It involves limiting your propulsion to careful use of (hideously slow and inefficient) cold-gas thrusters and leveraging vector-control to get a tow from other ships or celestial bodies (in which case, being careful to ensure that you keep your effect on their apparent mass below the threshold that will trigger alerts in their engineering department or your target’s paranoid skywatching AIs.).  And, of course, essentially none of this will help if someone happens to look out the wrong window or point a telescope in the wrong direction and spot you visually.

But it’s difficult and constrained enough – especially since you have to enter systems via the choke-points of their stargates – or suffer the above lighthugger problems – that it’s usually much easier to pretend to be something other than what you are, or bury yourself inside an asteroid big enough to act as a decent thermal sink, or get an insider agent to plant a You Can’t See Me data worm in their traffic-control systems, or otherwise engage in some kind of tactics that are more masquerade and less outright stealth.

(The ontotechnological engineers are working on – well, technically, working on the possible theory that might just possibly begin to underlie the engineering principles of – an actual bona-fide cloaking device that bypasses at least some of these difficulties.  Still some awkward implications from physics, though: firstly, it’s inescapably double-blind, so while no-one can see you, you can’t see out either.  The possibilities for things to go horribly wrong for you while you can’t see them are… large.  Secondly, it involves basically hiding behind the domain wall of your own personal baby universe, possibly the only thing that does retain heat with 100% efficiency, which is to say, it actually makes the heat dissipation problem worse.  Better have really good heat sinks, or you’ll cook yourself to death in really short order… and then release all that heat in a nice position-illuminating flare anyway.)

Trope-a-Day: Generation Ships

Generation Ships: The Empire itself has never used generation ships, despite thinking of the concept.  Regular lighthuggers don’t count – the whole immortality thing means that while children may well be born en voyage, the people who got on will by and large be the same people who’ll get off.  Their first burst of interstellar colonization (the Thirteen Colonies) was done subluminally, but the Deep Stars carried frozen colonists, so they don’t count either.  And the wandering city-ships don’t count simply because they’re not a means of transport, they’re places people live – and people come and go all the time, any time they pass through a system.

Which is not, of course, to say that the concept’s never been used by anyone else; I’m sure it has, probably quite a bit, and still is in places beyond the Associated Worlds, or where they’re still en route.  And, arguably, the couple of nomadic cultures (the londian, for one example) who live on wandering city-ships and have nowhere to leave them for but other city-ships might well count.

Trope-a-Day: Casual Interstellar Travel / Casual Interplanetary Travel

Casual Interstellar Travel / Casual Interplanetary Travel: It’s a little complicated.  Technically, yes, you can travel interstellarly fairly casually, since while you have to drag one end of your wormhole at subluminal speed to wherever you want it, interstellar travel to places where you have one already is pretty damn casual.  Step through and you’re there.  Ping.

Of course, wormholes and their associated stargates are Really Damn Expensive, and so is interstellar travel to anywhere that isn’t on the stargate networks involving as it does the many years relativity demands of you even in lighthugger starships, the great expense of said lighthugger, and for that matter, the even greater expense of the thousands or tens of thousands or even, for the largest luggers, hundreds of thousands of tons of antimatter you need to fuel the thing.

Further, and to subvert this slightly, while there’s casual interstellar travel, what there isn’t is casual interplanetary travel (speed-wise; it’s much more casual cost-wise).  No-one’s invented a convenient magical gravity drive that lets you whip up nigh-instantaneous thousands of gravities of acceleration (while there are vector-control drives, neither acceleration nor delta-v are any better, and indeed usually worse, than equivalent reaction drives; blame conservation of mass-energy), so getting anywhere in-system, including out to the stargate, still takes days or weeks, and for interstellar travel, that means on both ends of the wormhole.

This is resubverted for those with the right metaphysical attitude, because if you don’t go into quivering neo-Luddite theofear at the thought of having your mind separated from your body and transmitted elsewhere to be reinstalled in a different one at the far end (and granted, that’s not exactly most people outside the rampaging postsophontist neophile civilizations), then you can just mindcast where you want to go (assuming of course they have the right receiving equipment, which is by no means guaranteed outside the aforementioned civilizations).  Which is substantially quicker and counts as fully casual interplanetary/interstellar travel, because photons and (especially) tangle move a lot faster than your own personal meat/rock can be transported.

Make Yourself at Home

“Welcome to Tessil System Space. You are now entering the Tessil system advisory zone. Contact Tessil SysCon on channel 43.2 and identify. Current ephemerides and system documentation updates are now being transmitted. Procedural control is now in effect.”

“Current alerts: Undocumented debris has been spotted in Adírdis-Celéres brachistochrone route section four, moving at 4.1 miles per second. Subchannel 7 contains continuous loop data on this navigational hazard.”

“Outer system approach vectors between 225+75 and 210+60 have been closed off due to a lighthugger’s deceleration burn. These approach vectors will be cleared for traffic in 27 hours.”

“A hazardous material incident has closed primary docks and locks at Qéral Station, Tessil L4. Duration of closure will be 5.8 hours estimated. Starships and spacecraft arriving at Qéral Station within this window are advised to delay their arrival or divert to alternates. Starships and spacecraft lacking Δv for such maneuvers should contact Tessil SysCon on channel 43.2.”

“New alert: Solar monitoring satellites indicate magnetic flux activity over the acme polar region of the system primary. Estimated time to solar flare is 49 minutes from this mark. Duration estimated at four hours, with peak radiation output of 0.12 Gy per minute. Tessil SysCon recommends all unshielded sophonts seek radiation shelters within the next 30 light-lag adjusted minutes. Solar flare predictions are accurate to +/- 20%.”

“Message repeats. Welcome to Tessil System Space…”

– Tessil-Galáré stargate nav buoy, general broadcast

Ask Dr. Science

Today’s question for Dr. Science is, “Why do lighthuggers have to stay so far out? Can’t they use the same highports as normal starships?”

While it would certainly be more convenient to avoid the lengthy shuttle trip to meet a lighthugger, the risks attached to the amount of energy needed to propel a ship between the stars at near-light speed make them something best kept away from population centers.

The smallest lighthugger in production, close to the practical lower size limit, is the Evelantar-class staryacht, whose unfueled mass is 5,451 tons. It is propelled by a Nucleodyne Thrust Applications antimatter pion drive, with fusion supplementation for lower velocities, giving it a maximum cruising speed of 0.9 c.

The mass ratio, including operational safety margin, of the NTA pion drive – the ratio between its fueled mass and its unfueled mass – is 25; but since a lighthugger in many cases cannot guarantee that it can refuel at its destination, the Evelantar is equipped to carry fuel for a two-way trip.

Thus, such a staryacht can carry up to 136,275 tons of fuel one-way, or 272,550 tons fully fueled, of which just under half is antimatter in the form of metastable metallic antideuterium. And, of course, when fueled for a two-way trip, over half of its fuel – because of the additional fuel carried as a safety margin – remains in its cryocels when it arrives at its destination.

Such an amount of matter/antimatter fuel would, if detonated, produce an explosion of approximately 2.6 teratons. In orbit of a garden world, this would be sufficient to create massive earthquakes and volcanism, megatsunamis, global wildfires, major atmospheric damage, and a high-probability extinction-level event, in addition to the radiation effects. These radiation effects and indirect impulsive shock would also be lethal to any habitats or drifts within tens of thousands of miles of the explosion. And this is the fuel mass of the smallest production lighthugger.

While the probability of a cryocel containment-safety systems failure is infinitesimal, the magnitude of these consequences – along with the possibility of deliberate sabotage or the use of lighthugger fuel as a terror weapon – is sufficient for virtually all civilized systems to restrict lighthuggers to far outer-system ports of call.

Dr. Science

– from Children’s Science Corner magazine