aerospace cruiser

(Apology &) Glorious New Tractor Factory

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First, the apology.

As you’ve noticed, this is the first thing I’ve posted this December, for which I apologize to all my readers and especially to those kind enough to pay me for posting things. To explain – well, it’s a second-order effect of our summer being-raided-by-the-Feds experience. (Details here, for anyone who didn’t get them at the time.)

You see, way back at the start of the month, we were called upon once more by the FBI, who were quite unexpectedly bringing our property back. I must reluctantly credit them for taking only four months to decide that weren’t, in fact, holding corporate networks for ransom, which by the standards of the American government is quite uncanny speed and efficiency. They even went so far as to apologize for “the inconvenience”, which was both (a) entirely unexpected and (b) possibly the most delicate euphemism imaginable for “having our goon squad smash up your house, terrorize your family, and help themselves to your stuff”. Dear friends, it was not the former which left me too slack-jawed with incoherence to make a properly sarcastic response.

As such, I have found myself spending the month going through the returned items, taking inventory and determining what will be the subject of future claims due to being obviously faulty (the two servers with large chunks of their cases broken off, for a start) or more subtly faulty now (gee, could that high abnormal sector count have anything to do with the natural antipathy of hard drives and fucking grenades), and then ensuring that they are all purified, exorcized, and mind-cleansed before being returned to use (my network does not need a case of foamy fibbie fever, thanks so much), which has taken up pretty much all of time.

And then it was Christmas, which was a timely relief from stressful reminders of bullshit.

But, yeah, that’s what I was doing this month instead of writing. Mea culpa, but at least I have some back ideas stored up for next month?

That all said, now, let’s talk about tractors. The beams, that is. This is inspired by a question a reader asked over on the Discourse:

Say, why aren’t tractors and other vector control tech used for fast atmospheric vehicles (especially aerospace cruisers)? You’ve got plenty of remass just sitting around outside, so you should only be spending fuel for the energy to run the vector control core?

But really, to answer it, I need to talk some about tractor beams in general, and so I’m going to do that.

Ultimately, tractor and pressor beams (and the hybrid torquor beams, which I’m not going to talk about extensively here but which y’all can deduce from the information on tractors and pressors) aren’t beams in the strictest sense. They’re representatives of one offshoot of vector-control technology, which is to say, non-local force transfer; the relevant engineered devices in this family acquired the moniker because an easy way to point your non-local force transfer is to heterodyne the exotic ontoeffect on top of a carrier. Hence “beam”.

(This is not the only way to do it: you can build a much simpler projector pair which, when powered on, will exert tractor/pressor effects between themselves – but only themselves. You can’t redirect the force anywhere else or otherwise point them. That makes them useless for many purposes, although if you want to build those cool-looking catamaran spaceships without physical hull connections or flying cities that don’t crush any poor schmuck who walks underneath, they’re quite useful for that.)

Rather than get into the messy internal details, I’m going to describe their effects. Basically, you can think of them as a springs-only-without-the-springs. If you lay a tractor beam on a target, it acts like a spring stretched between the projector and the target that wants to return to its natural length of zero; the further away the target gets, the harder it pulls, and ultimately it wants to pull the target right into the projector. A pressor beam, meanwhile, acts like a spring squished between the projector and the target that wants to return to its natural infinite length; the closer the target, the stronger the push, and ultimately it wants to shove the target an infinite distance away.

(Both of these phenomena are, of course, limited in range by the range of the carrier beam; if you can’t focus it on the target, you can’t project the ontotransfer. As the carrier beam disperses, the effective ontotransfer diminishes until the beam “snaps”.

Also, I am simplifying by using the projector as reference frame when I talk about the effects on the target. As with local force transfers, Newton’s Third Law is in effect: the tractor “really” pulls things together, and the pressor “really” pushes things apart. It’s just easier to talk using the projector reference frame.)

On its own, a tractor isn’t really all that useful; it has all the problems of a towrope – magnified, in space use, by the lack of a friction-providing medium – insofar as you can’t stop something moving towards you with a pull. Or, to put it simply, if you, the Enterprise, start towing a million tons of asteroid with your tractor beam, when you stop doing so, you’d better dodge before you get a million tons of assteroid, if you know what I mean.

Thus, in practice, all “tractor beams” are actually combined tractor-pressor units. The combination gives you the ability to hold things in place (along one axis): the tractor and pressor are configured so that the push-pull balances out at the intended distance. If the target moves closer, the tractor’s pull weakens and the pressor’s push strengthens, moving it back out; if the target moves further away, the pressor’s push weakens and the tractor’s pull strengthens, moving it back in.

Note that using a single tractor-pressor unit in this way only keeps the target in a fixed position along the axis of the beam. This can be useful in some scenarios, but as anyone who’s ever towed someone will know, does not stop it from fishtailing all over the place, along the other two axes in the absence of gravity. Tugs and other professional towers will thus use multiple projectors pointed at multiple tractor points in order to prevent this.

(A lot of tugs in the ‘verse have a similar layout to the nuBSG Cylon basestars, to mount three big projects at the end of the three protruding arms, thus giving them plenty of leverage and three-axis coverage.)

What’s a tractor point? Well, as I said, Newton’s Third Law applies: when you use a tractor (or a pressor), all the force you’re transmitting through it – potentially the full weight of the target – is applied to both the projector and the specific part of the target the beam is pointed at. For this reason, the projectors are generally bolted directly and heavily to the major structural members of a ship mounting them; likewise, on the other side of the equation, tractor points are heavily reinforced plates also bolted directly and heavily to the main structure, to provide places where a tractor beam can be safely pointed.

For non-barges, think of them as the equivalent to the tow hooks they fit to cars for emergencies, and important for the same reason: hulls are not designed to bear that much weight, and much like the case of the idiot who ties the tow rope around the fender, that will come right off and make a nasty mess. Hell, using weaponized tractors to rip off big strips of hull was even in vogue for a while.

Why not point the beam at the whole ship, you say?

Well, a couple of reasons. One, it’s a beam. Much like light only illuminates the surface of an object, the carrier beam only transmits the ontoeffect to the surface of the object. That’s not as bad as it sounds: obviously light doesn’t interact only with the first layer of atoms and nor does the carrier beam (another point in the design of tractor points is maximization of penetrance), but you aren’t going to force either through the entire object without deleterious effects.

And two, dispersal affects efficiency. A highly collimated carrier beam can deliver the ontoffect on target with little lossage; the wider you disperse the beam, on the other hand, the more lossage you get (the inverse square law is not your friend). The limiting case of this is the “reactionless drive” that works, essentially, by pointing this particular ontoeffect at half of the observable universe, at which point you’ve successfully achieved efficiencies that make the photon rocket look good.

So, to return at last to the question:

Say, why aren’t tractors and other vector control tech used for fast atmospheric vehicles (especially aerospace cruisers)? You’ve got plenty of remass just sitting around outside, so you should only be spending fuel for the energy to run the vector control core?

(And there is at least part of me at this point that really wants to say “the answer should now be deducible from the information given above”, but I’m not that mean, and besides, it’s Christmas.)

Well, there are some applications that are used, such as using tractor tethers to swap momentum (seen here) or turn corners more quickly by club-hauling against fixed tractor points; and other related effects, such as using the distinct paragravitational family of vector-control effects to, for example, build magnetogravitic jets with no moving parts. But as for main-drive effects:

  • You can’t push off things, because they suffer your weight. If you use a downward-pointing pressor to keep your aircar up, everything underneath you gets crushed, and very little of it was built to be run over by an aircar. This includes all aircars using lower altitudes.
  • You can’t pull on things either, because they too suffer from your weight. The club-haul grapple turn looks cool when you pull it off, but it looks less cool when you yank the coffee shop on the corner and all its patrons into the middle of the street trying it.
  • You can’t fix either of those by dispersing the beam, since the same inverse-square phenomenon that reduces the harmful effects also murders your efficiency to death.
  • Air (presumably the remass in question?) isn’t very motivatable by tractor-pressor technology, because it’s not solid and as such sucks at intercepting the carrier beam. (We’ve seen hand tractors being used in air before, I believe.) Tractor-pressors _do_ lose some efficiency in air – and create some minor draughts, if sufficiently powerful – because of the fraction of the beam that is intercepted, but much like shining a beam of light through air, it’s a tiny fraction. (Dust particles or water droplets can intercept it, though, so if you are in a filthy place or it’s foggy, be prepared to keep wiping the projector lens off.)

In short, you’re better off using other bits of the vector-control family for propulsion, like the basic mass-twiddling, and paragravitational widgetry like the magnetogravitic jet/pump.

Speaking of aerospace cruisers, though, consider the later designs where, given the translocation rings allowing easy back-and-forth transit, they simply keep most of the ship in orbit and use tractor technology to lower the entire flight deck into atmo…

Neither Fish Nor Fowl

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And next in our review of less conventional starship types, we come to that odd duck, the aerospace cruiser. (And many of these remarks, naturally, also apply to its larger cousin, the aerospace carrier.)

Ever since the early Imperial Navy absorbed the old air forces into its Close Orbit and Atmospheric Command (CLATMOCOM, under the Second Space Lord), these specialized classes and their equally specialist crewers have existed in something of a limbo, engaging in practices often deemed unnatural among decent, right-thinking spacers. Such as, if I may write in hushed tones for a moment, streamlining.

In short, while normally one can rely on a comfortable dichotomy between airships – which stay down in the nice, warm, notably present air – and starships – which avoid atmosphere in the much the same way that a thirsty Leirite avoids water – the aerospace cruiser defies this. While even the interface vehicles that bridge these two realms tend to minimize their time spent in the inconvenient middle, it spends all its operational time in a realm too low for low orbit and too high for upper atmosphere, being beholden to neither.

This requires a large number of rather unsettling compromises. Let’s begin our examination with the fundamental reason why: the entire purpose of an aerospace cruiser is to provide a secure base from which atmospheric combat vehicles can sortie, and in order to let them be competitive ACVs, it is necessary not to weigh them down with large extra drive mechanisms just to enable them to get to and from the mama bird. Thus, said mothership must not operate merely in low orbit, but dipping well into the atmosphere – into the lower mesophere – at typical altitudes for lithic worlds no more than 65 to 80 km (211,000 – 264,000′) above the surface. Such altitudes are already painfully difficult to reach for dedicated air vehicles, but manageable with relatively small auxiliary aerospikes.

And yet, the implications! A non-interface starship at this altitude suffers from high levels of atmospheric drag, enough to rip any normal starship’s – one not designed for atmospheric entry – structure apart, and thus, aerospace cruisers must share the great attention to streamlining and the heavier structure required by interface vehicles, but to an even greater extent, since the aerospace cruiser must not only penetrate the entry interface, but hang in it while launching and receiving aircraft from its vomitories.

(This in turn involves various trade-offs in other starship systems, like radiators, which must be accommodated behind streamlined panels while still functioning effectively; the point-defense laser grid must be tuned to atmospheric frequencies despite the effects on performance – and aerospace cruisers are well within the practical offensive range of ground-based aircraft and anti-aircraft systems; the engines must not choke when run in atmosphere; and so forth.)

The next issue, fortunately, partly cancels out this one. While an aerospace cruiser sustaining (via continuous burn; copious fuel supplies and an oiler or two to restock them are also essentials for space-to-atmo operations) orbit at 72 km would have to deal with an arbitrarily long period of fending off the atmosphere at 8 km/sec, consider that the period of such an orbit is a little under 1.5 hours, meaning that an aerospace cruiser maintaining its “natural” orbital velocity will pass very rapidly over the battlespace and out of air range; and pilots in general, it should be said, are notably unappreciative when their mothership leaves them behind.

To avoid this, aerospace cruisers are required to operate in forced orbits, maintaining station above a particular location. This requires, of course, even more copious supplies of fuel and multiplies the required continuous – and for those not familiar with the concept, continuous here means if the drive ever stops, you fall right out of the sky and die – station-keeping burn considerably, but at least it spares you quite so much brutalization by the atmosphere and makes launching and receiving aircraft practical, not just theoretically possible.

So before we continue and look at specific types, let’s raise a glass to these low-flying, fuel-gulping, plasma-shocking, sky-hanging abominations of nature, and all that sail in them! We don’t look down on you – except literally – but we wouldn’t have your jobs for a Service pension and a nice retirement moon.

– the Big Boys’ Book of Boom

Trope-a-Day: Standard Sci-Fi Fleet

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Standard Sci-Fi Fleet: Well, most of these classes exist – although it is particularly important to realize that the Empire alone fields literally thousands of specialized class vessels that don’t fit neatly into any of these categories, and that to a certain extent, trying to shove everyone’s ship designs into the approximate same paradigm is an exercise in futility…

Ignoring the permanent city-ships, and starting with the military classes, we have, first, the regular fighting-ship classes.  These begin with the frigate and destroyer (including the latter’s stealthy recon variant), small and fast ships used in “wolf-packs” for scouting, escorts, and screening elements, but which don’t themselves have the resilience or firepower to stand up in the wall of battle.

The middleweight combatants, and the most maneuverable/versatile, are the cruisers and battlecruisers, which also serve as screening elements for heavier ships, but are more often seen as the standard patrol and task-force element, often operating in flotillas (a cruiser wing with a battlecruiser or two thrown in for stiffening) or even independently (especially the battlecruisers).  And since this type of operation (power projection, anti-piracy patrol, general keeping the peace of the spacelanes) is the bread-and-butter of the Powers and their naval forces, most navies, the IN included, field more cruisers and battlecruisers than just about any other type of starship.

These are also classes that come with a large number of variants.  Most recognized among the cruiser classes are the assault cruiser (optimized for planetary assaults, i.e., heavy on the ship’s troops and capable of launching drop shuttles and drop pods into atmosphere; some of these are aerospace cruisers, which air fighters can sortie from before there’s an orbithead established); the diplomatic cruiser (a big stick to transport the softly-speaking); the point-defense cruiser (the one type of cruiser you might see in the wall, designed specifically to augment the point-defense of other ships); and the interdictor cruiser (specializing in the volume-security mission, which is to say, to chase down, capture and board other starships).  The primary battlecruiser variants are the command battlecruiser (optimized to carry the admiral commanding a CC/BC task force) and the carrier-battlecruiser (which carries AKVs – see below – as well as its internal armament; this is the type of BC usually found operating alone, due to its significantly enhanced operational envelope and capabilities).

Then we come to the actual ships of the wall, battleships, carriers, and dreadnoughts.  The battleships are the mainstays of the wall, large and slow vessels mounting heavy, long-range firepower for fleet engagements; and the carriers, even larger vessels, carrying an extensive complement of AKVs (autonomous kill vehicles, the missile/attack-drone fighter-interceptor hybrids described under Space Fighter, to swarm and destroy enemy starships at sub-“knife fight” range – i.e., hopefully inside the minimum effective range of their point defenses).  The dreadnoughts are effectively “super-battleships” built on carrier hulls, used in relatively small numbers to stiffen the wall.

Superdreadnoughts are either dreadnought-class vessels built on even larger hull frames, or regular dreadnoughts with only battleship armament, using the extra internal volume to hold specialized systems; common examples are the command superdreadnought which houses the admiral in charge of a large task force or fleet; the information-warfare superdreadnought; the loadout-heavy mauler superdreadnought, the anti-RKV superdreadnought, etc., etc.

At the top end of the regular classes, we have the hyperdreadnought – taking the design principles of the superdreadnought classes even further – of which the Empire fields three, each unique within its class; Invictus, Imperiatrix, and God of War.  In order, they are the home of Admiralty Grand Fleet Operations, the Imperial Couple’s personal flagship, and the literal embodiment of the archai/eikone of war.  Any one of them turning up on the battlefield would have implications that, by and large, no-one wants to think about thinking about.

Less regular military classes include the starfighter, a frigate-sized mini-carrier with four to eight AKVs clamped to its outer hull, used primarily for covert operations and commerce raiding; the fleet carrier, a giant (and not itself offensively armed) lighthugger starship on the lugger model (see below) whose purpose is to ferry naval task forces to systems not connected to the stargate plexus; the fluffships – whose design is implicit in their name – that police systems for debris, ricochets, and misses after battles; and the relativistic kill vehicles for practicing MAD on an interstellar scale with giant lighthugger missiles capable of shattering planets, given a good run-up.

Among civilian ships, there are also various recognizable classes of starship for different purposes:

For freight transport, for example, one can recognize both the immense grapeships (from the appearance of the external cargo pods) or megahaulers, which transport vast amounts of containerized cargo along the largest and most dependable trade routes, and their smaller cousins the haulers, smaller freighters which handle more volatile but still regular traffic everywhere, and are willing to handle breakbulk as well as containerized cargo, and of course the volatiles-hauling tankers; and finally, picking up irregular and speculative trade and filling in the gaps, the thousand different classes of free traders (and their somewhat more combative overlapping variants beloved of smugglers and irregular commerce-raiding privateers, the blockade runner and corsair.)  For routine transportation of volatiles, ore, and other such bulk and fungible cargo, fully automated slowhaulers often take up the task.

For passenger transport, likewise, we begin with the luxurious highliners and liners – analogous to the megahaulers and haulers in size and usage upon routes, and their express cousins the fastliners.  And then, for those travelling off the regular routes or seeking a more unique experience, a great many free traders are just as happy to carry passengers as they are to carry anything else.  Of course, the relatively wealthy and privacy-desiring have the option to travel in their private yachts, as ever, and at the other end of the scale, steerage-class transport is available to the relatively indigent on any number of iceliners, ships – often used as colonization transports – designed for the specialized task of transporting bodies in cryostasis or nanostasis, and minds recorded on data substrate.

In more specialized uses, dedicated classes abound: when messengers, mail, and packets need to get there really fast, within the stargate plexus at least, engine-heavy couriers are on the job; wrecks, debris, and flotsam are salvaged by debris recovery vehicles; hospital ships provide medical services (and reinstantiation services) to military fleets and disaster or epidemic-struck regions; logistics ships provide repair and construction services wherever they’re needed; oilers and tenders provide fuel, supplies, and other necessities to other starships; science, research, and exploration are done in the ubiquitous, customizable service/operations vehicles; smelterships render down asteroids into usable metal and other elements; and tugs and their larger cousins, the antimatter-torch equipped superlifters, move ships, modules, materiel – and in the case of the latter, entire habitats, asteroids, and even small moons – to where they’re needed to be…

…and if we’re willing to classify flying cities that are as much drift-habitats as starships, then we must include the civilization-backup ships, preserving archives, museums, and mind-states in the far reaches, ready to flee news of existential disasters; All Good Things, ICC, spreading the good word of commerce to underdeveloped regions with its skymalls; the empire ships, massive floating conferences/exhibitions/showpieces/parties flying endless loops around the Imperial Core and its many distant exclaves keeping population, culture, and knowledge well-distributed; and the embassy ships, similar exhibitions paying diplomatic calls on foreign polities and recently contacted worlds, bringing religiosity to the fuzzy-wuzzies and suchlike.

For local transport, small craft abound.  For freight, lighters scurry about transporting cargo ship-to-ship, ship-to-station, and ship-to-ground; for passengers, pinnaces provide the same service, and in moving about between local stations or habitats in a cluster, the automated commutersphere provides rapid transport. Skydivers skim gas giants for fuel; maintenance and construction are carried out by the ubiquitous workpod; and other myriad local functions are served by the flexible, customizable cutter.

All of these, of course, exist within the framework of the stargate plexus.  Outside that, a different type of ship entirely is required – lighthuggers need much more powerful engines (antimatter torch drives, for the most part) to reach the high fractions of c that make interstellar travel practical, sophisticated particle shielding to survive it, etc., etc.  Let us leave aside for the moment the shardcruisers (not true lighthuggers, but hybrid ships built to service outposts in the outer cometary cloud of star systems, whose longest-range examples fade into slow, short-range luggers); and also the starwisps, ultra-light – a matter of pounds – light-sail vessels propelled by lasers at their point of origin, carrying information, tangle, or the smallest probes across interstellar space.

These then divide into clippers – high-acceleration, relatively low-mass vessels carrying premium cargo and passengers at the highest possible speeds, including, in the limiting case, the private staryachts of the very wealthiest; and luggers, their relatively low-acceleration higher mass vessels carrying passengers and freight in larger quantity.  Specialized classes of lugger include the shiphauler (designed to transport docked starships rather than cargo directly; the military fleet carrier is an example of this type); the seedship (carrying ecopoesis packages and a startup colony); and the linelayer (transporting one half of a stargate pair to its destination system).