BY LETTER
New Brooklyn Worldships
 Image from Steve Bowers | |
| A ship from the First Fleet of worldships that left New Brooklyn in 5031 AT | |
Since the Version War, the independent Inner Sphere polity known as 'New Brooklyn' has been launching worldship fleets twice a millennium. Each fleet contains five to six of the giant ships that are the result of centuries of construction and is aimed at distant locations thought to be uninhabited and (at the time of launch) not known to be targeted by other colonization efforts. The first departed in 5031 AT for Omega Centauri, a globular cluster or dwarf galaxy nearly 16,000 light-years from Earth.
Though risky due to the chance of computer or memetic infection, two worldships in each fleet maintain a nanogauge commgauge wormhole link to the edge of terragen space. This allows travel by aioids and uploads between the fleets and home. More importantly, it gives New Brooklyn timely alerts of any trouble or failure of the missions. However, the ships are deliberately not linelayers for traversable wormholes, which is meant to isolate the ships from vast changes in terragen space during the journeys.
PASSENGERS
Each worldship is launched with an active population of thousands of modosophonts and a few transapients. There is the expectation that the population will grow over millennia of flight to several million inhabitants. Tens of millions of additional New Brooklyners contribute nondestructive uploaded copies of themselves that are kept in inactive storage, allowing them to sleep away the long journeys, while a smaller fraction of the uploads are active in the ships' virch worlds. The mix of live and uploaded colonists provides redundancy and fallback strategies.In addition to the modosophonts, each ship is governed by an S2 shipmind and each fleet has an S3 "fleet mind." There is also a pair of transvot S3 Secdats monitoring wormhole communications, one of which remains in New Brooklyn. The S3 minds in the ships use small, dedicated volumes of S4-tech plasma processors not available for general computing.
PROPULSION
The worldships are propelled by distributed displacement drives. The ships use a noticeable percentage of New Brooklyn's void mote production to produce enough void motes for each behemoth ship and their long journeys, and the bottleneck in production is the primary reason they are only launched every 500 years. Every ship since the Third Fleet (launched in 6007AT) has used S5 void motes with greater endurance than traditional S4 displacement drive motes. The importance of the engines is such that they are kept in the stern of the ships, using even the habitat as a last line of shielding. Habitat occupants are backed up, but the displacement drives are not replaceable mid-flight. (The fleets could theoretically stop, build a void forge, and then more motes, but hope to avoid such a time-consuming endeavor.) The displacement drives are able to push the massive ships to 1G, but this capability is only used during launch and braking. Most in-flight maneuvers use far less thrust.The giant ships have plenty of mass to spare for secondary propulsion systems. They include powerful conversion rockets (suited for 0.01G acceleration) backed with ramscoops to gather mass for conversion and to act as electromagnetic brakes and steering systems. However, the available delta-V of stored reaction mass is only on the order of 0.1c, insufficient to fully start or stop the ships without sacrificing hull mass.
Sometimes boost beams have been utilized in the launch system, the system from which they depart the Wormhole Nexus. Boost beams also offer an interesting braking option, especially in resource-constrained emergencies. The fleets are quite able to detach much-smaller support ships to race ahead of them, reach a sufficiently distant system, and construct mass beam arrays that can decelerate the fleet.
DEFENSES
The worldships use relatively conventional, high transapient armor, active anti-debris systems, magnetic scoops, and pathfinder lasers. With longer flights than most relativistic ships, the New Brooklyn worldships deploy several types of supporting vessels up to fifteen billion kilometers (100 AU) ahead to support a leading column of smart dust, further than the pathfinder laser's effective range.The ships that range ahead of the pathfinder lasers include active defense platforms with powerful sensors, lasers, and smart munitions ("dust busters"); freighters that disperse and recover clouds, disks, and columns of smart dust ("dust bunnies"); and the small platforms that electromagnetically maintain coherent formations of the smart dust ("dust bugs"). This enormous defensive depth is used for two reasons: first, it gives the ships hours to enact the next defensive option, which is dodging. Second, at 0.7c debris produces radiation flashes equivalent to about 10 megatons per kilogram of debris. 100AU gives volume for the explosion to harmlessly disperse without disrupting the entire defensive column.
Dodging must be done with care. The worldships are capable of accelerations that would ravage their spin-maintained habitat interiors and thus rarely use more than 0.01G. This requires several minutes to move a kilometers-wide ship completely out of line with small debris. Further, any dodge risks moving out from behind the smart dust column and space debris rarely travels alone - one pebble is probably part of a comet's tail, for example.
Sensors are arguably the first line of defense. The networked, interferometric telescope systems, lidars, radars, and more exotic systems on the ships and their dust busters give a New Brooklyn worldship fleet a fantastic view of threats even light-years ahead. While individual pebbles cannot be seen at such distances the ships are able to estimate concentrations of interstellar dust and gas years in advance and plan maneuvers to minimize risk.
The ships themselves have potent defensive weapons (such as the pathfinder lasers) and the prows of the ships, of course, have robust relativistic debris armoring developed by the lesser archailects of New Brooklyn. However, those are considered defenses of last resort. If the ship itself is engaging dust, the leading defenses have failed.
The ships do not operate independently. The entire fleet integrates their sensors and defenses. Further, the ships use the simple expedient of 'drafting.' In the now-standard 6-ship fleet, the worldships travel in three well-spaced columns (or squadrons) of two ships. The fleet's squadrons generally travel abreast with each squadron spaced 10 AU apart. One of the outer squadrons has the commgauge wormhole, typically in the trailing position - though not so much as a single ship in any of the 12 fleets have actually been lost, let alone suffered a wormhole failure. Within a squadron spacing is much closer, typically less than 10 million kilometers to minimize flight time for intrafleet shuttles and to minimize the time for drifting space dust to fill the path cleared by the smart dust column. A squadron is unlikely to survive its trailing ship suffering a wormhole failure, but otherwise the configuration puts the full bulk of one worldship ahead of the other. Any object that seriously damages one worldship is unlikely to reach the next ship in the squadron with its original velocity.
In addition to the heavy bow armor and debris defenses the ships are clad in radiation shielding thick enough to shed even cosmic rays and, when combined with the ship's Emple-Dokcetic shielding, might protect a ship from a commgauge wormhole failure in another ship in the fleet. The interiors are better-protected than even the habitats in New Brooklyn.
It is recognized that the fleets represent major colonization efforts worth subversion via their wormhole communication links. All the world fleets thus elaborately protect their wormholes and internal computers. The first line of defense is a pair of dedicated S3 Secdat AIs, one on each end of the wormhole carried by a fleet. The second is that the fleets utilize unique computronium architectures, operating systems, and software, which are developed separately for each new fleet and then, as best possible, deleted from records in the New Brooklyn shipyards. Conventional programs and even AI viruses simply won't run. Vital subturing systems depend on non-rewriteable storage and hardwired circuits for core functions.
Visiting sophtware is run in virtual machines on specialized biological substrates. These biological computers are unable to interface directly with the other computers of the ship, which cannot understand the chemical signals of the biological computers. While these biological computers are powerful enough to put a modosophont in engenerated human-scale bodies, visiting transapients are stuck in large, immobile processors and their limited virch worlds. There is not enough bioprocessor capacity on a ship to run more than one visiting S2 entity and then only at speeds much lower than the plasma processors and ultimate chips used by the ships' resident transapients. Finally, the isolation of wormholes to two ships in each fleet allows additional barriers to be placed between the rest of the fleet. Because New Brooklyn "only" has S4 entities, it is assumed S5 or S6 archailects could still find a way to defeat the defenses and subvert the ships, but the only noted attempts have been from sub-archailects and normal Known Net malware that have not foiled the Secdats.
WORLDSHIP DESIGN HISTORY
The fleets have gone through several configurations. The driving concerns are providing spin "gravity" during the long flight; compensating for acceleration during launch and braking maneuvers; minimizing exposure to interstellar dust and gas; and containing catastrophic damage.A cylindrical design neatly addresses the first and third issues, but preventing slumping of interior terrain while under acceleration is difficult. The First Fleet nevertheless built its five ships as cylinders. At launch, the enormous ships splayed open their habitats into six individually-sealed sections. At "high" acceleration (defined as 0.5G to the ships' maximum 1.5Gs), the habitat was entirely de-spun and fully opened so that the habitat arms formed a 6-rayed stay around a central drive core. The larger frontal area necessitated greater smart dust dispersal rates than in cruise configuration, but a 1G boost phase allowed the fleet to reach its cruising speed in less than 9 months. Near the end of its boost phase, the First Fleet ships would taper off engine thrust over the course of a day while beginning to spin and closing their habitats. Extensive use of long-rooted plants in the soil, barriers in habitat walls, and anti-slosh shore designs allow the ships to perform 0.01G maneuvers during flight. It will be a decision for the crew to spend decades performing a gentle braking maneuver at Omega Centauri or again open the habitat into a braking configuration for fast deceleration.
The First Fleet's ships had habitats 5 kilometers in diameter and 50 kilometers long. With the risk of the habitats being pierced by debris, the habitats remain separated by their diamondoid and sapphiroid bulkheads. However, this still puts the entire habitat in line with head-on collisions. Ahead of the habitat are the heavy bow armor; dust buster/bunny/bug hangars; gigatons of smart dust raw materials; and nanofabs and cargo bays for developing Omega Centauri. The stern has the engineering section of the ship. Except for displacement drives, each section of the worldship duplicates the vital capabilities of the other sections. The habitat, for example, had enough nanofab capability to convert some of its enormous bulk into conversion drives and reaction mass to brake should the bow and engineering sections be lost.
The Second Fleet uses a transitional system between the First and Fourth Fleets. The cylindrical habitat was constructed of a series of twenty stacked toruses each 6 kilometers in diameter and 3 kilometers long, forming a cylinder some 60 kilometers long. This effectively produced transverse bulkheads in a long, subdivided cylindrical habitat that reduced the risk of through-habitat penetration found in First Fleet. However, each torus had to flex outwards (in the manner of First Fleet's habitat arms) to accommodate sustained acceleration above 1G and did so at 12 points, making the habitat subdivided into 240 sections of approximately 1.5 by 3 kilometers. The ships' architects used this to produce a staggering range of environments and ecosystems to keep the residents entertained in their long flight, but most passengers were former residents of megastructures who preferred larger, open habitats. In addition, the accumulating centuries flight experience of First and Second Fleets showed that debris defenses were working well.
The Third Fleet this significantly simplified the "flexing torus" design of Second Fleet by having only a single, large torus. Some magmatter cables did lace across the diameters of the rings to hold it together in case an the ring was severed in one location, but presented negligible cross-section to interstellar dust. During some docking operations, a small hub could be grown from a couple of temporary spokes to provide a non-spinning docking port. Instead of using massive, mechanical pivot joints like the Second Fleet, the worldships of the Third Fleet use pandifico to allow modules of the ring to flex outward (at their interior bulkheads) and balance the linear acceleration (limited to 0.1G) with centripetal acceleration during launch. Four engineering sections are distributed around the ring, while cargo and smart dust reserves are kept on the leading edge. Third Fleet worldships were again 50 kilometers in diameter.
The Fourth Fleet and subsequent fleets shifted to an all-ring configuration, eliminating even the hub except in ships carrying wormholes. Some magmatter cables did lace across the diameters of the rings to hold it together in case the ring was severed in one location, but presented negligible cross-section to interstellar dust. During some docking operations, a small hub could be grown from a couple of temporary spokes to provide a non-spinning docking port. Instead of using massive, mechanical pivot joints like the Third Fleet, the worldships of Fourth Fleet use pandifico to allow modules of the ring to flex outward (at their interior bulkheads) and balance the linear acceleration (limited to 0.1G) with centripetal acceleration during launch. Four engineering sections are distributed around the ring, while cargo and smart dust reserves are kept on the leading edge. Fourth Fleet worldships were again 50 kilometers in diameter. The Sixth Fleet's (launched 7512AT) modest refinement was aesthetic: the worldships' hulls were streamlined to a simple, elegant black form without the obvious extension joints and bulges like the Fourth and Fifth Fleets.
Later worldships grew at the rate of about 10 kilometers diameter per fleet until the Twelfth Fleet, launched in 10509AT, consisted of ships 125 kilometers in diameter.
The ring shape and large habitat spaces are imperfectly protected against shipwrecking collisions. There are more defensible, survivable configurations. For example, a ship with only uploaded passengers could be a great deal more compact, armored, and survivable than one with large, open-volume terrestrial habitats. Indeed, the New Brooklyn worldships carry passengers in that state because of their survivability. The large habitats and compromise configurations are an aesthetic choice, one affordable to the fleets' makers that probably will not interfere with the success of the fleets. Success is just more expensive in terms of energy and mass than smaller, habitat-free designs.
Finally, like many modern, large ships, the New Brooklyn worldships can reconfigure into many small packets for wormhole travel. This cuts thousands of light years from the sub-light journeys, even if the transit tolls sometimes set records and necessitates "mothballing" habitat interiors.
 Image from Steve Bowers | |
| A Twelth Fleet worldship, showing the four displacement drive units and, in the centre, support systems for the commgauge wormhole. | |
MODERN WORLDSHIPS
The Twelfth Fleet's ring habitat has an external cross section of a box with beveled edges. The box center of the ring is 20 kilometers long (bow to stern) and 10 kilometers thick, while the beveled bow and stern have triangular cross sections each 10 kilometers long, making the ship 40 kilometers long. The exterior diameter of the ring is 125 kilometers. Inside the outer hull is the habitat ring, which has an ellipsoidal cross-section. It is 25 kilometers long and 9 kilometers thick.The space between the habitat and outer hulls is filled with cargo bays, docking bays, smart dust reserves, and ship systems. The leading edge is particularly well-filled to help absorb energy from armor failures. With up to 7.5 kilometers between the edge of the outer hull and edge of the habitat ring, even Information Age materials could absorb explosions rated in petajoules (or megatons, in the vernacular of the era). However, high transapient armoring raises that considerably; the ultimate strength of the structure is such that the human passengers and terrestrial habitats will be destroyed by the shockwaves long before the structure fails.
The habitat ring is separated into four habitat 'arcs' that each occupy 85 kilometers of the circumference. In between the arcs are four engineering sections that are 13 kilometers long and have a quarter of the displacement drive's void motes of displacement drives each. Each habitat arc is subdivided into 3 sections about 28 kilometers long by double bulkheads. When the ship needs to brake or accelerate by more than 0.01G, the ring splays open slightly at extension joints between the double bulkheads. This allows the centripetal acceleration of the ring to add with linear acceleration to produce an acceleration vector in the same direction as pre-maneuvering acceleration. In other words, flat surfaces seem to stay flat. In practice, the result is imperfect due to terrain and habitat curvature. During normal operations, the bulkheads also have sizable openings to allow passengers, air, and water to move between habitat sections.
The curved floor of the habitat ring offers 30 kilometers of usable surface area, totaling 10,200 square kilometers of habitat space. During the multi-millennia flight of the worldships, this is expected to be populated to a density of 1000 humans per square kilometer, albeit concentrated in urban areas at even higher densities (up to 7500 per square kilometers). This would give each worldship in the Twelfth Fleet a live population of about 10 million by the time it reached its destination. There was considerable leeway for overpopulation; the ships had mass reserves to rebuild from catastrophic damage, let alone address an improbable pink goo outbreak.
The habitat arcs had different themes for their environments that vary within a ship and across ships of the fleet. At launch the terrain had been arranged by transapient artists to produce works like Perfect Art like a Kar Vara habitat, with the understanding that growing populations would continually modify the interiors. This planned occupancy and development limits the terrain choices to those that will readily host growing human populations. Two ships in the Twelfth Fleet have To'ul'h habitat arcs.
A perpetual source of entertainment for modosophont passengers is the Fleet's sensors. In addition to watching for debris, the active optical arrays covering the ships' surfaces allow the ships to turn large areas of their surfaces into powerful astronomical instruments. The six ships of the fleet form a multispectral interferometer 100AU across. Though hardly comparable to the Argus Array, they give an amazing "live" view of the galaxy around the fleet. These views are crafted into a varying night "sky" inside the habitats.
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Text by Mike Miller
Initially published on 14 April 2015.
Initially published on 14 April 2015.
