A Secret History of Jump Drive

or, how one item of technology shaped 10,000 years of human history

Humans on Vland invented jump drive in the year -9235. By that date, the Vilani had already established colonies using STL ships, but the new drive enabled them to found a true interstellar empire – the first since the downfall of the Ancients.

However, Vilani theories of jumpspace were flawed, and the drives they produced operated on a different principle to those in common use today. The main differences can be summarised as follows:

1) The Vilani jump drive (abbreviated as vJ-drive henceforth, as opposed to conventional J-drive) had no built-in method of precipitating a ship out of jumpspace at the end of its voyage. Instead, this was achieved by "running the ship up against a gravity well": (there is a more technical explanation, but it would be incomprehensible to a non-specialist). If done successfully, the ship would reemerge into normal space right on the 100-diameter limit. If the ship's vector failed to intersect a large enough gravity well, the ship would remain in jumpspace until its jumpfield collapsed and the ship was destroyed.

2) The operating principles of the vJ-drive meant that a maximum jump distance of two parsecs was all that could be achieved.

3) The vJ-drive had an extremely high power requirement at the moment of entering jump-space. Furthermore, it was also very vulnerable to power surges at this time, since even a tiny fluctuation of the drive could displace the exit point from jumpspace by several AUs – which due to the other problems of the vJ-drive might well result in a catastrophic misjump. To avoid any such risk, it was common practice to shut down all non-essential electrical systems on a starship making a jump – the origin of "jump dimming".

For over 3,800 years, the Vilani used the vJ-1 drive to expand. However, its inability to make jumps into deep space meant that astrography, and the existence of mains and clusters, had an overwhelming influence on the nature of their expansion. Even narrow rifts, such as that found a few parsecs to spinward of Vland, were almost insurmountable barriers. The only way to jump from one main to another was if a suitably large asteroid, comet or similar object could be located within the rift – and spotting a small, non-radiating object from a one parsec distance was almost a matter of chance. Whenever one of these bridges across a rift was located, it would quickly become a major focus of exploration and colonisation missions. On some rare occasions, the Vilani government bureaux would create an artificial bridge, by attaching thrusters to an asteroid and moving it through realspace into the rift. However, such endeavours had a huge cost, took many years to complete, and had an uncertain payback, so they were very rare.

In the year -5430, Vilani scientists finally achieved what their theories had long said was possible: a two-parsec jump drive. This revolutionised space travel. The strategic implications of the vJ-2 drive were quickly realised, and it was made an official, Government monopoly. vJ-1 drives had been freely sold to minor races and client states, but the vJ-2 drive was used to outfit fleets of warships that went out to conquer those non-Vilani states.

Under the Ziru Sirka, the vJ-2 drive remained a state secret. Virtually every high-population planet was able to make vJ-1 drives (although even then knowledge of how to produce and maintain them was usually reserved to certain specialist castes), but only certain selected strategic centres were permitted to make the more powerful system. Their output was mostly reserved for military and government use. The bureaux did maintain fleets of jump-two capable merchant ships, but these were almost always used to cross rifts and connect clusters, rather than in general trade. These state-owned bulk freighters and jump tenders would carry cargoes and privately-owned starships from one main to another, creating a makiidi or "ferry" to back up the naturally-occuring "bridges".

The ferry system was very profitable; and it was also a major tool of social control. The threat of removing a ferry, or the promise of setting up a new one, could often bring a troublesome planet back into line. In the case of major unrest, a cluster could even be completely isolated from the rest of the sector. Of course, the fact that all trade, passenger travel and information flow between clusters also passed through the bureaux' hands was highly significant. In consequence, over the years the government came to discourage the use of natural bridges, or even suppress knowledge of them; and it completely ceased creating artificial ones. In fact, there is some evidence of a deliberate psychohistorical project to make the idea of fastening engines to large rocks and firing them off into space seem ludicrous, primitive and dangerous to the average Imperial citizen. As for the bridges which already existed, since they were no longer recorded on maps or used for legitimate commerce many of them became havens for smugglers, dissidents and pirate bands.

Meanwhile, on another world far from Vland, other scientists were working independently on the concept of jumpspace. The theory that the Terrans developed in -2434 was very different to that used by the Vilani, and is accepted today as being correct. The first Terran J-1 starships were therefore capable of jumping to deep space, rather than only to a gravity well – which is fortunate, since Terra's nearest neighbours are two parsecs away. However, the ships were also unreliable and very fuel-intensive, and were unable to carry sufficient fuel to make several jumps in succession – meaning that the Americans had to set up a refuelling base in deep space as a staging post for their first expedition to Barnard's Star in -2424.

The resulting contact with the Vilani led, after just 16 years, to war. However, by the time the war broke out the Terrans not only had starships, but jump-two capable starships.

Vilani jump drive had been an eagerly sought-after item of technology, and the Vilani traders were happy to sell vJ-1 drives to the ignorant Terran barbarians. This was a classic part of Imperial strategy: sell high-technology machinery to the minor races, make them dependent on it, but keep knowledge of how to maintain and replace the equipment a Vilani secret. Soon the foreigners would be begging to be made part of the Ziru Sirka. It had always worked before – and the idea that the primitive Terrans would be able to produce their own version of jump drive seemed ludicrous to most Vilani. Indeed, even after the early Interstellar Wars apparently gave the lie to this, many Imperials persisted in believing that the Terrans could not have developed the technology themselves, and must instead have been secretly supplied it by dissident Vilani. The resulting fruitless witch-hunts for these traitors would be a major distraction from the Ziru Sirka's war effort.

Using the imported drives bought from the early traders, the European colony on Prometheus immediately began exploring and colonising the "Outback" cluster of stars. However, over half of the vJ-drives bought from the Vilani disappeared into government and private research centres, workshops and laboratories all over Terra, where engineers quickly set about reverse-engineering the Vilani jump drive. While the native-built J-drive might offer theoretical advantages, the vJ-drive had 6,800 years of technological development behind it – it was incredibly reliable, efficient, easy to maintain, and cheap. Pure scientific research into jumpspace theory was largely abandoned in the rush to assimilate, catch up with and improve on the vast body of data acquired from the Vilani.

However, the vJ-1 drive was unable to cope with the 2-parsec gap between Terra and her colonies. The Vilani governor's office made an offer to set up a ferry system for the Terrans, but they – recognising the trap – politely declined. Soon after, the first Terran vJ-2 ships appeared. It is unknown how the technology was acquired: by bribery and corruption of lax Vilani officials, by straightforward scientific extrapolation from existing data, or by covert action [ie "a small group of skilled but disreputable adventurers seizing a Vilani vJ-2 starship and piloting it home to Earth"]. Regardless of the source, this development was a huge breach of both Imperial law and immemorial custom, and was a primary cause in the breakdown of relations that lead to war.

For the next two centuries, both Terrans and Vilani waged war with ships that used the vJ-2 drive. However, the period of peace and prosperity enjoyed by the Terran Confederation after the Seventh Interstellar War allowed it to re-devote resources into pure science again, instead of always playing "catch-up". The old jump-space theories had been largely ignored for 200 years, on the basis that since the Vilani were so successful, their interpretation of the facts must be the correct one. A new generation of scientists such as the notorious Dr Robert Meson, less overawed by the influence of the Ziru Sirka, looked again at the old theories and proved their validity. The result was the Terran invention of the J-3 drive, and the final defeat of the Vilani fleets.

Under the Rule of Man, the Terrans built many new factories to construct J-3 drives: and the same plants were also able to make J-2 and J-1 drives economically. However, the vJ-1 and vJ-2 drives did not fall out of use immediately. Partly, this was a question of scale and inertia: there were thousands of planets producing vJ-1 drives, and hundreds of thousands of starships using them. However, strategic factors also played a role. Officially, the Terrans rejected the old Vilani controls on technology, and called for free trade. In practice, the Navy – which meant the government – recognised the military importance of J-3 drive, and tried to restrict its availability. Shipyards capable of making the new drives were restricted to a handful of "easy-to-protect" planets – usually the same ones that had been authorised to build vJ-2 drives under the Ziru Sirka. Most such drives were purchased by the military, or by the aggressive Terran trade corporations. The old Vilani system of "ferries" was allowed to fall into disuse, as it smacked too much of state regulation and bureaucratic control. Instead, Terran-owned cargo lines set up trade routes directly between profitable centres of commerce – bypassing many worlds that had previously played a key role in the local cluster's economy, and sending them into a spiral of economic decline.

By the end of the Second Imperium, probably 30% of its starships (by number of hulls) used the new drives. The old vJ-2 drive had fallen out of use, but about 70% of starships still relied on the old vJ-1 drive (although when the calculation is done by tonnage instead of by number of ships, the new J-drives were far more important). Ironically, as the Long Night deepened it was the vJ-drive that would remain in production longer. The J-drive was manufactured on a handful of worlds, and its main purchaser was the goverment – so when long-distance trade collapsed and the government ran out of money, it was these companies that went out of business first. Individual planets could still make vJ-1 drives with their own resources, and maintain links with their neighbours. However, the decay of the ferry system meant that each cluster was now isolated from its neighbours, with no way to cross the rifts between them; and so the Rule of Man gradually fragmented into hundreds of minor states, each separated from the rest by the facts of astrography. As trade declined further, many worlds turned to their own resources and abandoned star travel entirely.

It was this decay of technology that made the final triumph of the J-drive over the vJ-drive possible. Economies of scale and production expertise had kept the less effective vJ-drive in use despite a better alternative being available, but only while the existing industrial system functioned. The Long Night created a clean slate. A world such as Sylea that was rebuilding an interstellar society from scratch could learn from the mistakes of the past and produce the superior J-drive instead of the faulty vJ-drive. Indeed, historical researchers often found it easier to rediscover knowledge of the Terran system, since information on it had been freely published while the Vilani had regarded all technical specifications as caste secrets. By the time of the founding of the Third Imperium, Sylea was again constructing starships with J-3 capabilities.

By approximately 200, the vJ-drive was no longer in use anywhere within Imperial borders. Most of the starships that had been equipped with these engines had been relics of the Long Night – many of them centuries old – and by 200 they had all been replaced by shiny new J-drive ships sold by the Imperial megacorporations. Similarly, the few planets that had maintained some shipbuilding capability through the Long Night – usually an old Vilani vJ-1 installation – had by then been economically integrated into Imperial society. Their shipyards were either modernised by megacorporate investment, or driven out of business by competition from their more up-to-date rivals.

This new technology meant that in theory, the Third Imperium's trade and colonisation efforts were no longer dependent on mains, clusters and rifts. However, events such as the discovery of the Spinward Main were still cause for excitement. Partly this was due to tradition, and the fact that popular thought had not caught up with the possibilities that technology now brought. In addition, the fact that the Long Night had made clusters and mains into isolated entities gave them a political importance entirely separate to their economic role. The Imperial system of rigid, rectangular subsector borders was a deliberate attempt to undermine the independence of such "organic" political units, but one with dubious success.

During the following millennium the Imperium developed, in succession, the J-4, J-5 and J-6 drives. Current theory states that J-6 is the maximum attainable. Certainly no known society that attained greater than TL F (such as the Darrians) has been able to sustain a jump for further than six parsecs. (The capabilities of the Ancients in this regard are unknown, although the more fanciful commentators have claimed that the sheer extent of their empire, stretching from Zhodane to Terra and beyond, implies some faster form of travel or communication).

However, it is known that in rare instances, misjumping ships can travel as far as 36 parsecs – leading some researchers to speculate that a J-36 drive may one day be possible. This theory states that jumpspace comprises several layers, and the ß-layer stands in the same relation to the a-layer as that layer does to realspace. A misjump is caused by the ship entering the ß-layer (or even higher layers, such as y-, d-, or e-) instead of the a-layer. In most cases the ship is destroyed; but if a means is ever found to use the phenomenon of the "misjump" in a controlled and safe manner, the effect on human society will be as revolutionary as those first experiments on Vland 10,000 years ago.