Otherspace

The higher-order dimension that most people just call “otherspace” is the discovery that birthed the Foundation as it exists today. Access to it is what allowed humanity to colonise the stars, but that access is still limited and poorly understood. The technology used to transition between realspace and otherspace is strongly affected by gravitational fields, to the extent that shifting an entire ship into otherspace is impossible in the gravity well of a star. If a ship wants to make use of its Llewellyn Drive for faster-than-light travel, it needs to travel to the outer reaches of its current system first. Likewise, ships that “collide” with an unexpected gravity well in otherspace are torn back to the lower level of reality - often with serious damage as a result.

The stronger the gravitational fields you are subject to, the more energy you need shift even a small object into otherspace. By expending huge amounts of power, it’s possible to send electromagnetic energy into otherspace within a star’s gravity well - but only energy, not matter. This has allowed for the creation of ships that can redirect their energy signatures into an extradimensional heat sink, but it seems that is as far as the technology will go for now.

Astrogation

The calculations required to navigate a ship through otherspace to a given realspace destination are far too numerous and complex for a human to ever perform. No captain actually pilots their ship between the stars; they simply plug their destination into the astrogation terminal, engage the Llewellyn Drive, and wait.

This hassle-free process relies on the captain having a navkey: a precalculated set of extradimensional vectors and formulae for a destination. Without one, the ship’s onboard computer can’t perform the calculations required for a safe voyage through otherspace. Navkeys require immense computing power to generate, and they are made up of an enormous quantity of information. That means that sending one via radio would take weeks; they generally need to be distributed in person, on a dataslab.

Of course, navkeys don’t just appear out of thin air; someone needs to create them. Nor can you just tell a supercomputer to crunch the numbers for a month and spit one out. The only way to create a navkey is by mapping out the extradimensional route with an exploratory vessel. This is a slow and dangerous process, requiring many “blind jumps” that carry you closer and closer to your destination in a series of short hops. It is during these trailblazing missions that many of the greatest of otherspace’s hazards manifest.

Navkeys to well-travelled systems have been in circulation for a long time. They come preloaded onto most ships, and can be easily obtained for a small fee at any station. Navkeys to previously “uncharted” systems, on the other hand, are treasures that can command a small fortune. If no one but you has the navkey for a star, no one but you can get there quickly and safely. For those who wish to be left alone, or to live beyond the grasp of the Foundation or any other authority, a private navkey is the ultimate asset.

Strange Horizons

For adventurers that travel between the stars, otherspace is two things: it’s the medium that you must travel through to achieve faster-than-light travel, and it’s a mysterious and poorly understood place filled with strange and sometimes dangerous phenomena that defy explanation. Otherspace has captured the popular imagination as a haunted, beautiful and deadly place; it’s no surprise, then, that the Foundation is full of ghost stories and urban legends about it.

When you’re travelling through otherspace with a Llewellyn Drive, the area around your ship is an envelope of reality in an unreal world. Seen through viewports and cameras, it appears as an eerie iridescent bubble whose mottled surface is a constantly-shifting swirl of fizzing colours. Anything that passes beyond the surface of that bubble is simply gone - people, debris, probes. No one knows what happens to things which leave the envelope, and nothing has ever been recovered once it passes through.

The jury’s still out on the reverse, though. Interstellar veterans have all kinds of stories about things they’ve seen in otherspace. Strange shapes, ominous visions, and even the faces of loved ones have been glimpsed hanging in the veil of colour. There are even scattered reports of so-called otherspace horrors emerging from that bubble and hitching a ride on unsuspecting ships - and some believe the alien pests known as Myriad originate from otherspace.

Otherspace visions are generally considered by the mainstream scientific community to be a delusional syndrome caused by the reality warping properties of the envelope, and the official advice is “don’t look”.

Extradimensional Hazards

The biggest threat to any interstellar traveller is one that originates in realspace: a black hole, rogue planet, or unexpected gravity well. These things are rarely a problem on well-known and frequently travelled routes, but they’re the bane of the trailblazers that make blind jumps in search of new stars. Encountering a significant gravity well where you didn’t expect to find one is enough to unravel your ship’s envelope and pull it violently back into realspace.

There’s usually at least some damage when a ship gets torn from otherspace, and deep space light years from civilisation is not where you want to be doing critical repairs. It happens a lot more frequently than you’d think, given the vastness of the cosmos - that’s because the currents of otherspace bend around gravity wells, creating “shoals” that can ensnare the unwary astrogator.

The strange eddies and currents of otherspace sometimes shift and change unexpectedly, changing the topology of this mysterious space and making it difficult to navigate. Established navigational routes are carefully plotted to avoid this turbulence wherever possible.

Those explorers or unlucky souls who do get caught up in an otherspace current tend to end up in the same places, though, for reasons currently unknown - there are “graveyards” of the lost and forgotten out there in the black, aggregated over centuries. There even some exceptionally brave or foolhardy travellers who try to ride those currents on purpose, hoping to pick the bones of the dead and emerge with a fortune of salvaged grave goods.