Data File Updated: Thursday, April 24, 2008

FTL (Faster Than Light) travel in Outsider is via "jump drive", which is a form of point-to-point hyperspace travel. It works similarly to the systems described in Niven & Pournelle's The Mote in God's Eye or C.J. Cherryh's Downbelow Station mileu: a ship "jumps" through hyperspace from one star to a nearby star, then crosses the space between jump points using normal drives. There are no "gates", just a point or vector you want to be on toward the next star, so that the destination star's gravity well will suck you back out of hyperspace. Vector and momentum are preserved; you come out of jump with the same velocity you had before you jumped. The jump is almost, but not quite, instantaneous. I should probably refer to "jump points" as "jump zones", since that's a more descriptive term. A jump zone is a conical volume centered on the vector connecting two masses (Fig. I). The outbound jump zone is very wide, and extends a great distance out into interstellar space; as long as your initial vector will carry you close enough to the destination star for its gravity well to pull you back out of hyperspace (and as long as you are far enough out / have enough velocity from the departure star to escape its own well), then you don't have to be exactly on the line (the “jump vector”). The inbound jump zone is much smaller; a ship coming out of hyperspace will appear fairly close to this jump vector; how far from the destination star it appears will depend on the ship's hyperspace momentum, which is increased by departure velocity and decreased by jumping from deeper within the departure star’s gravity well. The more hyperspace momentum you have, the closer you will appear to the arrival star. If you have too much momentum it’s possible to exit hyperspace too close to or even inside the star, or to overshoot it entirely causing a hyperspace “miss.” If you don’t have enough momentum to escape the departure star’s gravity well, you’ll be pulled back in, either exiting hyperspace inside the star or popping out the other side still in hyperspace, again causing a miss. The greater the mass of the target star, the greater the chance of a hit, but also greater is the chance for an "overjump". The outside boundaries of both outbound and inbound zones are "fuzzy"; the farther away from the jump vector you are when outbound increases the risk that you may miss your target, and you can never be sure exactly where along the inbound zone a ship will reappear. No one is certain what happens on a hyperspace “miss”; ships are presumed to either exit hyperspace somewhere far, far off target… or perhaps never exit hyperspace at all. In a few instances, when a “near-miss” occurred, ships have reappeared an unusual distance from the normal inbound jump zone. This is also why system transit speeds need to be kept reasonably low, since jumping at a higher speed requires jumping from deeper within the departure well, which is higher-risk.

Jumps and exit points can't be calculated exactly, because the exact geometry of the hyperspace-time "curve" you'll be traveling on can't be directly measured. The n-dimensional curvature of hyperspace is chaotic and is affected by many sources, from the gravitation of nearby stars, planets and interstellar gas and dust, to the rotation of the stellar masses and their electromagnetic fields, not all of which you can measure accurately, so there is always an uncertainty factor to account for in your calculations. If you jump close on the jump vector, you limit the perturbing influence of your departure star's gravity well to a linear quantity, meaning that it might only affect how deep into the destination star system you arrive. If you jump from a tangential point (Fig. II), then the departure star is pulling you laterally rather than directly back, increasing the chance that you might miss the target altogether. In theory, if your calculations are correct you can jump from a tangent point as illustrated above, but in practice it's extremely dangerous. Maximum arrival distance from the destination varies with the mass of the star, but a successful "short-jump" can often bring you in at the edge of system, outside the orbits of most of the planets.

In most cases, the maximum jump distance between stars is about 10 light years, and preferable safe distance is about 6 light years or less.The limitation on jump ranges is based both on limited ability to calculate trajectories past a certain distance (the chaotic element causes the effect of tiny errors to increase geometrically with distance), but also on the interference of nearby stars. The farther you try to jump, the more likely that other stars are going to perturb your trajectory.

What happens when an inbound ship tries to share the same space as a much smaller piece of matter that already exists there?

They go "boom." When a ship re-enters normal space in an inbound jump zone, it retains the same velocity as it had on outbound jump; this is usually enough kinetic energy to heat any matter it would collide with to fusion temperatures. The odds of collision under normal circumstances are very low, however. Jump zones are usually out of the ecliptic plane.

I meant what happens at the point of transition, when the ship stops being here and starts being there? What happens if there some matter (hydrogen gas, micro-meteorites) at the exact point the ship tries to jump into? Atomic scale ka-boom as matter tries to share the same location?

A ship re-entering normal space from hyperspace doesn't "materialize", but rather pushes its way in from an n-dimensional portal. As such it would be treated as a normal collision. Since you have to jump out with enough velocity to escape the departure star's gravity well, you come in to the destination with enough velocity to destroy you if you contact any significant matter, regardless of whether you materialized inside it or not. Since no area of space is a complete vacuum, we have to assume the process (jump field, or deflectors, or whatever) can push trace gas and particles out of the way as you come in.

What about jump sickness, anything like that?

Varies from species to species. Humans find it uncomfortable and disorienting; it can be a source of psychological stress on long voyages involving multiple jumps in a short period of time. Umiak sometimes require extensive medical assistance to cope with jump sickness, but this varies greatly between the different Umiak strains. Loroi are generally unaffected by jump.

hmmm, it should be possible to go around the front line's, neh? there are plenty of stars around after all....and everyone of 'em are a potential jumpgate..... which effectively makes the jumpzone a 360x360 degree sphere..... neh?

Not really. Only nearby stars have workable jump links (max 10 light years, and preferable safe distance is about 6 light years or less). Earth has 7 jump points (Alpha Centauri, Sirius, Barnard's Star, Ross 154, Lalande 21185, Wolf 359 and Luyten 726-8, if you want to know), but only the two shortest are used by most shipping (Alpha Centauri and Barnard's). Most systems will have fewer points. All the entry points must be accounted for in a defense scheme; raiding aside, if an enemy can get a significant force past your front lines into undefended territory, the war is over. All borders must be guarded. That said, finding a new "back door" into enemy territory is the Holy Grail of a frustrated combatant. New systems that might offer a new route to enemy territory are always being sought -- hence the plight of the Humans and other would-be neutral entities.

It's always possible to take the way-long way around and try to come into enemy territory from the rear, but it can take a long time (each system transit can take several days to a week), and supply can become an issue. Such missions will also have a poor survivability rate; if you go the long way around, you have to return the same way, which may take months. If you were damaged in the raid, or if you should happen to run into enemy forces on the way in or back...

Remember also that the Loroi are not easily taken unawares; thanks to their telepathically amplified farseers, they can often tell when the attacks are coming, and can arrange for a fleet to meet the raiders. Loroi don't spread their forces across the front; they concentrate them at the point of attack.

Did humanity develop any slower-than-light travel methods before they got Hyperspace? Say, for instance, Bussard ramjets?

Unlikely, but even if they had, they would have been overtaken by the FTL ships that were developed soon after.

If I’m a jump zone, how easily and how accurately can i jump to somewhere else in the same zone? If it's a field, can you 'jump' photons, or other really fast particles?

Generally, you can't jump to somewhere else in the same system. To escape being pulled into the primary star, you usually need to have escape velocity out of the star's gravity well, on a vector for another star. Entering "hyperspace" you're hurled toward the other star, the gravity of which rips you back out into normal space. If you try to jump say, from Jupiter to Saturn, chances are you will either be pulled back into the Sun, or you will overjump Saturn and end up who knows where.

Is there some sort of massive signal that a jump gives off, especially when it arrives? Could you tell what type of ship was jumping with it?

There is a flash of light that is proportional to the mass of the ship.

How long does it take, in hyperspace, to go 1 ly? And for in-system purposes, what's the max speed for most ships?

The jump is almost instantaneous, but since your jump range is limited to about 10 LY, traveling a long way means making a lot of jumps, and traveling in-system from one jump point to another. There's no maximum in-system speed, but ships will very rarely go more than 10% lightspeed (because it would take too long to stop, otherwise). So, it will generally take several days to transit each system. It took the Bellarmine nearly two months to reach Loroi space from 82 Eridani, a distance of 217 LY.

So, if you miss, you may never drop out of FTL?

Those ships that have overjumped have never been seen again... so it's hard to say for sure what happens to you. You might drop out of hyperspace very far away. You might end up slamming into a star. You might go to the same extradimensional place that the Event Horizon went. Liberate tu ta me ex infernis!

IF you missed everything, then head in the only direction that is truly up (up being opposite of down; down being towards matter)

The problem there is that the jump is nearly instantaneous, and for the fragmentary moment you're in hyperspace, you're ballistic. Either you hit the target, or you go bye-bye to goodness knows where. Don't burn too many neurons over this... it's completely inconsequential to the story.

Also; why is your jump range limited to 10 ly? If only a massive gravity well can pull you out, then isn't it only limited by how much risk you're willing to take?

That's right. Because stars are so densely packed, a "safe jump" is usually 10 LY or less. If you were trying to jump somewhere outside dense galactic space, your safe range might be much longer, but that's outside the scope of the story.

if coming out of hyperspace makes a lot of light (right now I'm assuming all wavelengths), then with a big enough mass coming out of hyperspace, couldn't you fry a lot of things? And would it also create an EM shockwave?

Not quite that much light. If you tossed a planet through hyperspace at them I'm sure you'd cause a great deal of havoc, but none of the combatants has access to quite that much energy.  

Keep in mind any sizable Loroi fleet will have telepathic sensors capable of seeing into the next system.

The Loroi telepathic "farseeing" ability only allows them to detect manned vessels. Drones, mines, or other unmanned defense systems have no telepathic signature. Also, Farseers may have difficulty distinguishing defensive installations from planetary populations if the system is inhabited.