Space Travel

## Interstellar Travel

Travel between stars is accomplished by means of a blue-shift FTL drive. Shift drives are the only known means to exceed the speed of light and make travel between systems a possibility.

When a ship blue-shifts into FTL, it is much like stepping off a highdiving platform. The shift moves the ship immediately to an exponent of the speed of light (see table below with FTL velocities) depending on the ship's power, ship's mass, and engines. Once underway, the ship *cannot* deliberately exit FTL until they enter a star's gravity well, which is powerful enough to jerk a ship back out of FTL and into normal space again.

When the ship re-enters normal space, they will be X light-seconds out from the star that popped their FTL bubble, where X is the sun's surface gravity, times four. For a ship travelling to Sol, for example, the sun's surface gravity is approximately 27 standard Earth gravities, so the ship would emerge 108LS from the sun (which places the ship roughly halfway between the sun and Mercury.) Denser stars and black holes have correspondingly more powerful gravity wells, and so the ship will emerge farther away.

To enter blue-shift FTL, the ship must be far enough away from a major gravity source to escape the effect that negates the blue-shift field. This is called the shift break limit, and it is a sphere twice as large as the sphere where the FTL effect is negated. In other words, if a ship shifts to FTL and travels to Sol, it will emerge 108LS from the sun, and must travel to at least 216LS from the sun (for Sol, that's approximately Mercury orbit) before it can engage its shift drive again. Ships exit FTL with zero momentum.

Planetary gravity also prevents the engines from blue-shifting, but those planets are much less potent, gravity-wise, than the sun. To blue-shift while in proximity to Earth, for example, the ship must be at least 8LS from the planet (a little more than 3x the moon's orbit). Jupiter's surface gravity is about 2.5 x Earth normal, and so a ship must get 20LS from Jupiter to shift to FTL. While this does mean planets *could* interfere with a ship's shift-drive as it arrives in-system, it's virtually unheard of, and it can't be used to zip around in-system as planets are far too small for astrogation computerse to discern and travel to with any reliability, and if the pilot misses... see "cannot deliberately exit FTL until they enter a gravity well" above. It's dangerous enough that only the truly desperate would make the attempt.

## Intrastellar Travel

When maneuvering in real space, ships use gravity drives that both move the ship through space and create gravity for those on board witin the gravity drive bubble.

Like interstellar travel, the speed at which a ship can accelerate/decelerate is based on the ship's power output, engines, and mass. Larger ships are slower, but only to a limited extent since they can mount much larger antimatter powerplants. Unlike FTL travel, the shift bands for sublight acceleration do not follow exponents, they follow something more akin to the Fibbonaci sequence. An engine only capable of alpha-band acceleration generates a single gravity of forward acceleration. Omega-band engines can accelerate their ships at 233G, the fastest band yet achievable with current tech.

While the gravity engines are online, the ship's passengers will experience 1G, and inertial compensators ensure the passengers don't get squished into finely mashed salsa. These acceleration/deceleration rates are, however all based on assuming 1G is 9.8m/s/s, Earth standard. A ship's engineer or science officer can modify what "1G" is considered to be, then, and multiply their forward velocity by that much.

Example, the Pandora's Hope has Omega-band engines, and can manifest 233G of acceleration. This would normally translate to 2283m/s/s of acceleration. But if the Hope is really pushing hard, Thunderpaws can dial up the 'felt' gravity onboard the Hope from 9.8m/s/s Earth standard, to, say, 4G - 39.2m/s/s. By doing so, he would boost the Hope's in-system acceleration to 9133m/s/s, giving them a huge speed advantage. Ships are essentially limited by their crew's ability to handle g-forces, which makes people from high-G worlds, and people unaffected by G's (like cyborgs) an edge in ship maneuverability and combat.

Travel inside a system is generally spent setting their intercept heading, accelerating for half the trip, then decelerating for the second half of the trip. Ships do not need to turn around like they would using rocket thrusters to slow themselves down, they just invert the field and it goes from "accelerating forwards" to "accelerating backwards" acting as brakes.

## Interface ships, System Patrol, and Fighters

Interface ships are ships used to travel from orbit above a planet, to a docking facility on the ground. They are generally only capable of Gamma or Delta acceleration bands, which they use to escape a ship's gravity well and cannot shift into FTL at all.

System Patrol ships - SysPat - are ships used to patrol a system by the the local Gov (whoever that may be) and are generally beefier, better armored, better armed, and faster than an Interstellar-capable ship, because they can use all the mass and tech dedicated to the FTL drives for guns and armor, instead. They usually run patrols from around the sun's arrival sphere, where most of the traffic will be, and out-system along all the different lanes that would take an arriving ship to a planet or orbital hab station.

Fighters are like SysPat ships, in that they lack FTL capabilities (and usually, long-term life support), but they are small enough and light enough they can travel FTL attached to a larger carrier, and hit upsilon or omega speeds as they race in to attack targets.

## Ramming speed!

Q: Why can't a ship ram a planet at 2048x the speed of light?

A: Because the planet's gravitational field will pop the blue-shift field that allows the ship to break the speed of light. It would get to (planet's gravity x4) light seconds away and pop out of FTL, with zero momentum.

Q: Why can't a ship just get up a good head of speed with its sublight system and ram the planet that way? A few days of accelerationg at 2.2kps would get pretty quick...

A: Well, it can, but watching out for threatening ships, ships that have gone out of control and are coasting in at extreme speeds, are all a major part of what SysPat does. They can and will shoot up ships if the ship has crossed the "turnover" deceleration point but isn't slowing down any.