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Three core ideas make faster than light travel possible: p-shields, the hackdrive, and sungates.

P-shields

Privileged shields (“p-shields” or usually just “shields”) create a privileged frame of reference in a spheroid around a spacecraft. The shields create a pocket universe of sorts inside. The universe has its own inertial frame of reference. It’s not (usually) completely cut off from the regular universe, but it’s difficult to detect with normal equipment.

The shields make the ship impervious to conventional ballistic and energy weapons. Nuclear weapons reach temperatures of 100 million degrees, but the blasts don’t last long, but they’re still effective against p-shields. The best attack on a p-shield is another p-shield. Military units carry missiles with small p-shield generators.

Hackdrive

A hackdrive allows extremely fast travel without inertia. P-shields make it possible for the craft to step out of the universe but there’s no conventional way to travel then. Hackdrives exploit rounding errors in the computational information space of the universe, letting the ship’s p-shield (and its contents) step forward the thickness of the shield (typically around 10 cm). Repeat this little “hack” fast enough, and the ship’s bubble moves through the universe.

After Earth invented the hackdrive in 2115, they ran some unmanned tests to determine the limits of the speed. It turns out that speed depends only on the frequency rate of the hackdrive’s clock, and a ship can “spin up” that clock rapidly and travel at incredible speeds, unlimited by the speed of light. The ship can turn and maneuver in non-Newtonian ways, like taking a right-angle turn at the speed of light, assuming the hackdrive has equipment that can do those tricks with the hackdrive’s gyroscopes and clocks.

Running the hack faster requires a faster oscillator. New Rome’s technology produces oscillators that run 3-6 GHz, allowing speeds up to about 2c. That is, the fastest hackdrives can reach about twice the speed of light. The drive provides no real acceleration, so they can’t just accelerate forever to go faster and faster. Even at speeds of 2c, it would take a year or so to reach a jump-1 star neighbor. Right now, cooling requirements prevent interstellar hackdrive travel at any reasonable speed.

Hackdrives are occasionally used for travel between planets in a system or even between cities on a planet. However, because they are extremely expensive, mainly only governments own them. Some governments might allow a very powerful corporation to build hackdrives, but the military value of such a vehicle is so high that most governments carefully regulate who may legally own a starship.

Sungates

Not long after the invention of hackdrives, Earth discovered a type of artificial wormhole just below the sun’s surface. Unmanned hackdrive probes with strong shields were able to penetrate the wormhole to the other side, then return with telemetry data for Earth. It turns out that there is a web of these wormholes connecting numerous nearby stars. Earth named them sungates.

Every sungate Earth discovered had a single destination, another star with 3-4 light years. It is not understood who created these gates, or why. Powerful shields are required to protect ships from the [nuclear energy of stars | stellar heat]. Most of the danger of interstellar travel is during the close approach to the star. Miss the gate, fly too close to a coronal mass ejection, and the ship’s shields will fail and the craft will disintegrate.

Recently, Earth discovered deeper sungates, buried further beneath the surface of stars. For a decade, even shielded robotic probes could not survive the journey, but improvements to p-shields have opened up these “jump-2” gates, which can reach stars up to 8 light years away.

Jump-2 technology has opened up new vistas for exploration. New Rome has encountered two space-faring cultures, both of which have (for now) only jump-1 technology. It is only a matter of time until spies or traitors leak the secrets of jump-2 to these civilizations, or they capture a jump-2 vessel and plumb its secrets. It is only a matter of time until Earth encounters a culture with similar or superior military technology, and then the real war begins.

Differences from standard Traveller jumps

In the original Traveller universe (OTU), jumps are special teleportation travel from any point to any other point within jump distance. In this universe, jumps are just normal travel through a sungate, which is a wormhole that folds space between two fixed points. Enter the sungate one one side; emerge from the sungate on the other side. The sungate destinations are not negotiable.

In the OTU, a starship must travel to a jump point far away from the gravity of the system’s star. Typically, this is a distance equal to 100 times the diameter of any nearby object. Since the Sun is 1.4 million km in diameter, a ship in the OTU must travel at least 14 million km away from it before jumping (and also clear other planets and such). In this universe, ships must travel to a sungate just inside the photosphere of the Sun. Gravity doesn’t prevent jumps at all.

In the OTU, a jump-1 ship can carry twice as much fuel and make two short jumps to cover the same distance as a jump-2 ship. It just takes twice as long. In the New Rome universe, the “jump” doesn’t really cost fuel (it’s just normal travel across the sungate boundary) and it’s instantaneous.

In the OTU, ships use hydrogen as fuel. In this universe, ships don’t want explosive hydrogen anywhere near their ships. They do carry ice, used for cooling. The ship generates a fair amount of waste heat, and there’s not much universe to dissipate the heat into. The ship can always drop shields and extend its “feathers” to bleed off excess heat, but in many circumstances that might not be an option. During jumps, the power plant is running at its highest capacity, and the shields have to stay up to protect the ship from the 5,000C heat of the star. Thus, the ship carries densely packed cold material to equalize the temperature.

In the OTU, ships have a maneuver drive (m-drive) that burns and ejects reaction mass for movement. They accelerate at high rates (to 6G and above) and have normal relativistic momentum. In this universe, reaction mass drives are far less efficient than hackdrives for interplanetary travel. Hackdrives do not burn reaction mass, so they don’t need much fuel. They’re typically powered by electricity generated by nuclear power. A ship inside a p-shield is essentially massless and immovable (from inside or out). The hackdrive cheats the rules of the universe to move it forward a few centimeters at a time, many times per second. This isn’t movement. It’s translation of location, or very short teleportation. The direction is controlled by a gyroscopic mechanism inside the ship, so the craft can ignore normal momentum and turn on a dime. The ship doesn’t accelerate; it just moves. It goes from zero to light speed instantaneously.

In the OTU, shielded ships are still vulnerable to outside attack using conventional weapons. The shield is essentially subject to the physics of the ship’s universe. In the New Rome universe, the p-shield is really a bubble universe containing the ship, much like the black globe generator of Classic Traveller. Conventional weapons just go around the p-shields as if it weren’t there. However, in the New Rome universe, p-shields are vulnerable to contact with other p-shields, so missiles equipped with p-shield generators can puncture a ship’s defenses and bring down the shields.

In the OTU, ships flying under m-drive are visible and easily tracked within a star system. In this universe, the p-shields effectively warp space around the ship, making it invisible and forcing the pilot to fly blind. Pilots can oscillate the dropping of their shield at a slow rate compared to the movement clock rate (say, drop the shield five cycles out of 10000) and use the five consecutive cycles to get a radar ping in or out, or get visual telemetry data. This makes the shield less than perfectly invisible. A ship that has “gone dark” doesn’t drop shields at all, moving along a planned trajectory for a long distance. These ships are possible to spot with special equipment that detects the ripples in spacetime created by the p-shields, but it’s tough.

In the OTU, conventional rocket-powered missiles can easily track targets and hunt them down. In this universe, a hackdrive can just skip sideways at a right angle relative to the missile, repeatedly, until the missile runs out of fuel. Hackdrive-powered missiles are very, very expensive, but they’re able to track hackdrive targets effectively.

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Traveller: New Rome AdamDray