FTL Travel (Our Stars)

Travelling faster than light was long a dream in the world of fiction - but at the end of the 22nd century, scientists on Earth cracked its secret, and heralded a new age of interstellar exploration and settlement with the invention of the Resonance drive.

History
With the invention of the Resonance drive, humanity became interstellar beings - a momentous year of such historical importance that a new calendar was adopted - any year before it was the Planetary age, whereas the first FTL journey would mark the beginning of the Interstellar age. Exploration and colonisation soon followed, not driven by national interests but by the curiosity of scientists and people alike. Other thought they would find refuge from the confines of their terran lives, and find a new place to live far away from it. And so humanity began to spread across the stars, slowly but steadily.

Description
A Resonance drive works by tuning a spacecraft to the underlying resonance of space-time, allowing it sideline certain constraints in the laws of physics and travel faster than light - in short, it works with the help of Handwavium™.

The process is not instantaneous, but allows a spacecraft to travel faster than the speed of light by several orders of magnitude - a journey between two stars that would take a photon years to traverse will instead take hours for a spacecraft making use of a Resonance drive. This still means that travel between star systems can take a long time, meaning that the all spacecraft from the smallest one-man ships to the largest cargo and military vessels are designed with longer journeys in mind - a one person ship will most likely have a lavatory and a bed, as well as large spaces for cargo such as food.

Modern Resonance drives have the full descriptive name of STRD - Space-Time Resonance Drive. This has led to FTL journeys getting the nickname "stride".

Interstellar lighthouse
Despite the incredible speed of a Resonance drive, travelling truly large distances between many stars can take an extraordinary amount of time - days, weeks, or even months. To speed up such journeys, a mechanism known as an interstellar lighthouse (also known as "Interstellar beacons" and colloquially known as both "lighthouses" and/or "beacons") were devised. These are massive space stations that are built and placed in orbit around a major planet in order to facilitate faster travel with Resonance drives between beacons. These structures are incredibly expensive not just to build, but running and maintaining one also costs an incredible amount of energy and resources, making interstellar lighthouses feasible only for heavily populated planets that have enough interstellar traffic to warrant the construction of such a massive project.

Interstellar lighthouses work by acting as beacons in the resonance of space-time. This means that spacecraft currently travelling with their Resonance drives are able to pick up on the signals and more finely tune their path and speed accordingly. The lighthouse also acts to "excite" the resonance, allowing it to help "pull" a spacecraft towards it, further increasing its speed. One lighthouse which is active on its own at the destination of a ship travelling FTL will decrease the time of travel by three to four times - it is when there's a lighthouse at the departure point that speeds really start increasing to staggering levels. Here the two lighthouses will combine their power to excite the resonance and aid the ship's fine-tuning in such a way that a spacecraft can travel between 20 to 25 times faster than if it had been without any lighthouse assistance. This means that two systems that both have active lighthouses will cut down resonance travelling time between them dramatically.

There is one further "level" of lighthouse efficiency: planet-side lighthouses. These are much more complicated to build and maintain due to the gravity and weather of a planet, but in return, it can use the planetary body its built on to further amplify its effect on the space-time resonance. This effect is noticeable but not very significant, and it's generally considered a waste of time and resources to construct a lighthouse on a planet. Only one planet-side lighthouse exists in the local region, which was an experimental one built on Tôr as a prototype proof of concept. While it worked as expected and performed its function well, the eventual ruin of Tôr and the ensuing exodus has rendered the lighthouse long since inactive.