Fold Drive

The **Fold Drive** is a simple, yet ingenious FTL method used by numerous intelligent species for basic interstellar travel within the confines of their home galaxies. Though they lack the range of a Fissure Drive and are not as imaginative as the Swapper Dynamos used by the Kaeolians, Fold Drives are a staple FTL method across The Cluster thanks to their reliable and basic design.

## History and Development

Despite its simplicity, the Fold Drive holds the record for being one of the oldest technologies to exist within The Cluster, having been developed and used by civilizations throughout the entire span of history. Ancient, derelict spacecraft from civilizations that crumbled to dust many millions of years ago have been found to possess FTL systems resembling Fold Drives, operating by many of the same principles shared by all Fold Drive variants. Though the Fold Drives used by different civilizations have their own unique designs and are of varying degrees of efficiency, they all operate in virtually the same way, showing just how universal this type of FTL travel really is. The commonality of the Fold Drive is largely the result of its basis in graviton manipulation, an elementary field of science for any burgeoning interstellar civilization. The discovery of the graviton by any alien race makes interstellar travel not just feasible, but convenient, assuming such a discovery is used to build devices that accelerate spacecraft using gravity.

Though the actual efficiency of such a device is limited due to the resources involved, there are some civilizations that are known to have pioneered more advanced forms of Fold Drive technology, giving their civilizations more reach in space. These include the First Vecuuri Empire and Infinity Guild, who are known to have had an extremely good understanding of gravity science, allowing them to build some of the most advanced Fold Drives in the recent history of The Cluster. The Vecuuri deserve special attention, as their Fold Drives gave them access to almost the entirety of the Spur Trinity. Though the efficiency of these devices was reduced following the technological setbacks the Vecuuri faced after the collapse of the First Vecuuri Empire, they remained one of the crowning achievements of Vecuuri civilization, and are cited as being one of the things that allowed the Coalition of Intelligent Organisms to expand so quickly despite its young age.

## Mechanics and Usage

Fold Drives derive their name from the unique way they generate the thrust needed to accelerate ships to faster-than-light speeds, which involves "folding" the space in front of a ship, causing it to accelerate forward. To do this, Fold Drives use graviton manipulation to form a highly-condensed "bubble" of gravitons in front of a ship and keep it a safe distance away so that its gravity still has a significant effect on the ship, but does not rip it apart. This graviton bubble has immense gravity but no discernible amount of mass, making it akin to a miniature, semi-harmless black hole. The ship accelerates towards the bubble because of its gravity, always moving to collide with it. However, the Fold Drive is able to keep the bubble the same distance away from the ship no matter its speed, ensuring that the ship can accelerate exponentially as the bubble's gravity increases. Fold Drives can change the direction of their graviton bubble to alter the direction of the ship's acceleration, allowing ships to both accelerate and decelerate exponentially by simply reversing the direction of the gravity well. When a ship approaches lightspeed using a Fold Drive, it becomes separated from the rest of the universe by a space-time bubble, allowing time and space to operate normally inside of the ship and allowing the ship to continue accelerating beyond lightspeed. Time does not pass outside of this bubble for a ship traveling at lightspeed or faster, though interstellar distances mostly remain the same. This means that, for an external observer, a ship using a Fold Drive will only take an hour or so to travel between two moderately-distanced star systems. This is exclusively the time taken to accelerate/decelerate into and out of FTL speed, as any time the ship experiences while in FTL is not experienced by outside observers. Inside of a ship, the journey may take several additional hours, depending on the maximum speed rating of the Fold Drive.

The generation and manipulation of gravitons is not something easy to achieve. One of the greatest draws of the Fold Drive is its considerable energy requirements, which are almost impossible to satisfy without the aid of cold fusion reactors. This energy is used to power the gigantic gravity centrifuges that generate the gravitons used by the Fold Drive for FTL travel, which often make up a large portion of the ship's mass. Some of the more advanced civilizations have swapped out these centrifuges for Lavernium cores, which make use of the unique properties of Lavernium to generate gravitons with a much greater degree of efficiency. However, since Lavernium is a Metasubstance, and is inherently difficult to produce in large amounts, the accessibility of Lavernium-based Fold Drives is limited.