A stitch drive, also called an s-drive or a stitcher, is a crucial element of modern space travel throughout the Ealdremen System. The installation of a stitch drive in an interstellar craft enables travel and navigation over distances normally inaccessible due to physical limitations of traveling close to the speed of light and being unable to surpass that speed. Instead of traversing distance through real space, a stitch drive allows a craft to enter into the Ravel, a collection of other planes of existence that dwell "between" pockets of real space. These planes, called Braids, all have different laws of physics that govern them, including different applications of distance and time, which results in crossing through them taking less time than it would to traverse the distance in real space — so long as the stitch drive is correctly calibrated to pass through Braids where time and space are favorable for such travel. From this, the drives get their name, as they allow a vehicle to "stitch" together realities to form an ideal path for travel.
While a stitch drive permits passage through the Ravel, it alone does not make the process any safer, and ships built with stitch drives must often make compromises to ensure the stitch drive has adequate power when necessary and is not overexerted in bringing vast quantities of mass across dimensions. A malfunctioning stitch drive can strand ships in the Ravel temporarily or even permanently, making maintenance of stitch drives a critical part of modern aerospace engineering.
Generally, larger "stitches" do not take longer than shorter ones, but they are inherently more prone to pilot or navigator error or a mechanical malfunction, and not every ship or stitch drive is capable of leaping multiple parsecs through the Ravel at once. However, because it is typical for a single stitch to last around seven days if there are no issues during the stitch, even a series of stitches is often significantly faster than attempting to fly across any distance in real space outside of a nearby orbit.
Stitch drives are sometimes called "jump drives" for their perceived ability to "jump" across realities, though this term is not in common use.