Xindi Subspace Vortex

One of the most striking aspects of 22nd century Xindi technology, the subspace vortex, a mode of faster-than-light transport, involved the actual penetration of subspace, an underlying dimension of normal space. While most ships were observed to only have the ability to travel a few light years, Xindi-Aquatic vessels (namely Cruiser-type ships) were witnessed using vortices to traverse great distances at speed, such as the 50-plus light-year journey from the Delphic Expanse to Earth, achieved in a matter of hours where it would normally take six weeks. The larger a vortex, the more unstable it was. Degra said he would have great difficulty creating a vortex large enough to carry the Xindi superweapon and four other vessels; he warned one or two of the ships might be destroyed.

While most technologies of the five Xindi species were developed naturally through centuries of refinement and progress, the vortex transit was one that both accelerated the Xindi's evolution into a space-faring people and also marked the first time the Guardians significantly aided in the progression of the culture. Though the Guardians didn't simply hand the technology to the Xindi, they nonetheless spoon-fed them the fundamental principles of subspace theory and let them develop the basic machinery on their own. Following nearly a century of experimentation, the Xindi finally succeeded in penetrating subspace and made their first FTL flight at the beginning of the Earth year 1890. Over the next three hundred years, the technology would advance, but one key component would stay the same: Subspace manipulation.

In the Expanse, though not known to the Xindi at the time, the “Guardians”, in fact the Sphere Builders, were at work modifying the very fabric of space, attempting to make it habitable for their own kind to colonize. While not existing in any one realm, they were nevertheless able to manipulate the laws of physics in varying dimensions and managed to create a network of tunnels throughout subspace that spanned even beyond the barriers of the Expanse. While the Xindi had developed the technology to enter subspace, it was only through these tunnels that they were able to actually travel vast distances beneath normal space. As mentioned, the Aquatics were the Xindi race who utilized the tunnels most effectively. Over time however, the deception of the Sphere Builders became known and, with the help of the Human starship Enterprise NX-01, the Xindi were able to defeat their “Guardians” and prevent them from further altering their region of space. The resulting effect of the Sphere Builders' withdrawal from our realm was the collapse of the Delphic Expanse itself. The thermobaric cloud perimeter that isolated that region of space from the outside galaxy dissipated, the vast fields of spacial anomalies were receded and, unfortunately for the Xindi, their network of tunnels within subspace soon began to collapse. Without further contact from the Sphere Builders or access to their subspace manipulation technology, the Xindi were forced into more than a decade of exile, during which they adapted existing technology from various other "Expanse" species to create their own version of warp drive.