Faster-than-light technologies

Faster-than-light 'jump' drives are a critical underpinning of human space, in the same way that automobiles and aircraft were in the 20th and 21st and oceangoing boats were in the 19th. Without the ability to transit between stars, the scattered worlds of humanity would be seperated by years and decades and centuries.

The basic operating principle behind a standard jump drive is simple; upon activation the drive and a volume of space surrounding it undergo a macroscale translocation (the 'jump') to arrive at a distant location. The actual mechanism is vastly more complex of course and relies upon the reality-modifying and information-processing ability of delta dust. Suffice to say that a jump drive cannot (at least with current understanding and engineering) be used to violate causality and act as a time machine.

The actual jump itself is not instantaneous; the effect (and thus the ship inside) propagates at a measurable superluminal velocity. Early-generation units from the late 21st century had pseudovelocities of 100-200 c while modern drives can travel two orders of magnitude faster. However, jump pseudovelocity as a measure of transit speed is deceptive as jump drives operate on a node-to-node model and a ship must travel through normal space between 'jump zones'. A doubling of pseudovelocity does not equate to a halving in transit speed, particularly over long distances.

In addition, jumps can cause substantial mechanical stresses on the contents of a jump envelope; there is a direct relation between propagation pseudovelocity and induced stress. In essence a drive that flies faster is also being squeezed harder. First generation drives were slow enough that the induced stresses would not exceed the inherent structural strength of the host ship, but more modern designs required integral stress-management systems. Even a minor failure of a drive's stress management system can inflict cosmetic (or not so cosmetic) structural damage to a ship. A major failure can tear it apart, and a total failure converts the entire contents of the envelope into a smear of exotic particles and graviton waves. Resetting the stress management system is one of the critical limits on how fast a ship can recycle its drive for an interstellar-range jump.

The potentially catastrophic nature of a drive failure means that modern drives (particularly military ones) are engineered with a large margin for error. Almost all ships can 'sprint' over short distances (2-4 jumps) by only doing a partial drive reset between each jump and then having a longer-than-normal recycle period at the end. This helps to create some of the trade patterns in developed space; in short, local travel is substantially faster than long-haul.

For comparison, a bulk carrier with a jump drive rated at 200 c takes approximately 18 days to cross a nominal 10-LY jump. With another 4-5 days spent in-system to travel between jump zones, it would have an effective velocity of 160-165 c.
A military cruiser with a drive rated at 10,000 c would cover that same distance in only 9 hours but would still spend 3-4 days recycling its jump drive. As a consequence its effective velocity is approximately 830-1100 c.
Higher propagation speeds as a control on the functional transit sped of a ship are thus are swiftly eclipsed by the time taken to reset the drive.

This had major implications during the Breakdown when most ships were using 2nd generation drives; capable of 3-5 times the effective velocity of first-generation drives they had pushed the earlier models to the edges of profitability. However when the RFM-1 virus compromised stress management controllers across known space almost all FTL ships were grounded; a significant number of ships pushed too hard with a failing stress controller in a mad dash to reach an inhabited system and arrived barely intact.