From https://robertsspaceindustries.com/comm-link/transmission/15371-Portfolio-Tarsus-Electronics
Summary:
Quantum drives are what we have now that allows us to travel fast between comm arrays.
Jump drives will take you between star systems.
Jump drives were extremely expensive, only governments and major corporations had them, and only official RSI engineers were permitted to fix.
One day a jump drive enabled ship needed emergency repairs at an unauthorized repair station.
Two engineers got a first look at the fabled jump drive realized that the jump drive was just a quantum drive that was modified in a way that was easily replicated.
These two engineers then made their own modified versions which were cheap to make and jump drives were opened up to the larger population!
Summary:
Quantum drives are what we have now that allows us to travel fast between comm arrays.
Jump drives will take you between star systems.
Jump drives were extremely expensive, only governments and major corporations had them, and only official RSI engineers were permitted to fix.
One day a jump drive enabled ship needed emergency repairs at an unauthorized repair station.
Two engineers got a first look at the fabled jump drive realized that the jump drive was just a quantum drive that was modified in a way that was easily replicated.
These two engineers then made their own modified versions which were cheap to make and jump drives were opened up to the larger population!