The T-Space Drive is a piece of equipment which allows a starship to enter T-space and attain faster-than-light speeds therein.
Not all spaceships are equipped with a T-space drive. The necessary equipment takes up less than 10% of the total tonnage of the ship, but not every shipyard can build ships with it.
Ships equipped with T-space drives also require enough supplies for the crew and passengers to last the duration of the journey.