A primitive form of space age transportation. They are a precursor to Gravity/Warp Drives. They are also called Tachyon Drives, and Hyperwave Drives.
Mass Drive, effectively uses tachyon-graviton waves to send a ship flying past the speed of light. It is essentially an electromagnetic field, working upon the mass of the ship and everything inside. Due to the nature of the system, occupants inside must be placed in Hypersleep to avoid aging to death.
It is this feature that causes the internal structure of the ship to use more archaic forms of technology, such as CRT Tubes as opposed to flatscreen monitors and hologram projectors, due to them being (at that point in the species' development) easier to make more long lasting.