Complex sentence: A quantum vacuum plasma thruster (or Q-thruster) is a theoretical deep-space thruster that uses quantum vacuum fluctuations to propel a spacecraft, and hence the spacecraft would not need to carry any propellants for their operation.
Split into simpler sentences: A quantum vacuum plasma thruster (or Q-thruster) is a theoretical deep-space thruster that uses quantum vacuum fluctuations to propel a spacecraft, and hence the spacecraft would not need to carry any propellants. Thus, a spacecraft utilizing such thrusters would not need to carry any propellants on board for their operation.