propulsion

noun

1. (countable, uncountable)The process of propelling, driving, or pushing, typically forward or onward; a propulsive force or impulse.
2. (countable, uncountable)That which propels.

   “However, nuclear propulsion provides a very high specific impulse and consistent, long duration energy source.”

   “This propulsion provides an initial velocity for the vehicle in a short time span.”

   “Solar-electric propulsion accelerates a spacecraft by means of a low-thrust ion jet.”