iÂ·deÂ·a. n. 1. Something, such as a thought or conception, that is the product of mental activity. 2. An opinion, conviction, or principle: has some strange political ideas. 3. A plan, purpose, or goal: She started school with the idea of becoming a doctor. 4.
The direction of the thrust is normally along the longitudinal axis of the rocket through the rocket center of gravity. But on some rockets, the exhaust nozzle and the thrust direction can be rotated, or gimbaled. The rocket can then be maneuvered by using the torque about the center of gravity. The magnitude of the thrust can be determined by the general thrust equation.
Thrust from photons emitted from a laser array could be used to propel a spacecraft. All spacecraft operate by firing propellant in the opposite direction to the way they want to travel. Traditionally this propellant is fuel and has to be carried on board the spacecraft, making it heavier and slowing it down.