A vehicle with less than 1G of thrust cannot lift off from Earth due to gravity's downward pull, requiring greater than 1G to achieve vertical lift. However, once airborne, a vehicle can theoretically reach escape velocity over time with any acceleration, as altitude decreases the required escape velocity. The discussion highlights that escape velocity is not solely dependent on thrust but on accumulated energy and altitude. Concepts like using a rail system to reduce drag and achieve orbital velocity are explored, indicating that thrust can be less than 1G once in a suitable environment. Ultimately, achieving escape velocity involves overcoming gravitational forces and maintaining sufficient thrust over time.
