How does a rocket launched into space take off? How does a rocket launched into space take off? Hot gas shoots out from the rocket and, through the conservation of momentum, the rocket moves in the opposite direction. By converting mass-energy to potential energy. The hot rocket exhaust expands the air beneath the shuttle, propelling it forward. Its rocket engines push against the launch pad, propelling the rocket upwards. By achieving lift from its wings in the same way that airplanes do.