Because rockets do accelerate in space and have been able to do so for a long time.
Answer: Option D
<u>Explanation:</u>
A rocket is made to reach the sky and its required destination by the burning of fuels in the rocket. So there is no need of any other external forces to propel them in space. As per Newton's third law, the action and reaction forces will help the rockets to escape the orbit of earth.
And then the remaining energy required by the rocket to travel in space will be obtained from the burning of fuels in the compartments. This burning of fuels in respective compartments will propel the rockets in space. So it is a complete myth that space travel was impossible before because of inability to provide propulsion in space.
