Space is a vacuum with no air resistance from "summary" of Rocket Science: A Beginner's Guide to the Fundamentals of Spaceflight by Andrew Rader
In space, there is no air. This may seem like a simple statement, but it has important implications for spaceflight. On Earth, we are used to the presence of air all around us. We feel its resistance when we move through it, whether we are walking, driving, or flying in an airplane. This resistance is known as air resistance, and it is a force that opposes motion. When a rocket is launched from Earth, it has to overcome the force of gravity, as well as the force of air resistance. This is why rockets are designed to be aerodynamic, to minimize the effects of air resistance as they travel through the Earth's atmosphere. But once a rocket reaches space, it no longer has to contend with air resistance. In the vacuum of space, there is no air to slow down a rocket's motion. This means that a rocket can travel at incredible speeds with very little resistance. It also means that a rocket can travel in a straight line without having to constantly adjust its course to compensate for air resistance. The absence of air resistance in space has important implications for the design and operation of spacecraft. For example, spacecraft can be built with shapes and structures that would not be feasible on Earth, where air resistance would cause problems. This allows for more efficient and innovative designs.- The concept that space is a vacuum with no air resistance is a fundamental principle of spaceflight. It allows for rockets and spacecraft to travel through space with ease, enabling us to explore the universe beyond our planet.
