To kick off “Aerospace Month” on the Engineer’s Pulse, let us first examine what the term aerospace refers to. As the word indicates, aerospace studies the motion of objects through both air (in the Earth’s atmosphere) and space (outside the Earth’s atmosphere).
The field of study can therefore be broken down into two principal areas: aeronautical (within the atmosphere) and astronautical (within space). Examples of aeronautical navigation include aircrafts (aviation), helicopters, and even hot-air balloons. Astronautical navigation is limited to spacecrafts and satellites.
There is no real line in the sand, where the atmosphere becomes space; there is just a very gradual transition between the two extreme states. Near the surface of the Earth, the medium known as air is a reasonably dense gas, with roughly 1 atm of pressure (101.3 kPa); this figure depicts how tight the molecules of the matter are packed together. In space, at about 300 km altitude, we begin to see the other extreme, where molecules like Oxygen may travel a kilometre before colliding with another molecule.
