Rocket science is the science behind getting rockets into outer space. More formally, it's aerospace engineering. The field requires a wide range of knowledge of physics, aerodynamics, mathematics, propulsion dynamics, and other types of science and math. A rocket scientist, or aerospace engineer, may specialize in one or more fields of study, and this will determine what kind of job he or she looks for.
Anything that gets and keeps a spacecraft in outer space is included under the rocket science umbrella. For instance, an aerospace engineer who specializes in chemistry and propulsion dynamics may work on a spacecraft’s fuel issues. This person will need to know how much propellant, and what kind, will launch a spacecraft most efficiently.
The field also includes design. Someone had to design the space shuttle, for example, and those aerospace engineers specialized in formulating the plans for the world’s first reusable spacecraft. Then metallurgical engineers and their crews took over, deciding what kind of metals would be best for the shuttle’s body and frame. Scientists considered what the robot arm be made from, how much weight it be able to support, and how much weight (or payload) the shuttle carry and safely launch.
Even though the technology is mostly obsolete, viewing the movie Apollo 13 will give someone a good idea of everything this field entails. As the call goes around the room for a go/no-go for launch, those at each station answer for their particular responsibility for the spacecraft: booster, retro, electrical and environmental, guidance, flight dynamics, etc. Later in the film, the engineers come up with a solution for fitting the command module’s square lithium hydroxide canisters into the round receptacles for the lunar module. This project also required a number of specialists in various fields. Most aerospace engineers have master’s degrees, if not doctoral degrees, in their field, so a job in aerospace engineering requires extensive education.