Astronautics , It is alternatively called cosmonautics, is the theory and practice of navigation beyond the Earth’s atmosphere. It is the science and technology of spaceflight.
The term astronautics was coined by analogy with aeronautics. As there is a certain degree of technology overlapping between the two fields, the term aerospace is often used to describe them both.
As with aeronautics, the restrictions of mass, temperatures, and external forces require that applications in space survive extreme conditions: high-grade vacuum, the radiation bombardment of interplanetary space and the magnetic belts of low Earth orbit. Space launch vehicles must withstand titanic forces, while satellites can experience huge variations in temperature in very brief periods. Extreme constraints on mass cause astronautical engineers to face the constant need to save mass in the design in order to maximize the actual payload that reaches orbit.
Although many regard astronautics itself as a rather specialized subject, engineers and scientists working in this area must be knowledgeable in many distinct fields.
- Astrodynamics: the study of orbital motion. Those specializing in this field examine topics such as spacecraft trajectories, ballistics and celestial mechanics.
- Spacecraft propulsion: how spacecraft change orbits, and how they are launched. Most spacecraft have some variety of rocket engine, and thus most research efforts focus on some variety of rocket propulsion, such as chemical, nuclear or electric.
- Spacecraft design: a specialized form of systems engineering which centers on combining all the necessary subsystems for a particular launch vehicle or satellite.
- Controls: keeping a satellite or rocket in its desired orbit (as in spacecraft navigation) and orientation (as in attitude control).
- Space environment: although more a sub-discipline of physics rather than astronautics, the effects of space weather and other environmental issues constitute an increasingly important field of study for spacecraft designers.