Astronautics is the branch of engineering that deals with machines designed to work outside of Earth's atmosphere, whether manned or unmanned. In other words, the science and technology of space flight.

Astronautics was coined by analogy with aeronautics. As with aeronautics, the restrictions of weight, heat and external forces require that applications in space survive extreme conditions, whether the heat of reentry, the radiation bombardment of interplanetary space, or the magnetic belts of orbit, space vessels must be designed to withstand forces almost unknown on Earth. More over, because every gram is precious, astronautic engineering is constantly faced with the need to reduce the mission payload, in order to save propellant that powers the impulse engine.

The early history of astronautics is theoretical, long before it was possible to send vessels into space, the question of space flight interested such figures as Jules Verne and HG Wells. The practical history of astronautics begins with liquid fueled rockets.

Branches of Astronautics are Astrodynamics, Space Environment, Spacecraft Design , Rocketry, Attitude Dynamics & Control, Navigation.

See Konstantin Tsiolkovsky, Space Race, Robert Goddard, Wernher von Braun, Spacefaring.