A spacecraft is a complex machine designed for travel in outer space, engineered to operate independently of planetary atmospheres. These vehicles utilize various principles of physics and engineering, including sophisticated propulsion systems that generate thrust to achieve orbital velocity or interplanetary trajectories. Spacecraft vary greatly in scale and complexity, ranging from small scientific probes designed for atmospheric entry to massive vehicles intended for long-duration missions. Their primary functions include transmitting scientific data about celestial bodies, performing remote observations of planetary dynamics, testing new propulsion technologies, and establishing positional markers in the solar system. System design must account for the extreme conditions of the vacuum, radiation exposure, and temperature extremes encountered outside of a planetary magnetic field.