Planetary protection is a field of study and practice that aims to prevent contamination of celestial bodies such as planets, moons, and asteroids by microorganisms from Earth, and vice versa. It is essential in the context of space exploration and the search for extraterrestrial life, as introducing Earth-based microbes to other planets could compromise the integrity of potential alien ecosystems and skew scientific results. Planetary protection guidelines and procedures are developed and implemented by space agencies and organizations to ensure that spacecraft and instruments are sterilized before launch, and that all missions are conducted in a way that minimizes the risk of contamination.