Space Regulatory Glossary Orbital Mechanics

perigee

/ˈpɛrɪdʒiː/ noun

1. The point in a satellite's orbit where it is closest to Earth. For a circular orbit, perigee altitude equals apogee altitude; for an elliptical orbit, perigee defines the low point of the orbital path.
2. Perigee altitude is a critical parameter in orbital debris mitigation analysis — spacecraft at lower perigees experience greater atmospheric drag and deorbit faster. Perigee altitude also determines the maximum atmospheric density a satellite encounters per orbit.

Related terms

apogee The point in a satellite's orbit where it is farthest from Earth. In a geostationary transfer orbit, the apogee is at… inclination The angle between a satellite's orbital plane and Earth's equatorial plane, measured in degrees. An inclination of 0… TLE Two-Line Element set. A standardized data format for describing a satellite's orbital elements at a specific epoch,…

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