lowEarthorbiting

Low Earth orbiting, or low Earth orbit (LEO), describes orbits around the Earth at altitudes between about 160 and 2,000 kilometers above the planet’s surface. In LEO, orbital periods are around 90 minutes and velocities near 7.8 kilometers per second. The relative proximity to Earth enables high-resolution sensing, short data downlinks, and easier crewed access, but subjects spacecraft to stronger atmospheric drag and faster orbital decay than higher orbits.

LEO is the most common regime for satellites that image the surface, conduct Earth science, or provide communications. Mission designs often use sun-synchronous or near-polar inclinations at 600–700 km to ensure consistent lighting, while other constellations follow various inclinations to optimize coverage and latency.

Challenges include atmospheric drag, which demands periodic reboosts, and the risk from space debris. The radiation and thermal environments, as well as the need for frequent ground support and tracking, add to operational costs.

Notable examples include the International Space Station at about 408 km, and large satellite constellations such as SpaceX Starlink and OneWeb that aim to provide global broadband. Earth-observation fleets and research satellites also predominantly operate in LEO to balance resolution, latency, and access.

LEO is distinct from higher orbits such as MEO and GEO. Some sources define very low Earth orbit (VLEO) as roughly 180–300 km, which subjects spacecraft to extreme drag and requires active attitude and orbit control to maintain.