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# Low Earth Orbit (LEO)
- URL: https://proximareport.com/glossary/low-earth-orbit-leo/
- Published: 2026-10-08T16:51:56.000Z
- Updated: 2026-10-08T17:08:18.000Z
- Description: Low Earth orbit (LEO) is the region of space closest to Earth, widely used by satellites, space stations, and crewed spacecraft.
- Author: Proxima Report
- Tags: glossary

# Low Earth Orbit (LEO)

**Low Earth orbit (LEO)** is the region of space around Earth at altitudes below roughly **2,000 kilometers (1,200 miles)**. It is the most commonly used orbital region for satellites, crewed spacecraft, Earth observation, and large satellite constellations.

## Key Facts

- **Altitude:** Roughly 160–2,000 km (100–1,240 mi)
- **Orbital velocity:** About 7.8 km/s (17,500 mph)
- **Typical orbital period:** Around 90 minutes
- **Notable spacecraft:** International Space Station
- **Common uses:** Communications, Earth observation, science, crewed missions, and satellite constellations

## What Is Low Earth Orbit?

LEO is the portion of Earth’s orbit closest to the planet where spacecraft can maintain a stable orbit.

A spacecraft in LEO is traveling extremely quickly. Rather than simply flying around Earth, it is continuously falling toward Earth while moving forward fast enough to keep missing the surface. This creates an orbit.

The lower the orbit, the faster a spacecraft generally needs to travel to remain in orbit.

LEO does not have one specific altitude. The lower boundary is generally considered to be around 160 km, where atmospheric drag becomes extremely strong. The upper boundary is commonly defined as approximately 2,000 km.

## What Is LEO Used For?

LEO is used for a wide range of space missions, including:

- **Earth observation** and imaging
- **Weather monitoring**
- **Communications**
- **Scientific research**
- **Crewed spacecraft and space stations**
- **Technology demonstrations**
- **Military and reconnaissance satellites**
- **Large satellite constellations**

The [**International Space Station**](https://www.nasa.gov/international-space-station/?ref=proximareport.com) operates in LEO, as do many commercial communications satellites operated by companies such as SpaceX and OneWeb.

## Why Does LEO Matter?

LEO is attractive because spacecraft remain relatively close to Earth.

The shorter distance can provide **lower communications latency**, while Earth-observation satellites can capture detailed images of the planet. Reaching LEO also generally requires less **delta-v** than reaching higher orbits.

The major disadvantage is **atmospheric drag**. Even at several hundred kilometers above Earth’s surface, the atmosphere is thin enough to slow spacecraft gradually. Satellites in lower LEO therefore need periodic orbital adjustments or will eventually descend and **reenter the atmosphere**.

## Related Terms

- Medium Earth Orbit (MEO) — An orbital region above LEO and below geostationary orbit.
- [Geostationary Orbit (GEO)](https://proximareport.com/glossary/geostationary-orbit-geo/) — An orbit that allows a satellite to remain above approximately the same point on Earth’s surface.
- Orbital Velocity — The velocity required for an object to maintain an orbit.
- Delta-v — The change in velocity required to perform a maneuver.
- Atmospheric Drag — The resistance spacecraft experience from the Earth’s upper atmosphere.
- Reentry — The process of an object returning through Earth’s atmosphere.

## In Short

**Low Earth orbit (LEO)** is the region of Earth orbit below roughly **2,000 km** in altitude. It is widely used for satellites and crewed spacecraft because it is relatively close to Earth and generally requires less energy to reach than higher orbits.