What is LEO? Low Earth Orbit Explained
Low Earth Orbit is the most commercially valuable region of space, home to the ISS, Starlink, and thousands of Earth observation satellites. This guide explains what LEO is, why it matters, and how the business landscape is evolving.
If you follow the space industry at all, you have seen the acronym LEO everywhere: LEO broadband, LEO constellations, LEO debris, LEO economy. But what exactly is Low Earth Orbit, why does it dominate commercial space activity, and what are the trade-offs of operating there? This guide breaks it down.
Defining Low Earth Orbit
Low Earth Orbit is generally defined as the region of space between approximately 160 km and 2,000 km above the Earth's surface. Below 160 km, atmospheric drag is too strong for any satellite to maintain a stable orbit for more than a few revolutions. Above 2,000 km, you enter Medium Earth Orbit (MEO), home to navigation constellations like GPS and Galileo.
Within that range, the characteristics of an orbit can vary significantly:
- Very Low Earth Orbit (VLEO): 200-400 km. Higher drag, shorter lifespan without propulsion, but excellent imaging resolution. Some newer Earth observation satellites are pushing into VLEO for competitive advantage.
- ISS altitude: ~420 km. The International Space Station orbits here, requiring periodic reboosts to counteract atmospheric drag.
- Starlink shell: ~550 km. SpaceX chose this altitude for its broadband constellation because it balances latency, coverage geometry, and orbital decay (satellites will deorbit naturally within a few years if they fail).
- Sun-synchronous orbits: Typically 600-800 km. These polar orbits keep a constant angle to the Sun, making them ideal for Earth observation satellites that need consistent lighting conditions.
- Upper LEO: 1,200-2,000 km. Less atmospheric drag, longer orbital lifetime, but higher radiation exposure from the inner Van Allen belt.
Why LEO Matters Commercially
LEO is where the bulk of commercial space activity is concentrated, and that dominance is only growing. There are several reasons:
Latency. At 550 km altitude, a radio signal takes roughly 3.7 milliseconds to travel from a ground terminal straight up to a satellite and back down, compared with about 240 milliseconds for the same trip via a geostationary satellite at 35,786 km. For broadband internet, video calls, and real-time applications, this difference is transformative. It is why Starlink, OneWeb, and Amazon Leo (formerly Project Kuiper) are building LEO constellations rather than geostationary fleets.
Resolution. For Earth observation, closer means sharper. A camera at 500 km can resolve details an order of magnitude finer than the same camera at 36,000 km. Companies like Planet, BlackSky, and Capella Space operate in LEO specifically because proximity to Earth is their competitive advantage.
Launch cost. Getting to LEO requires less energy, and therefore less propellant and smaller rockets, than reaching higher orbits. Reaching LEO takes roughly 9.3 to 10 km/s of delta-v including drag and gravity losses, and geostationary transfer orbit needs about another 2.3 km/s on top of that. With SpaceX rideshare prices of $7,000 per kilogram (50 kg minimum, 2026), LEO is accessible to startups, universities, and even high school teams building CubeSats.
Constellation economics. LEO constellations require many satellites because each one covers a smaller ground area and moves across the sky in about 90 minutes. But the falling cost of satellite manufacturing, driven by mass production techniques pioneered by SpaceX and OneWeb, means deploying hundreds or thousands of small satellites is now economically viable.
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The Challenges of Operating in LEO
LEO's advantages come with real trade-offs:
- Orbital debris: LEO is getting crowded. As of 2026, over 10,000 active satellites orbit Earth, the majority in LEO. Defunct satellites, spent rocket stages, and collision fragments add tens of thousands of trackable objects. The risk of collision (and the cascading Kessler Syndrome scenario) is a serious concern for regulators and operators.
- Atmospheric drag: At lower altitudes, residual atmosphere gradually slows satellites, lowering their orbit until they reenter and burn up. Operators must carry propellant for station-keeping, or accept a limited mission lifetime. SpaceX uses this to its advantage: at Starlink's low altitudes, a failed satellite falls back into the atmosphere on its own.
- Constellation size: Because each LEO satellite covers a small footprint and moves quickly, global coverage requires large constellations. In January 2026 the FCC authorized SpaceX to deploy 15,000 second-generation Starlink satellites, and in October 2026 about 11,100 Starlink satellites were working (Jonathan McDowell). The operational complexity of managing such a fleet (including collision avoidance, frequency coordination, and ground segment logistics) is immense.
- Radiation: While LEO is below the worst of the Van Allen belts, solar particle events and South Atlantic Anomaly passages still expose electronics to radiation. Satellites must be hardened or designed to tolerate periodic upsets.
- Regulatory complexity: LEO operators must coordinate with the ITU for spectrum, the FCC or national regulators for licensing, and increasingly must submit orbital debris mitigation plans. The regulatory burden is growing as the orbit becomes more congested.
The LEO Economy
The economic activity in LEO is staggering and growing rapidly:
- Broadband: SpaceX's Connectivity segment, mostly Starlink, reported $11.4 billion of revenue in 2025 (SpaceX S-1 filing), with competitors Amazon Leo (formerly Project Kuiper) and Eutelsat OneWeb ramping up.
- Earth observation: Most Earth-imaging satellites fly in LEO, serving agriculture, insurance, defense, and climate monitoring.
- Space stations: The ISS has operated in LEO since 1998. Commercial replacements from Axiom, Vast, and Orbital Reef will continue this tradition, hosting research, manufacturing, and tourism.
- In-space services: A growing ecosystem of companies offers LEO satellite servicing, debris removal, and inspection services, businesses that only exist because of LEO congestion.
The Future of LEO
LEO will only become more important. The convergence of cheaper launch, mass-produced satellites, and insatiable demand for connectivity and data ensures that this orbital regime will remain the center of gravity for commercial space. The key question is whether the international community can manage the commons: preventing debris cascades, coordinating spectrum, and maintaining LEO as a sustainable resource for future generations.
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