Satellite internet explained how low Earth orbit networks work

[Inland Sienna]

TL;DR

• Low Earth orbit (LEO) satellite networks fly a few hundred kilometres up, far closer than traditional geostationary satellites at about 35,786 km, which cuts latency dramatically
• SpaceX's Starlink dominates, with more than 10,000 satellites launched by spring 2026 and service in over 100 countries and territories
• Competitors are scaling up: Amazon Leo (formerly Project Kuiper) began full scale deployment in 2026, Eutelsat OneWeb operates around 650 satellites, and the EU's IRIS2 constellation is planned to begin deployment around 2027
• Direct to phone satellite services, such as T-Mobile's service with Starlink launched in 2025, are bringing basic connectivity to ordinary handsets
• Concerns include space debris, astronomy, dependence on a few operators and security of ground terminals and links

Why satellite internet is having a moment

For decades, satellite internet meant slow, expensive connections with frustrating delays, used mainly where nothing else was available. Signals travelled to geostationary satellites about 35,786 kilometres above the equator and back, adding around half a second of delay to every round trip. Video calls and online games were painful. That reputation is changing quickly

Low Earth orbit constellations have transformed what satellite internet can do. By placing thousands of satellites a few hundred kilometres up, operators cut latency to levels comparable with many terrestrial connections and offer speeds suitable for streaming and video calls. Rural households, ships, aircraft, disaster zones and remote industries now have practical options. Governments and militaries have taken note too

This thread explains how LEO networks work, who the main players are, what they are good and bad at, and the wider issues they raise. It aims to be balanced, recognising both the remarkable engineering and the legitimate concerns. Figures are drawn from reported sources and dated where possible. The sector moves fast, so updates in the replies are welcome

How LEO networks work

A LEO satellite orbits the Earth roughly every 90 to 120 minutes, so any single satellite is overhead for only a few minutes. To provide continuous coverage, constellations need many satellites arranged in multiple orbital planes, with user terminals handing over from one to the next seamlessly. Phased array antennas in user terminals steer beams electronically without moving parts, tracking satellites across the sky. This combination of large constellations and smart antennas makes the system work

Traffic must reach the wider internet. Early designs relayed signals from a user terminal up to a satellite and down to a nearby ground station connected to fibre. Newer satellites use laser links between satellites, passing traffic across the constellation before sending it down, which reduces the need for ground stations everywhere and enables coverage over oceans and polar regions. Laser links also allow traffic to travel long distances through space, sometimes with lower latency than terrestrial routes

Latency in LEO systems typically ranges from about 25 to 60 milliseconds, compared with around 600 milliseconds or more for geostationary links. Capacity depends on how many satellites are overhead and how many users share them. Performance can dip in busy areas or during peak times. Operators manage this by launching more satellites and limiting sign ups in congested cells

Spectrum is a shared resource. Satellite operators must coordinate frequencies with each other and with terrestrial services through national regulators and the International Telecommunication Union. Disputes over interference between constellations have become more common as networks grow. Spectrum policy quietly shapes what services are possible

The main players

SpaceX's Starlink is by far the largest operator. Reports in April 2026 counted more than 10,300 Starlink satellites launched, with regulatory approvals for around 15,000 and plans for many more, and service available in more than 100 countries and territories. Reusable Falcon 9 rockets have let SpaceX launch satellites at a pace no competitor has matched. Starlink serves households, businesses, maritime and aviation customers and governments

Amazon's constellation, originally called Project Kuiper and renamed Amazon Leo in 2025, plans more than 3,200 satellites. After prototype launches and early batches, a United Launch Alliance launch in April 2026 deployed 29 satellites in what was described as the first full scale deployment, with 239 launched by that point. Amazon has said it aims to offer services to consumers, businesses and governments, leveraging its cloud infrastructure. It faces the challenge of catching up with Starlink's head start

Eutelsat OneWeb operates around 650 satellites in a somewhat higher orbit, focusing on enterprise, government and mobility customers rather than mass market consumer broadband. It is Europe's main operational LEO alternative. The European Union's IRIS2 programme, a planned constellation of around 290 satellites combining LEO and medium Earth orbit, aims to provide secure connectivity for governments and citizens, with deployment expected to begin around 2027 and services before 2030. China is also building large constellations, including Guowang and Qianfan

Business models differ. Some operators sell directly to consumers, while others focus on wholesale capacity for mobile networks, airlines, shipping companies and governments. Partnerships with telecom operators let satellites fill coverage gaps in existing networks. These differences matter for how competition develops

Direct to phone connectivity

A newer development connects satellites directly to ordinary mobile phones. Instead of a dish, the satellite acts like a cell tower in the sky, using mobile spectrum that standard handsets can receive. T-Mobile in the US launched a commercial service with Starlink in July 2025, initially supporting text messaging and expanding to data for some apps. Companies such as AST SpaceMobile are building satellites designed for broadband to phones

Direct to phone services are currently limited in bandwidth compared with dish based connections, but they can be lifesaving in emergencies and remote areas. Apple's emergency SOS via satellite, launched in 2022 with Globalstar, showed demand for basic connectivity anywhere. Mobile standards bodies have added support for non terrestrial networks in 5G specifications. Coverage gaps may gradually disappear for basic messaging

Strengths and limitations

The strengths are clear. LEO satellite internet reaches places fibre and mobile networks do not, can be deployed quickly after disasters and supports moving platforms such as ships, aircraft and vehicles. It has helped schools, clinics and businesses in remote areas get online. In Ukraine, Starlink terminals became vital for communications after infrastructure was damaged

Limitations remain. Capacity per area is finite, so dense cities are poorly suited compared with fibre and 5G. Dishes need a clear view of the sky, and heavy rain or obstructions can affect performance. Costs for equipment and subscriptions, while falling, remain significant for many households in lower income countries

Pricing has changed quickly. Equipment costs have fallen, and operators offer different plans for homes, travel and businesses, with prices varying widely by country. Some governments subsidise satellite connections for remote households as part of broadband programmes. Affordability remains a barrier in many lower income regions

Dependence on a few operators is a strategic concern. A small number of companies, and one in particular, control much of the world's LEO capacity. Governments have worried about service availability during conflicts and about policy decisions made by private firms. That concern is a major motivation for programmes such as IRIS2 and national constellations

Space debris and the night sky

Thousands of satellites raise the risk of collisions and debris. Operators design LEO satellites to deorbit within a few years at end of life, and at low altitudes atmospheric drag pulls failed satellites down relatively quickly. Even so, the number of objects in orbit has grown rapidly, and collision avoidance manoeuvres have become frequent. Space agencies and researchers warn that careful traffic management is essential to avoid cascading collisions

Astronomers have raised concerns about satellite streaks in telescope images and radio interference with observatories. The International Astronomical Union has called for measures to protect dark and quiet skies. Operators have experimented with darker coatings, sunshades and orientation changes to reduce brightness. Collaboration continues, but the issue grows as constellations expand

Researchers are also studying the environmental effects of satellites burning up on re-entry, which release metal particles such as aluminium oxide into the upper atmosphere. The long term effects are not yet well understood. As launch and re-entry rates increase, monitoring will matter. This is an emerging area of science worth following

Launch emissions add to the environmental picture. Frequent rocket launches release exhaust into the upper atmosphere, and the climate effects of soot and other emissions at altitude are an active research topic. Reusable rockets reduce manufacturing impacts but not launch emissions. A full accounting of satellite internet's footprint is still emerging

Security considerations

Satellite networks face cybersecurity challenges like any infrastructure. User terminals are computers exposed to physical access, and researchers have demonstrated fault injection attacks on consumer satellite dishes, such as a 2022 presentation at Black Hat by Lennert Wouters on a Starlink terminal. Operators patch vulnerabilities and run bug bounty programmes. Jamming of signals has been reported in conflict zones, prompting rapid software updates to improve resilience

Encryption of user traffic and links between satellites and ground stations is essential. Research published in 2025 found that many geostationary satellite links carried unencrypted traffic, a reminder that security varies widely across the satellite industry. Long lived satellites also need cryptography that can be updated, including a path to post quantum algorithms. Satellites launched today may still be operating when quantum threats mature

What to watch

• Amazon Leo's commercial launch and how it competes on price and performance
• IRIS2 deployment progress and European strategic connectivity
• Direct to phone services expanding from messaging to data
• Space traffic management rules and debris mitigation enforcement
• Astronomy mitigation measures and their effectiveness
• Post quantum cryptography plans for satellite links and terminals

Closing thoughts

Low Earth orbit satellite internet has moved from ambitious concept to everyday reality for millions of users in just a few years. It is connecting remote communities, supporting emergency response and changing how ships, planes and businesses stay online. Competition and public programmes are growing, which should improve choice and resilience. The challenges of debris, astronomy, concentration and security deserve sustained attention as constellations grow

If you use satellite internet, please share your experience of speeds, reliability and setup. Professionals in space, telecoms or astronomy are very welcome to add context. Balanced perspectives make this thread more useful for everyone


Key references for citation

• Reporting on Starlink constellation size and Amazon Leo deployment, April 2026
• European Commission, IRIS2 programme
• T-Mobile, T-Satellite service launch with Starlink, July 2025
• International Astronomical Union, Centre for the Protection of the Dark and Quiet Sky from Satellite Constellation Interference
• Wouters, Glitched on Earth by Humans, Black Hat USA, 2022

[Owen84]

Living in rural Wales, LEO internet changed everything for us. We went from barely usable copper broadband to video calls without a second thought. My partner can now work from home properly

The dish needed a clear view north, which meant a pole on the roof. Setup took an afternoon

Speeds drop a little in the evenings but remain far better than before. Our children no longer complain about homework uploads. Weather has caused only a couple of short outages. Heavy snow was the worst case