How Starlink Works: Satellites, Lasers, Gateways and the Path of a Packet
Starlink is the largest satellite constellation ever built, and it is also just an internet service provider with an unusual last mile. This guide explains how the system works at a network level: what is in orbit, what sits on your roof, where the traffic goes, and which parts of the design matter for India’s security rules. It is deliberately technical. For the current political and regulatory situation in India, see our separate post on the Starlink India delay and the Musk and Ambani row.
Figures below are dated, because the network changes quickly. Where a number comes from a company disclosure, a measurement study or a press summary, we say so.
The system in one picture
Starlink has three segments, and every packet crosses all of them:
| Segment | What it is | Job |
|---|---|---|
| Space | Roughly 11,000 satellites in low Earth orbit | Relay traffic between users and ground stations, and between each other |
| Ground | Gateway sites and points of presence | Connect the satellites to the ordinary internet |
| User | A flat phased-array dish and a router | Talk to whichever satellite is overhead |
Public trackers put the constellation at about 11,100 satellites in orbit in August to October 2026 (KeepTrack lists 11,137 on Oct 8; Jonathan McDowell’s count, reported by Space.com, was 11,102 on Aug 27). Counts differ by tracker because they treat satellites being lowered for disposal differently.
Why low orbit changes everything
Older satellite internet uses geostationary satellites about 35,786 km up. Radio signals travel at the speed of light, roughly 299,792 km per second, so the geometry sets a hard floor on delay. A signal that goes up to a geostationary satellite and down to a gateway, then repeats the trip for the reply, covers about 143,000 km, which is at least 477 ms before any processing. In practice such links run 600 ms or more.
Starlink flies most of its satellites at about 550 km. The same calculation for a satellite directly overhead of both ends gives about 2,200 km of travel and a floor near 7 ms. Real latency is higher because satellites are rarely directly overhead, the gateway may be far away, and routing and queueing add delay. Starlink’s own July 2025 network update put the US median peak-hour latency at 25.7 ms, with a stated goal of a stable 20 ms.
The trade-off is motion. At 550 km a satellite travels at about 7.6 km per second and circles the Earth roughly every 95 minutes (standard orbital mechanics, our calculation). No single satellite stays above you for long, so the system needs thousands of them and constant handoffs between them.
The altitude is changing. In January 2026 Starlink’s engineering VP Michael Nicolls announced that all satellites at about 550 km, roughly 4,400 of them, would be lowered to about 480 km during 2026. The stated reason is safety: at solar minimum, a dead satellite at 550 km could take more than four years to decay, against a few months at 480 km, and there is less debris below 500 km (The Register).
The satellites
Starlink satellites have grown with each generation. The table uses mass and capacity figures from public sources, which vary slightly.
| Generation | Introduced | Notable features |
|---|---|---|
| v1.0 | Nov 2019 | About 260 kg; Ku-band user links and Ka-band gateway links |
| v1.5 | Jan 2021 | About 295 kg; first with laser inter-satellite links |
| v2 mini | Feb 2023 | Larger solar arrays, reported around 800 kg; launched on Falcon 9 |
| v3 | 2026 | About 2,000 kg; designed for Starship; 1 Tbit/s downlink |
Each v3 satellite is described as carrying around 1 Tbit/s of downlink capacity, with uplink figures between 160 and more than 200 Gbit/s depending on the source, and thousands of beams, against 192 downlink beams on v2 (Wikipedia, which cites SpaceX). On September 28, 2026, Starship’s 14th flight deployed the first 26 operational v3 satellites (Space.com).
Satellites carry electric Hall-effect thrusters that use krypton or argon for station-keeping and deorbiting, and star trackers for precise pointing. Satellites are not immune to failure: in December 2025 one satellite vented propellant, tumbled and released debris, which fed into the decision to lower the shell (The Register).
The user terminal
The dish contains no moving reflector. It is a phased array: many small antenna elements whose signal timing is adjusted electronically to steer a beam across the sky. This is how a fixed flat panel can follow satellites crossing overhead in minutes.
User links use the Ku band: about 10.7 to 12.7 GHz for downlink and 14.0 to 14.5 GHz for uplink, according to the FCC-based descriptions summarised by KeepTrack. Gateway links use higher bands, covered below.
A 2022 security teardown by researcher Lennert Wouters, summarised on Wikipedia, found a custom system-on-chip with a quad-core ARM Cortex-A53 processor running Linux, digital beamformers each driving 16 front-end modules, and a GPS receiver. The GPS receiver is why terminals know where they are, which matters for the geofencing discussion later.
Handoffs every 15 seconds
Measurement studies found that the network reconfigures satellite assignments on a fixed 15-second cycle, with changes landing at the 12th, 27th, 42nd and 57th second of each minute, synchronised across measurement sites (arXiv 2307.00402). One analysis estimates handover spikes add roughly 30 to 50 ms (CircleID). The exact effect of each handover depends on load and on how many candidate satellites are visible, and is still being studied.
Gateways and points of presence
A satellite is only a relay. To reach the internet, traffic comes down to a gateway, a ground station with large dishes and a fibre connection. Starlink said in 2025 that it operated more than 100 gateway sites in the United States, placed to minimise latency (The Register). A typical station has been described as several 2.86 m antennas inside a fenced compound.
Gateway links used the Ka band until early 2023. SpaceX also sought E-band spectrum (around 71 to 86 GHz) for the second-generation system, which the FCC approved in March 2024. E-band offers wide bandwidth but is more affected by rain.
Starlink said on October 7, 2026 that it had built 20 gateway sites in India with hundreds of antennas.
Laser links: a mesh in orbit
From v1.5 onward, satellites carry optical inter-satellite links. A satellite can pass data to its neighbours by laser and send it down to a gateway far from the user. This lets service reach places with no nearby gateway: Antarctica has none, so polar satellites route over lasers to stations in South America, New Zealand and Australia.
In a January 2024 conference talk, a SpaceX engineer reported more than 9,000 lasers in service, each sustaining about 100 Gbit/s with peaks near 200 Gbit/s, link uptime above 99%, and more than 42 petabytes of customer data per day moved over them, according to TechSpot. Those figures are from 2024 and will have grown.
Lasers also help latency on long routes. Light travels about 299,792 km per second in vacuum but roughly 200,000 km per second in glass fibre, so a path through space can beat fibre over distance even with extra hops.
The path of a packet
Putting it together, a request from your laptop travels like this:
- The router sends it to the dish over your home network.
- The dish beams it up, in Ku band, to the satellite currently assigned to it. According to measurement studies, the assignment is made centrally by Starlink’s scheduler and refreshed on the 15-second cycle.
- If a gateway is visible to that satellite, the satellite sends the packet straight down (a “bent pipe”). Otherwise it is relayed over lasers to a satellite that can see one.
- The gateway hands the packet to a point of presence, where it enters the public internet.
- The reply returns by the same kind of path, possibly through different satellites.
Your IP address
Starlink’s help centre states that its default IPv4 setup uses carrier-grade NAT, which does not allow inbound connections, and that a public IPv4 option exists on some plans (Starlink support). The stock Starlink router is also described as not supporting port forwarding, so inbound access needs a third-party router. Plan eligibility changes, so check your account. We could not load Starlink’s page directly, so this reflects how it is quoted by others.
This is the same CGNAT problem that affects many Indian broadband connections. Our guide to CGNAT on Indian ISPs explains it, and the CGNAT Checker tells you whether your connection is affected. IPv6 avoids the problem where it is available, as we explain in IPv6 in India.
Performance, with caveats
Starlink’s July 2025 network update gave a combined capacity of nearly 450 Tbps, more than 6 million customers and over 7,800 satellites at that time, a US median peak-hour download of 200 Mbps, and about 5 Tbps of new capacity per week (The Register). All of these were US figures and are now more than a year old. Independent speed-test aggregators generally report lower medians than company figures, because methods and sampling differ. Capacity also depends on load: users in the same area share satellite beams, so busy cells slow down.
Physical limits apply too. Ku-band signals weaken in heavy rain, the dish needs a clear view of the sky, and handovers add jitter. If you want to see your own latency to different regions, our Global Latency Checker measures it from your browser, and our guide to what a good ping is explains how to read it.
Where the architecture meets India’s rules
India’s Department of Telecommunications issued security conditions for satellite licensees in a circular dated May 5, 2025. We could not locate the circular text, so the points below come from press and legal summaries, including MediaNama, Business Standard and Storyboard18. Check the official text before relying on the details.
The reported requirements, mapped to the architecture above:
- Gateways in India, cleared one by one. Each gateway site needs separate security clearance, and network control centres and lawful-interception and monitoring systems must sit in Indian territory.
- No bypassing Indian gateways. User traffic may not be routed via foreign gateways or through inter-satellite links in a way that avoids Indian infrastructure. This is the main technical tension with a laser mesh, which is built to move traffic wherever is fastest.
- No copying or decrypting abroad. Indian data may not be mirrored, copied or decrypted outside the country.
- Terminal control. Terminals must be registered and located in real time, and services must be geofenced, with the ability to deny service in specific areas.
- Special monitoring zones. Areas within 50 km of international borders and out to 200 nautical miles from the coast are designated for closer monitoring.
- Blocking and metadata. Operators must keep blocked sites blocked and support metadata collection.
Analysts have raised technical questions about enforcement. A Takshashila Institution paper argues that restrictions on inter-satellite routing are hard to verify from the ground, since ground monitoring cannot see what happens in orbit, and that direct-to-device service would make gateway-based localisation largely ineffective. These are the authors’ arguments, not settled facts. Starlink says it has built India-specific controls and that Indian user data will stay in India.
What to take from this
Starlink’s speed advantage comes from three design choices: low orbits, a laser mesh and a steerable flat dish. Each also creates a question for regulators, because the network can route traffic in ways that depend on decisions made in orbit and by the operator rather than on the ground in any one country. That is the technical background to India’s gateway, interception and geofencing conditions. Whether and when those conditions are met is a separate matter, which we cover in our news post on the current Starlink India row.