← Did You Know?
🛰️Space8 min read

How Starlink Works

The dish on the fence post has no lens to point and barely moves, yet it tracks satellites crossing the sky at 27,000 km/h, swapping between them constantly without dropping your call.

In plain English

Satellite internet used to mean one enormous satellite parked 36,000 kilometres up, so far out that it orbits at exactly the speed the Earth turns and hangs over one spot. That distance is the problem. Radio travels at the speed of light, and even light needs a quarter of a second to make that round trip twice, out to the satellite and back, then out and back again with the reply. Every click felt like posting a letter.

Starlink turns the arrangement inside out. Instead of one satellite very far away, it uses thousands very close: most around 550 kilometres up, sixty-five times nearer. At that height the light-speed delay almost vanishes, and the connection feels like ordinary broadband.

The price of being close is that nothing stays overhead. A satellite at that altitude crosses the sky in minutes, so coverage means a swarm, with your dish passed from one to the next like a runner handing off a baton, silently, many times an hour, without dropping the connection.

Five things to file under "wait, what?"

  • The dish steers a beam without moving. The antenna is a phased array: hundreds of small emitters firing together, with the beam steered by adjusting the timing between them by fractions of a nanosecond. Delay one side of the array a whisker and the combined beam leans to one side, no motors required. It is the same trick a warship's radar uses, sold as consumer kit and sitting on a shed.

  • In space, light outruns fibre. Light in glass fibre travels at about two-thirds of its speed in vacuum. Starlink satellites pass traffic between each other with lasers, in vacuum, so on long routes the sky path can genuinely beat the cable. Financial traders, who pay fortunes for microseconds, noticed immediately.

  • The satellites are deliberately disposable. Each one is designed to live roughly five years, then steer itself down and burn up, replaced by a newer model already launching. The constellation is not a monument like a traditional satellite; it is a rolling fleet, permanently mid-replacement, which is also its debris plan: at that altitude, dead hardware falls out of the sky on its own within a few years.

  • It is most of everything in orbit. By mid-2026 the constellation numbers somewhere around nine or ten thousand spacecraft, comfortably more than every other operator on Earth combined, launched in batches of dozens on reusable rockets. Nothing on this scale has been flown before, which is exactly why astronomers watch it nervously.

  • Astronomers see it as graffiti on the sky. Each satellite is a moving point of reflected sunlight, and long-exposure images collect them as streaks. The Rubin Observatory, which photographs the entire southern sky every few nights and has its own story on this site, is the instrument with most to lose. Darkening treatments have helped; the tension has not gone away.

The full story

The tyranny of the far satellite

Geostationary orbit is a beautiful idea: park at 35,786 kilometres over the equator and you turn with the Earth, appearing fixed in the sky, so a dish can be bolted down and forgotten. One satellite covers a third of the planet.

But physics charges rent. A signal to geostationary orbit and back covers over 71,000 kilometres, and a full question-and-answer exchange does it twice. Before any computer has processed anything, half a second is gone. For television, which flows one way, that is irrelevant. For a video call, a game, or anything conversational, it is misery. Low orbit is the only cure, and low orbit forces everything else: the swarm, the handoffs, the clever dish.

The handoff dance

From your garden, any single Starlink satellite is usable for only a few minutes as it sweeps from horizon to horizon. The network therefore runs on a schedule: your dish is told which satellite to use and when to switch, and swaps its beam to the next one in an instant, far faster than any mechanical dish could slew. You notice nothing.

The satellite overhead needs somewhere to send your traffic. Originally that meant bouncing it straight down to the nearest gateway station wired into the internet, which limited coverage to places within reach of one. The laser links removed that leash: traffic can now hop satellite-to-satellite across an ocean or a desert and come down wherever a gateway exists, which is how ships, islands and polar stations get served.

What it is genuinely good for

Rural Britain is the honest use case. A farmhouse three kilometres from the cabinet, quoted five figures for a fibre trench, can have working broadband by the afternoon: dish on a pole, clear view of the sky, done. The same logic applies to disaster zones, where the terrestrial network is rubble but the sky still works, and to everywhere infrastructure was never built.

The trade-offs are real too. It needs open sky and suffers in heavy rain. The hardware and subscription cost more than urban fibre. And it concentrates a strategic chunk of the world's connectivity in a single private company, a fact governments have started to think about out loud.

The part worth remembering

None of it is exotic physics. It is the speed of light, taken seriously as an engineering constraint: move the satellite closer, accept that closeness means motion, and solve motion with numbers, timing and thousands of identical machines instead of one precious one. The dish on the fence post is doing radar-grade beam steering while the satellites above it are handing your packets to each other by laser. That this now counts as ordinary household kit is the most science-fiction thing about it.

Go deeper

For the curious:

On YouTube:

Keep going

More things worth knowing

All topics →