Technical Brief / Iss. 01 Low Earth Orbit Internet

How Starlink
works.

A ten-thousand-satellite mesh in low Earth orbit, a pizza-box phased-array on your roof, and a fleet of laser links rewriting how the internet routes around the planet.

10,300+ satellites
Active in orbit / May 2026
480km altitude
75× closer than geostationary
25–50ms latency
Comparable to fiber broadband
01 — Orbit

The whole trick is in the altitude.

Why LEO Traditional satellite internet uses geostationary satellites parked 35,786 km away. Light, even at lightspeed, takes ~240 ms to make the round trip. Starlink flies 75× closer, collapsing the delay budget.

A signal up to LEO and back takes under 3 ms. To geostationary orbit and back takes nearly 240 ms.

Geostationary satellites have one huge advantage: they appear stationary in the sky, so a dish on the ground can point at them once and never move. The price you pay is distance. The signal has to travel a tenth of the way to the Moon and back, twice, for every packet.

Starlink flies low. The cost: each satellite is only visible from a given spot on the ground for a few minutes, and you need thousands of them to guarantee one is always overhead.

GEO Round-trip

~240ms

LEO Round-trip

~3ms

GEO Coverage

3sats for the world

LEO Coverage

10k+sats required
The photon race London → New York · One way · Slowed 40×
Starlink laser mesh~7,300 km · vacuum · c
0ms
Subsea fiber~6,800 km · glass · 0.67c
0ms
Geostationary bounce~75,000 km · vacuum · c
0ms

Idealized one-way propagation times. Light in glass fiber travels at two-thirds of its vacuum speed — so for long routes, a path through space can beat the cable on the seafloor.

02 — Signal

The journey of one packet.

End-to-end path Six hops between you and the wider internet, completed in well under the time it takes you to blink. Two of those hops happen in space.
01
Your device
Laptop, phone, tractor in a field. Packet goes over Wi-Fi or Ethernet to the dish.
02
The dish
Phased-array antenna picks a satellite overhead and aims an electronic beam at it.
03
Uplink
Ku-band radio sends the packet 480 km up in under 2 milliseconds.
04
Laser hop
If no ground station is nearby, the satellite lasers data to neighbors in orbit.
05
Downlink
A satellite over a ground station shoots the packet back down to a big dish.
06
Internet
From the ground station, fiber carries it the rest of the way to its destination.
03 — Mechanics

Three moving pieces, mostly invisible.

What Changes Nothing on the roof needs to swing around. The terminal steers a radio beam electronically, hands the session to the next satellite as the sky moves, and the satellites pass traffic across laser links overhead.
Phased-array antenna · Live wave simulation

The beam turns because the timing changes.

Each of the dish's 1,280 patch antennas sends the same radio signal with a tiny delay. Add a smooth delay across the grid and the waves reinforce in one direction while fading everywhere else.

The dish — nicknamed Dishy McFlatface — is not physically aiming at a satellite. The radio pattern is being re-shaped in silicon, quickly enough to track several candidates across a 120° field of view and switch without a motor. The target it stays locked onto is 480 km up and moving at 7.5 km per second — eight times faster than a rifle bullet.

Patch antennas1,280
Field of view120°
Mechanical motionNone
Steering methodPhase delay
FIG. 01 · Top-Down View Running
Beam Angle 0°
Phase Shift Δφ 0.00 rad
Elements 16
Wavelength λ 40 px
Steering Angle 0°
Antenna Elements 16

More elements → tighter beam, less spillover (sidelobes).

Wavelength 40px

Shorter wavelength → finer beam, but the array spans fewer wavelengths.

Satellite handoff

Your client is always choosing the next satellite.

A low-orbit satellite tears across the sky at 27,400 km/h — it rises, becomes the best target, and drops toward the horizon in about five minutes. The terminal keeps backup candidates in view and shifts the active beam before the old link gets weak.

To you it looks like one connection. Underneath, the endpoint in space is being swapped again and again while routing state follows the session.

Orbital velocity27,400 km/h
Overhead pass~5 min
User experienceOne link
Network realityMany passes
Inter-satellite links

Satellites can route around the planet.

Every modern Starlink carries four optical laser terminals that aim near-infrared beams at ~1,550 nm: permanent links to neighbors in the same orbital plane, temporary ones to crossing planes. A packet can move sideways through space before it ever comes down to a gateway.

Light in glass fiber slows to 200,000 km/s; in vacuum between satellites it stays at 300,000 km/s. For long-distance routes, the constellation can beat fiber on its own terms.

Laser terminals / sat4
Wavelength1,550 nm
Same planeFore / aft
Cross planeSide links
04 — Architecture

A shell within a shell within a shell.

Constellation Design Starlink isn't one big swarm. It's a precise lattice of orbital planes at multiple altitudes and inclinations, designed so that from any populated patch of ground, at least one satellite is always overhead.
FIG. 02 · Live constellation model Drag to rotate
53° main shell 53.2° mid shell 97.6° polar shell Altitudes exaggerated for clarity · hover a shell row to isolate it

The bulk of the fleet sits in a shell at roughly 53° inclination, with 72 satellites per orbital ring, in multiple staggered rings. That covers the populated band from Patagonia to the Aleutians. Additional inclined shells fill in mid-latitudes, and polar shells provide coverage all the way to the poles.

Starting in 2026, SpaceX is lowering the main shell from 550 km down to 480 km. Lower means lower latency and faster cleanup of dead satellites by atmospheric drag, at the cost of more handoffs per minute.

Each satellite is designed for a five-year operational life. When one fails or runs out of station-keeping fuel, atmospheric drag pulls it down within a few years and it burns up on reentry. The fleet is in constant turnover.

480km
Primary shell, 53° inclination — populated latitudes
MAIN
540km
53.2° shell — mid-latitude fill
MID
560km
97.6° polar shell — full Earth coverage
POLAR
12k
FCC approval ceiling — Gen2 constellation
APPROVED
42k
Total satellites in current filings
PROPOSED
05 — Scale

Built like a production line.

Industrial Scale None of the orbital mechanics matter without the unglamorous part: a factory that turns out satellites like consumer electronics, and a reusable rocket that flies often enough to keep ten thousand of them replenished.
0launches
Starlink missions in 2025 — one every ~4 days
0satellites
Deployed per Falcon 9 flight
~0tonnes
Hardware placed in orbit to date
0%
Of all active satellites in orbit are Starlink
A rocket every four days Dedicated Starlink launches · each tick = one rocket
2019
2
2020
14
2021
19
2022
34
2023
63
2024
89
2025
96
2026 · MAY
41

The satellites come off an assembly line in Redmond at a rate of several per day — they are built to be replaced, not repaired. A five-year design life isn't a flaw; it's what lets every generation of the fleet carry current-year silicon instead of decade-old radiation-hardened antiques.

The launch side is the same story: flight-proven Falcon 9 boosters flying their twentieth-plus mission, landing, and flying again days later. The constellation exists because the cost of a kilogram to orbit collapsed.

The numbers in space are just as industrial. More than 9,000 laser terminals are firing between satellites right now, each one good for 100 Gbps — roughly 4,000 simultaneous 4K streams per link — carrying tens of petabytes across the mesh every day.

Lasers in orbit9,000+
Per laser link100 Gbps
Mesh traffic / day42+ PB
4K streams / link~4,000
06 — Performance

What it actually delivers.

Field Measurements Real-world numbers vary by terminal type, location, time of day, and how many neighbors are streaming. These are typical figures for a residential dish in 2026.
Median Latency
25–50ms
Comparable to ground-based broadband. Geostationary satellite internet is 10× slower at 250+ ms.
Download Speed
100–300mbps
Typical residential plan. Peak speeds touch 1 Gbps on Gen2 hardware.
Frequencies
Ku · Ka
Ku-band for user terminals, Ka-band for ground stations, E-band/optical for satellite-to-satellite.
Mobility
60mph
Standard dish maintains connection at vehicle speeds. Maritime and aviation variants handle higher.