Starlink

Starlink is internet access from space. It is operated by SpaceX, Elon Musk’s rocket company. Normal internet reaches a house via cable, usually fiber optic or old telephone lines. Starlink replaces this cable with a radio connection to satellites, meaning devices orbiting the Earth at an altitude of a few hundred kilometers. For this, the customer sets up a flat antenna outdoors, which roughly looks like a large tablet. Over 6,000 of these satellites are now in operation, more than any other provider.

Internet for regions without cable

Laying a cable costs a lot of money per kilometer. In densely built cities this pays off, because hundreds of households share the cost. For a single house at the edge of a forest or a research station, it never pays off. Starlink fills exactly this gap: the satellites are already up there, and an additional customer costs the operator almost nothing extra.

As a result, Starlink has also become politically important. In the Ukraine war, the military and administration used the network because radio towers and lines had been destroyed. This raised an uncomfortable question: a single private company can decide who gets the service and where it gets switched off. Several governments are therefore working on their own satellite networks, the European Union for instance on the IRIS² project.

For investors, Starlink is also the part of SpaceX that regularly brings in money. Rocket launches are individual contracts, whereas internet subscriptions continue on a monthly basis. A Starlink IPO has for years been considered one of the most discussed possibilities in the financial markets.

Why the satellites fly so low

Older satellite internet services use an orbit at roughly 36,000 kilometers altitude. There a satellite appears to stand still above a point on Earth, which makes reception simple. The downside is the distance: the signal must travel about 72,000 kilometers there and back. Even at the speed of light this creates a delay of half a second. For video games or phone calls, that is unusable.

Starlink satellites fly at only about 550 kilometers altitude. This reduces the delay to values that are barely noticeable. The price for this: at this altitude, a satellite races around the Earth once in about 90 minutes. So it never stands still, but disappears over the horizon after just a few minutes. That is why thousands of satellites are needed so that one is always within range.

The customer’s antenna aligns itself electronically, without rotating, and continuously hands the connection off to the next satellite. You can imagine it like a relay race, where the baton is passed on every few minutes. From there the signal goes to a ground station connected to the normal internet. Newer satellites additionally pass data to one another via laser.

From the mountain hut to the night sky

In everyday life, you encounter Starlink where cables are missing. Airlines use it to offer WiFi on board, cruise ships and freighters use it on the open sea. Construction sites, disaster relief workers, and farmers with machinery in the field are also among the customers. In Germany the service is available, but costs significantly more than a typical cable connection.

Starlink also becomes visible in the sky. Shortly after a launch, the satellites move across the night sky like a string of pearls. Astronomers criticize this because the bright trail ruins telescope images. A second point of contention is space debris: the more objects orbiting in low orbit, the greater the risk of collision.

A common misconception: Starlink does not replace a mobile network. The phone does not connect directly to the satellite, but to the antenna on the house or in the vehicle. SpaceX is indeed working on satellites that reach phones directly, but so far this is limited to short text messages. In news reports, the two are often lumped together.