GUIDES / BASICS
Starlink or the space station? How to tell them apart
By Jeroen Wouda · 2 November 2026 · Basics
You are outside because a pass was due at 20:14. Something bright appears on cue, tracks across the sky and disappears. It could be the station. It could also be one of several thousand Starlink satellites, and in the first minute of looking, the two are easy to confuse.
The differences are real and fairly easy to read once you know what to watch for. They come down to height, formation, brightness and timing.
Two objects at very different altitudes
The International Space Station orbits at roughly 400 kilometres. It is the largest artificial object in orbit, more than a hundred metres across with its solar arrays deployed, and on a good pass it outshines every star in the sky. It is a single object, and there is nothing else like it.
Starlink satellites orbit higher, most of the operational constellation at around 540 to 570 kilometres. Each one is a flat, compact spacecraft the size of an office desk, and the difference in apparent brightness between one Starlink satellite and the station is roughly the difference between a star and a streetlight.
That altitude difference has a visible consequence. Because they fly higher, Starlink satellites stay in sunlight longer after the ground has gone dark, so they can remain visible well into twilight when the station has already faded into the Earth's shadow.
The train
The giveaway is the formation. Starlink satellites are launched in batches and released close together, then spread slowly along the same orbital path over the following weeks. In the days after a launch they appear as a line of evenly spaced points, all moving in the same direction along the same track, one after another like beads on a wire.
The line crosses the sky over several minutes. Individual points are usually faint, and some are near the limit of what the eye can see from a town, which is why the train often reads as a string of dim stars that should not be moving. The spacing is regular, and that regularity is the thing to notice. No natural object and no other spacecraft produces that pattern.
Within a few weeks the satellites raise their orbits and spread out, and the tidy line dissolves into a scatter of individual satellites passing at unrelated times.
Brightness, colour and behaviour
The station is steady. It does not blink, flash or change colour, and its brightness rises smoothly to a peak near the middle of the pass, then falls away. Because it is large and complex, it can brighten sharply for a few seconds when a solar panel catches the sun at the right angle, then settle back.
A Starlink satellite is also steady, and much fainter. In the first weeks after launch the flat panels can catch the sun and flare, producing a short bright glint, but that is a flare, not a pattern.
An aircraft is the third thing people mistake for both. Aircraft have navigation lights: a red light on one side, green on the other, white strobes flashing at intervals, and usually a steady white anti-collision beacon. They also move more slowly across the sky, and you can often hear them. A satellite makes no sound and shows no lights other than reflected sunlight.
A meteor is the fourth. It is there and gone in under a second, usually with a taper and a bright head. Nothing in orbit moves like that.
Speed and direction
The space station crosses the sky in about five minutes on a high pass. It looks fast, roughly the apparent speed of a high-flying aircraft, and it holds a dead straight line. On a low pass near the horizon it seems slower, and it may dim and brighten as it moves through thicker atmosphere.
Starlink satellites move at a similar apparent rate, because they are at similar orbital altitude and follow similar geometry. Speed alone will not separate them. The formation will, and so will the numbers: if you are watching one dot and there is no second dot a few degrees behind it, you are most likely looking at the station.
Direction does help a little. The station's ground track is inclined 51.6 degrees to the equator, so from mid-latitudes it usually rises in a westerly or south-westerly direction and sets towards the east or north-east. Starlink orbits are inclined around 53 degrees, close enough that the paths look similar from the ground, so this is a weak test at best.
A field checklist
- A single steady point, very bright, crossing in five minutes: almost certainly the ISS.
- A line of evenly spaced faint points, all following the same track: a Starlink train shortly after launch.
- A steady point far fainter than the station, alone, crossing at a similar speed: probably a single Starlink satellite or another craft.
- Flashing red, green or white lights: an aircraft.
- A streak lasting less than a second: a meteor.
- Nothing at all at the predicted minute: the pass was low, the sky was hazy, or the prediction was for a different location.
Where to go next
- ISS passes gives the times, elevations and directions for the station at your location.
- What is a flyby versus a pass? clears up the vocabulary used in most local news reports.
- ISS orbit and the 51.6 degree inclination explains why the station's path across your sky always looks the way it does.
More guides
- Best time of year to watch the ISS — There is no single best month. The good weeks depend on the angle between the orbit and the Sun, and here is how that cycle works.
- How often does the ISS pass over my city? — The station circles Earth 15 times a day, yet you can go weeks without a visible pass. Here is why the schedule behaves that way.
- How to photograph the ISS — A moving point of light, a dark sky and a camera, and what it takes to turn a pass into a photograph worth keeping.