Bright satellites
On any clear evening, a few dozen points of light cross the sky without blinking. One of them is far brighter than the rest, and it is the only one this platform can tell you where to find.
The brightest of them
The International Space Station outshines everything else in orbit by a wide margin. It reaches roughly magnitude −4 on a high overhead pass — as bright as Venus, and brighter than any star. It manages that by being large, low and highly reflective: a hundred metres across, four hundred kilometres up, with an acre of solar array angled at the Sun.
Its orbit right now
Live417km
Altitude now
low enough to appear fast and bright
7.7km/s
Orbital speed
crosses the sky in a few minutes
93min
Orbital period
several chances a day, few of them visible
51.6°
Inclination
the latitudes it can ever pass over
What makes a satellite visible
Sunlight, and only sunlight.Satellites emit nothing. Every one you have ever seen was reflecting the Sun, which is why they appear in the hours around dusk and dawn: high enough to still be lit while the ground below has turned away. Watch one long enough after sunset and it will often fade out mid-sky as it enters Earth's shadow — not setting, but eclipsing.
Low is bright. Brightness falls with the square of distance, so an object at 400 km can be a hundred times brighter than the same object at 4,000 km. Almost everything visible to the naked eye is in low Earth orbit; geostationary satellites, at 36,000 km, are far beyond it.
Big, flat and reflective helps. Solar arrays and radiators are large flat surfaces, and when the geometry lines up they can flare briefly to many times their usual brightness. That is why a satellite can appear to pulse: it is tumbling, and its reflecting faces are turning.
It does not blink. The commonest misidentification is an aircraft. Aircraft carry flashing navigation lights and, at altitude, are usually audible on a quiet night. A satellite is a steady point of light, silent, moving at a constant rate, and typically crossing the whole sky in three to six minutes.
Why the others are not listed here
A list of bright satellites would be easy to write and useless to read. Brightness alone tells you nothing about whether an object is above your horizon tonight, and predicting that needs current orbital elements for each one. AsteriaStar has no source of those it can legally and reliably use: the public catalogue is served by hosts that refuse automated access or require credentials whose terms do not permit this, and scraping a tracking site is not something this platform does.
So rather than publish a table of magnitudes that cannot be turned into a sighting, this page carries the one satellite whose trajectory is genuinely known and an explanation of what you are looking at when you see any of the others. The reasoning in full is on the live status page.
Provenance
One satellite is tracked live on this platform, and it is the International Space Station — because NASA publishes its operational trajectory openly and documents it. General catalogues of orbital elements for other satellites are either behind credentials whose terms do not permit this use, or served by hosts that refuse automated access. AsteriaStar does not scrape satellite-tracking sites, so the rest of the sky is honestly absent rather than approximately present.
ISS operational ephemeris
Live- Status
- Live
- Kind
- Model product
- Provider
- NASA ISS Trajectory Data
- Organisation
- NASA Johnson Space Center, Flight Operations Directorate (TOPO)
- Fetched
- 2026-09-16 11:56 UTC
- Generated by provider
- 2026-09-14 15:42 UTC
- Valid until
- 2026-09-29 12:00 UTC
- Provider cadence
- 3 d
- Cached for
- 6 h
- Treated as stale after
- 4 d
- Licence
- Public domain (US Government work), NASA/JSC.
Source file: https://nasa-public-data.s3.amazonaws.com/iss-coords/current/ISS_OEM/ISS.OEM_J2K_EPH.txt
ISS operational ephemeris (CCSDS OEM) from NASA ISS Trajectory Data, fetched from https://nasa-public-data.s3.amazonaws.com/iss-coords/current/ISS_OEM/ISS.OEM_J2K_EPH.txt. NASA regenerates this file every few days and it covers fifteen. Six hours is a small fraction of the interval between publications, and re-parsing five thousand state vectors on every page view would be pure waste.
A predicted trajectory, not a measurement: state vectors from NASA's operational determination and propagation, in the mean equator and equinox of J2000, at four-minute spacing. It covers fifteen days from its creation and NOTHING beyond that — the station manoeuvres, and no position is offered past the end of the file. Positions between tabulated epochs are interpolated by the method the CCSDS standard specifies.
Sources & references
The primary and reference sources this topic draws on.
- NASANational Aeronautics and Space Administration
Mission data, planetary science, space telescopes, and public-domain imagery.
Most NASA-produced imagery is in the public domain; individual items are checked for usage terms before publication.