Live · NASA Johnson Space Center

The International Space Station

Four hundred kilometres up, moving at nearly eight kilometres a second, and circling the Earth roughly every ninety-three minutes. This is where it is, from the trajectory file its own flight controllers use.

Right now

Live

42.85° S
Latitude
sub-satellite point
20.46° E
Longitude
sub-satellite point
433.4km
Altitude
above the WGS-84 ellipsoid
7.652km/s
Orbital speed
27546 km/h

Computed for 2026-09-17 03:41 UTC, interpolated between NASA's four-minute state vectors by the method the CCSDS standard specifies.

Ground track

Path already flown
Path ahead
Position now
51.6° inclination limit

Each orbit crosses the map west to east and falls about 22.5 degrees of longitude west of the last, because the Earth turns beneath it. The dotted lines are the ±51.6° limits set by the station's orbital inclination.

The track never reaches beyond 51.6° north or south, because that is the station's orbital inclination — the angle its orbit makes with the equator, chosen in the 1990s so that both Baikonur and Cape Canaveral could reach it. Each successive orbit falls about 22.5° of longitude west of the last, because the Earth turns underneath.

The orbit, measured

92.90min
Nodal period
measured between equator crossings in the file
15.50
Orbits per day
derived from that period
344h
Trajectory published ahead
about 222 orbits
463.2t
Station mass
as recorded in the ephemeris header

The period is measured, not assumed: the ephemeris is scanned for the moments the station crosses the equator northbound, and the mean interval between them is the nodal period. That is the right quantity for a satellite in a flattened gravity field, and it differs by a few seconds from the two-body value a textbook formula would give.

How this is checked

Converting NASA's J2000 state vectors into a position over the Earth needs precession, nutation and Earth rotation. Get any of it wrong and the ground track is displaced by a fraction of a degree — which looks entirely plausible. So it is checked against the provider: every ephemeris file states the Earth-fixed longitude of the station's first and last equator crossings, computed by NASA. Running our own transformation at those moments gives:

The latitude column is the independent half of the check: an ascending node is by definition at zero.
Node	NASA longitude	Computed here	Computed latitude	Disagreement
first equator crossing	21.70559°	21.70556°	-0.00005°	3.2 m on the ground
last equator crossing	-55.34250°	-55.34251°	-0.00001°	1.3 m on the ground

The two crossings are fifteen days apart, so agreement at both also rules out an error in the rotation rate rather than merely in its offset. The same comparison runs as a build gate, against the live file.

Seeing it

The station is the brightest thing in the sky after the Sun and Moon, and it is easy to recognise: a steady white point, as bright as Venus, gliding silently from one horizon to the other in a few minutes without blinking. It is visible only when it is in sunlight and you are in darkness, which restricts it to the couple of hours after dusk and before dawn. Work out when it crosses your sky →

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: 2026-09-17 03:41 UTC
Generated by provider: 2026-09-16 18:33 UTC
Valid until: 2026-10-01 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.