ISS Pass Time Predictor
Track the International Space Station in real time and find out when it will pass over your location. See live position, current altitude, speed, and distance from you — updated every 3 seconds directly from NASA telemetry.
What Is the International Space Station?
The International Space Station (ISS) is a modular space station in low Earth orbit, a collaborative project between NASA (US), Roscosmos (Russia), JAXA (Japan), ESA (Europe), and CSA (Canada). It has been continuously inhabited since November 2, 2000, making it the longest running human presence in space — over 24 years. The station measures approximately 109 meters wide and 73 meters long, roughly the size of a football field, with a mass of 420,000 kg. It serves as a laboratory for scientific research in microgravity, a testbed for space technologies, and a stepping stone for future deep-space missions including the Artemis lunar program. As of 2026, over 270 people from 21 countries have visited the ISS.
How to Spot the ISS From the Ground
The ISS is the brightest man-made object in the night sky and can be seen with the naked eye from any location on Earth between 51.6° north and south latitude — covering nearly all populated areas. It appears as a bright, steady white dot (it does not blink like aircraft navigation lights) moving smoothly across the sky from west to east in about 6 minutes. The best viewing conditions are in the hour after sunset or before sunrise, when the observer is in darkness but the station is still illuminated by sunlight. During these "golden windows," the ISS can reach magnitude -5.9 — brighter than Venus. Use NASA's free Spot the Station website or the ISS Spotter, GoISSWatch, or MyShake apps for precise sighting predictions including elevation angle, direction, and brightness for your exact location.
Understanding the Live ISS Data
This tracker uses the wheretheiss.at API, which receives position data from NASA's Trajectory Operations and Planning Office (TOPO) and updates the ISS ground track in near real-time. The latitude and longitude show the point on Earth's surface directly below the ISS (the sub-satellite point). Altitude is the vertical distance from Earth's surface, which averages around 408 km and fluctuates as the station's orbit naturally decays due to atmospheric drag and is periodically reboosted. Speed is the orbital velocity relative to Earth's surface, approximately 7.66 km/s (27,600 km/h). The distance from your location is the total 3D distance from you to the ISS, combining the horizontal ground distance and the ISS altitude. When the ISS is directly overhead, this equals roughly its altitude; when on the other side of the world, it can exceed 13,000 km.
About the Pass Time Estimation
The pass time estimation in this tool uses a simplified orbital mechanics model based on the ISS's current position, its 92-minute orbital period, and your location's latitude and longitude. The ISS's orbital inclination of 51.6° means it sweeps over a different strip of Earth's surface on each orbit, shifted approximately 2,600 km westward due to Earth's rotation. The tool calculates when the ISS ground track will next come closest to your coordinates, giving a rough estimate of the next overhead pass. Note that this is an approximation — actual visible passes depend on elevation angle (must be above 10° for a good sighting), cloud cover, and local horizon obstructions. For precise pass predictions with times and viewing directions, always verify with NASA's official Spot the Station resource at spotthestation.nasa.gov.