The International Space Station (ISS) is a large spacecraft orbiting Earth at an average altitude of approximately 420 kilometers (260 miles). It serves as a microgravity research laboratory where astronauts from NASA, ESA, Roscosmos, JAXA, and CSA conduct experiments in biology, physics, astronomy, and materials science. The ISS has been continuously occupied since November 2000, making it the longest-running human presence in space.

The ISS travels at an incredible speed of approximately 28,000 kilometers per hour (17,500 miles per hour) – that's about 7.66 kilometers per second. At this velocity, the ISS completes one full orbit around Earth every 90 to 93 minutes, meaning astronauts aboard the station experience about 16 sunrises and sunsets every single day.

Yes! The ISS is the third brightest object in the night sky after the Moon and Venus. It appears as a bright, fast-moving point of light that crosses the sky in about 2 to 6 minutes. The best viewing times are shortly after sunset or before sunrise when the ISS is illuminated by sunlight while the ground below is in darkness. Use the pass prediction tool above to find the next visible pass from your location.

The ISS typically hosts a crew of 7 astronauts at any given time, though this number can vary between 3 and 11 during crew rotation periods. Crew members come from NASA (United States), Roscosmos (Russia), ESA (Europe), JAXA (Japan), and CSA (Canada). Expeditions usually last about 6 months per crew member.

The ISS maintains an orbit at an average altitude of approximately 420 kilometers (260 miles) above Earth's surface. However, this altitude gradually decreases due to atmospheric drag, so the station requires periodic reboost maneuvers using visiting spacecraft (like Russia's Progress or Northrop Grumman's Cygnus) to maintain its orbital height. The altitude typically fluctuates between 400 km and 430 km.

You can track the ISS live using this tracker tool, which updates the station's position every 5 seconds using data from the wheretheiss.at API. The map displays the exact latitude, longitude, altitude, velocity, and visibility status. You can also use NASA's Spot The Station service, various mobile apps (like ISS Detector), or amateur radio to track the ISS.

The ISS orbits at ~420 km because this altitude balances several factors: it's high enough to minimize atmospheric drag (reducing fuel needed for reboosts), low enough to be accessible by resupply spacecraft, and within Earth's protective magnetosphere to shield astronauts from harmful cosmic radiation. A lower orbit would cause more drag; a higher orbit would require more fuel to reach and increase radiation exposure.

The ISS footprint refers to the circular area on Earth's surface from which the space station is theoretically visible at a given moment. With a diameter of approximately 4,600 km (2,860 miles), anyone within this circle can potentially see the ISS – if it's illuminated by sunlight and the sky is dark enough. The footprint is shown on the tracker map as a semi-transparent circle around the ISS marker.

The ISS was assembled in space over a period of more than 13 years. The first module, Zarya, was launched by Russia in November 1998, and the station was declared "assembly complete" in 2011. Over 40 assembly flights were required to deliver and connect all modules, trusses, and solar arrays. The ISS is now the largest human-made structure in space, spanning about 109 meters (357 feet) end-to-end – roughly the size of an American football field.

Absolutely! With a DSLR or mirrorless camera on a tripod, a wide-angle lens, and a long exposure (10–30 seconds), you can capture a beautiful streak of light as the ISS crosses the sky. For detailed close-up images of the ISS structure, advanced astrophotographers use telescopes with motorized tracking mounts and high-speed video cameras. Check the pass predictions above to plan your photography session.