What is the International Space Station?

International Space Station
Image Courtesy of NASA

The International Space Station (ISS) is a collaboration effort between no less than 16 nations including the United States of America, Canada, Russia, United Kingdom, Japan, Brazil and many other Countries across Europe. Now that the primary construction stage is complete, the station is being used to carry out multiple scientific experiments in zero gravity for the benefit of all kinds of fields in science. Construction began in 1998 and continued until 2011 when NASA’s shuttle fleet went out of service. Since then, the station relies on various re-supply and transportation spacecraft such as the Russian Soyuz and Progress craft, the American Dragon and Cygnus and the Japanese H-II Transfer Vehicles. The ISS is the largest artificial body in orbit and can be clearly seen in the night sky. At the moment, the space station is a whopping 239 x 356 ft (72.8 x 108.5m).

Viewing possibilities

The ISS travels at 17,500 mph and completes one Earth orbit every 92 minutes. Therefore, the observing window from any given location is quite short. The huge structure which is permanently manned, takes around 5 minutes to cross from western to eastern horizon on an overhead pass. Although the station orbits every 92 minutes, it will not always be visible on every pass. First, it has to be illuminated by sunlight when the sun is below the horizon (most commonly in the first few hours before sunrise and after sunset), and secondly it has to be passing within visible range of your latitude. The ISS is visible to 95% of the habitable land on Earth, but due to its low Earth orbit, is only visible when its orbit path is near your location in global terms (within a few hundred miles).

Finding ISS pass times for your location

There a few resources online to find out when the ISS passes over your location.