Satellites, the ISS and Satellite Tracking

There are a large number of man-made satellites in orbit around the Earth. At the time of writing, well over six thousand artificial satellites have been launched!

The first object to be put into orbit around the Earth was the Russian-built Sputnik 1 in October 1957. This tiny spherical satellite measured a mere 58cm excluding the four attached radio antennae. Sputnik 1 transmitted radio information back to Earth for 3 weeks until its on-board batteries ran out, and it eventually burned up on re-entry to the Earth's atmosphere in January 1958, 3 months after it was launched.

Modern satellites are powered by solar panel arrays, so a short battery life is no longer an issue. It is these solar panels that make it possible to view a number of the Earth's man-made satellites with the naked eye, given the correct conditions.

What are satellites used for?

Satellites are used for a wide variety of purposes, including relaying global telecommunications, television signals, astronomy, observation of climate change, weather forecasting, and navigation.

GPS systems work by receiving signals from at least 3 different satellites and calculating your position between them using a process called 'trilateration'. The more satellite signals that can be locked onto, the more accurately your location can be determined.

ISS - The International Space Station

One of the most easily viewed of all of the satellites is the International Space Station. This differs from almost all other satellites in that it is permanently manned by a crew of up to 6 people, and has been manned continuously since November 2000.

ISS is used as a space research laboratory and space port, and is a joint venture between NASA and many other countries including Russia, Japan, Canada several European nations. It's comparatively large size (it is the largest artificial object in space) and huge solar arrays (covering a whole acre) mean that it can regularly be seen from Earth with great ease.

The ISS is a modular satellite - that is, it has been built from many separate modules that have been launched from Earth and assembled in space to create what now exists. The first module, Zarya, was launched in November 1998. Assembling the various modules has required 184 spacewalks by its crew, totalling almost 50 days.

According to NASA, it has about as much habitable space as a six bedroom house and featured a gym and a 360 degree viewing window.

ISS Tracker

There are a number of utilities that allow you to track the location of the ISS at any given time, and one of these can be found below. This updates continuously showing the current location.

ISS Spotting

Finding the ISS in the night sky is easier than ever - there are several Android and iPhone apps that can be used to forecast when you will next be able to see the ISS from your location, and to guide you towards locating it.

The best Android utility that I've found for this purpose is ISS Detector, which also allows you to track many other satellites, such as the Iridium satellites. It will tell you how visible the ISS is likely to be for each pass (magnitude), when it is visible from and to, the angle of elevation and whereabouts in the sky to look for it (it will guide you on-screen using your phone's compass and built-in GPS.)

For iOS devices such as iPhone and iPad, ISS Spotter is probably the best option.

Both are free, with paid versions available.

You can also check out NASA's 'Spot The Station' page, which will tell you when you'll be able to see the ISS from your location.

It goes without saying that the best conditions for viewing the ISS and other satellites are night time and during clear weather!

ISS Facts

The ISS has to be moved periodically to avoid damage from collisions with the massive amount of space junk that is also in orbit around our planet.

The ISS has to be resupplied from Earth and this is carried out solely by Russian spacecraft since the retirement of the US Space Shuttle programme.

The ISS has other names and identifiers; its International Designator or NSSDC ID is 1998-067A (which relates to the first module, 'Zarya' but has been retained as the ISS has grown). It is also known by its NORAD ID; 25544. Its call sign for radio purposes is either 'Alpha' or simply 'Station'.

It is by no means the first space station to be built - the Russian-built Salyut 1 being the first in 1971, NASA's Skylab not being launched until 1973. In fact there have been 11 previous space stations, 8 of which were manned. At present the only operational space stations are the ISS and 'Tiangong 1' which was launched by China in 2011, which is a fraction of the size.

The future of the ISS beyond 2020 is currently uncertain due to Russia having banned the US from using their section of it after that time in retaliation for sanctioned imposed against Russia for their apparent actions in Ukraine. The Russian section of the ISS can function independently from the US section - the US section cannot function independently of the Russian section however.

Live ISS Feed

ISS Figures and Statistics