London, May 21 : The International Space Station (ISS) would be visible to the naked eye as many as four times in a day, from May 21 to May 23, 2008.
According to a report in New Scientist, the space station zips around Earth at about 30,000 kilometres per hour, remaining visible to an observer on the ground for about 5 minutes during each pass.
The space station, which orbits at an altitude of 386 kilometres, is by far the biggest and brightest manmade satellite circling the planet. It looks as bright as Venus or Jupiter and can be seen even in well-lit cities.
But, the next few days will provide prime-viewing opportunities for anyone interested in catching a glimpse of the International Space Station (ISS) passing overhead.
The space station is normally visible once or twice a day, but from May 21 to May 23, 2008, it can be seen making as many as four daily passes over North America and Europe.
Satellites like the ISS are only visible on Earth when they are in sunlight and the viewer is in deep twilight or darkness.
Such a scenario can occur more often at certain times of the year, when the Earth's orientation relative to the Sun allows the ISS to move out of Earth's shadow.
That will occur from Wednesday to Friday, when the station will be bathed in sunlight almost constantly. Since it takes just 90 minutes or so to orbit the Earth, it will be visible multiple times around dawn and dusk.
According to Nicole Cloutier, a spokesperson at NASA's Johnson Space Center in Houston, Texas, "You don't need anything to see it, although I would recommend if you have binoculars to try them because then you see a much more detailed view."
The ISS will appear to sweep quickly across the sky, remaining visible for about 4 to 5 minutes during each pass.