Discover the cosmos! Each day a different image or photograph of
our fascinating universe is featured, along with a brief
explanation written by a professional astronomer. 2010 April 14
Explanation: The International Space Station is the largest
object ever constructed by humans in space. The station
perimeter now extends over roughly the area of a football field,
although only a small fraction of this is composed of modules
habitable by humans. The station is so large that it could not
be launched all at once -- it is being built piecemeal with
large sections added continually by flights of the Space
Shuttle. To function, the ISS needs huge trusses, some over 15
meters long and with masses over 10,000 kilograms, to keep it
rigid and to route electricity and liquid coolants. Pictured
above, part of the immense space station was photographed out of
a window by a member of the visiting Space Shuttle Discovery
STS-131 crew. Visible in the foreground is Japan's Kibo research
module, while a large truss is visible