Part of their mission is to take photographic images of the planet to highlight the natural wonders and human development that can often be seen in a far different context from in orbit than on the ground.
The spectacular image to the right was taken on October 28, 2010, as the ISS passed over the Sahara Desert.
One fascinating aspect of the image is how the lights at night reveal that nearly all of Egypt’s population is concentrated along the Nile River.
The historic waterway looks like a brilliant, long-stemmed flower, with the capital of Cairo forming a particularly bright base of the flower.
The smaller cities and towns within the Nile Delta show up as distinctive glows, connected by a complex network of roads.
Also visible are the lights of Israel and the Palestinian territories at the far eastern end of the Mediterranean Sea. The lights of Paphos, Limassol, Larnaca and Nicosia can also be seen dotting the island of Cyprus to the northeast of the Nile Delta.
Far below the orbit of the ISS and about 60 miles above the surface of the land and sea is a thin, yellow-brown band tracing Earth’s curvature. Known as airglow, it is a faint band of light emissions that results from solar radiation interacting with atoms and molecules at the highest level of Earth's atmosphere.
Astronaut Photo: NASA