Problem of the Fortnight #3

 

Big Brother Watches All!

               

The International Space Station (ISS) orbits the earth at an elevation of about 358 kilometers above the surface of the earth.  The earth itself can be thought of a sphere of radius 6371 kilometers.  What percentage of the earth’s surface is directly visible from the International Space Station at any moment?

 

(Problem courtesy of B. Delgado)

 

Solutions are due by 4pm on Friday, October 7th in Goodrich 108