"place a ruler on the horizon line"

South Dakota prairie from above in 1930

Altitude: 72,000 ft
= 23 km

Missouri River

ISS041-E-84312_edited_edited.jpg

South Dakota prairie from the ISS 2014

ISS altitude: 450 km
= 1.5 million ft

Missouri River

Missouri River

ISS altitude 450 km - 1,476,378 ft

Average cruising altitude 35,000 ft - 10 km

"Orion at a 125,000 ft"

ISS Nile & Red Sea fly over