Complex sentence: Cities are easily distinguishable from surrounding countryside by both shuttle astronauts in an Earth orbit 135 miles (217 kilometers) high as from space stations, which orbit much higher, circling the planet at c.250 miles (400 kilometers).
Split into simpler sentences: Cities are easily distinguishable from surrounding countryside by both shuttle astronauts in an Earth orbit 135 miles (217 kilometers) high. They are just as visible on the Space station, which is in a higher orbit, circling the planet at 250 miles (400 kilometers).