Sometime last December I watched some astronauts talking about their experiences of seeing the earth from afar. Some pictures like these accompanied their remarks. The earth is surrounded by its atmosphere which provides both the Oxygen fuel that we all need to live (in the Troposphere layer that is about 6 miles deep), and other layers which absorb high-energy X-rays and UV radiation from the Sun. The  approximate boundary between our atmosphere and outer space is known as the Kármán Line  and is about 62 miles up (100km). Seeing our little earth against the vastness, blackness, and relative emptyness of space (a truly appropriate name), started me thinking about that 62-mile fuel store and shield around mankind’s ship in the universe. Not a unique idea I know, but wouldn’t the effective maintenance of those precious 62 miles be the absolute top priority of the ship’s passengers?