20thcentury 999 ancient artificialsatellites astronautics astronauticsinliterature astronauticsinmassmedia atlantis(legendaryplace) australian civilianuse civilization culturalproperty cuneiforminscriptions exploration history interpersonalrelations outerspace philosophy popularculture projectmariner sexcustoms socialaspects spacearchaeology spacecolonies spacedebris spaceflighttomars spacevehicles sumerian unitedstates