Earth's Moon, A Familiar Face . ... Credit Copyright: Clementine , BMDO, NRL , LLNL Explanation: The above mosaic of the Earth's Moon was compiled from photos taken by the spacecraft Clementine in 1994. ... The Moon revolves around the Earth about once every 28 days. ... As the Moon travels around its orbit, the Earth based view of the half of the Moon that faces the Sun changes causing the regular monthly progression of Lunar phases. ... NASA Web Site Statements, Warnings, and Disclaimers . ...