3-D Mars North Pole . ... Credit Copyright: MOLA Team, MGS Project , NASA . Image: Greg Shirah ( SVS ) Explanation: This dramatic premier three-dimensional visualization of Mars' north pole is based on elevation measurements made by an orbiting laser. ... The measurements also indicate that the cap is composed primarily of water ice with a total volume of only about four percent of planet Earth's Antarctic ice sheet . ... Where did all the water go? ... U. Based on Astronomy Picture Of the Day ...