Huge amounts of Ice found on Mars
The European spacecraft Mars Express arrived in Mars orbit in december 2003 to study the planet. It included a giant radar called MARSIS which was designed to look below Mars' surface using long wavelength radio waves. In order to produce the long wavelengths you need a very large aerial, in this case 40m long. This was deployed explosively which the engineers were very worried would destroy the rest of the spacecraft. In the middle of 2005 they finally deployed the aerial which was sucessful.Since 2005 the team has been aquiring and analysing data from below the surface of Mars. On Mars's South pole there is a large ice cap, the land rises around the edge of it, so sceintists assumed that it continued to do so under the ice cap, making it quite small. However new data from the MARSIS radar shows that the land levels off so the ice cap is 2-3 miles thick, and at least 90% water. This is enough water to cover the whole of Mars with 11m of water.
However from features on Mars there must have been ten times more water than this so scientists are still looking for the remainder.