The Flag is the symbol of the Association, but originally it was the banner of the Martian Star Navy, illustrating just how intimately intertwined the Navy is with the history of the Association itself. At the centre are two red circles, representing the worlds of Old Mars and New Mars. Superimposed upon them is a larger red circle which binds the two. This circle, representing the Navy itself, bears the Japanese character 'tsue', which means 'armed'.
The three red circles are backed by three horizontal stripes, representing the Space Navy (top), Ground Forces (centre) and Marine Corps (lower). The Space Forces stripes are blue, the Ground Forces stripe sand ('dirt') coloured. On the modern MSN Ensign these blue stripes are rendered in black.