This is the art I recently submitted for the Mars Society 2013 Convention poster contest.
I didn't win, but I have a special honorable mention from the Mars Society. See here for more info and a look at the smart winner poster by Cody Edwards.
I made this poster with Inkscape as it's mostly vector work (including the characters and the lights in the sky). The few textures were prepared on Gimp before use in Inkscape.
The theme of the contest was "Finding Life and Bringing Life on Mars". I chosed focused on "Bringing Life" : the descending ships like seeds falling down to the soil, the "Earthrise" habitable dome behind the horizon, and a group of pioneers standing on the Martian surface, starting life and culture on the barren planet.