On this site, we prefer not to use the word colonize, as that term can have negative connotations to some cultures on Earth. Eventually, humans will most likely journey to Mars. Getting astronauts to the Martian surface and returning them safely to Earth, however, is an extremely difficult engineering challenge. A thorough understanding of the Martian environment is critical to the safe operation of equipment and to human health, so the Mars Exploration Program will begin to look at these challenges in the coming decade. You can read more at http://mars.jpl.nasa.gov/science/human/