You can thank Percival Lowell, the Arizona mathematician and astronomer, with the genesis of the Martian myth. Lowell observed Mars streaked with straight lines, which, he surmised, were canals and channels dug out for water, as straight lines rarely occur in nature. Since then countless pens put to paper propagated that myth, and by dawn of the Space Age countless more planned missions to put it to rest once and for all. The latter goes on to this day, with NASA’s Phoenix lander sent to seek out the history of water on mars.

On this day, August 4, in 2007, the Phoenix lander launched from Cape Canaveral, Florida, on its way for a two-month mission to the red planet. Its mission was to land on the Martian arctic, where most of the planet’s water reserves are thought to lay, frozen just below the surface. The lander was to dig through and attempt to reach that ice.

As predicted, the Phoenix stopped operating in the long and cold Martian arctic winter, but before then it did confirm the existence of patchy but widespread deposits of underground ice. Phoenix also detected discovery of perchlorate, an chemical that exists on Earth and sustains certain microbes. What all that means, according to Peter Smith, Phoenix principal investigator at the University of Arizona in Tucson, is “You can have a thin film layer of water capable of being a habitable environment. A micro-world at the scale of grains of soil — that’s where the action is.” Smith was silent on the bigger question of martians.