The director of NASA Charles Bolden, who was himself an astronaut and went into orbit, is sure that Mars is habitable planet. According to him, the mysterious signs that Mars rovers find on the surface of the planet are drawings of the ancient race. The similar images can be seen on the walls of the ancient temples in Ireland.
Bolden says that life did not just exist on Mars, but it does now. He makes a conclusion that the planet is inhabited, basing on the identity of this planet with Earth.
It's no coincidence that scientists consider Mars as a future colony of earthlings. This planet is Earth's "sister", says Bolden, in the Solar System Mars is designed to sustain life too.
Search for life on Mars is the major task the scientists give to the Mars rovers that come to the Red Planet.