Mars and seasonal cycles of Mars are likewise similar to those of Earth, as is the tilt that produces the seasons. Mars is the site of Olympus Mons, the largest volcano and second-highest known mountain in the Solar System, and of Valles Marineris, one of the largest canyons in the Solar System. The smooth Borealis basin in the northern hemisphere covers 40% of the planet and may be a giant impact feature. Mars has two moons, Phobos and Deimos, which are small and irregularly shaped. These may be captured asteroids, similar to 5261 Eureka, a Mars trojan. There are ongoing investigations
Mars One 2013. Canadian former astronaut Julie Payette said during the opening speech for an International Civil Aviation Organization conference that she does not think Mars One "is sending anybody anywhere". In January 2014, German former astronaut Ulrich Walter strongly criticized the project for ethical reasons. Speaking with Tagesspiegel, he estimated the probability of reaching Mars alive at only 30%, and that of surviving there more than three months at less than 20%. He said, "They don't care what happens to those people in space... If my tax money were used for such a mission, I would organize a protest." Space tourist