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 for public viewing. Mars One initially estimated a one-way trip, excluding the cost of maintaining four astronauts on Mars until they die, at 6 billion USD. Lansdorp has declined questions regarding the cost estimate. A proposed global reality-TV show was intended to provide funds to finance the expedition, however, no such television show has emerged and no contracts have been signed. The astronaut selection process (with some public participation) was to be televised and continue on through the first years of living on Mars. Discussions between Endemol started in June 2014, producers of the "Big Brother" series, and Mars One