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 Base Camp its moons (Deimos and Phobos), and serve as a proving ground in preparing humans for future missions to the Martian surface. The concept was published in May 2016 by Lockheed Martin, and it is a design for a spacecraft for carrying humans to Mars orbit and conducting operations in Mars orbit. Mars Base Camp harnesses many NASA technologies in development, or technology goals at the time of the 2010s. In September 2017, the plan was updated including a concept for a reusable crewed shuttle called MADV (Mars Ascent Descent Vehicle), which would connect to the MBC Mars space station. Mars