Human mission to Mars propellant from the Martian Atmosphere. This proposal drew on concepts developed by the former "Case for Mars" conference series. Over the next decade, Zubrin developed it into a mission concept, Mars Direct, which he presented in a book, "The Case for Mars" (1996). The mission is advocated by the Mars Society, which Zubrin founded in 1998, as practical and affordable. In 1991 in Toulouse, France, the International Space University studied an international human Mars mission. They proposed a crew of 8 traveling to Mars in a nuclear-powered vessel with artificial gravity provided by rotation. On the surface, 40 tonne habitats
Human mission to Mars considerations for using aerocapture on crewed missions is a maximum G-limit to experience, for which it was noted 5-g's (5 times Earth gravity) was a common limit to be planned for. There may be several landers, for example, separate ones for the crew, a habitat, rover, supplies, ascent vehicle, etc. Landed spacecraft on the surface of Mars: One of the big challenges to landing on Mars was overcome by Mariner 4, when it showed the properties of the atmosphere. Another was a basic survey of the planet, to know what place might be suitable to land. This has been overcome