The Troy spacecraft concept consists of an robotic precursor mission, including an Earth Departure Stage, and a Mars Transfer Stage. There is a habitation module, a storage module, and a propulsion module to be deployed from the spacecraft to land together at a selected site on the Martian surface to form a base. There are also ferry vehicles that would transfer crew members to and from the base to an orbiting crewed spacecraft. There would be three precursor spacecraft to Mars to set up three bases on the planet to enable maximum exploration of the planet's surface.