On the exploration of the red planet mean not only SpaceX, but also NASA, that you just chose six private enterprises with a view to the construction of new space stations.
Within the framework of the project the Next Space Technologies for Exploration Partnerships (NextSTEP), the Agency wants to prepare prototypes of the space stations on the surface of the Earth, and the most appropriate of them to build already in space, as it did on the occasion of the international space station (ISS).
NASA wants to put them on the Earth orbit, the Moon or Mars. Thanks to them, the astronauts will be able to more quickly and easily examine the space objects and move the solar system.
Above you can see the most promising of them.