Remember the other day when we told you that NASA had six possible ideas for getting to Mars? No? Well, we did. Look, it’s right here.

Now, Boeing has come forward with one of those ideas, unveiling their Deep Space Gateway. This, they say, could act as a staging outpost around the Moon before going to Mars. In a statement yesterday, the company said this would be a habitat placed in cislunar space – the region between Earth and the Moon.

Powered by Solar Electric Propulsion (SEP), or ion propulsion, "the habitat could support critical research and help open opportunities for global government or commercial partnerships in deep space,” the statement reads.

The ultimate goal would be to use this space station as an outpost for missions to Mars. It could also host a new deep space transport vehicle that NASA is working on, which would transport humans to the Red Planet.

Astronauts would travel on this vehicle to Mars, leaving behind the Deep Space Gateway, where they could control robots on the surface from orbit or perhaps land there themselves. It’s not clear how the first missions to Mars will play out, but it’s looking like they’ll begin with orbital missions, before we return and actually land on the surface.

^{Artist's impression of a deep space transport vehicle at Mars. Boeing}

One company, Lockheed Martin, has already come forward with a proposal to build a space station around Mars, although it’s not clear if this is part of NASA’s plan (we've asked NASA for confirmation).

Truth be told, it’s not entirely clear what makes Boeing’s lunar idea especially unique, but it does clarify who exactly is working with NASA on building a gateway space station to Mars around the Moon.

This seems to be NASA’s main long-term goal at the moment. They’re going to have about $3.5 billion extra to spend on human exploration when the ISS is retired in 2024 or 2028, so it’s good to have a plan.

They’ll also have their new heavy-lift rocket, the Space Launch System (SLS), up and running by the turn of the 2020s. This will be used to launch the components of any future space station or a mission to Mars. The next step will presumably be to pick one of the plans to move ahead with.