At the Marshall Space Flight Center in Alabama, engineers and scientists are working out how to make the Mars mission a reality.

Paul Gilbert, manager of the science programs office at the Center, says they're still in the very early stages of working out how to get to the red planet.

"Part of that is working with our partners from the International Space Station. We're working through that organization, having discussions, what's their ideas, here are some of our ideas. And so, we're in the early sketchpad phases of trying to work that out and the partners have ideas and desires and things they want to do in cislunar space."

Teams at the Marshall Space Flight Center are taking ideas from concept to design, developing spacecraft that will land on Mars and support life in frigid temperatures.

At the Advanced Concepts Office, aerospace engineer Tara Polsgrove is giving a presentation about designs for a Mars lander that would safely deliver humans to the surface of the planet.

A Mars lander is essentially two parts. The bottom half is the descent stage, it has the propulsion systems on it to enable that soft landing. And, on top, is the payload. So, we treat this kind of like a flatbed truck. So, any kind of payload would sit on top."

Elsewhere in the facility, designs for a spacecraft that would take humans through deep space are being tested.

NASA's David Smitherman is a specialist in space habitats and he explains what the facility contains.

"You have a utility room down on the lower level, exercise room, kind of like a basement, downstairs. Your main floor level has room for the four bedrooms for the crew."

Teams are also using simulated Martian rock and soil to advance 3-D printing that could help astronauts build structures on Mars with materials already there.

Sections of the Space Launch System, which will carry the Orion spacecraft, are being constructed across the United States.

NASA scientists and engineers are now working towards the first flight of Orion on top of the Space Launch System rocket. This test will not have humans on board.

Rocket engines are being tested and NASA expects the launch of the first version of the SLS in 2018.

The first expedition to Mars is planned for the 2030s.