What is NASA's plan for landing humans on Mars?

NASA wants the world to know that putting boots on Mars is not just a sci-fi dream.

The space agency has been helping promote the new film "The Martian," which hits theaters across the United States today (Oct. 2), as a way to publicize its own plans to send astronauts to the Red Planet in the 2030s. 

Setting up a crewed outpost on Mars is NASA's chief long-term goal in the realm of human spaceflight. Indeed, the space agency's operational robotic Mars craft — the Opportunity and Curiosity rovers, and the orbiters Mars Odyssey, Mars Reconnaissance Orbiter (MRO) and MAVEN (Mars Atmosphere and Volatile Evolution) — can be seen as scouts for the human pioneers to come, NASA officials say. [5 Manned Mission to Mars Ideas] 

"The evolution of a Martian starts with our science — starts with our ground-truth that we get from our rovers — and it builds up to human exploration," Jim Green, director of NASA's Planetary Science division, said Thursday (Oct. 1) at Kennedy Space Center in Florida, during an event focusing on "The Martian" and the space agency's Red Planet plans.

Making it happen

NASA is working on a number of different fronts to make a crewed Mars mission happen, Green said.

For example, the agency and its partners are currently conducting an unprecedented yearlong mission aboard the International Space Station (ISS). (Crewmembers generally stay aboard the orbiting lab for 5 to 6 months.)

Researchers are monitoring how NASA astronaut Scott Kelly and cosmonaut Mikhail Kornienko respond physiologically and psychologically to their extended time off Earth, in an effort to help prepare future pioneers for the long journey to Mars and back.

Furthermore, astronauts recently grew lettuce aboard the ISS — and ate it as well — as part of an experiment called "Veggie." The long-term goal of such projects is to make voyaging astronauts less dependent on Earth.

NASA is also developing a crew capsule called Orion and the Space Launch System (SLS) megarocket to help get astronauts to, and from, distant destinations such as Mars. Orion aced its first uncrewed test flight last December, and the SLS is scheduled to make its maiden voyage in 2018.

Technological development is ongoing in other key areas as well. For instance, reseachers are working to improve solar-electric propulsion systems, which use energy from the sun to strip electrons off gas molecules, then send these ions streaming out the back of a spacecraft to generate thrust.

"These are going to be huge ion engines that will allow us to haul tens of tons of material back and forth to Mars," Green said.

Much of this heavy gear — which will consist of human habitat modules and other infrastructure — must make it down to the Martian surface. That's a tall order, since the 1-ton Curiosity rover maxed out NASA's "sky crane" landing system. [How to Land on Mars: Martian Tech Explained (Infographic)]

So NASA is developing new tech, such as inflatable "decelerators" and an enormous supersonic parachute, to help get hefty payloads down safely and softly on the Red Planet. NASA has tested a prototype of this system twice during balloon-aided flights off Hawaii; the decelerator worked perfectly, but the parachute tore both times.

Robotic Red Planet explorers

The science work being done by Red Planet robots feeds into the crewed effort as well. For example, data and images gathered by MRO have allowed researchers to determine that the dark streaks that appear on steep Martian slopes during warm weather are caused by liquid water — a resource that future pioneers might be able to exploit.

"We're developing the science tools now — the continually orbiting and roving on Mars — to be able to get us the information to know what Mars is really like," Green said.

NASA's next Mars rover, which is scheduled to launch in 2020, will continue to build up the knowledge base, while also making concerted strides toward human exploration.

One of the Mars 2020 rover's instruments is a technology demonstration designed to generate oxygen from carbon dioxide in the Red Planet's atmosphere. Another instrument, a ground-penetrating radar, is capable of discovering subsurface aquifers of liquid water, if any exist in the landing zone, Green said.

The path to Mars

NASA is not planning to make the big leap directly from low Earth orbit, where the ISS circles, all the way to Mars. Rather, the agency first aims to test technologies and gain deep-space experience in the "proving ground" of Earth-moon space.

One proving-ground project is the Asteroid Redirect Mission, which involves plucking a boulder off a near-Earth asteroid with a robotic probe and towing the chunk of space rock to lunar orbit for future visitation by astronauts.

NASA plans to accomplish this — the robotic and crewed aspects (which will employ Orion and the SLS) — by 2025.

And the first crewed Mars mission may land not on the Red Planet but on one of its two tiny moons, Phobos and Deimos. Such a strategy would prove out the technologies required to get to Mars orbit, and also dilute the risks and costs of a crewed Red Planet campaign, advocates say.

So some of the steps along the path to Mars still need to be worked out. But the ultimate destination — the Martian surface — is not in doubt, NASA officials say.

"[Putting] boots on Mars is possibly the most exciting thing humans will ever do," NASA chief Charles Bolden said last month during an event at NASA Headquarters in Washington, D.C. that detailed NASA's crewed Mars plans.

"We have been engaged in getting to Mars — getting humans to Mars — for at least 40 years, beginning with the first precursors," he added. "I have no doubt that we can accomplish what we have set our minds to do."

Follow Mike Wall on Twitter @michaeldwall and Google+. Follow us @Spacedotcom, Facebook orGoogle+. Originally published on Space.com.

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