While humans have dreamed about going to Mars practically since it was discovered, an actual mission in the foreseeable future is finally starting to feel like a real possibility.

But how real is it?

NASA says it’s serious about one day doing a manned mission while private companies are jockeying to present ever-more audacious plans to get there. And equally important, public enthusiasm for the Red Planet is riding high after the Curiosity rover’s spectacular landing and photo-rich mission.

Earlier this month, scientists, NASA officials, private space company representatives and other members of the spaceflight community gathered in Washington D.C. for three days to discuss all the challenges at the Humans to Mars (H2M) conference, hosted by the spaceflight advocacy group Explore Mars, which has called for a mission that would send astronauts in the 2030s.

But the Martian dust devil is in the details, and there is still one big problem: We currently lack the technology to get people to Mars and back. An interplanetary mission of that scale would likely be one of the most expensive and difficult engineering challenges of the 21st century.

“Mars is pretty far away,” NASA’s director of the International Space Station, Sam Scimemi said during the H2M conference. “It’s six orders of magnitude further than the space station. We would need to develop new ways to live away from the Earth and that’s never been done before. Ever.”

There are some pretty serious gaps in our abilities, including the fact that we can’t properly store the necessary fuel long enough for a Mars trip, we don’t yet have a vehicle capable of landing people on the Martian surface, and we aren’t entirely sure what it will take to keep them alive once there. A large part of the H2M summit involved panelists discussing the various obstacles to a manned Mars mission.

“I’ve said repeatedly I’ll know when we’re serious about sending humans to the Mars surface when they start making significant technology investments in particular areas,” engineer Bobby Braun, former NASA chief technologist, told Wired.

The good news is that there’s nothing technologically impossible about a manned Mars mission. It’s just a matter of deciding it’s a priority and putting the time and money into developing the necessary tools. Right now NASA, other space agencies, and private companies are working to bring Mars in reach.

Here, Wired presents the most challenging obstacles we’ll have to overcome to get to Mars and how to fix them.