The new movie "Interstellar" is set in a not-so-distant future, but distant enough that they've managed to build something still elusive in 2014: a spaceship that can travel between solar systems. Such starships have been a technological mainstay in science fiction for decades, but they remain a crazily complicated proposition in everything from propulsion to human reproduction.

Still, that hasn't stopped researchers from trying. Last month, a bunch of rocket scientists, microbiologists and entrepreneurs gathered in Houston’s George R. Brown Convention Center to discuss — in level and serious tones — how to become a spacefaring civilization.

The meeting is called the 100-Year Starship symposium, and it’s brought brains together once a year since 2011 to figure out what we need to do now if we want to have an interstellar spacerocket a century from now. The group has made progress defining the challenges and pointing their noses toward solutions, but much work remains (like, say, building a starship).

To quote Contact, it “sounds less like science and more like science fiction.” Nonetheless, the 100-Year Starship adherents—backed by NASA and the Defense Advanced Research Projects Agency (DARPA)—keep plugging away. At their most recent gathering, 7 major hurdles emerged from their three days of discussion.

1. Before we can make an Enterprise, we may have to make an enterprise.

With all the obvious tech challenges, this top hurdle is easy to overlook — but it’s a question of human motivation. What would motivate people to work on something that won’t be finished till they’re dead? Like Veruca Salt, when we want things, we want them now.

But even if we manage to motivate ourselves, what mechanism can provide continuity in funding and oversight across decades, let alone across generations? Government funding is fickle and depends on election cycles and budget reviews. Philanthropy rests on the whims of the wealthy. The long-term viability of crowdfunding is unproven.

If we could create an “econosphere” around long-term space travel — one that makes money and produces spinoff products, so people get salaries and gadgets — it could support itself.

Space travel may have to become a business. And not just any business: a profitable one. Companies like Virgin Galactic, Deep Space Industries, and Planetary Resources are aiming to do just that.

2. We have to move fast.

It's in the very definition of the project that we have to get to the stars. But it took poor Voyager 38 years just to get out of the solar system. Ain’t nobody got time for that.

We have to figure out how to move fast through space, for a long-ass time. Engineers have a few ideas: Fusion rockets, ion drives, hydrogen-scooping ramjets, and antimatter annihilation systems, for instance.

3. Staying alive, staying alive.

A starship has to be both sustainable and life-sustaining. It will be a closed ecosystem that must either have or produce everything humans need to survive and make more humans. Oxygen, food, and water are no-brainers. But we also need our microbiome, and we’re only now starting to investigate what happens to our symbiotic microbes off-Earth.

The microbiomes of babies born en route remain a totally open question. And if they’re in microgravity, will those babies’ eye cells know where to migrate to become eye cells?

4. Take me to the space hospital.

Nobody likes going to the hospital, but it’s nice to know they’re there if you get MRSA or need an MRI. An interstellar starship will have limited machinery, limited medicine, a limited supply of doctors.

Plus, access to new Earth-medicine techniques would be delayed or nonexistent. (If the ship travels, say, a light-year away, word of a cancer treatment discovery would take a year to reach the crew.) Its residents would in turn need to train the next generation of caregivers. Medical professionals draw parallels between this situation and that in developing nations with little health-care infrastructure. Studying either could benefit the other.

5. Crew-on-crew interaction.

After a certain amount of time locked in a room together, you and even the most unobtrusive person will get on each other’s nerves. You’ll be like, “Why do you always have to look at me like that?” and they’ll be like, “I’m not looking at you like anything.” Etc.

Now imagine that drawn out over years or decades on an interstellar mission. And beyond the everyday communication problems, disseminating information in a crisis — without causing panic or misinformation — could prove difficult. Imagine small-town social dynamics, in space.

That's why it’s important to choose a mix of crew members most likely to succeed. But first we have to find out what that mix is. Agencies across the world are already investigating this psychological puzzler. The Mars HI-SEAS experiment began its third mission on October 15, and six (lucky?) people will spend eight months on a simulated martian colony in Hawaii. The European Space Agency teamed up from 2007-2011 with the Russian Institute for Biomedical Problems to do the Mars 500 mission, in which three different crews experienced isolation together aboard a pseudo-spaceship and then on a pseudo-Martian surface.

6. Oops-factor.

When you break your printer beyond repair, you go buy a new one. But when you break your 3-D space printer that makes all of the parts for your other space stuff? You’re in trouble.

The 100-Year Starship team is endorsing what they term a “steampunk” approach: Teaching spacefarers how to make high-tech things work with low-tech, macgyvered solutions.

7. Stepping stones.

One does not simply walk into Mordor, and one does not simply build an interstellar starship. Giant leaps aren’t real: They’re just a bunch small steps added together. To become interstellar, we have to start with simply sending humans to space regularly, cheaply.

We have to start manufacturing and mining off-planet. And we need to establish human colonies on the Moon, and probably on Mars, to make sure we have enough resources and practice before we set off toward Earth 2.0.

Currently, the best bet rests in the hands of private industry. NASA’s asteroid capture mission promises a step in that direction. But private companies like Planetary Resources and Deep Space Industries, which have both announced partnerships with NASA, may be able to make space their material domain faster and cheaper.