How will humans live on Mars? Well, NASA's not really sure yet, but if you've got any ideas you can submit them now. The agency has just put out a call for proposals for "deep space habitation prototypes."

In the 2016 funding bill, Congress called on NASA to get going on making a deep space habitat that can get humans to Mars and back, and they want to see a prototype by 2018. That deadline would give NASA time to test the habitat around the moon in the 2020s, before sending it off to Mars in the 2030s or so.

NASA selected a first round of contracts last year. As before, selected partners will receive partial funding from NASA.