NASA has declared the winners of its 3-D printed Habitat Challenge Design Competition in which contestants were asked to submit proposals of the future habitat for astronauts that will live on Mars.

Team Space Exploration Architecture and Clouds Architecture Office (SEArch and Clouds AO) won first place with a cash prize worth $25,000.

The team's design is called "Mars Ice House" and it is a smooth-edged pyramid made out of Martian ice.

"Recognizing that water is the building block to life, the team used a 'follow the water' approach to conceptualize, site and construct their design. Our proposal stood out as one of the few entries not to bury the habitat beneath regolith, instead mining the anticipated abundance of subsurface ice in the northern regions to create a thin vertical ice shell capable of protecting the interior habitat from radiation while celebrating life above ground," said SEArch and Clouds AO, according to Huffington Post.

Second place, for $15,000, went to a modular, inflatable habitat by Team Gamma. The design is proposed to be made with a Regolith Additive Manufacturing System that will serve as a shield around the habitat. Despite placing second, it is deemed to have the most practical design because it provides head room for unexpected circumstances during the mission, according to ZME Science.

Third place had no cash prize, but it went to a design by Team LavaHiv. The team also used a modular design, but it uses "lava-casting" construction techniques, ZME Science adds.

The program is an effort to encourage the development of technologies that could enable dwellings to be built using 3-D printers and locally available resources on Mars and other locales away from Earth, Space reports.

Teams were judged on many factors, including architectural concept, design approach, habitability, innovation, functionality, Mars site selection and 3-D print constructability, according to NASA.