NASA has chosen five winners to create innovative 3-D printed homes for human visitors to the red planet. Since the first phase of the $3.15 million competition kicked off in 2014, 18 teams have worked to print virtual models of an environmentally-conscious Mars house that could be built using recycled material and “indigenous resources” like Martian rocks or nearby debris.

According to Quartz, each of the five winners received around $20,000 for their designs.

“We are thrilled to see the success of this diverse group of teams that have approached this competition in their own unique styles,” said Monsi Roman, program manager for NASA’s Centennial Challenges. “They are not just designing structures, they are designing habitats that will allow our space explorers to live and work on other planets.”

According to Roman, the first extraterrestrial 3-D printed house could be ready “somewhere around late 2030.”

In the next and final stage of the competition, NASA will challenge the remaining competitors to focus on building the robot that could autonomously print part of the design. The final winner will get $2 million in prize money.

“We are excited to see their designs come to life as the competition moves forward,” said Roman.