One of the problems NASA is facing in its plans for space exploration concerns building habitats on other worlds for its astronauts. The expense of taking building materials all the way from Earth to the moon, not to mention Mars, would be enormous. The space agency long ago concluded that using local materials to build habitats and other infrastructure would lower their cost. 3d printing
using lasers to heat and form structures of basalt, a type of soil formed by heating and cooling, either by volcanism or by meteor strikes.
The NASA scientists used an infrared laser to heat and fuse together simulated lunar basalt particles to form a rough cone structure on a lab bench. The results were promising, though more work needs to be done before the process can be done to scale. However, the way the technology is progressing, 3D printing of full-scale models should only be a few years away.
The way the process would work involves sending a group of robots to the moon, for example, to prepare a prefabricated lunar base. Some robots would mine and gather the basalt and others would form it into buildings using the laser-driven 3D printing process. In the fullness of time, astronauts would arrive to find the structure of a fully formed base that they would outfit and live in.
As with much of what NASA does, the 3D printing buildings has earthly applications. One can imagine the same process that can build a lunar base could be used to build structures near volcanos, where basalt is plentiful. The cost of transporting materials would be reduced. As a bonus, basalt is environmentally benign, causing less pollution than other building materials.