Pellets made from simulated lunar regolith, or dirt, and polymers are being used to test a Zero Launch Mass 3-D printer in the Swamp Works at NASA's Kennedy Space Center in Florida. The printer can be used for construction projects on the Moon and Mars, and even for troops in remote locations on Earth. Zero launch mass refers to the fact that the printer uses these pellets to prove that space explorers can use resources at their destination instead of taking everything with them, saving them launch mass and money. The group is working with Marshall Space Flight Center in Huntsville, Alabama, and the U.S. Army Corps of Engineers to develop a system that can 3-D print barracks in remote locations on Earth, using the resources they have where they are.