The 3D printers that are being developed for the Moon are designed to build structures and roads from local materials. Foster + Partners has developed a structured honeycomb dome structure to protect against micrometeoroids and cosmic radiation, including a sealed inflatable shelter for astronauts. To make 3D printing on the Moon feasible, scientists are looking for materials that are already on the Moon or Mars, as transporting materials from Earth to the Moon or Mars will be difficult and expensive.