http://www.space-travel.com/reports/Sandcastles_On_The_Moon_999.html Sandcastles On The Moon Robots are coming to a Moon near you very soon. Aside from a new fleet of orbiters, some will be landing within three years. There will be rovers deployed on the Moon, and sample return missions. This new wave of missions is brought to you by the governments of the USA, China, India and a collection of private ventures. With so much attention focused on revisiting the Moon, it's time to re-explore a basic task that's never really been practiced before. Can we work effectively with the lunar regolith? Any serious talk of working or staying on the Moon includes ways of using lunar materials to our advantage. In its most crude form, this means shoveling lunar soil on top of a lunar base, to protect it from radiation and meteorite impacts. Other uses would be more sophisticated, such as making concrete from the soil, or refining the soil to extract metals, oxygen and other useful things. Landing areas for spacecraft would need to be built, free from the debris that's normally kicked up by rocket exhaust. Berms of lunar soil would protect fragile structures from nearby launches and landings. We may even want to dig deep underground, to bury certain items. All of this sounds simple in theory. Just take a big shovel or some type of construction gear, and dig. But is it really this straightforward? We don't properly understand the mechanical properties of the regolith, dust and rocks. We don't know how well equipment and techniques that work well on Earth will perform on the Moon. During the Apollo missions, astronauts were surprised by the behavior of the lunar soil. It adhered quickly to their spacesuits and equipment. The regolith was also more difficult to penetrate than mission planners had suspected. Planting a rod for a flag was tricky. During an attempt to drill a core sample, Apollo 15 astronaut James Irwin apparently suffered a minor cardiac problem, according to biometric telemetry. We will need to gather more data on the handling of lunar soil if we want to do anything ambitious on the Moon, and the best way to do it is with machines, long before astronauts return. Some private companies are already proposing small robotic lunar dump trucks, which could excavate and move the soil. Over a long period of time, these could steadily build up large structures. But how long would it take, and how effective would it be? That's not known right now. Doing something as simple as getting a robot to build sandcastles on the Moon would be a step forward. It would be an exercise in mechanical engineering, and a test of how disturbed regolith behaves. Can we make lunar bricks by fusing the soil with heat? Is it better to build up a berm of raw soil, then "cook" the exterior for strength? These are also unresolved issues. Other tests we need to perform include placing radiation dosimeters under artificial lunar mounds, to test their shielding properties. Firing mortar shells or pellets at structures would also simulate meteorite strikes. These questions can only be answered with a lot of missions, and a lot of testing. It will take time, but it needs to be done. Without this knowledge, we will never be able to use the Moon to its full advantage.