Earth's first off-world colonies will be built on soil

Fine as talcum powder, sharp as glass and seemingly everywhere, these super-fine particles coated the astronauts like soot and permeated their crew cabin, where it became more than a mere nuisance. Not only did it interfere with their equipment, it irritated their nostrils and eyes, giving some a mild allergic reaction. Nevertheless, between 1969 and 1972, Apollo astronauts brought back nearly 385 kilograms of lunar rock, pebbles and powder back to earth. Today, NASA deems interplanetary dust and dirt -- also known as regolith -- one of the greatest risks to long-term space settlements. On the Moon, it wears away at multi-million-dollar instruments and lodges into the slightest crevasses, weakening seals on pressure suits and causing hardware to malfunction.