From Popular Science: Walls of water could protect astronauts from radiation while recycling their bodily waste and purifying the air, under a new NASA concept. The “Water Walls” design takes a page from mother nature and uses water for passive protection.The concept’s formal name is Highly Reliable and Massively Redundant Life Support Architecture, and it’s part of NASA’s Innovative Advanced Concepts program, meaning it just received funding for further study. It would use a framework of hexagon-shaped polyethylene bags serving as the walls of a spacecraft. They’d be filled with various bacteria, algae and filters to clean and purify water and air and provide food — algae as food may not be tasty, but it would be nutritious — and shield the spacecraft’s occupants from space.