Water could replace spacecraft heat shield tiles New Scientist

Space scientists looking for new ways to cool spacecraft on re-entry into Earth’s atmosphere are turning to one of the world’s oldest coolants: water. Existing heat-shield technology leaves a lot to be desired. In the 1960s Apollo rockets used a heat shield that burnt off slowly – but this is no good for reusable spacecraft like NASA’s fleet of space shuttles. And the silica tiles the shuttle uses are fragile and prone to damage.