How Can Tardigrades Survive the Vacuum of Space?

Tardigrades are tiny animals that look like bears with eight legs. They can survive anywhere, even in space! When things get too dry or cold, they puff up and then shrink down into a little ball called a tun. In this tun state, they stop moving and wait for better conditions. It is like holding your breath underwater until you are ready to come back up. Scientists have sent them into the vacuum of space where there is no air, and they survived! When water returns, they wake up and walk away as if nothing happened.