Of all the worlds beyond Earth, Titan is the only one you could step onto without a pressure suit: the air is thick enough that you would need no suit at all, only heavy protection from the deadly cold and a supply of oxygen

Of all the worlds beyond Earth, Titan is the only one you could step onto without a pressure suit: the air is thick enough that you would need no suit at all, only heavy protection from the deadly cold and a supply of oxygen

Most of us get this wrong about space suits. We think of them as an air supply, and they are that. But much of the engineering goes into a different problem: pressure. Out in the vacuum of space, or on a thin-air world like Mars, the suit is basically a pressurized bubble holding your body together. Without it, gases would rapidly expand and water in exposed tissues could begin to vaporize. The suit’s main job is not simply to feed you oxygen. I…