An astronaut can die many ways, but decompression is one of the more gruesome. A punctured space suit means a race to sanctuary, before the envelope of pure oxygen surrounding the body bleeds away and hypoxia causes the person to black out. Rapid pressure loss isn’t explosive, but it’s ugly: Water in the body begins to vaporize and tries to escape, the lungs collapse, and circulation shuts down.
No one’s dying today, though, at least not on Phobos. The suit he’s wearing isn’t a pressurized balloon. It’s the reverse, really—a squeeze suit, with a lattice of smart-memory alloys that binds it to the body, replacing an oxygen cushion with direct, mechanical counterpressure. The result is formfitting and nimble; it requires less energy to move andincreases an astronaut’s range on foot. And in the event of a rupture, the suit remains viable: It can be patched on the spot with a space explorer’s equivalent of an Ace bandage, its own shape-memory alloys pulling tight to seal the breach.
By the time the patch is in place, the alarms have stopped. Epidermal biosensors and path-planning algorithms have shortened the astronaut’s trek across the surface, from six miles out to just over four. He’ll call mission control to argue against this shortcut when his heart rate settles. A nasty bruise isn’t going to kill him. And he didn’t travel 100 million miles from home to turn back now.