Orbiting the Earth is a bit like living in a minefield, with millions of tiny flecks of space junk whizzing about at thousands of miles per hour. If a rice-sized pellet whacked into the International Space Station, it could pack the punch of a hand grenade, causing precious oxygen to seep into space.
So materials scientists have developed a clever fix that could buy astronauts the time they need to fully repair a breach: A "self healing" material, consisting of a reactive liquid sandwiched between two layers of a solid polymer. When the researchers shot a bullet through the material (shown in the video below), the liquid reacted with oxygen in the air to form a solid plug in less than a second.
Such a material could see its way into everything from spaceship hulls to astronaut suits to military vehicles on Earth. More saliently, it's a step toward the inevitable future in which human society is taken over by self-healing machines. Glad we're still making progress on that.