NASA's new titanium tires can never get a flat

Ever since man started thinking about putting things on other planetary bodies, transport has been a concern. Wheels are the obvious means of getting around, but using a standard air-filled rubber tire presents all kinds of problems in space -- particularly, what happens if it pops a flat. So the first moon buggy used metal wheels with steel springs, which provide the supple give of a tire without any need to contain gas. The problem is that steel springs degrade and plastically deform over time...