The astronauts working on the International Space Station now have a new zero-G Bowflex, with its requisite bad-ass acronym name: aRED, or Advanced Resistance Exercise Device. Wired took a look at how it works. Unlike the Bowflex's rubber bands (which, coincidentally, were used by the machine being replaced, the iRED), the aRED uses piston-driven vacuum cylinders that provide adjustable resistance