The video says it all, but read on below for a bit more background: [HTML1] That’s SEAL Cmdr. Chris Cassidy aboard the International Space Station, giving a quick glimpse (very quick, thanks to sped-up video with an appropriately lighthearted soundtrack) at how to shave one’s head in zero gravity. Key quote: “I don’t think I’ve looked like this since Plebe Summer.” The 1993 Naval Academy grad shed his hair late last month in anticipation of the arrival of Luca Parmitano, an Italian astronaut who, well … who saves on barbershop bills. Parmitano and two other flight engineers arrived aboard the…