ISS035-E-017874 (8 April 2013) --- NASA astronaut Chris Cassidy, Expedition 35 flight engineer, performs Body Mass Measurement activities using the Space Linear Acceleration Mass Measurement Device (SLAMMD) in the Columbus European Laboratory aboard the Earth-orbiting International Space Station. Since crew members can?t weigh themselves in zero-g, they use this method as the next best thing. Skylab astronauts, the first NASA crew members to fly in space for over a month at a time, some 40 years ago, used a body mass measurement device that was somewhat different from this.