From Gren Yuill
You wrote that Microsoft’s “Kinect gaming sensor… helps calculate astronauts’ weight in zero gravity” (24/31 December 2011, p 16). I could do the same thing for only half the cost of Kinect. My device is a card with “zero” on it. Astronauts can read it whenever they want to find out what they weigh. Mass, however, is a bit more difficult.
Placitas, New Mexico, US
