EditorialIn an undated photo from NASA, Surveyor 3, which successfully landed on the moon, photographed by the Apollo 12 astronauts in November 1969. (NASA/JPL-Caltech via The New York Times)
EditorialSurveyor chain of 20 meters, Measuring chain with spring ring to be divided into two parts of 10 meters. 50 centimeters per link (from ring to ring). Provided with an oval ring with a keep in groups of two links. At the beginning a round brass handle, ...