Narration: Ryan Fitzgibbons


90 meters. The distance between each laser pair. In order to measure the slope across the laser's path in a single pass of the satellite, ATLAS uses three pairs of beams spaced 90 meters apart with a reference track between the beams. Then on following passes, even if the two beams are slightly upslope or downslope from where they were on the first pass, scientists can still calculate the elevation change of that key track.