WEBVTT FILE 1 00:00:00.060 --> 00:00:04.100 [music] 90 meters. The 2 00:00:04.120 --> 00:00:08.150 distance between each laser pair. In order to measure the slope 3 00:00:08.170 --> 00:00:12.250 across the laser's path in a single pass of the satellite, ATLAS 4 00:00:12.270 --> 00:00:16.360 uses three pairs of beams spaced 90 meters apart with a 5 00:00:16.380 --> 00:00:20.570 reference track between the beams. Then on following 6 00:00:20.590 --> 00:00:24.760 passes, even if the two beams are slightly upslope or downslope from 7 00:00:24.780 --> 00:00:29.020 where they were on the first pass, scientists can still calculate the elevation 8 00:00:29.040 --> 00:00:33.080 change of that key track. [music] 9 00:00:33.100 --> 00:00:35.047