WEBVTT FILE 1 00:00:00.030 --> 00:00:04.050 As a Landsat satellite flies over the surface of the Earth 2 00:00:04.070 --> 00:00:08.100 the instruments aboard the satellite 3 00:00:08.120 --> 00:00:12.150 are able to view a swath 185 kilometers wide 4 00:00:12.170 --> 00:00:16.190 and collect images along that swath as the satellite proceeds 5 00:00:16.210 --> 00:00:20.230 through its orbit. The spacecraft travels at approximately 6 00:00:20.250 --> 00:00:24.260 4.7 miles per second. The satellite travels 7 00:00:24.280 --> 00:00:28.290 from north to south while it's over the sunlit portion of the Earth, 8 00:00:28.310 --> 00:00:32.310 and travels south to north over the dark side of the Earth. 9 00:00:32.330 --> 00:00:36.320 One orbit takes about 99 minutes, so that's about 10 00:00:36.340 --> 00:00:40.380 approximately 15 orbits in a 24 hour period. 11 00:00:40.400 --> 00:00:44.410 The orbit's maintained such that after 12 00:00:44.430 --> 00:00:48.440 16 days. the entire surface of the Earth has come 13 00:00:48.460 --> 00:00:52.460 within view of the Landsat instruments, while sunlit, 14 00:00:52.480 --> 00:00:56.480 and then on day 17 the first ground path 15 00:00:56.500 --> 00:01:04.520 is repeated. So we get to view the entire surface once every 16 days 16 00:01:04.540 --> 00:01:08.530 17 00:01:08.550 --> 00:01:14.988 [beeping]