1 00:00:00,020 --> 00:00:04,170 2 00:00:04,190 --> 00:00:05,850 3 00:00:05,870 --> 00:00:08,530 [ Narrator ] NASA and the USGS are preparing a new satellite, 4 00:00:08,550 --> 00:00:12,710 the Landsat Data Continuity Mission, called LDCM. 5 00:00:12,730 --> 00:00:16,840 Landsat satellites have been orbiting earth since 1972, 6 00:00:16,860 --> 00:00:20,939 taking scientific measurements of land cover and land use. LDCM is the eighth Landsat satellite 7 00:00:20,960 --> 00:00:21,070 and will continue the world's longest global data record of changes of the Earth's land surfaces. 8 00:00:21,090 --> 00:00:25,259 and will continue the world's longest global data record of changes of the Earth's land surfaces. 9 00:00:25,280 --> 00:00:29,440 LDCM data will also play a critical role in monitoring, understanding, and managing 10 00:00:29,460 --> 00:00:33,820 the world's forests, agriculture and water. [ Betsy Forsbacka ] What this data is useful for 11 00:00:33,840 --> 00:00:38,000 is to provide information to the scientists, particularly 12 00:00:38,020 --> 00:00:42,180 out in the Western states where water is a very 13 00:00:42,200 --> 00:00:46,360 big deal. This data, this remote data allows them to determine 14 00:00:46,380 --> 00:00:50,540 where areas are being irrigated, and how much and how often. 15 00:00:50,560 --> 00:00:54,710 [ Jim Irons ] TIRS is the Thermal Infrared Sensor 16 00:00:54,730 --> 00:00:58,839 that is being built and tested here at Goddard Space Flight Center for flight on the 17 00:00:58,860 --> 00:01:02,990 next Landsat mission. It's designed to measure the amount of 18 00:01:03,010 --> 00:01:07,110 thermal radiation emitted by the surface of the earth as a function of the earth's temperature. 19 00:01:07,130 --> 00:01:11,220 All objects that are warmer than zero, 20 00:01:11,240 --> 00:01:15,240 absolute zero, emit radiation. 21 00:01:15,260 --> 00:01:19,290 The hotter an object is, the shorter in wavelength is the peak radiation. 22 00:01:19,310 --> 00:01:23,330 [ Narrator ] For example, the sun is very hot, about 10,000 degrees, 23 00:01:23,350 --> 00:01:27,460 and its radiation peaks at about 0.5 micrometers. That's exactly in the region 24 00:01:27,480 --> 00:01:31,560 our eyes can see. Earth is much cooler, so its radiation has a much longer 25 00:01:31,580 --> 00:01:35,650 wavelength, about 10 micrometers. And that's in the far infrared region, well beyond 26 00:01:35,670 --> 00:01:39,830 what we can see. [ Jim Irons ] So, basically what the Thermal Infrared 27 00:01:39,850 --> 00:01:44,020 Sensor allows us to do is to determine 28 00:01:44,040 --> 00:01:48,330 the temperature of the surface of the earth at different locations around the globe. 29 00:01:48,350 --> 00:01:52,410 [ Narrator ] Using these surface temperatures, resource managers can determine how fast 30 00:01:52,430 --> 00:01:56,500 a field uses water. Rain or irrigation starts a cycle 31 00:01:56,520 --> 00:02:00,570 in which water ultimately returns to the atmosphere. Evaporation of water 32 00:02:00,590 --> 00:02:05,480 from the ground, and the transpiration of water from leaves, cools off both the soil and the plants. 33 00:02:05,500 --> 00:02:08,560 [ Betsy Forsbacka ] You put those two words together and you have 34 00:02:08,580 --> 00:02:12,620 the science term, evapotranspiration, and that's precisely what TIRS is measuring. 35 00:02:12,640 --> 00:02:16,660 These hot and cold signatures, that give us 36 00:02:16,680 --> 00:02:20,840 information on evapotranspiration where 37 00:02:20,860 --> 00:02:25,010 the water is transpiring through the plants and evaporating into the atmosphere 38 00:02:25,030 --> 00:02:29,190 The instrument is going to pick that up as a cool signature in areas that are not 39 00:02:29,210 --> 00:02:33,360 irrigated well will come across as a warm area to the instrument. 40 00:02:33,380 --> 00:02:36,450 [ Narrator ] To measure these warm areas and cool signatures, the TIRS instrument 41 00:02:36,470 --> 00:02:39,620 uses a technology array developed primarily 42 00:02:39,640 --> 00:02:42,670 at NASA's Goddard Space Flight Center, called 43 00:02:42,690 --> 00:02:45,829 Quantum Well Infrared Photodetectors. These QWIPS are 44 00:02:45,850 --> 00:02:48,859 more sensitive and precise than the thermal detectors used on previous 45 00:02:48,880 --> 00:02:52,000 Landsat satellites. But to operate correctly they need to be kept very cold. 46 00:02:52,020 --> 00:02:55,190 [ Betsy Forsbacka ] They have to be cooled to less than 47 00:02:55,210 --> 00:02:58,310 43 degrees Kelvin and so that's only 48 00:02:58,330 --> 00:03:01,500 43 degrees above absolute zero 49 00:03:01,520 --> 00:03:04,650 which is the coldest you can get. Very, very cold. 50 00:03:04,670 --> 00:03:07,839 [ Veronica Otero ] The interesting thing about TIRS is we have 51 00:03:07,860 --> 00:03:10,950 different thermal zones, you know like 52 00:03:10,970 --> 00:03:14,120 our detectors are around 43 Kelvin 53 00:03:14,140 --> 00:03:17,220 and then you have our telescope at 180 Kelvin 54 00:03:17,240 --> 00:03:20,400 and then you go to the warmer end of our instrument which is the 55 00:03:20,420 --> 00:03:23,489 structure and some other components that are around, 56 00:03:23,510 --> 00:03:26,670 you know, zero C or 273 Kelvin. 57 00:03:26,690 --> 00:03:29,720 [ Narrator ] Keeping these different TIRS components at these different temperatures 58 00:03:29,740 --> 00:03:32,850 is challenging because as the satellite orbits the earth every 59 00:03:32,870 --> 00:03:35,890 90 minutes its either being blasted by the heat of the sun or being frozen 60 00:03:35,910 --> 00:03:39,030 by the cold of space. [ Veronica Otero ] So you're exposing the 61 00:03:39,050 --> 00:03:42,210 instrument to these two harsh conditions 62 00:03:42,230 --> 00:03:45,359 and you're cycling it from one to the other. 63 00:03:45,380 --> 00:03:48,540 One of the things that we do on our sensor unit is we have multi- 64 00:03:48,560 --> 00:03:51,670 layer insulation blankets. These work really well 65 00:03:51,690 --> 00:03:54,840 in space because there's no 66 00:03:54,860 --> 00:03:57,940 environment, there's no air. 67 00:03:57,960 --> 00:04:01,120 The blankets protect us from these extreme conditions 68 00:04:01,140 --> 00:04:04,230 The other thing we use is we have an earth shield. 69 00:04:04,250 --> 00:04:07,410 [ Betsy Forsbacka ] It is basically a five foot door. 70 00:04:07,430 --> 00:04:10,510 It's about five feet long and it shields much of the instrument 71 00:04:10,530 --> 00:04:13,670 from the earth, from parts of the earth 72 00:04:13,690 --> 00:04:16,740 that we're not imaging. That's a tremendous help 73 00:04:16,760 --> 00:04:19,920 in trying to make sure that we only detect the signals that we're interested in. 74 00:04:19,940 --> 00:04:22,950 The heat sources that we're interested in. [ Narrator ] And detecting those heat 75 00:04:22,970 --> 00:04:27,480 sources accurately helps to monitor water use in irrigated fields. 76 00:04:27,500 --> 00:04:29,160 [ Jim Irons ] Observations that are collected with 77 00:04:29,180 --> 00:04:32,300 Landsat sensors are much more than pretty pictures. 78 00:04:32,320 --> 00:04:35,480 They are accurate, 79 00:04:35,500 --> 00:04:38,620 well calibrated, precise 80 00:04:38,640 --> 00:04:42,280 scientific measurements. One of the things we're learning 81 00:04:42,300 --> 00:04:44,930 with thermal data and will continue to learn more about 82 00:04:44,950 --> 00:04:48,120 with TIRS is just how much water 83 00:04:48,140 --> 00:04:51,229 is being used for 84 00:04:51,250 --> 00:04:54,410 food production and how much more 85 00:04:54,430 --> 00:04:57,510 might be needed in the future to increase food production 86 00:04:57,530 --> 00:05:00,700 to keep up with a growing population. 87 00:05:00,720 --> 00:05:03,760 [ Narrator ] TIRS' thermal data, as part of the LDCM mission, 88 00:05:03,780 --> 00:05:06,890 will add to the more than 3 Million images of the Earth that make up the Landsat data archive. 89 00:05:06,910 --> 00:05:16,500