1 00:00:00,544 --> 00:00:03,127 (dreamy music) 2 00:00:04,600 --> 00:00:07,453 Mars, our planetary neighbor. 3 00:00:09,860 --> 00:00:12,750 It's very cold and dry 4 00:00:12,750 --> 00:00:16,123 and its weak gravity only holds a thin atmosphere. 5 00:00:19,540 --> 00:00:22,540 As probes started to visit the Red Planet, 6 00:00:22,540 --> 00:00:25,540 we gained a more accurate view of the surface 7 00:00:25,540 --> 00:00:28,033 and scientists began to wonder. 8 00:00:30,806 --> 00:00:33,463 Mars had once been much warmer. 9 00:00:34,400 --> 00:00:37,310 It had rivers, and in its early years, 10 00:00:37,310 --> 00:00:39,053 might have sustained life. 11 00:00:42,009 --> 00:00:44,592 (wind howling) 12 00:00:46,747 --> 00:00:49,790 A succession of new techniques have been deployed, 13 00:00:49,790 --> 00:00:52,283 trying to unlock the secrets of the Red Planet. 14 00:00:55,660 --> 00:00:58,290 And while our knowledge of the Martian geology, 15 00:00:58,290 --> 00:01:01,780 its atmosphere and its weather has grown immensely, 16 00:01:01,780 --> 00:01:04,490 each new mission to Mars raises more questions 17 00:01:04,490 --> 00:01:05,523 than it answers. 18 00:01:07,780 --> 00:01:11,210 We still don't know if Mars has at some time 19 00:01:11,210 --> 00:01:13,515 been a home to life. 20 00:01:13,515 --> 00:01:17,182 (inspiring orchestra music) 21 00:01:39,829 --> 00:01:44,000 In 1877, astronomer Giovanni Schiaparelli made 22 00:01:44,000 --> 00:01:48,110 what he thought was the most accurate map of Mars yet drawn. 23 00:01:48,110 --> 00:01:50,223 On it, he showed canals. 24 00:01:52,090 --> 00:01:53,810 In the early 20th Century, 25 00:01:53,810 --> 00:01:57,440 American astronomer Percival Lowell was convinced the canals 26 00:01:57,440 --> 00:02:01,330 were signs of a civilization existing on the Red Planet. 27 00:02:01,330 --> 00:02:04,463 So began the search for life on Mars. 28 00:02:06,830 --> 00:02:11,193 In 1962, the Soviet Union sent the first probe, the Mars M1, 29 00:02:12,150 --> 00:02:13,890 on a flyby mission. 30 00:02:13,890 --> 00:02:18,230 It was an audacious project and it failed, 31 00:02:18,230 --> 00:02:20,340 the first of many failures by both the 32 00:02:20,340 --> 00:02:22,853 Soviet Union and the United States. 33 00:02:24,373 --> 00:02:27,190 Cold War rivalry provided the motivation 34 00:02:27,190 --> 00:02:28,603 for these early missions. 35 00:02:29,709 --> 00:02:33,923 In 1971, NASA sent Mariner Nine to Mars. 36 00:02:36,790 --> 00:02:39,810 It was the first probe to orbit another planet, 37 00:02:39,810 --> 00:02:42,500 but scientists discovered that Mars was enveloped 38 00:02:42,500 --> 00:02:44,143 in a planetary dust store. 39 00:02:46,747 --> 00:02:49,370 On orbit photography revealed little more 40 00:02:49,370 --> 00:02:50,873 than a red cloud. 41 00:02:53,260 --> 00:02:56,310 Soon, Mariner Nine was joined by two Soviet orbiters, 42 00:02:56,310 --> 00:02:58,023 both equipped with landers. 43 00:03:00,940 --> 00:03:03,100 The Mars Two Lander crashed, 44 00:03:03,100 --> 00:03:06,700 but the Mars Three lander made it to the surface intact. 45 00:03:06,700 --> 00:03:10,493 It returned one garbled image and then stopped functioning. 46 00:03:12,280 --> 00:03:14,890 Mars now had three orbiting spacecraft, 47 00:03:14,890 --> 00:03:18,220 all looking at a dusty, featureless planet. 48 00:03:18,220 --> 00:03:20,670 The two Soviet probes were identical, 49 00:03:20,670 --> 00:03:23,953 but the American probe had one key design difference. 50 00:03:25,140 --> 00:03:28,360 While the Soviet orbiters began photographing the planet 51 00:03:28,360 --> 00:03:30,860 following predetermined schedules, 52 00:03:30,860 --> 00:03:34,600 NASA were able to command Mariner Nine to wait 53 00:03:34,600 --> 00:03:37,563 in hope that the dust would eventually settle. 54 00:03:39,472 --> 00:03:44,060 It took months for the atmosphere to clear, but when it did, 55 00:03:44,060 --> 00:03:48,360 Mariner Nine saw three craters protruding above the dust. 56 00:03:48,360 --> 00:03:50,460 They were the tops of giant volcanoes 57 00:03:50,460 --> 00:03:52,933 on what was called the Tharsis Plateau. 58 00:03:55,090 --> 00:03:59,250 Soon, more complex geological features began to emerge. 59 00:03:59,250 --> 00:04:01,790 In places, the surface was cratered, 60 00:04:01,790 --> 00:04:04,730 suggesting the tectonic forces that constantly 61 00:04:04,730 --> 00:04:08,410 renew the Earth's surface were absent on Mars. 62 00:04:08,410 --> 00:04:11,360 Volcanic activity that built the solar system's largest 63 00:04:11,360 --> 00:04:14,883 volcanoes had stopped billions of years ago. 64 00:04:18,683 --> 00:04:21,820 This enabled NASA scientists to compile 65 00:04:21,820 --> 00:04:24,360 an accurate global map of Mars 66 00:04:24,360 --> 00:04:27,290 and to decide upon landing sites for the Viking probes 67 00:04:27,290 --> 00:04:29,383 that followed in 1976. 68 00:04:35,140 --> 00:04:38,610 Viking One and Two were identical orbiters, 69 00:04:38,610 --> 00:04:41,150 with landers that both made successful landings 70 00:04:41,150 --> 00:04:42,163 on the surface. 71 00:04:43,410 --> 00:04:46,243 Both returned pictures of the Martian landscape. 72 00:04:47,753 --> 00:04:50,630 The primary objective of the Viking program 73 00:04:50,630 --> 00:04:53,470 was to find signatures of life, 74 00:04:53,470 --> 00:04:56,540 but researchers now feel the three experiments tasked with 75 00:04:56,540 --> 00:04:59,223 carrying out the analysis had limitations. 76 00:05:01,230 --> 00:05:03,360 As researchers on Earth began looking 77 00:05:03,360 --> 00:05:06,200 for traces of life in extreme environments, 78 00:05:06,200 --> 00:05:09,833 they began to rethink where life on Mars might survive, 79 00:05:11,320 --> 00:05:14,385 yet the consensus at the time was that Mars was sterile 80 00:05:14,385 --> 00:05:17,999 and the idea of life on Mars died. 81 00:05:17,999 --> 00:05:20,916 (mysterious music) 82 00:05:25,820 --> 00:05:28,730 After a 20-year hiatus in Mars research, 83 00:05:28,730 --> 00:05:32,283 Mars Global Surveyor went into orbit in 1996. 84 00:05:38,960 --> 00:05:42,010 The pictures it relayed back were clearer than anything yet 85 00:05:42,010 --> 00:05:43,443 seen from the Red Planet. 86 00:05:45,966 --> 00:05:49,550 Although most Mars orbiters have been tasked with mapping 87 00:05:49,550 --> 00:05:51,963 the planet's surface, this was different. 88 00:05:52,960 --> 00:05:55,970 The high resolution images that the Mars Global Surveyor 89 00:05:55,970 --> 00:05:59,930 sent back revealed rivers and even river deltas, 90 00:05:59,930 --> 00:06:03,460 but the occasional impact crater suggested that nothing has 91 00:06:03,460 --> 00:06:06,113 flowed in these systems for billions of years. 92 00:06:09,634 --> 00:06:13,730 In July 1997, another probe arrived. 93 00:06:13,730 --> 00:06:17,310 The Mars Pathfinder was one of a new breed of missions being 94 00:06:17,310 --> 00:06:19,670 pushed by NASA's new administrator 95 00:06:19,670 --> 00:06:23,661 under the guiding philosophy of faster, better, cheaper. 96 00:06:23,661 --> 00:06:26,244 (wind howling) 97 00:06:29,120 --> 00:06:32,712 The idea was to cut development times, cut budgets, 98 00:06:32,712 --> 00:06:35,550 and although the risk of failure would rise, 99 00:06:35,550 --> 00:06:38,713 the reduced price tag could mean more missions. 100 00:06:40,706 --> 00:06:44,870 Pathfinder would land a small rover on the surface. 101 00:06:44,870 --> 00:06:49,053 To do this, it used radically new airbag technology. 102 00:06:50,380 --> 00:06:53,620 The technique drew more from automotive safety systems 103 00:06:53,620 --> 00:06:56,152 than from previous space missions. 104 00:06:56,152 --> 00:06:58,902 (engine roaring) 105 00:07:01,880 --> 00:07:05,140 The landing site in Mars' Northern Hemisphere known 106 00:07:05,140 --> 00:07:09,040 as Ares Vallis is one of the planet's rockiest areas, 107 00:07:09,040 --> 00:07:11,523 yet it was thought to be a safe area to land. 108 00:07:12,540 --> 00:07:15,300 The broad array of different rock types are believed to have 109 00:07:15,300 --> 00:07:17,783 been deposited during an ancient flood. 110 00:07:20,673 --> 00:07:24,290 The new landing technique worked perfectly and served as 111 00:07:24,290 --> 00:07:27,843 a proof of concept that would be used on future missions. 112 00:07:27,843 --> 00:07:30,426 (wind howling) 113 00:07:33,664 --> 00:07:37,640 Pathfinder consisted of a base station equipped with three 114 00:07:37,640 --> 00:07:40,473 solar panels that unfolded like petals. 115 00:07:41,969 --> 00:07:45,360 There were sensors to measure atmospheric pressure, 116 00:07:45,360 --> 00:07:47,740 air temperature, and wind speed, 117 00:07:47,740 --> 00:07:50,423 as well as a transmitter to communicate with Earth. 118 00:07:52,999 --> 00:07:56,730 In addition, Pathfinder acted as a base station 119 00:07:56,730 --> 00:08:00,670 for the Sojourner Rover that explored the surrounding area. 120 00:08:00,670 --> 00:08:02,950 Sojourner was fitted with cameras and an 121 00:08:02,950 --> 00:08:05,880 alpha particle x-ray spectrometer. 122 00:08:05,880 --> 00:08:09,060 It was the first mission to have its own website. 123 00:08:09,060 --> 00:08:12,720 The rover returned thousands of images and important detail 124 00:08:12,720 --> 00:08:14,881 about the atmosphere and geology and 125 00:08:14,881 --> 00:08:18,873 its popularity guaranteed more Mars missions. 126 00:08:20,524 --> 00:08:23,274 (engine roaring) 127 00:08:27,980 --> 00:08:30,780 On the morning of April the 7th, 2001, 128 00:08:30,780 --> 00:08:33,023 another Mars orbiter was launched. 129 00:08:35,980 --> 00:08:39,660 Mars Odyssey was equipped with three primary instruments 130 00:08:39,660 --> 00:08:42,440 and it had the ability to act as a relay satellite 131 00:08:42,440 --> 00:08:46,133 between future surface missions to the Red Planet and Earth. 132 00:08:48,854 --> 00:08:50,640 On its arrival at Mars, 133 00:08:50,640 --> 00:08:53,800 it used a new technique to go into orbit. 134 00:08:53,800 --> 00:08:57,080 After firing a relatively brief pulse of its engine, 135 00:08:57,080 --> 00:09:00,380 Mars Odyssey went into a highly elliptical orbit, 136 00:09:00,380 --> 00:09:02,600 that at its closest approach, 137 00:09:02,600 --> 00:09:06,280 had it skimming the planet's thin upper atmosphere, 138 00:09:06,280 --> 00:09:08,150 called aerobraking. 139 00:09:08,150 --> 00:09:11,280 This technique allowed the craft to circularize its orbit 140 00:09:11,280 --> 00:09:13,360 over a period of three months 141 00:09:13,360 --> 00:09:16,293 and it saved around 200 kilograms of fuel. 142 00:09:19,157 --> 00:09:22,110 The probe is still in operation today, 143 00:09:22,110 --> 00:09:25,563 breaking all records as the longest serving Mars mission. 144 00:09:30,888 --> 00:09:34,793 In December 2003, a new player arrived at Mars. 145 00:09:37,680 --> 00:09:41,600 The European Space Agency, using a Russian launcher, 146 00:09:41,600 --> 00:09:46,060 had sent Mars Express, its first planetary explorer. 147 00:09:46,060 --> 00:09:48,803 It was equipped with a lander known as Beagle. 148 00:09:51,950 --> 00:09:54,360 Though all contact was lost with the lander, 149 00:09:54,360 --> 00:09:58,230 Mars Express continues to return valuable data. 150 00:09:58,230 --> 00:10:00,700 The mission has been granted several extensions, 151 00:10:00,700 --> 00:10:02,563 the latest till 2020. 152 00:10:05,244 --> 00:10:09,170 Equipped with a high resolution stereo camera, 153 00:10:09,170 --> 00:10:13,083 the probe returned unique 3D views of the planet's surface. 154 00:10:16,693 --> 00:10:19,820 The orbiter determined that the polar ice caps 155 00:10:19,820 --> 00:10:23,903 contain a blend of frozen CO2 and water ice. 156 00:10:26,846 --> 00:10:30,480 In the atmosphere, Mars Express detected first methane 157 00:10:30,480 --> 00:10:32,170 and then ammonia. 158 00:10:32,170 --> 00:10:35,650 Both gasses deteriorate rapidly in sunlight, 159 00:10:35,650 --> 00:10:38,943 so there must be sources on Mars continually producing them. 160 00:10:40,900 --> 00:10:45,523 Methane and ammonia can rarely be made inorganically, 161 00:10:45,523 --> 00:10:47,763 but they're generally associated with life. 162 00:10:51,150 --> 00:10:54,000 One month after Mars Express went into orbit, 163 00:10:54,000 --> 00:10:56,210 a NASA lander arrived at Mars, 164 00:10:56,210 --> 00:10:59,725 followed three weeks later by a second identical craft. 165 00:10:59,725 --> 00:11:02,475 (craft rumbling) 166 00:11:06,758 --> 00:11:09,990 They were the Mars exploration rovers called 167 00:11:09,990 --> 00:11:12,329 Spirit and Opportunity. 168 00:11:12,329 --> 00:11:14,912 (wind howling) 169 00:11:20,770 --> 00:11:25,440 Spirit, the first to land, was targeted at the Gusev crater. 170 00:11:25,440 --> 00:11:28,140 Opportunity would land at the Meridiani Planum 171 00:11:28,140 --> 00:11:30,378 on the opposite side of Mars. 172 00:11:30,378 --> 00:11:35,378 (mysterious music) (wind howling) 173 00:11:38,350 --> 00:11:39,840 Though they were much heavier than their 174 00:11:39,840 --> 00:11:41,600 Pathfinder predecessor, 175 00:11:41,600 --> 00:11:44,183 they used the same bounce landing technique. 176 00:11:46,384 --> 00:11:50,870 Both landings were successful and on target. 177 00:11:50,870 --> 00:11:52,950 After the craft had righted itself, 178 00:11:52,950 --> 00:11:56,860 it detached from the lander and began autonomously unfolding 179 00:11:56,860 --> 00:11:58,813 its solar panels and camera mass. 180 00:12:00,810 --> 00:12:01,960 While this was happening, 181 00:12:01,960 --> 00:12:05,490 the team back at the Jet Propulsion Laboratory waited. 182 00:12:05,490 --> 00:12:07,790 Signals confirming the craft's safe arrival 183 00:12:07,790 --> 00:12:10,438 took 15 minutes to travel back to Earth. 184 00:12:10,438 --> 00:12:13,188 (crowd cheering) 185 00:12:16,800 --> 00:12:18,870 Many of these people had invested years 186 00:12:18,870 --> 00:12:20,570 of their lives in this project, 187 00:12:20,570 --> 00:12:23,247 and the real mission had only just commenced. 188 00:12:23,247 --> 00:12:26,150 (crowd cheering) 189 00:12:26,150 --> 00:12:30,240 Both rovers were designed to operate for 90 Mars days. 190 00:12:30,240 --> 00:12:32,950 A solar day on Mars is about 40 minutes longer 191 00:12:32,950 --> 00:12:36,040 than an Earth day, and to avoid confusion, 192 00:12:36,040 --> 00:12:38,040 the science team operating the rovers 193 00:12:38,040 --> 00:12:40,273 refer to a Martian day as a sol. 194 00:12:44,330 --> 00:12:48,200 Mission designers, knowing about the dust storms on Mars, 195 00:12:48,200 --> 00:12:50,330 felt that the solar panels on the two rovers 196 00:12:50,330 --> 00:12:54,030 would eventually be blocked with dirt and stop functioning, 197 00:12:54,030 --> 00:12:56,290 but it became clear that the winds on Mars 198 00:12:56,290 --> 00:12:57,723 were clearing the panels. 199 00:13:02,320 --> 00:13:05,840 Soon, NASA announced that Opportunity had found evidence 200 00:13:05,840 --> 00:13:10,017 confirming liquid water had once flowed on Mars. 201 00:13:10,017 --> 00:13:13,490 There were pictures from the Meridiani Planum of stratified 202 00:13:13,490 --> 00:13:16,880 patterns in the rocks, suggesting sedimentation. 203 00:13:16,880 --> 00:13:20,150 The distribution of chlorine and bromine at the site were 204 00:13:20,150 --> 00:13:23,693 clues to the area's past as the shore of a salty sea. 205 00:13:26,970 --> 00:13:30,910 In April 2004, NASA announced it would extend the rovers' 206 00:13:30,910 --> 00:13:32,933 missions from three to eight months. 207 00:13:36,730 --> 00:13:39,833 It would be the first of many such mission extensions. 208 00:13:42,471 --> 00:13:46,090 The rovers were equipped with an abrasion tool to grind away 209 00:13:46,090 --> 00:13:49,320 a portion of a rock's surface for a more detailed, 210 00:13:49,320 --> 00:13:52,573 uncontaminated analysis of geological samples. 211 00:13:57,025 --> 00:14:00,410 This was first done by Spirit at a rock named 212 00:14:00,410 --> 00:14:02,493 Adirondack at Gusev crater. 213 00:14:06,890 --> 00:14:09,323 It was a first in planetary geology. 214 00:14:11,070 --> 00:14:14,500 Researchers agonized before using the tool because of 215 00:14:14,500 --> 00:14:17,273 the drain it makes on the rover's energy budget. 216 00:14:18,780 --> 00:14:23,020 The rock was made of olivine, pyroxene, and magnetite, 217 00:14:23,020 --> 00:14:26,193 making it very similar to volcanic basalt on Earth. 218 00:14:27,432 --> 00:14:30,790 When Spirit's right front wheel stopped working, 219 00:14:30,790 --> 00:14:33,650 engineers used a duplicate rover to devise 220 00:14:33,650 --> 00:14:35,620 a reversing technique that enabled 221 00:14:35,620 --> 00:14:37,863 the rover to drag its frozen wheel. 222 00:14:38,790 --> 00:14:41,410 This left a furrow behind in the soil, 223 00:14:41,410 --> 00:14:44,773 which presented a new area of research for the science team. 224 00:14:46,950 --> 00:14:50,350 White or yellow deposits seen within the furrow were 225 00:14:50,350 --> 00:14:52,690 various types salts that only form 226 00:14:52,690 --> 00:14:54,373 in the presence of hot water. 227 00:14:55,440 --> 00:14:58,410 On Earth, hot water provides an environment in which 228 00:14:58,410 --> 00:15:00,203 microbes can thrive. 229 00:15:01,340 --> 00:15:04,230 Spirit limped on for another three years before it 230 00:15:04,230 --> 00:15:06,103 became stuck in loose sand. 231 00:15:08,160 --> 00:15:10,730 Again, the engineers began working with a replica, 232 00:15:10,730 --> 00:15:14,050 which they placed in an identical situation 233 00:15:14,050 --> 00:15:16,430 When nothing was able to free the rover, 234 00:15:16,430 --> 00:15:19,123 it was declared a stationary research platform. 235 00:15:20,090 --> 00:15:22,200 Further attempts were made to position the rover 236 00:15:22,200 --> 00:15:25,350 so its solar panels could operate more effectively, 237 00:15:25,350 --> 00:15:27,263 but even this was not possible. 238 00:15:29,860 --> 00:15:33,163 The last communication from Spirit was in March 2010. 239 00:15:34,020 --> 00:15:37,088 Opportunity lasted until June 2018, 240 00:15:37,088 --> 00:15:39,653 when dust clogged its solar panels. 241 00:15:43,810 --> 00:15:48,380 In March 2006, NASA's Mars Reconnaissance Orbiter arrived at 242 00:15:48,380 --> 00:15:52,003 Mars and began the now routine business of aerobraking. 243 00:15:52,870 --> 00:15:55,710 Though this procedure took roughly six months, 244 00:15:55,710 --> 00:15:58,690 the saving in fuel will see the craft functioning at Mars 245 00:15:58,690 --> 00:16:00,173 into the 2030s. 246 00:16:04,810 --> 00:16:07,350 One of the primary functions of the new orbiter 247 00:16:07,350 --> 00:16:10,110 is as a communications relay station. 248 00:16:10,110 --> 00:16:12,540 It's three meter antenna transmitting in the 249 00:16:12,540 --> 00:16:17,160 ultra high frequency band enables very high data rates. 250 00:16:17,160 --> 00:16:18,920 By November 2013, 251 00:16:18,920 --> 00:16:21,520 it had tripled the amount of data sent to Earth by 252 00:16:21,520 --> 00:16:23,833 all the other NASA missions combined. 253 00:16:28,577 --> 00:16:31,830 Its high resolution camera began revealing 254 00:16:31,830 --> 00:16:34,483 the surface of Mars in the finest detail. 255 00:16:35,520 --> 00:16:40,067 These are active falling dunes in East Coprates Chasma. 256 00:16:41,400 --> 00:16:44,280 The polar region, free of the seasonal dry ice, 257 00:16:44,280 --> 00:16:46,463 again surrounded by dunes. 258 00:16:47,860 --> 00:16:49,330 In the Southern Hemisphere, 259 00:16:49,330 --> 00:16:52,803 pits in the residual cap of carbon dioxide. 260 00:16:52,803 --> 00:16:57,803 (mysterious music) (wind howling) 261 00:17:01,230 --> 00:17:04,610 The poles of Mars were now attracting keen interest. 262 00:17:04,610 --> 00:17:07,363 Follow the water had become NASA's catchcry. 263 00:17:08,661 --> 00:17:12,790 The Phoenix lander was targeted at the Northern polar region 264 00:17:12,790 --> 00:17:15,610 to follow up on information from Mars Odyssey, 265 00:17:15,610 --> 00:17:18,050 suggesting frozen water lay beneath 266 00:17:18,050 --> 00:17:19,743 the surface near the poles. 267 00:17:23,604 --> 00:17:27,690 Because imaging had revealed the region to be unvarying, 268 00:17:27,690 --> 00:17:29,683 a rover was deemed unnecessary. 269 00:17:31,132 --> 00:17:34,584 The lander had been designed to use a parachute decelerate 270 00:17:34,584 --> 00:17:38,300 with rocket thrusters to deliver the craft to the surface 271 00:17:38,300 --> 00:17:41,593 unlike NASA's previous three rovers, which had bounced. 272 00:17:43,720 --> 00:17:47,230 This decision proved controversial as one strand of research 273 00:17:47,230 --> 00:17:49,540 suggested the rocket fuel would contaminate 274 00:17:49,540 --> 00:17:52,993 the very area that the lander was tasked with analyzing. 275 00:17:56,458 --> 00:17:59,140 The craft waited 15 minutes to allow 276 00:17:59,140 --> 00:18:02,283 any dust to settle before it deployed its solar panels. 277 00:18:04,773 --> 00:18:07,490 Phoenix had landed during the early spring 278 00:18:07,490 --> 00:18:09,320 in Mars' Northern Hemisphere, 279 00:18:09,320 --> 00:18:11,850 so the solar panels would receive plenty of light 280 00:18:11,850 --> 00:18:13,833 for the planned 90 day mission. 281 00:18:16,472 --> 00:18:18,930 As well as its camera mass, 282 00:18:18,930 --> 00:18:21,510 Phoenix was equipped with a meteorological station 283 00:18:21,510 --> 00:18:23,670 that recorded the daily weather. 284 00:18:23,670 --> 00:18:25,530 It featured a wind indicator and 285 00:18:25,530 --> 00:18:27,910 pressure and temperature sensors. 286 00:18:27,910 --> 00:18:30,620 In addition, a vertically pointed LIDAR 287 00:18:30,620 --> 00:18:34,210 was able to observe cirrus clouds forming in the region 288 00:18:34,210 --> 00:18:36,713 and snow falling in the polar atmosphere. 289 00:18:39,780 --> 00:18:42,223 These phenomena had not been observed before. 290 00:18:45,668 --> 00:18:48,260 The lander also had a robotic arm that could 291 00:18:48,260 --> 00:18:50,240 dig half a meter into the soil 292 00:18:50,240 --> 00:18:52,770 and deliver samples to the analyzer, 293 00:18:52,770 --> 00:18:55,280 a combination of eight high temperature ovens 294 00:18:55,280 --> 00:18:56,563 and a mass spectrometer. 295 00:19:00,290 --> 00:19:03,640 In one excavation, the cameras recorded a white substance, 296 00:19:03,640 --> 00:19:05,900 which gradually disappeared. 297 00:19:05,900 --> 00:19:09,110 Given the temperatures and the time it lasted, 298 00:19:09,110 --> 00:19:11,233 it could only have been water ice 299 00:19:11,233 --> 00:19:13,923 that sublimated after it was exposed. 300 00:19:16,290 --> 00:19:19,500 The soil was slightly alkaline and the presence of 301 00:19:19,500 --> 00:19:22,100 perchlorate, which kills bacteria, 302 00:19:22,100 --> 00:19:24,933 was not good news for those hoping for Martian life. 303 00:19:26,610 --> 00:19:29,640 Phoenix operated for two months longer than planned 304 00:19:29,640 --> 00:19:31,470 before the gathering winter completely 305 00:19:31,470 --> 00:19:32,803 shaded its solar panel. 306 00:19:35,207 --> 00:19:37,790 (upbeat music) 307 00:19:39,230 --> 00:19:43,130 While the planet still had subterranean deposits of ice, 308 00:19:43,130 --> 00:19:45,690 there was precious little left at the surface, 309 00:19:45,690 --> 00:19:48,400 yet it was now understood that many of the Red Planet's 310 00:19:48,400 --> 00:19:51,630 features had been carved by running water. 311 00:19:51,630 --> 00:19:54,180 Samples analyzed from across the planet 312 00:19:54,180 --> 00:19:58,290 affirmed that water and nothing else had made these changes 313 00:19:58,290 --> 00:19:59,563 to the Martian landscape. 314 00:20:03,528 --> 00:20:06,640 Mars had once been more like Earth, 315 00:20:06,640 --> 00:20:08,430 yet it had lost its surface water 316 00:20:08,430 --> 00:20:10,220 and most of its atmosphere, 317 00:20:10,220 --> 00:20:12,860 and the question of life persisted. 318 00:20:12,860 --> 00:20:15,953 Could it have emerged in a warmer, wetter past, 319 00:20:15,953 --> 00:20:19,133 and could it still be present below the surface? 320 00:20:22,070 --> 00:20:25,640 The next Mars mission would be NASA's most ambitious yet. 321 00:20:25,640 --> 00:20:27,330 Known as Curiosity, 322 00:20:27,330 --> 00:20:31,000 the car sized rover would be powered by a nuclear battery, 323 00:20:31,000 --> 00:20:33,070 making it immune to the dust problems 324 00:20:33,070 --> 00:20:35,593 experienced by Spirit and Opportunity. 325 00:20:37,730 --> 00:20:39,530 Seven, six. 326 00:20:39,530 --> 00:20:41,920 Curiosity was launched on an Atlas V 327 00:20:41,920 --> 00:20:44,900 from Cape Canaveral in November 2011. 328 00:20:44,900 --> 00:20:46,020 One. 329 00:20:46,020 --> 00:20:47,850 Main engine, start. 330 00:20:47,850 --> 00:20:50,738 Zero and lift off. 331 00:20:50,738 --> 00:20:52,960 (engine rumbling) 332 00:20:52,960 --> 00:20:54,180 In mid 2012, 333 00:20:54,180 --> 00:20:57,323 it entered the Martian atmosphere heading for Gale crater. 334 00:21:01,020 --> 00:21:04,460 The Jet Propulsion Laboratory monitored the entry closely, 335 00:21:04,460 --> 00:21:06,833 but had no control over events. 336 00:21:08,870 --> 00:21:10,290 In Mars' thin atmosphere, 337 00:21:10,290 --> 00:21:12,710 the parachute could only slow the heavy craft 338 00:21:12,710 --> 00:21:15,760 to around 320 kilometers per hour. 339 00:21:19,086 --> 00:21:21,253 (engine rumbling) 340 00:21:21,253 --> 00:21:22,086 Nearing the surface, 341 00:21:22,086 --> 00:21:24,760 the rover descent stage dropped out of the aero shell 342 00:21:24,760 --> 00:21:26,003 and rockets kicked in. 343 00:21:27,243 --> 00:21:31,240 At this stage, radar was guiding the lander to the surface 344 00:21:31,240 --> 00:21:33,410 and a small camera was recording images 345 00:21:33,410 --> 00:21:35,023 of the terrain below the rover. 346 00:21:38,720 --> 00:21:41,400 Next, Curiosity was lowered on a tether 347 00:21:41,400 --> 00:21:42,993 beneath the descent stage. 348 00:21:46,140 --> 00:21:48,700 This sky crane technique was used to 349 00:21:48,700 --> 00:21:50,450 avoid too much swirling dust, 350 00:21:50,450 --> 00:21:52,763 exposing the rover to unnecessary danger. 351 00:21:53,613 --> 00:21:56,446 (engine rumbling) 352 00:21:59,977 --> 00:22:02,150 (crowd cheering) 353 00:22:02,150 --> 00:22:04,920 Everything had worked exactly as it was supposed to 354 00:22:04,920 --> 00:22:07,273 and the American engineers were relieved. 355 00:22:11,990 --> 00:22:14,543 The landing had been the most precise ever. 356 00:22:17,010 --> 00:22:19,370 Before Curiosity could start work, 357 00:22:19,370 --> 00:22:22,070 its computer went through a checklist to make certain that 358 00:22:22,070 --> 00:22:24,233 all systems were operating correctly. 359 00:22:27,640 --> 00:22:30,500 It was a day before the rover deployed its camera mass 360 00:22:30,500 --> 00:22:32,243 and communications antennas. 361 00:22:33,930 --> 00:22:36,610 It's thought that Gale crater is three and a half billion 362 00:22:36,610 --> 00:22:38,960 years old and that its sediments have been 363 00:22:38,960 --> 00:22:42,253 laid down first by water and then by wind. 364 00:22:46,830 --> 00:22:50,310 NASA now has a sophisticated mobile science laboratory 365 00:22:50,310 --> 00:22:52,800 on Mars connected to Earth by the most 366 00:22:52,800 --> 00:22:54,760 advanced communications link, 367 00:22:54,760 --> 00:22:57,644 courtesy of the Mars Reconnaissance Orbiter. 368 00:22:57,644 --> 00:23:00,644 (satellite beeping) 369 00:23:03,030 --> 00:23:06,970 The rover's primary objective is to discover if conditions 370 00:23:06,970 --> 00:23:11,283 suitable for life ever existed or still exist on Mars. 371 00:23:12,703 --> 00:23:16,210 It's also gathering detailed information about the current 372 00:23:16,210 --> 00:23:18,130 conditions on the Red Planet, 373 00:23:18,130 --> 00:23:21,190 particularly the radiation levels that will have an impact 374 00:23:21,190 --> 00:23:22,753 on proposed manned missions. 375 00:23:25,830 --> 00:23:28,370 Curiosity has analyzed the dust 376 00:23:28,370 --> 00:23:30,290 from a number of holes it drilled, 377 00:23:30,290 --> 00:23:35,290 revealing sulfur, nitrogen, hydrogen, oxygen, phosphorus, 378 00:23:35,390 --> 00:23:38,803 and carbon, or elements essential to life. 379 00:23:40,440 --> 00:23:42,920 In its six years on the surface of Mars, 380 00:23:42,920 --> 00:23:45,610 Curiosity has traveled around 20 kilometers, 381 00:23:45,610 --> 00:23:48,450 but the driving is taking its toll. 382 00:23:48,450 --> 00:23:51,740 It routinely sends back a series of self-portraits, 383 00:23:51,740 --> 00:23:53,593 mainly for diagnostic reasons. 384 00:23:55,200 --> 00:23:57,140 Its wheels have taken severe damage, 385 00:23:57,140 --> 00:23:59,900 which will undoubtedly lead to design changes 386 00:23:59,900 --> 00:24:01,143 for future rovers. 387 00:24:04,740 --> 00:24:07,440 Its computers are also giving problems, 388 00:24:07,440 --> 00:24:09,750 but a new suite of missions is slated to arrive 389 00:24:09,750 --> 00:24:13,423 at Mars in 2020 that will continue profiling the planet. 390 00:24:19,360 --> 00:24:22,140 There is one aspect of the Martian environment 391 00:24:22,140 --> 00:24:23,960 that has never been investigated, 392 00:24:23,960 --> 00:24:25,823 but that's about to be addressed. 393 00:24:26,950 --> 00:24:29,600 The Mars InSight probe has been targeted 394 00:24:29,600 --> 00:24:33,120 at the flat Elysium Planitia, close to the equator, 395 00:24:33,120 --> 00:24:35,873 to spend two years investigating the planet's interior. 396 00:24:38,060 --> 00:24:41,133 It made a flawless landing in November 2018. 397 00:24:43,360 --> 00:24:45,310 After unfurling its solar array, 398 00:24:45,310 --> 00:24:47,650 it spent weeks selecting a suitable spot 399 00:24:47,650 --> 00:24:50,120 to deploy a seismometer onto the surface 400 00:24:50,120 --> 00:24:51,843 to monitor Mars quakes. 401 00:24:54,547 --> 00:24:58,540 It's clear that Mars had a warm, wet past, 402 00:24:58,540 --> 00:25:01,290 but it's cold and very dry now. 403 00:25:01,290 --> 00:25:04,470 Learning about the planet's geological activity will help 404 00:25:04,470 --> 00:25:06,493 us know why Mars has changed. 405 00:25:08,970 --> 00:25:12,300 The InSight probe also hammered a thermal sensor into the 406 00:25:12,300 --> 00:25:15,513 surface to gather data on heat flow from the planet's core. 407 00:25:20,030 --> 00:25:23,010 By understanding processes within Mars, 408 00:25:23,010 --> 00:25:26,400 we can learn how the geological histories of Mars and Earth 409 00:25:26,400 --> 00:25:27,250 began to diverge. 410 00:25:29,526 --> 00:25:32,943 (bright orchestra music)