1 00:00:02,535 --> 00:00:06,939 I was just praying with my eyes closed that this was going to work. 2 00:00:08,541 --> 00:00:11,777 Things, if they're gonna go wrong, do go wrong. 3 00:00:11,811 --> 00:00:13,645 This thing could fail, you know? 4 00:00:13,680 --> 00:00:16,081 [Scott] If it doesn't work, it's over. 5 00:00:16,116 --> 00:00:17,616 Lights off. 6 00:00:17,650 --> 00:00:21,253 [narrator] Exploring the Solar System is not for the faint of heart. 7 00:00:21,287 --> 00:00:26,291 It requires courage, determination and ingenuity. 8 00:00:26,326 --> 00:00:29,728 [James Garvin] This is like the first Renaissance voyage over the oceans, 9 00:00:29,763 --> 00:00:32,097 but it's to another planet. 10 00:00:33,333 --> 00:00:36,235 Can we send a spacecraft through that environment? 11 00:00:36,269 --> 00:00:38,337 There's no question whatsoever that this is 12 00:00:38,371 --> 00:00:40,950 one of the most difficult technological jobs 13 00:00:40,974 --> 00:00:42,908 that the human species has ever tried. 14 00:00:42,942 --> 00:00:46,645 It's a very violent, dangerous, deadly place. 15 00:00:46,679 --> 00:00:49,848 [narrator] Through failure and triumph, the people who risked it all 16 00:00:49,883 --> 00:00:53,786 for human exploration are providing new insights. 17 00:00:54,921 --> 00:00:58,924 - [James] Holy gosh. - [Fran] I was stunned. 18 00:00:58,958 --> 00:01:00,526 We found the holy grail. 19 00:01:00,560 --> 00:01:04,029 [woman] It's definitely the most interesting place in the Solar System. 20 00:01:04,064 --> 00:01:07,733 Wouldn't that be cool, if Pluto has or had life? 21 00:01:07,767 --> 00:01:11,437 We're thinking, "Holy crap, Batman." 22 00:01:11,471 --> 00:01:13,906 [narrator] These are the missions that change 23 00:01:13,940 --> 00:01:17,743 how we see the Solar System and ourselves. 24 00:01:17,811 --> 00:01:22,681 We are the only generation that will ever explore the Solar System 25 00:01:22,715 --> 00:01:24,650 for the first time. 26 00:01:41,401 --> 00:01:44,403 [Eugene speaking] 27 00:02:02,122 --> 00:02:03,922 [narrator] This prediction was more accurate than 28 00:02:03,957 --> 00:02:07,526 Eugene Cernan could have known in 1972. 29 00:02:13,733 --> 00:02:17,769 Fifty years later, for the first time in human history, 30 00:02:17,804 --> 00:02:22,407 we now have images in stunning detail of the major planets, 31 00:02:22,442 --> 00:02:25,177 many moons, asteroids and comets, 32 00:02:25,211 --> 00:02:28,380 taken from space by manmade machines. 33 00:02:29,983 --> 00:02:33,385 These images bear witness to the tireless work of the people 34 00:02:33,419 --> 00:02:37,723 who went in search of answers to humanity's biggest questions. 35 00:02:39,893 --> 00:02:43,328 [Nicola] Humanity, I think, has a general quest for knowledge. 36 00:02:43,363 --> 00:02:47,666 We tend to just ask questions and wonder why. 37 00:02:47,700 --> 00:02:50,936 The nature is to look up and to look around you 38 00:02:50,970 --> 00:02:53,138 and to want to understand your surroundings. 39 00:02:53,173 --> 00:02:55,541 And so the first thing anyone looked up 40 00:02:55,575 --> 00:02:57,743 and wondered about was the Sun. 41 00:03:11,157 --> 00:03:15,427 The Sun at the center of the Solar System is an incredibly hot object. 42 00:03:16,829 --> 00:03:20,232 This hot, raging ball of gas. 43 00:03:21,568 --> 00:03:24,970 In order to be able to truly see the Sun, the interior, 44 00:03:25,004 --> 00:03:29,007 the surface, the atmosphere, we have to go into space. 45 00:03:29,042 --> 00:03:31,043 -[mission control] Status check. -[technician] Go, Delta. 46 00:03:31,077 --> 00:03:35,347 -[mission control] Go, PSP. First stage, propulsion. -[technician] Go. 47 00:03:35,381 --> 00:03:36,682 - Hydraulics. - Go. 48 00:03:36,716 --> 00:03:38,417 - Box. - Go. 49 00:03:38,451 --> 00:03:40,219 [man] This mission has been a long time coming, 50 00:03:40,253 --> 00:03:43,622 you know, that for 60 years we tried to do this mission. 51 00:03:43,656 --> 00:03:50,295 We're going to go to the most extreme environment in our entire Solar System. 52 00:03:50,330 --> 00:03:53,332 We're going to go in and we're going to touch the Sun. 53 00:03:53,366 --> 00:03:57,336 [announcer] Eight, seven, six, five, 54 00:03:57,370 --> 00:04:02,808 four, three, two, one, zero. 55 00:04:02,842 --> 00:04:06,278 Liftoff of the mighty Delta IV heavy rocket 56 00:04:06,312 --> 00:04:08,413 with NASA's Parker Solar Probe, 57 00:04:08,448 --> 00:04:11,116 a daring mission to shed light on the mysteries 58 00:04:11,150 --> 00:04:13,986 of our closest star, the Sun. 59 00:04:17,357 --> 00:04:20,792 The Sun is a constant in our lives, it rises every morning, 60 00:04:20,827 --> 00:04:23,829 it sets every night, and yet when you look at the Sun, 61 00:04:23,863 --> 00:04:26,932 you will see that it is anything but constant. 62 00:04:26,966 --> 00:04:32,170 It is a continually changing, incredibly active star. 63 00:04:32,205 --> 00:04:37,876 [narrator] The story of the Sun is very much the story of the Solar System. 64 00:04:37,910 --> 00:04:42,781 Finding out how it works is still a work in progress. 65 00:04:42,815 --> 00:04:46,485 That hazy atmosphere that you see during a total solar eclipse, 66 00:04:46,519 --> 00:04:50,355 the Sun's corona, is hotter than the surface of the Sun, 67 00:04:50,390 --> 00:04:53,358 and that really doesn't make sense, it breaks the laws of physics. 68 00:04:53,393 --> 00:04:56,762 [Matthew] And we don't know why. 69 00:04:56,796 --> 00:05:01,867 If it's that hot, why does the gas stay on the Sun? 70 00:05:02,969 --> 00:05:06,938 Hot materials move really fast. 71 00:05:06,973 --> 00:05:12,277 And if the gas molecules are traveling faster than escape velocity, 72 00:05:12,312 --> 00:05:17,015 there should be a wind streaming away from the Sun. 73 00:05:17,050 --> 00:05:22,254 [Lucie] And this radical idea was predicted by an American astronomer, 74 00:05:22,288 --> 00:05:24,823 Eugene Parker. 75 00:05:27,760 --> 00:05:31,697 [narrator] In 1958, space was thought to be a hard vacuum. 76 00:05:31,764 --> 00:05:35,534 And while the light and heat from the Sun could pass through space, 77 00:05:35,568 --> 00:05:37,703 the enormous gravity of the Sun 78 00:05:37,737 --> 00:05:42,908 would prevent any matter such as gas from reaching us. 79 00:05:42,942 --> 00:05:45,777 But Parker thought differently. 80 00:05:45,812 --> 00:05:48,914 [Parker speaking] 81 00:05:52,352 --> 00:05:55,287 [Lucie] He went through the mathematics, he went through the physics, 82 00:05:55,321 --> 00:06:00,659 and he predicted the hot atmosphere of the Sun has a high pressure. 83 00:06:00,693 --> 00:06:03,195 So the gas is wanting to push outwards. 84 00:06:03,229 --> 00:06:07,232 And there's a really important consequence of that. 85 00:06:07,266 --> 00:06:10,836 The gas streams out into the Solar System. 86 00:06:10,870 --> 00:06:15,173 The Sun is literally expanding into space. 87 00:06:15,208 --> 00:06:17,943 [Parker speaking] 88 00:06:21,948 --> 00:06:26,918 [narrator] Publication of Parker's radical idea was repeatedly rejected, 89 00:06:26,953 --> 00:06:31,356 but finally he convinced The Astrophysical Journal to accept it. 90 00:06:31,391 --> 00:06:34,726 But still it's ridiculed. 91 00:06:46,839 --> 00:06:51,009 [mission control] ...three, two, one, zero. 92 00:07:03,189 --> 00:07:05,123 [Lucie] And they did indeed discover 93 00:07:05,158 --> 00:07:10,228 that the Sun does have this outflow of gas coming from it. 94 00:07:10,263 --> 00:07:12,364 The solar wind does exist. 95 00:07:22,074 --> 00:07:24,443 [Matthew] This discovery was... was momentous. 96 00:07:24,477 --> 00:07:29,514 All of a sudden, space is no longer a void, it's no longer a vacuum. 97 00:07:29,549 --> 00:07:33,885 It's filled with material, it's filled with this wind from the Sun. 98 00:07:35,188 --> 00:07:40,192 And it has some real, significant effects on our planet. 99 00:07:42,728 --> 00:07:47,999 [narrator] In 2018, NASA launched a spacecraft called the Parker Solar Probe. 100 00:07:48,034 --> 00:07:50,635 [announcer] ...two, one. 101 00:07:50,670 --> 00:07:52,938 Liftoff of the mighty Delta IV heavy rocket... 102 00:07:52,972 --> 00:07:54,906 [narrator] It's the only spacecraft ever to bear 103 00:07:54,941 --> 00:07:57,375 the name of a living scientist. 104 00:08:01,447 --> 00:08:04,015 [woman] Wow! Go, baby, go. 105 00:08:10,923 --> 00:08:14,059 [cheers and applause] 106 00:08:22,335 --> 00:08:24,836 [narrator] The Parker Solar Probe would reveal the Sun 107 00:08:24,871 --> 00:08:28,306 to be as dynamic as Eugene's research predicted. 108 00:08:30,743 --> 00:08:35,013 The strange, powerful phenomena Parker observed when it touched the Sun 109 00:08:35,047 --> 00:08:37,115 characterized the celestial body 110 00:08:37,149 --> 00:08:41,953 as incomprehensibly hot and enormously variable. 111 00:08:41,988 --> 00:08:45,991 So it followed that Mercury, the planet closest to our star, 112 00:08:46,025 --> 00:08:47,993 would be a blistering world of extremes. 113 00:08:48,027 --> 00:08:49,995 [mission control] ...two, one, and zero. 114 00:08:50,029 --> 00:08:54,900 [narrator] But even here, explorers would find something that few expected. 115 00:08:54,934 --> 00:08:57,302 [James Green] When I became the head of Planetary Science, 116 00:08:57,336 --> 00:09:01,840 MESSENGER had launched and it was on its way to Mercury. 117 00:09:03,910 --> 00:09:07,445 MESSENGER was all about exploring the full surface 118 00:09:07,480 --> 00:09:09,114 that we had never seen before, 119 00:09:09,148 --> 00:09:12,050 but also we had to really think about how we develop our technology 120 00:09:12,084 --> 00:09:14,753 to survive this environment. 121 00:09:14,787 --> 00:09:18,723 [narrator] The MESSENGER spacecraft was designed to travel millions of miles 122 00:09:18,758 --> 00:09:23,528 and survive a temperature range of over 1,100 degrees Fahrenheit, 123 00:09:23,563 --> 00:09:28,533 and it went into orbit around Mercury seven years after launch. 124 00:09:28,568 --> 00:09:33,271 What MESSENGER did was it provided, as its top science priority, 125 00:09:33,306 --> 00:09:38,810 a high-resolution image of the entire surface of Mercury. 126 00:09:38,844 --> 00:09:42,514 But the mystery was that there were bright spots, 127 00:09:42,548 --> 00:09:46,117 there were small bright spots. 128 00:09:46,152 --> 00:09:52,123 And then one of the MESSENGER scientists took all of the bright spots 129 00:09:52,158 --> 00:09:56,094 and laid them down on the map of Mercury. 130 00:09:57,663 --> 00:10:04,269 Every single bright spot was inside of a crater that is permanently shadowed. 131 00:10:05,371 --> 00:10:08,840 We have found what we believe is ice. 132 00:10:08,874 --> 00:10:10,875 Water ice at Mercury. 133 00:10:10,910 --> 00:10:14,779 It's in one of the hottest regions in our Solar System. 134 00:10:14,814 --> 00:10:17,682 So how did the ice get in there? 135 00:10:20,219 --> 00:10:24,489 [narrator] No-one expected Mercury to contain water ice. 136 00:10:24,523 --> 00:10:29,327 And water indicates one exciting possibility to planetary scientists: 137 00:10:29,362 --> 00:10:32,197 the possibility of life. 138 00:10:33,132 --> 00:10:35,533 When you're talking about where life is 139 00:10:35,568 --> 00:10:39,537 and where the kind of chemistry and ultimately biology 140 00:10:39,572 --> 00:10:43,074 that might produce something like us could take place... 141 00:10:43,109 --> 00:10:46,344 At the moment, it's looking like it might be broader 142 00:10:46,379 --> 00:10:51,650 than just one little planet at the Goldilocks distance. 143 00:10:55,688 --> 00:10:57,322 [narrator] Extraterrestrial life 144 00:10:57,356 --> 00:11:00,692 is the holy grail of space exploration. 145 00:11:00,726 --> 00:11:03,428 What it could reveal about the universe, 146 00:11:03,462 --> 00:11:07,699 Earth and humanity itself is a powerful incentive, 147 00:11:07,733 --> 00:11:13,171 but knowledge isn't the only motivator for human activity in space. 148 00:11:13,205 --> 00:11:17,442 We can't deny that we rode to the Moon and to the other planets, 149 00:11:17,476 --> 00:11:19,711 you know, on the wings of war. 150 00:11:26,952 --> 00:11:29,054 [narrator] Our Solar System holds the answers 151 00:11:29,088 --> 00:11:31,623 to some of humanity's greatest questions, 152 00:11:31,657 --> 00:11:36,895 but historically it's been world politics rather than pure curiosity 153 00:11:36,929 --> 00:11:40,765 that drives innovation in space. 154 00:11:40,833 --> 00:11:44,636 The Cold War led to some particularly radical science. 155 00:12:16,302 --> 00:12:18,937 Space exploration has a dark side. 156 00:12:22,608 --> 00:12:27,078 We can't deny that we rode to the Moon and to the other planets, 157 00:12:27,113 --> 00:12:29,214 you know, on the wings of war. 158 00:12:31,550 --> 00:12:33,818 The reason we have these rockets 159 00:12:33,853 --> 00:12:37,188 that can launch payloads into orbit and beyond 160 00:12:37,223 --> 00:12:41,860 is because they were developed to destroy cities. 161 00:12:50,069 --> 00:12:54,639 [narrator] The Cold War made space exploration a matter of national pride for the U.S. 162 00:12:54,673 --> 00:12:59,210 and the Soviet Union, a dynamic that ultimately led to 163 00:12:59,245 --> 00:13:04,649 numerous groundbreaking missions, including Venera 9. 164 00:13:04,683 --> 00:13:09,888 This huge, complex Russian spacecraft was built to send back the first image 165 00:13:09,922 --> 00:13:11,890 from the surface of another planet. 166 00:13:13,225 --> 00:13:15,760 The race to Venus was on. 167 00:13:18,364 --> 00:13:21,366 [Anatoly speaking] 168 00:13:38,584 --> 00:13:41,352 [narrator] This component of the Venera 9 spacecraft 169 00:13:41,387 --> 00:13:45,757 had become the first manmade object to enter orbit around Venus. 170 00:13:48,093 --> 00:13:50,895 But the mission was far from over. 171 00:13:52,431 --> 00:13:54,399 The lander began the long process 172 00:13:54,433 --> 00:13:57,135 of touching down on the far side of the planet. 173 00:14:17,690 --> 00:14:20,625 [narrator] The heat shield and a sequence of three parachutes 174 00:14:20,659 --> 00:14:26,598 slowed the lander from 820 feet per second to 160 feet per second. 175 00:14:27,733 --> 00:14:31,135 During this descent, the lander's top was ejected 176 00:14:31,170 --> 00:14:34,138 and data collection began. 177 00:14:44,550 --> 00:14:46,618 [indistinct radio communications] 178 00:14:46,652 --> 00:14:51,055 [narrator] The first parachute sequence ended when the third detached. 179 00:14:51,090 --> 00:14:54,092 [Anatoly speaking] 180 00:14:59,431 --> 00:15:01,633 [narrator] The lander would then spend 20 minutes 181 00:15:01,667 --> 00:15:05,136 methodically taking measurements of the atmosphere. 182 00:15:05,170 --> 00:15:08,806 But its brutal voyage was not over yet. 183 00:15:10,376 --> 00:15:13,378 [Anatoly speaking] 184 00:15:21,020 --> 00:15:25,023 [David] The atmosphere gets hotter and hotter and more and more dense 185 00:15:25,057 --> 00:15:30,194 to the point where it's 100 times as dense as the atmosphere on Earth, 186 00:15:30,229 --> 00:15:33,631 and that means that you're falling through... It's not quite a liquid, 187 00:15:33,666 --> 00:15:36,701 but it's a gas that is approaching the properties of a liquid, 188 00:15:36,735 --> 00:15:38,870 and that would slow your fall. 189 00:15:40,472 --> 00:15:42,273 And then when you get to the surface, 190 00:15:42,308 --> 00:15:45,710 it's almost like going through the ocean. 191 00:15:45,744 --> 00:15:49,948 [narrator] Venera 9 wasn't the first lander to get to the surface of Venus... 192 00:15:53,385 --> 00:15:55,954 ...but it was the first to send back pictures. 193 00:15:59,058 --> 00:16:04,595 This was the first image ever taken by humans on the surface of another planet. 194 00:16:09,068 --> 00:16:12,370 And that was a real triumph of exploration. 195 00:16:17,776 --> 00:16:22,013 [narrator] This remarkable scientific accomplishment was just the beginning. 196 00:16:22,047 --> 00:16:25,783 Spacecraft have now sent back images of numerous other planets, 197 00:16:25,818 --> 00:16:28,386 asteroids and comets, 198 00:16:28,420 --> 00:16:31,422 but few have had the emotional impact 199 00:16:31,457 --> 00:16:33,658 as our journey to Mars. 200 00:16:37,763 --> 00:16:41,532 [James Green] These rovers were not inanimate objects to us. 201 00:16:41,567 --> 00:16:45,303 We were part of them and they were part of us. 202 00:16:46,538 --> 00:16:49,040 [narrator] In 2004, two rovers, 203 00:16:49,074 --> 00:16:50,942 Spirit and Opportunity, 204 00:16:50,976 --> 00:16:54,879 landed on the Red Planet in search of one thing: 205 00:16:54,913 --> 00:16:57,815 sedimentary rock. 206 00:17:01,020 --> 00:17:03,588 [James Green] When geologists go out in the field here on Earth, 207 00:17:03,622 --> 00:17:06,190 they want to look for layers of sediment 208 00:17:06,225 --> 00:17:08,726 that have accumulated over time. 209 00:17:10,763 --> 00:17:15,967 This is literally the historical pages of the Book of the Earth. 210 00:17:17,503 --> 00:17:20,538 At this level was where the dinosaurs were, 211 00:17:20,572 --> 00:17:26,277 and at this level they died, and at this level, new life became. 212 00:17:26,311 --> 00:17:29,247 You can just read that book of history. 213 00:17:31,383 --> 00:17:33,551 [narrator] Scientists chose Martian landing sites 214 00:17:33,585 --> 00:17:36,921 based on their likelihood of containing sedimentary rock. 215 00:17:39,758 --> 00:17:44,729 Spirit landed in an ancient drainage channel off of Gusev Crater, 216 00:17:44,763 --> 00:17:48,866 but all it found was a vast, scorched lava field. 217 00:17:50,569 --> 00:17:54,906 [Matt] We were crestfallen that none of our predictions 218 00:17:54,940 --> 00:17:59,243 about what materials would be there were... You know, that we were wrong. 219 00:17:59,278 --> 00:18:02,780 [wind blowing] 220 00:18:04,383 --> 00:18:07,685 [Matt] Opportunity was completely different. 221 00:18:11,557 --> 00:18:13,825 [Rod] Opportunity really hit the bull's eye 222 00:18:13,859 --> 00:18:16,260 because it landed in a place called Eagle Crater, 223 00:18:16,295 --> 00:18:19,764 in which Mother Nature has done you a big favor. 224 00:18:19,798 --> 00:18:23,234 At some point, she slammed a meteorite into the surface of the planet, 225 00:18:23,268 --> 00:18:27,672 excavating this big hole, and basically gave you 226 00:18:27,706 --> 00:18:30,508 this archeological dig, if you will. 227 00:18:30,542 --> 00:18:33,678 [Matt] These were sedimentary rocks that would have been formed by... 228 00:18:35,781 --> 00:18:39,784 ...liquid water, and it was a classic sedimentary sequence 229 00:18:39,818 --> 00:18:43,254 that we've seen on the Earth in many places. 230 00:18:45,491 --> 00:18:48,659 And this is where it really gets interesting. 231 00:18:51,130 --> 00:18:53,631 [James Garvin] We see these little bead-like things in the soil. 232 00:18:53,665 --> 00:18:55,399 We thought, "What could these be?" 233 00:18:55,434 --> 00:18:57,702 I mean, people started conjecturing, 234 00:18:57,736 --> 00:18:59,871 but when we put the infra-red eyes on them, 235 00:18:59,905 --> 00:19:02,740 we can see iron and oxygen in them. 236 00:19:02,774 --> 00:19:08,579 We're thinking, "Holy crap, Batman." We found hematite. 237 00:19:12,217 --> 00:19:18,022 [James Green] Hematite is a mineral here on Earth that's formed in water, 238 00:19:18,056 --> 00:19:22,927 and a lot of it, in moving water that allows this mineral to be formed, 239 00:19:22,961 --> 00:19:25,563 and they were all over the place! 240 00:19:27,499 --> 00:19:31,202 Holy gosh. We found the holy grail. 241 00:19:38,443 --> 00:19:41,546 [narrator] The rovers were expected to last 90 days, 242 00:19:41,580 --> 00:19:46,217 but Opportunity's hematite discovery was just the beginning. 243 00:19:48,587 --> 00:19:53,324 [James] They outdid their warranty by factors of hundreds. 244 00:19:55,561 --> 00:20:00,798 [Matt] We're several years into the mission that we had real trouble with Spirit. 245 00:20:03,835 --> 00:20:06,971 Spirit had lost one drive wheel. 246 00:20:08,507 --> 00:20:12,743 In doing so, we got stuck in a sandy crater, 247 00:20:12,778 --> 00:20:15,446 and that was the end of Spirit, yeah. 248 00:20:18,650 --> 00:20:22,987 But Opportunity just shines like a radiant star 249 00:20:23,021 --> 00:20:26,224 because this rover keeps going and going and going. 250 00:20:31,430 --> 00:20:34,732 [Rod] Then in 2012, a new rover drops into the party. 251 00:20:35,734 --> 00:20:37,768 Curiosity, equipped with a drill 252 00:20:37,803 --> 00:20:40,204 and carrying an entire laboratory on its back. 253 00:20:40,239 --> 00:20:42,440 This machine rolled into town 254 00:20:42,474 --> 00:20:45,309 and immediately changed our view of the Red Planet. 255 00:20:47,512 --> 00:20:53,150 [James Green] As we dug into the soils and we found, to our delight, 256 00:20:53,185 --> 00:20:58,389 it had carbon, hydrogen, oxygen, nitrogen, phosphorus and sulfur. 257 00:20:58,423 --> 00:21:02,360 That's everything between these two fingers. 258 00:21:04,329 --> 00:21:10,501 All the right stuff that life is made of is on Mars. 259 00:21:17,943 --> 00:21:21,312 [narrator] Opportunity roamed Mars for 15 years, 260 00:21:21,346 --> 00:21:25,950 exploring more distance than any other rover in history, 261 00:21:25,984 --> 00:21:29,453 but its journey came to an end in 2018 262 00:21:29,488 --> 00:21:31,889 when a severe dust storm struck. 263 00:21:31,923 --> 00:21:35,793 It's this unstoppable machine. It just keeps driving. 264 00:21:35,827 --> 00:21:39,030 And then in June of 2018... 265 00:21:41,333 --> 00:21:43,734 ...here's a dust storm in the distance... 266 00:21:47,606 --> 00:21:50,174 ...that turns out to be a whopper. 267 00:21:53,445 --> 00:21:55,813 [Matt] The Sun was almost blacked out. 268 00:21:58,050 --> 00:22:02,920 And at that point, there was no power getting to the panels 269 00:22:02,954 --> 00:22:07,591 and we tried for months and months and months until there was just nothing. 270 00:22:09,995 --> 00:22:12,063 And at that point, you've eventually... 271 00:22:12,097 --> 00:22:14,832 you know, you say that's the end, yeah. 272 00:22:23,108 --> 00:22:27,645 We had one final day where they called the team out to JPL, 273 00:22:27,679 --> 00:22:30,614 the Jet Propulsion Laboratory, where anybody that wanted to come 274 00:22:30,649 --> 00:22:33,084 and be there when they sent the final commands could come. 275 00:22:36,955 --> 00:22:40,291 We had all gathered in this area called the Dark Room 276 00:22:40,325 --> 00:22:43,928 overlooking mission operations and we're watching the flight commanders 277 00:22:43,962 --> 00:22:46,130 sending off the last commands to the rover. 278 00:22:46,164 --> 00:22:48,966 We did, basically, four final pings. 279 00:22:54,005 --> 00:22:56,073 The, like, time delay 280 00:22:56,108 --> 00:22:58,476 comes and goes, we got no signal, 281 00:22:58,510 --> 00:23:00,578 and everybody just kind of sits there in silence. 282 00:23:05,817 --> 00:23:09,153 And then the manager of the mission, John Callas... 283 00:23:09,187 --> 00:23:14,291 This concludes operations for MER-1, spacecraft ID 253. 284 00:23:14,326 --> 00:23:18,362 ...says, you know, "Thank you for your 15 years of service." 285 00:23:18,397 --> 00:23:20,097 Thank you. 286 00:23:20,132 --> 00:23:25,469 [Tanya] "But this is the end, so, you know, this is MER, signing off the net." 287 00:23:25,504 --> 00:23:28,005 MER project, off the net. 288 00:23:31,543 --> 00:23:34,278 In the Dark Room, it was just silence and everybody's kind of 289 00:23:34,312 --> 00:23:38,649 looking around, and we're like, "This is it. This is actually the end." 290 00:23:44,022 --> 00:23:46,257 [narrator] Opportunity's mission was over, 291 00:23:46,291 --> 00:23:49,226 but its dogged pursuit of knowledge lives on 292 00:23:49,261 --> 00:23:53,864 as scientists strive to learn more about our mysterious universe. 293 00:23:57,836 --> 00:24:02,273 And where better to look for answers than comets? 294 00:24:02,307 --> 00:24:05,342 Leftovers from the formation of the Solar System, 295 00:24:05,377 --> 00:24:08,512 comets contain the building blocks of our world. 296 00:24:11,750 --> 00:24:14,452 [Mark] To learn more, you want to go and rendezvous with a comet. 297 00:24:14,486 --> 00:24:16,353 You want to fly alongside it. 298 00:24:16,388 --> 00:24:20,090 And, of course, then the idea comes up you would want to touch down on the surface. 299 00:24:20,125 --> 00:24:22,560 You want to land there, sample material. 300 00:24:25,030 --> 00:24:31,335 To do all of that in one mission is incredibly gutsy. 301 00:24:31,369 --> 00:24:34,572 [countdown in foreign language] 302 00:24:34,606 --> 00:24:39,410 The first time I heard about the mission, I thought they must be joking. 303 00:24:39,444 --> 00:24:42,847 [countdown in foreign language] 304 00:24:45,917 --> 00:24:48,352 [Paolo] We launched in March 2004. 305 00:24:51,189 --> 00:24:55,926 The whole travel to the comet, it was an adventure for Rosetta. 306 00:25:00,765 --> 00:25:05,236 [Mark] So, we did this thing to use the planets and to use their gravity 307 00:25:05,270 --> 00:25:07,705 to slingshot us through space 308 00:25:07,739 --> 00:25:10,341 on a different trajectory with more speed 309 00:25:10,375 --> 00:25:12,543 in order to be able to get to the comet. 310 00:25:13,845 --> 00:25:17,648 After this, we came back to Earth. 311 00:25:17,682 --> 00:25:20,017 This one gave us the last big kick. 312 00:25:23,121 --> 00:25:28,659 We were really launched very fast, but getting very far from the Sun. 313 00:25:36,434 --> 00:25:40,571 We could not keep all the systems on board active 314 00:25:40,605 --> 00:25:44,942 because the illumination of our solar panels was getting very weak. 315 00:25:49,948 --> 00:25:53,117 So the decision was made, in fact, to turn it off. 316 00:25:55,587 --> 00:25:58,088 I hated that concept from the very beginning. 317 00:25:58,123 --> 00:25:59,723 I've been fighting it for years. 318 00:25:59,758 --> 00:26:04,461 I was convinced we would never do it. It was too crazy. 319 00:26:04,496 --> 00:26:10,301 [Paolo] Switching off the radio signal is like cutting a vital link. 320 00:26:10,335 --> 00:26:12,903 [Andrea] You've been flying a spacecraft for seven years. 321 00:26:12,938 --> 00:26:16,607 It's at hundreds of millions of kilometers away. And what do you do? 322 00:26:16,641 --> 00:26:18,943 You send a command to switch it off and wake it up three years later. 323 00:26:18,977 --> 00:26:22,980 This just doesn't make sense. And this is what we did. 324 00:26:23,014 --> 00:26:27,251 [Paolo] We spent two and a half years without contact. 325 00:26:27,285 --> 00:26:29,820 And we waited. 326 00:26:33,959 --> 00:26:36,994 [Mark] We couldn't talk to it while it was in hibernation. 327 00:26:37,028 --> 00:26:41,242 We needed it to wake up, which it was due to do 328 00:26:41,266 --> 00:26:44,501 on 20th January, 2014. 329 00:26:45,704 --> 00:26:48,205 [mission control] Three, two, one. 330 00:26:50,875 --> 00:26:53,444 [Paolo] We were sitting all in the control room, 331 00:26:53,478 --> 00:26:56,213 waiting for the signal to come, 332 00:26:56,247 --> 00:27:01,185 and this was probably the most tense moment of the mission. 333 00:27:03,355 --> 00:27:05,422 This was everything or nothing. 334 00:27:05,457 --> 00:27:07,558 It was life or death. 335 00:27:08,593 --> 00:27:10,394 "Why it's not coming?" 336 00:27:13,465 --> 00:27:16,567 [murmuring] 337 00:27:16,601 --> 00:27:19,436 [Mark] Everybody was getting very nervous. 338 00:27:20,605 --> 00:27:23,641 [Paolo] It was very difficult to bear. 339 00:27:25,777 --> 00:27:28,879 We started really getting worried. 340 00:27:29,881 --> 00:27:32,716 [Joel] Then suddenly the signal came. 341 00:27:32,751 --> 00:27:34,785 [cheers and applause] 342 00:27:34,819 --> 00:27:38,022 [Paolo] When the signal came, it was a big relief for me personally. 343 00:27:38,056 --> 00:27:40,424 There was an explosion of joy. 344 00:27:40,458 --> 00:27:46,063 [Joel] A little blip on a noise spectrum told us Rosetta was there 345 00:27:46,097 --> 00:27:47,965 and it was calling home. 346 00:27:47,999 --> 00:27:50,267 [applause] 347 00:27:53,805 --> 00:27:57,207 But now the mission starts because now we have to get to the comet, 348 00:27:57,242 --> 00:27:59,076 fly around the comet, orbit the comet 349 00:27:59,110 --> 00:28:03,147 and land on the comet, all within the next 10 months. 350 00:28:03,181 --> 00:28:07,184 [narrator] The Rosetta team had successfully woken a dormant spacecraft 351 00:28:07,218 --> 00:28:13,157 millions of miles away, but the real challenge was just beginning. 352 00:28:20,565 --> 00:28:23,701 [narrator] After two and a half years of radio silence, 353 00:28:23,735 --> 00:28:28,005 Rosetta had come back online right on schedule. 354 00:28:28,039 --> 00:28:32,209 A decade after launch, the spacecraft was about to touch a comet 355 00:28:32,243 --> 00:28:34,478 for the first time in history. 356 00:28:37,015 --> 00:28:39,650 [Mark] The comet we ended up deciding to go to 357 00:28:39,684 --> 00:28:42,453 was 67P/Churyumov-Gerasimenko. 358 00:28:47,692 --> 00:28:50,894 At the beginning, the comet was just a very small dot. 359 00:28:54,032 --> 00:28:55,866 And then day by day, the comet was growing 360 00:28:55,900 --> 00:28:58,135 in the field of view of the camera. 361 00:29:03,408 --> 00:29:08,412 [Joel] You have this spacecraft visiting an ambassador 362 00:29:08,446 --> 00:29:12,616 from the Solar System from 4.5 billion years ago. 363 00:29:12,650 --> 00:29:17,087 It's modern technology visiting an ancient relic. 364 00:29:19,791 --> 00:29:24,728 It's really profoundly emotional. 365 00:29:30,502 --> 00:29:33,237 [Paolo] We saw this incredible shape -- 366 00:29:33,271 --> 00:29:36,140 Some people have described it as a rubber duck. 367 00:29:40,178 --> 00:29:43,013 [Joel] It was amazing. It was beautiful. 368 00:29:43,047 --> 00:29:46,683 Scientists were just stunned with their mouths open. 369 00:29:54,159 --> 00:29:59,096 [Joel] Comet 67P is about 4 kilometers in size. 370 00:30:03,001 --> 00:30:06,069 If you were standing on the bottom of the comet, 371 00:30:06,104 --> 00:30:09,840 you might see a flat, dusty plain. 372 00:30:12,277 --> 00:30:17,314 If you were standing on the head of the comet, it might look more rocky. 373 00:30:17,348 --> 00:30:19,983 If you were standing on the neck of the comet, 374 00:30:20,018 --> 00:30:23,020 you would be in this interesting valley, 375 00:30:23,054 --> 00:30:26,957 kilometer-high cliffs on either side. 376 00:30:29,260 --> 00:30:34,131 There's so many different types of surfaces and variety. 377 00:30:34,165 --> 00:30:36,600 You could spend the rest of your life 378 00:30:36,634 --> 00:30:38,969 exploring every little part of the comet, 379 00:30:39,003 --> 00:30:41,371 not see the same type of thing twice. 380 00:30:49,781 --> 00:30:52,049 [narrator] The images the Rosetta mission returned 381 00:30:52,083 --> 00:30:55,152 are as visually stunning as they are informative, 382 00:30:55,186 --> 00:30:59,256 and scientists still analyze them today for anything they can reveal 383 00:30:59,290 --> 00:31:02,125 about comets and their place in our universe. 384 00:31:04,696 --> 00:31:07,364 But, of course, some of the most exciting data 385 00:31:07,398 --> 00:31:10,934 space science can provide isn't visual at all. 386 00:31:14,038 --> 00:31:18,542 In 1995, spacecraft Galileo arrived at Jupiter 387 00:31:18,576 --> 00:31:24,214 and began recording data that suggests conditions almost beyond imagination. 388 00:31:28,219 --> 00:31:31,855 The Galileo spacecraft carried along with it a probe, 389 00:31:31,890 --> 00:31:34,191 and it's sort of, like, this size 390 00:31:34,225 --> 00:31:36,860 and it had a big heat shield to protect it around it. 391 00:31:38,496 --> 00:31:40,330 [narrator] There were no cameras on board, 392 00:31:40,365 --> 00:31:44,601 only sensors designed to withstand an extremely violent introduction 393 00:31:44,636 --> 00:31:46,503 to Jupiter. 394 00:31:48,373 --> 00:31:52,476 And so, in July 1995, we launched that probe 395 00:31:52,510 --> 00:31:54,578 and sent it in the direction of Jupiter. 396 00:31:54,612 --> 00:31:58,582 Now, it didn't have engines, so we weren't guiding it and saying, "Go there." 397 00:31:58,616 --> 00:32:02,352 We just sort of sent it on a trajectory towards Jupiter. 398 00:32:11,763 --> 00:32:17,534 [Fran] It was coming in at something like 130,000 miles an hour, 399 00:32:17,568 --> 00:32:21,405 because it was pulled in by the gravity of Jupiter, and we had to slow it down. 400 00:32:23,241 --> 00:32:26,710 And so this heat shield heated up to about three times 401 00:32:26,744 --> 00:32:29,046 the temperature of the surface of the Sun. 402 00:32:38,890 --> 00:32:42,025 And then eventually we kicked off that heat shield, 403 00:32:42,060 --> 00:32:44,661 put out some parachutes. 404 00:32:46,864 --> 00:32:53,103 And so as it went down, we were able to get a sense of what it was like. 405 00:32:53,137 --> 00:32:58,208 What we were expecting was three separate layers of clouds. 406 00:33:02,313 --> 00:33:05,315 And we went down, it was like, "Where are the clouds? 407 00:33:05,350 --> 00:33:08,452 Where are the clouds? We're not seeing the clouds. What's going on?" 408 00:33:08,486 --> 00:33:13,123 [narrator] Ironically, after five months in space and years of mission planning, 409 00:33:13,157 --> 00:33:18,195 it would take a ground-based telescope to reveal Jupiter's secrets. 410 00:33:25,737 --> 00:33:29,406 [narrator] When Galileo reached Jupiter, the probe showed no evidence 411 00:33:29,440 --> 00:33:33,010 of the clouds scientists expected to find, 412 00:33:33,044 --> 00:33:35,746 and the team was baffled, 413 00:33:35,780 --> 00:33:39,983 but infra-red data taken from ground telescopes revealed the problem. 414 00:33:40,018 --> 00:33:45,022 The probe had landed in a particularly dry, hot location. 415 00:33:45,056 --> 00:33:49,793 So I think we realized that our whole idea of exploring these planets 416 00:33:49,827 --> 00:33:53,497 with single probes is a little bit susceptible to going into the wrong place. 417 00:33:55,233 --> 00:33:59,870 [Fran] By the time the probe had got down to about 160km, 418 00:33:59,904 --> 00:34:02,839 something like 23 times atmospheric pressure, 419 00:34:02,874 --> 00:34:05,742 it was now starting to get really hot. 420 00:34:05,777 --> 00:34:09,980 And so at that point, the electronics is just not working anymore 421 00:34:10,014 --> 00:34:12,182 and it stops communicating. 422 00:34:13,651 --> 00:34:16,420 But let's imagine what it would be like 423 00:34:16,454 --> 00:34:20,390 if you could be in a pressurized capsule as you get deeper down. 424 00:34:21,659 --> 00:34:24,161 It would get a little calmer, little less turbulent. 425 00:34:24,195 --> 00:34:27,197 The pressure would get higher and higher. 426 00:34:28,166 --> 00:34:31,468 [Scott] So hot, everything's vaporous. 427 00:34:31,502 --> 00:34:34,638 Eventually, get down to material that are almost like rock clouds, 428 00:34:34,672 --> 00:34:37,207 and they're probably precipitating. 429 00:34:37,241 --> 00:34:39,042 [Fran] Now, when you get down, 430 00:34:39,077 --> 00:34:41,289 something like 10% of the radius, 431 00:34:41,313 --> 00:34:44,681 you're now getting to the point where the pressures are about 432 00:34:44,715 --> 00:34:48,385 a million times Earth's atmospheric pressure 433 00:34:48,419 --> 00:34:51,688 and the density is getting really high. 434 00:34:51,722 --> 00:34:55,759 And at that point, hydrogen changes its phase. 435 00:34:55,793 --> 00:35:01,064 It's no longer molecules, protons and electrons connected together, 436 00:35:01,099 --> 00:35:04,334 but the protons and the electrons are moving separately 437 00:35:04,368 --> 00:35:06,670 and it becomes metallic. 438 00:35:06,704 --> 00:35:09,973 That is, it becomes electrically conducting. 439 00:35:10,007 --> 00:35:13,877 I suspect it would look like mercury, a glob of mercury, 440 00:35:13,911 --> 00:35:16,246 is what it would probably look like. 441 00:35:18,116 --> 00:35:22,619 If you existed, you would be, you know, unbelievably thin, flat-out pancake. 442 00:35:24,088 --> 00:35:27,057 [Fran] You get to the center of Jupiter, we're talking 443 00:35:27,091 --> 00:35:30,060 four times the temperature of the surface of the Sun, 444 00:35:30,094 --> 00:35:33,396 50 million atmospheres pressure, 445 00:35:33,431 --> 00:35:35,232 and a density that's denser 446 00:35:35,266 --> 00:35:39,236 than the heaviest metals that we have on Earth. 447 00:35:41,572 --> 00:35:43,874 [man] ...counting, this is Titan launch control. 448 00:35:43,908 --> 00:35:47,010 [Hunter] Without any doubt, the most risky element 449 00:35:47,044 --> 00:35:49,779 of any space mission is the launch. 450 00:35:49,814 --> 00:35:51,982 [mission control] T-minus 15 seconds. 451 00:35:52,016 --> 00:35:54,718 When you've put eight years of your life into designing 452 00:35:54,752 --> 00:35:57,687 and building and testing something which is going to go into space... 453 00:35:57,722 --> 00:35:59,689 [mission control] Nine, eight, seven... 454 00:35:59,724 --> 00:36:01,591 [Andrew] And then seeing it on the top of a rocket 455 00:36:01,626 --> 00:36:04,828 that's being vibrated and accelerated on its way to Saturn, 456 00:36:04,862 --> 00:36:07,063 it is quite a feeling. 457 00:36:11,769 --> 00:36:15,906 [Andrew] When it did go off, it created a huge amount of light. 458 00:36:16,941 --> 00:36:19,776 And then the rocket went behind a cloud. 459 00:36:21,913 --> 00:36:24,848 [Hunter] And then the nose cone came out and you're going, "Phew!" 460 00:36:35,326 --> 00:36:39,496 [narrator] Exploring a planet such as Saturn is a very risky business. 461 00:36:39,530 --> 00:36:41,798 The mission called Cassini-Huygens 462 00:36:41,832 --> 00:36:45,502 was one of the most technically demanding ever undertaken. 463 00:36:48,472 --> 00:36:51,441 When Cassini was approaching Saturn for the first time, 464 00:36:51,475 --> 00:36:54,477 our experiment was systematically scanning 465 00:36:54,512 --> 00:36:56,546 back and forth on the planet Saturn, 466 00:36:56,581 --> 00:36:59,749 and we were amazed to discover that the system 467 00:36:59,784 --> 00:37:03,253 was filled with molecules of oxygen. 468 00:37:05,056 --> 00:37:10,327 And we mapped this out and we noticed that the peak in the distribution 469 00:37:10,361 --> 00:37:16,499 was just a distance four times Saturn's radius from the center of the system. 470 00:37:16,534 --> 00:37:22,038 We knew that the moon Enceladus was orbiting just at that distance. 471 00:37:22,073 --> 00:37:24,307 [narrator] Enceladus is a tiny moon 472 00:37:24,342 --> 00:37:27,811 just over 300 miles in diameter. 473 00:37:27,845 --> 00:37:32,482 Enceladus originally was on the itinerary, but only marginally so. 474 00:37:32,516 --> 00:37:34,584 It was another very interesting Saturn moon. 475 00:37:34,619 --> 00:37:37,954 It's small, very shiny, very white, very bright, 476 00:37:37,989 --> 00:37:40,557 but other than that, too small to be interesting. 477 00:37:44,695 --> 00:37:48,465 [Elizabeth] It was in the first close fly-by that the magnetometer team 478 00:37:48,499 --> 00:37:52,068 detected something interesting that they didn't expect. 479 00:37:53,137 --> 00:37:55,805 [Earl] It looks like it has an atmosphere. 480 00:37:55,840 --> 00:37:59,409 Well, anybody that knows anything about moons says, "That's too tiny. 481 00:37:59,443 --> 00:38:02,812 It can't have an atmosphere. It's way too small to hold on to anything." 482 00:38:04,949 --> 00:38:08,218 [Elizabeth] If you flew by the south pole, it looked like there was an atmosphere, 483 00:38:08,252 --> 00:38:10,153 but if you flew by at the equator, 484 00:38:10,187 --> 00:38:13,023 you didn't see anything at all. 485 00:38:13,057 --> 00:38:16,126 [narrator] Yet Enceladus had another surprise in store 486 00:38:16,160 --> 00:38:21,731 and what Cassini found would open up a whole host of new possibilities. 487 00:38:28,606 --> 00:38:31,007 [narrator] When the Cassini spacecraft showed evidence 488 00:38:31,042 --> 00:38:34,210 of an atmosphere at Saturn's moon, Enceladus, 489 00:38:34,245 --> 00:38:37,514 the team was shocked, and what they found next 490 00:38:37,548 --> 00:38:42,018 permanently altered the existing conceptions of Jupiter's tiny moon. 491 00:38:43,321 --> 00:38:46,189 [Earl] We went back again and again and all of a sudden 492 00:38:46,223 --> 00:38:48,625 realized that not only it had an atmosphere, 493 00:38:48,659 --> 00:38:51,828 it was an icy atmosphere, but it had these plumes 494 00:38:51,862 --> 00:38:53,797 coming out of the southern pole. 495 00:38:58,903 --> 00:39:02,739 And here's water geysers, you know, on a... on a tiny moon. 496 00:39:07,011 --> 00:39:09,546 And that water that was coming out of the... 497 00:39:09,580 --> 00:39:12,215 what we've later found out to be an interior ocean, 498 00:39:12,249 --> 00:39:15,819 not only did it contain water vapor, but it had traces of 499 00:39:15,853 --> 00:39:20,390 ammonia, methane, H2, CO2, and then there was 500 00:39:20,424 --> 00:39:24,627 a whole host of organic compounds that we could also see. 501 00:39:24,662 --> 00:39:27,597 [Larry] And now we can put all that information together 502 00:39:27,631 --> 00:39:30,467 to get a picture of the shape of the eruption 503 00:39:30,501 --> 00:39:34,571 and also the material that's being erupted from inside of Enceladus. 504 00:39:34,605 --> 00:39:36,306 And amazingly enough, 505 00:39:36,340 --> 00:39:40,143 that material has the basic building blocks of life. 506 00:39:41,779 --> 00:39:44,892 This says to me that would be a good place to go 507 00:39:44,916 --> 00:39:47,350 and see if there's any form of life there. 508 00:39:53,858 --> 00:39:56,559 [narrator] It is increasingly evident that life might exist 509 00:39:56,594 --> 00:39:59,829 in even the unlikeliest of places, 510 00:39:59,864 --> 00:40:03,133 and where less likely to find life 511 00:40:03,167 --> 00:40:07,170 than the dwarf planet lingering at the edge of our solar system, 512 00:40:07,204 --> 00:40:13,009 an average of 3.7 billion miles from the Sun, Pluto? 513 00:40:13,043 --> 00:40:17,213 As we were flying up to Pluto and imaging it day after day 514 00:40:17,248 --> 00:40:21,618 and week after week on approach, we could see this bright feature 515 00:40:21,652 --> 00:40:23,720 on the surface. 516 00:40:26,957 --> 00:40:29,092 One morning, we got an image back, 517 00:40:29,126 --> 00:40:31,761 and as soon as it came up on the big screen, 518 00:40:31,796 --> 00:40:35,231 I remember a NASA official who said, 519 00:40:35,266 --> 00:40:37,734 "Do you see? That looks like a heart." 520 00:40:40,271 --> 00:40:42,739 And as we got closer and closer, amazingly, 521 00:40:42,773 --> 00:40:45,975 it looked more and more like a heart. 522 00:40:47,678 --> 00:40:51,247 I think that's what emblazoned Pluto into the public mind 523 00:40:51,282 --> 00:40:55,852 as this amazing place at the frontier of our Solar System. 524 00:40:55,886 --> 00:41:00,423 [narrator] Pluto's heart measures about 1,000 miles across 525 00:41:00,458 --> 00:41:03,226 and it's composed of nitrogen ice. 526 00:41:03,260 --> 00:41:06,663 We believe that structure might be supported 527 00:41:06,697 --> 00:41:09,332 by water underneath the surface. 528 00:41:12,069 --> 00:41:16,206 There could be an ocean underneath Pluto's surface. 529 00:41:17,541 --> 00:41:20,076 There probably is some kind of liquid water ocean. 530 00:41:20,110 --> 00:41:23,313 It's very deep down inside, but we think 531 00:41:23,347 --> 00:41:26,316 there's a pretty good chance that it's there. 532 00:41:26,350 --> 00:41:28,051 [Marc] It's one of those things where 533 00:41:28,085 --> 00:41:30,253 if you find water, is there a chance for life? 534 00:41:30,287 --> 00:41:33,957 Wouldn't that be cool, if Pluto is actually one of those places 535 00:41:33,991 --> 00:41:37,193 in the Solar System that has or had life? 536 00:41:37,228 --> 00:41:39,596 That's just mind-blowing, right there. 537 00:41:45,035 --> 00:41:49,339 [narrator] The exploration of our Solar System is far from over, 538 00:41:49,373 --> 00:41:52,041 but it has already taught us what a rich, 539 00:41:52,076 --> 00:41:54,577 varied and strange place it is. 540 00:41:57,515 --> 00:42:03,653 But scientists will agree the greatest discoveries are yet to come.