1 00:00:00,480 --> 00:00:05,519 This is a real photograph of a helicopter on the planet Mars. It was 2 00:00:05,519 --> 00:00:10,880 built by humans on Earth and became the first machine to fly using aerodynamic lift 3 00:00:11,119 --> 00:00:17,920 on an alien planet. NASA engineers have spent the past three decades working on 4 00:00:18,000 --> 00:00:23,960 interplanetary exploration technology, going from a very small Mars rover up to a very 5 00:00:24,079 --> 00:00:29,559 large Mars rover, and back down again to the miniature Martian helicopter. We 6 00:00:29,679 --> 00:00:33,960 are looking at the first steps on a journey that will unlock the secrets of 7 00:00:34,000 --> 00:00:39,799 the universe. This is how NASA reinvented their Mars rover. Before we can 8 00:00:39,840 --> 00:00:44,719 really talk about wings on Mars, we need to establish our foundation on wheels. 9 00:00:45,240 --> 00:00:49,479 Our upclose examination of Mars dates back to the mid nineteen seventies and the 10 00:00:49,560 --> 00:00:55,600 Viking Landers. These were essentially scientific instrument clusters that made an epic journey all 11 00:00:55,640 --> 00:00:59,759 the way down to the surface of the red planet and delivered first hand information 12 00:01:00,159 --> 00:01:04,280 about the composition of Martian soil. NASA launched both Viking one and Viking two 13 00:01:04,719 --> 00:01:10,000 in the summer of nineteen seventy six to take the most advantage of a close 14 00:01:10,040 --> 00:01:14,959 proximity window between Earth and Mars that only opens once every twenty six months. 15 00:01:15,400 --> 00:01:19,519 By placing two landers in different areas of the planet, NASA was getting the 16 00:01:19,599 --> 00:01:23,400 most diverse sample range possible, But these were still just two scoops of sand 17 00:01:23,480 --> 00:01:27,920 in a planet sized desert. The odds of finding an ancient fossilized Martian bacteria 18 00:01:29,000 --> 00:01:33,640 using this method were not in our favor, so Mars landings were put on 19 00:01:33,719 --> 00:01:38,319 hold for two decades as NASA worked on developing their solution for exploring the Great 20 00:01:38,400 --> 00:01:42,920 Unknown. In December nineteen ninety six, NASA was ready to send a new 21 00:01:42,959 --> 00:01:49,840 payload to Mars, the Pathfinder again. This was a scientific instrument station that 22 00:01:49,000 --> 00:01:53,760 unfurled itself on the Martian surface to reveal a collection of scopes, cameras, 23 00:01:53,799 --> 00:01:59,599 and meters. But Pathfinder also brought along with it a small prototype vehicle, 24 00:01:59,760 --> 00:02:04,319 this little guy, Sojourner. Anyone who is around in the late nineties remembers 25 00:02:04,359 --> 00:02:07,800 the original Mars rover. This thing was a pop culture icon. It was 26 00:02:07,919 --> 00:02:14,159 incredible. We were driving around a remote controlled car on another planet. The 27 00:02:14,199 --> 00:02:19,560 twenty first century had arrived. Sojourner was a technology demonstration. No one really 28 00:02:19,639 --> 00:02:22,879 knew what was going to happen when you started to drive around a tiny car 29 00:02:22,919 --> 00:02:25,800 millions of miles away on the surface of an alien planet, but there was 30 00:02:25,840 --> 00:02:30,520 only one way to find out. The first Mars rover was about the size 31 00:02:30,520 --> 00:02:34,159 and weight of a microwave oven. It had six wheels, each with their 32 00:02:34,159 --> 00:02:38,319 own independent electric motor, and an experimental new suspension system that was called the 33 00:02:38,479 --> 00:02:43,759 rocker Bogie. We know that the surface of Mars is not smooth and sandy 34 00:02:43,879 --> 00:02:46,319 like a desert. It's littered with small chunks of jagged rock, and the 35 00:02:46,400 --> 00:02:51,639 last thing NASA wanted was for their new rover to travel millions of miles through 36 00:02:51,639 --> 00:02:54,560 space just to get hung up on a rock before it could do any science. 37 00:02:55,120 --> 00:03:00,599 With this high tech suspension system, the rover could safely overcome oppsticles up 38 00:03:00,599 --> 00:03:05,840 to one third of its own size. In this iconic photo taken by the 39 00:03:05,840 --> 00:03:10,080 Pathfinder Landers camera, we can see the rover conducting an up close examination of 40 00:03:10,199 --> 00:03:16,080 a large boulder. Because this rover was in such an early phase of development, 41 00:03:16,240 --> 00:03:21,639 it didn't carry a whole lot of scientific equipment that was still mostly handled 42 00:03:21,680 --> 00:03:25,639 by the Lander platform. But Sojourner was equipped with a front facing instrument called 43 00:03:25,680 --> 00:03:30,479 an alpha proton X ray spectrometer, and that allowed it to determine the chemical 44 00:03:30,520 --> 00:03:36,039 composition of any rock that it could drive up to. The rover was even 45 00:03:36,080 --> 00:03:39,039 equipped with an early form of autonomous driving, not so different from what we 46 00:03:39,080 --> 00:03:45,000 see in modern vehicles. It used a combination of camera vision and lasers to 47 00:03:45,080 --> 00:03:50,319 identify obstacles and maneuver around the Martian landscape. Because the NASA team on Earth 48 00:03:50,360 --> 00:03:53,960 could only communicate with the rover once per day, they would essentially have to 49 00:03:53,960 --> 00:03:58,000 set a waypoint location that the rover would drive towards and then tune in the 50 00:03:58,039 --> 00:04:00,240 next day to see where it ended up. So it was a pretty slow 51 00:04:00,280 --> 00:04:04,680 process of exploration, with the rover covering about one hundred meters of driving in 52 00:04:04,719 --> 00:04:10,400 its three months of operation. That doesn't sound like much, but it was 53 00:04:10,520 --> 00:04:14,960 significantly more performance than NASA scientists had hoped for, and it gave the Space 54 00:04:15,000 --> 00:04:19,319 Agency enough confidence to double down on the Mars rover in a very big way. 55 00:04:20,240 --> 00:04:25,920 If one little Mars rover was able to captivate the world and write new 56 00:04:26,000 --> 00:04:30,319 chapters in planetary science, then just imagine what two big Mars rovers might accomplish. 57 00:04:30,439 --> 00:04:35,600 This was NASA's plan with the Mars Exploration rovers, Spirit and Opportunity Both 58 00:04:35,639 --> 00:04:40,560 machines were launched on separate Delta two rockets in the summer of two thousand and 59 00:04:40,560 --> 00:04:45,279 three, taking full advantage of that fleeting Mars transfer window. This time, 60 00:04:45,360 --> 00:04:48,759 instead of a lander that deployed a separate rover, the lander was the rover. 61 00:04:49,240 --> 00:04:55,279 After shedding its protective landing shell, each Exploration rover unfurled solar panels, 62 00:04:55,480 --> 00:05:00,519 scientific instruments, and wheels, then set off into the Martian desert. It's 63 00:05:00,759 --> 00:05:04,079 very difficult to get a sense for how big these machines actually are because we 64 00:05:04,199 --> 00:05:09,959 have no known reference points on Mars, so where the Sojourner Rover was about 65 00:05:09,959 --> 00:05:14,240 the size of a microwave, Spirit and Opportunity were closer to the size of 66 00:05:14,439 --> 00:05:19,160 golf carts. NASA had essentially just scaled up the six wheel drive Rocker Bogie 67 00:05:19,160 --> 00:05:26,839 system to create these next generation rovers. The extra size and capability allowed the 68 00:05:26,879 --> 00:05:30,879 full collection of scientific instruments from the lander to now be fully mobile for the 69 00:05:30,959 --> 00:05:34,560 first time. In the top of a one point five meters tall mast. 70 00:05:34,920 --> 00:05:41,199 Each rover had nine digital cameras. They were used for both navigation and to 71 00:05:41,279 --> 00:05:46,560 create three dimensional panoramic images of the Martian landscape. The exploration rover also had 72 00:05:46,600 --> 00:05:51,439 its main spectrometer placed on the end of a robotic arm that extended out from 73 00:05:51,480 --> 00:05:57,079 the front for closer examination of rocks and soil. With all of these upgrades 74 00:05:57,120 --> 00:06:00,720 over their predecessor, the twin Rovers were able to accomplish orders of magnitude more 75 00:06:00,759 --> 00:06:06,160 exploration and data collection than any previous Mars mission. The Spirit Rover had a 76 00:06:06,160 --> 00:06:12,519 lifespan of six years and drove four point eight miles, while the Opportunity exceeded 77 00:06:12,600 --> 00:06:17,399 all expectations to last over fourteen years and cover twenty eight miles of the alien 78 00:06:17,480 --> 00:06:23,519 landscape. This is the next generation of Mars rover. You're looking at a 79 00:06:23,600 --> 00:06:28,519 self portrait taken by a robot on the surface of the planet Mars. In 80 00:06:28,560 --> 00:06:31,600 the year twenty twelve, this rover, named Curiosity, became the first of 81 00:06:31,639 --> 00:06:35,600 a new breed of vehicle to roam the Martian surface. Again, we have 82 00:06:35,639 --> 00:06:40,560 to establish a sense of scale here, because this machine is a lot bigger 83 00:06:40,600 --> 00:06:45,560 than most people realize. So here's our microwave sized Sojourner, and here is 84 00:06:45,600 --> 00:06:49,360 our golf cart sized Opportunity. And now we bring in Curiosity. This is 85 00:06:49,399 --> 00:06:55,839 around the size of a crossover suv. It's really big. You'll notice we 86 00:06:55,959 --> 00:07:00,560 have the same six wheel drive powertrain and a much bigger and beefier version of 87 00:07:00,600 --> 00:07:03,680 the same rocker bogie suspension system. At this scale you can really see how 88 00:07:03,720 --> 00:07:06,959 the wheels are linked to the main body of the rover. It's now a 89 00:07:08,079 --> 00:07:13,839 tried and tested method for traversing the jagged, rocky surface. You'll also notice 90 00:07:13,839 --> 00:07:17,920 that, unlike its predecessors, Curiosity does not have solar panels. Instead, 91 00:07:18,040 --> 00:07:24,120 the rover is powered by a radio isotope thermo electric generator. Heat generated by 92 00:07:24,160 --> 00:07:29,519 the radioactive decay of a plutonium isotope is converted into electricity by thermo couples, 93 00:07:29,800 --> 00:07:33,759 and any excess heat not turned into electricity is used to keep the systems warm 94 00:07:33,839 --> 00:07:39,639 during the Martian night. With eleven pounds of plutonium two three eight on board, 95 00:07:39,759 --> 00:07:44,720 Curiosity's generator has a minimum lifespan of fourteen years, and the rover is 96 00:07:44,800 --> 00:07:48,319 still going strong to this day. In twenty twenty one, Curiosity was joined 97 00:07:48,319 --> 00:07:53,199 on Mars by its own twin rover, Perseverance, part of the Mars twenty 98 00:07:53,240 --> 00:07:58,199 twenty mission. Perseverance is mostly the same car sized platform as its older sibling, 99 00:07:58,560 --> 00:08:03,519 just with an upgraded collect of scientific instruments and recording tools. It carries 100 00:08:03,720 --> 00:08:09,519 seven primary payload instruments, nineteen cameras and two microphones. It was the first 101 00:08:09,519 --> 00:08:13,720 time that audio recording equipment had been sent to Mars, and that's how we 102 00:08:13,839 --> 00:08:16,839 know that the wind on the Red planet sounds like this. We can also 103 00:08:16,959 --> 00:08:22,360 hear the sound of the rover itself as the hollow metal wheels clang over the 104 00:08:22,360 --> 00:08:26,839 Martian rocks, the gentle whirring of the electric motors, and the squeaking of 105 00:08:26,879 --> 00:08:31,120 the suspension system. And thanks to a very special payload delivered by Perseverance, 106 00:08:31,199 --> 00:08:35,440 we have this. You are hearing the sound of a helicopter flying on Mars 107 00:08:35,840 --> 00:08:41,639 for the first time, and this is the view from eighty feet above the 108 00:08:41,720 --> 00:08:46,279 Martian surface, just like the Pathfinder back in nineteen ninety six, Mars twenty 109 00:08:46,320 --> 00:08:52,519 twenty brought along one small piece of experimental technology, a helicopter drone named Ingenuity, 110 00:08:52,639 --> 00:08:56,559 hitched a ride in the belly of the rover and was deployed on April 111 00:08:56,639 --> 00:09:01,279 third, twenty twenty one. We've seen NASA make some pretty amazing progress with 112 00:09:01,320 --> 00:09:05,440 their rover vehicles over the twenty five year period that we just covered, but 113 00:09:05,480 --> 00:09:11,120 there is still only so much that can be accomplished on wheels. This is 114 00:09:11,320 --> 00:09:16,519 rugged and uneven terrain. Inevitably you will reach a hill that is too steep 115 00:09:16,559 --> 00:09:20,120 to climb. If we want to take interplanetary exploration to the next level, 116 00:09:20,559 --> 00:09:24,240 we have to learn how to fly. In many ways. Ingenuity was NASA's 117 00:09:24,279 --> 00:09:30,159 biggest risk yet when it comes to tech demonstrations on Mars, because we knew 118 00:09:30,200 --> 00:09:33,639 without any doubt that wheels would work on Mars just as well as they do 119 00:09:33,759 --> 00:09:39,399 on the Earth. But propellers are a whole other story. This is a 120 00:09:39,600 --> 00:09:45,799 DJI Phantom drone. You've probably seen one before, maybe even own one yourself. 121 00:09:45,840 --> 00:09:50,559 It's not so different from NASA's Mars drone. The frame is a comparable 122 00:09:50,600 --> 00:09:54,440 size to Ingenuity. The Dji is a bit smaller overall and about one pound 123 00:09:54,559 --> 00:10:00,120 lighter. Using four tiny propellers, the Phantom can rise thousands of feet in 124 00:10:00,120 --> 00:10:03,879 to the air, while Ingenuity uses two relatively giant propellers with a four foot 125 00:10:03,919 --> 00:10:09,440 wingspan, and with this it achieves a maximum height of around eighty feet. 126 00:10:09,320 --> 00:10:16,080 Ingenuity needs much larger flight hardware to accomplish much less performance because it is flying 127 00:10:16,200 --> 00:10:22,039 in an environment with less than one percent the atmospheric density of the Earth at 128 00:10:22,039 --> 00:10:26,080 sea level. To find an equivalent air density on Earth, you would need 129 00:10:26,120 --> 00:10:31,000 to go to an altitude of eighty seven thousand feet. The highest anyone has 130 00:10:31,080 --> 00:10:35,960 ever flown a helicopter is just over forty thousand feet. In order to test 131 00:10:35,000 --> 00:10:39,679 the helicopter's flight system on Earth, NASA had to use a vacuum chamber that 132 00:10:39,759 --> 00:10:45,679 simulated the low density atmosphere of Mars. They also had to use a cable 133 00:10:45,720 --> 00:10:50,559 system that would pull up on the helicopter at just the right tension to simulate 134 00:10:50,600 --> 00:10:54,360 the reduced gravity effect as well. They even had fans blowing air across the 135 00:10:54,440 --> 00:11:00,720 chamber to try and simulate wind on Mars. Due to do all of these 136 00:11:00,759 --> 00:11:05,000 factors, the propeller system on Ingenuity is very unique. Each blade is shaped 137 00:11:05,039 --> 00:11:11,000 for maximum lift. They are constructed from am ultra lightweight foam with a carbon 138 00:11:11,039 --> 00:11:15,759 fiber reinforced shell. To achieve lift on Mars, the blades need to spin 139 00:11:15,879 --> 00:11:20,240 at doubled rpm that would be required on Earth. The two propellers are counter 140 00:11:20,360 --> 00:11:24,840 rotating to keep the drone stable in flight. A traditional helicopter uses a tail 141 00:11:24,919 --> 00:11:28,320 rotor to do the same job. And a quad copter. Drone uses two 142 00:11:28,320 --> 00:11:33,480 sets of counter rotating propellers on opposing corners. Because of the small size and 143 00:11:33,639 --> 00:11:39,879 high energy requirements, Ingenuity is limited to a maximum of ninety seconds flying time 144 00:11:39,919 --> 00:11:43,879 before it has to stop and recharge. The internal systems of Ingenuity have a 145 00:11:43,960 --> 00:11:48,120 lot in common with a modern smartphone. It uses two sony cameras, half 146 00:11:48,159 --> 00:11:52,600 a dozen sony lithium ion battery cells, a cell phone grade inertial measurement unit, 147 00:11:52,840 --> 00:11:58,320 and a Garmin ultimeter. The batteries are charged by a solar panel mounted 148 00:11:58,320 --> 00:12:01,759 to the top of the drone. With d all of the technology built into 149 00:12:01,960 --> 00:12:05,279 Ingenuity, there was still doubt that a helicopter would be able to perform on 150 00:12:05,360 --> 00:12:09,559 Mars. Even within NASA, there was opposition to the project, and some 151 00:12:09,759 --> 00:12:15,120 top officials thought it was a waste of resources to ship the drone along with 152 00:12:15,240 --> 00:12:20,360 Perseverance. But just like the Sojourner rover before it, the first Mars helicopter 153 00:12:20,720 --> 00:12:26,480 has far exceeded expectations for its performance and longevity. The initial technical demonstration had 154 00:12:26,559 --> 00:12:31,480 only planned for five flights on Mars. Two and a half years later, 155 00:12:31,919 --> 00:12:39,440 Ingenuity has completed sixty seven flights with a total of over two hours flying time. 156 00:12:39,159 --> 00:12:43,440 The helicopter is currently being used as a scouting vehicle to help plan out 157 00:12:43,480 --> 00:12:48,759 the journey of the Perseverance Rover as it navigates the steep river deltas of the 158 00:12:48,840 --> 00:12:54,080 Jezero Crater. The initial success has already begun to fuel new concept ideas at 159 00:12:54,159 --> 00:12:58,840 NASA. The Mars Science Helicopter is a six propeller drone with a mass of 160 00:12:58,879 --> 00:13:03,679 around thirty kilogram. The much larger hexaicopter would be able to fly up to 161 00:13:03,799 --> 00:13:07,840 ten kilometers in one mission and carry up to five kilograms of scientific payloads along 162 00:13:07,919 --> 00:13:13,559 for the flight. If we remember, the Spirit Rover covered just under eight 163 00:13:13,720 --> 00:13:18,480 kilometers in its entire six year lifespan, so to fly further in one day 164 00:13:18,480 --> 00:13:24,759 with the Mars Science Helicopter would be a gigantic leap forward in our exploration of 165 00:13:24,840 --> 00:13:28,600 the Red planet. We know that NASA is also envisioning a pair of Ingenuity 166 00:13:28,679 --> 00:13:35,399 like helicopters for their Mars sample return mission in twenty thirty. As the Perseverance 167 00:13:35,480 --> 00:13:39,960 Rover explores the Jesero Crater, it has been collecting samples from underneath the surface 168 00:13:39,000 --> 00:13:45,960 regolith and leaving them behind in sealed tubes. The idea is that eventually NASA 169 00:13:46,000 --> 00:13:48,840 will follow up to collect the sample tubes and return them to the Earth for 170 00:13:50,000 --> 00:13:54,919 study. The original idea was to use a fetch rover that would essentially retrace 171 00:13:54,960 --> 00:13:58,440 the Perseverance journey and collect the tubes, but with the unexpected success of their 172 00:13:58,480 --> 00:14:05,120 demonstration helicopter, NASA is thinking that flying machines will be much faster and more 173 00:14:05,120 --> 00:14:11,039 efficient for retrieving the samples. And this doesn't end on Mars either. Dragonfly 174 00:14:11,240 --> 00:14:16,240 is a quad copter drone that will fly on Saturn's moon Titan. This is 175 00:14:16,279 --> 00:14:20,480 a surreal world where the frozen surface is covered by flowing rivers and seas of 176 00:14:20,559 --> 00:14:26,440 liquid methane, so alien that it is almost incomprehensible, but the thick nitrogen 177 00:14:26,440 --> 00:14:33,159 atmosphere on Titan makes an ideal location to fly a drone. In many ways, 178 00:14:33,200 --> 00:14:37,600 we're lucky that Mars offers such a challenging environment to practice flying so relatively 179 00:14:37,600 --> 00:14:41,519 close to home, because if we can master the art of flight on Mars, 180 00:14:41,919 --> 00:14:45,000 then the possibilities will be nearly endless.