1 00:00:00,000 --> 00:00:05,000 So what's up? What else do the treehouse detectives need to know about space? 2 00:00:05,000 --> 00:00:09,000 How will humans overcome the harshness of space for travel to Mars? 3 00:00:09,000 --> 00:00:12,000 How will robots help lead the way to Mars? 4 00:00:12,000 --> 00:00:15,000 All this and more when the NASA Sci-Files continues. 5 00:00:15,000 --> 00:00:19,000 Don't forget to look for the answers to the following questions. 6 00:00:19,000 --> 00:00:22,000 What are galactic cosmic rays? 7 00:00:22,000 --> 00:00:26,000 Explain how spacecraft will be self-healing in the future. 8 00:00:27,000 --> 00:00:30,000 Why does NASA need new propulsion systems? 9 00:00:34,000 --> 00:00:36,000 Houston, how do you read us? 10 00:00:36,000 --> 00:00:40,000 Roger, Houston. We're at Mach 10.5 and everything looks okay. 11 00:00:42,000 --> 00:00:45,000 Guys, I'm reviewing protocols for an upcoming mission. 12 00:00:45,000 --> 00:00:52,000 It's so cool because you work directly with Mission Control to troubleshoot and solve problems throughout the entire mission simulation. 13 00:00:52,000 --> 00:00:59,000 Right now, I'm reviewing re-entry and landing procedures after successfully launching a new satellite to track RJ's exercise program. 14 00:00:59,000 --> 00:01:06,000 The counselors monitor your progress closely, and they even introduce problems into the mission simulation for the teams to solve. 15 00:01:06,000 --> 00:01:11,000 You really have to be prepared. Keep up the good work, RJ. Over and out. 16 00:01:12,000 --> 00:01:16,000 It kind of goes against the whole idea of working out, doesn't it? 17 00:01:16,000 --> 00:01:18,000 No, that's the beauty. 18 00:01:18,000 --> 00:01:22,000 No fat, frozen yogurt with sugarless sauce and toppings, and it even has fresh fruit. 19 00:01:22,000 --> 00:01:24,000 It's totally healthy. 20 00:01:24,000 --> 00:01:26,000 I'll just stick with the water. 21 00:01:26,000 --> 00:01:29,000 I have to admit, Bianca's right. 22 00:01:29,000 --> 00:01:32,000 Ever since we started exercising, I feel great. 23 00:01:32,000 --> 00:01:35,000 We're not quite ready to go into space, but we're getting there. 24 00:01:35,000 --> 00:01:39,000 Dr. V's comments on the potential danger of space travel do have me a little concerned. 25 00:01:39,000 --> 00:01:43,000 Me too. I've been going over all our research, and the radiation problem seems critical. 26 00:01:43,000 --> 00:01:45,000 So what do we do next? 27 00:01:45,000 --> 00:01:47,000 Time for the problem board. 28 00:01:47,000 --> 00:01:49,000 We know that space is an extreme environment. 29 00:01:49,000 --> 00:01:52,000 And NASA trains astronauts to live safely in that environment. 30 00:01:52,000 --> 00:01:55,000 And astronauts will also need to learn to live on the Moon and Mars. 31 00:01:55,000 --> 00:01:57,000 So what do we need to know? 32 00:01:57,000 --> 00:02:00,000 We need to know more about how astronauts will deal with radiation in space. 33 00:02:00,000 --> 00:02:05,000 Katherine mentioned in her report that she might be able to meet with Mr. Mark Whalen at the NASA Johnson Space Center to learn more about radiation. 34 00:02:05,000 --> 00:02:07,000 Good idea. 35 00:02:07,000 --> 00:02:10,000 We might even be able to learn how to send a triage detective to Mars. 36 00:02:10,000 --> 00:02:12,000 Excellent idea. 37 00:02:12,000 --> 00:02:14,000 Wait, what? Send someone to Mars? 38 00:02:14,000 --> 00:02:16,000 Are you crazy? 39 00:02:16,000 --> 00:02:18,000 I'm fine. 40 00:02:18,000 --> 00:02:21,000 Corinne is going to stop by the Mars Society's remote habitat in Utah. 41 00:02:21,000 --> 00:02:24,000 It actually simulates what working and living will be like on Mars. 42 00:02:24,000 --> 00:02:26,000 That is really cool. 43 00:02:26,000 --> 00:02:28,000 Where are you going? 44 00:02:28,000 --> 00:02:30,000 To see Dr. D? 45 00:02:30,000 --> 00:02:32,000 No, Dr. D isn't home. 46 00:02:32,000 --> 00:02:34,000 I'm going to get another banana split. 47 00:02:34,000 --> 00:02:36,000 You're kidding. 48 00:02:36,000 --> 00:02:38,000 No. 49 00:02:38,000 --> 00:02:40,000 When you eat the light version, sometimes you have to eat twice as much to fill up. 50 00:02:40,000 --> 00:02:42,000 You'll never learn. 51 00:02:48,000 --> 00:02:50,000 Hi, Mr. Whalen. 52 00:02:50,000 --> 00:02:52,000 Hi, Katherine. 53 00:02:52,000 --> 00:02:54,000 I'm glad you could stop by. 54 00:02:54,000 --> 00:02:56,000 I understand you want to learn more about radiation in space. 55 00:02:56,000 --> 00:02:58,000 Yes. 56 00:02:58,000 --> 00:03:00,000 We've read that radiation is very dangerous. 57 00:03:00,000 --> 00:03:02,000 But we're not exactly sure what it is. 58 00:03:02,000 --> 00:03:04,000 Well, radiation is one of the top biological concerns for our astronauts. 59 00:03:04,000 --> 00:03:06,000 There's two basic types of radiation, light and particles. 60 00:03:06,000 --> 00:03:08,000 How is light dangerous? 61 00:03:08,000 --> 00:03:10,000 Light comes in many different forms. 62 00:03:10,000 --> 00:03:12,000 The low-energy visible light that you're familiar with isn't dangerous. 63 00:03:12,000 --> 00:03:14,000 But light comes in a high-energy form called ultraviolet. 64 00:03:14,000 --> 00:03:16,000 Isn't that what causes sunburn? 65 00:03:16,000 --> 00:03:18,000 Well, that's right. 66 00:03:18,000 --> 00:03:20,000 X-rays and gamma rays are ultraviolet. 67 00:03:20,000 --> 00:03:22,000 X-rays and gamma rays are another form of light with more energy than ultraviolet. 68 00:03:22,000 --> 00:03:24,000 And they can cause serious damage to your body's cells. 69 00:03:24,000 --> 00:03:26,000 What about the particles? 70 00:03:26,000 --> 00:03:28,000 Very fast-moving particles are considered to be radiation. 71 00:03:28,000 --> 00:03:30,000 One example is high-energy protons, which are released by flares on the sun. 72 00:03:30,000 --> 00:03:32,000 Another, even more dangerous type of radiation are galactic cosmic rays, or GCRs. 73 00:03:32,000 --> 00:03:34,000 What's a galactic cosmic ray? 74 00:03:34,000 --> 00:03:36,000 GCRs are extremely fast-moving protons 75 00:03:36,000 --> 00:03:38,000 and nuclei of elements such as iron, silicon, and other elements 76 00:03:38,000 --> 00:03:40,000 that come from outside our solar system. 77 00:03:40,000 --> 00:03:42,000 Why are they so dangerous? 78 00:03:42,000 --> 00:03:44,000 Well, GCRs are extremely fast-moving protons 79 00:03:44,000 --> 00:03:46,000 and nuclei of elements such as iron, silicon, and other elements 80 00:03:46,000 --> 00:03:48,000 that come from outside our solar system. 81 00:03:48,000 --> 00:03:50,000 Why are they so dangerous? 82 00:03:50,000 --> 00:03:52,000 They can penetrate more than 100 centimeters into materials 83 00:03:52,000 --> 00:03:54,000 and can cause a lot of cell damage. 84 00:03:54,000 --> 00:03:56,000 They are also very difficult to shield against 85 00:03:56,000 --> 00:03:58,000 and they can even create additional radiation 86 00:03:58,000 --> 00:04:00,000 when they collide with metal spacecraft. 87 00:04:00,000 --> 00:04:02,000 Wow! 88 00:04:02,000 --> 00:04:04,000 I've heard that radiation can increase your chances of getting cancer. 89 00:04:04,000 --> 00:04:06,000 Is that true? 90 00:04:06,000 --> 00:04:08,000 That's correct. 91 00:04:08,000 --> 00:04:10,000 The greater the radiation exposure, the greater the risk of getting cancer 92 00:04:10,000 --> 00:04:12,000 and other effects such as cataracts, which is a clouding of the eye lens. 93 00:04:12,000 --> 00:04:14,000 What determines how much exposure you get? 94 00:04:14,000 --> 00:04:16,000 The length of the mission is one of the most important factors. 95 00:04:16,000 --> 00:04:18,000 A mission to Mars could take several years. 96 00:04:18,000 --> 00:04:20,000 Longer missions mean greater health risk from radiation exposure, 97 00:04:20,000 --> 00:04:22,000 especially compared to space shuttle missions, 98 00:04:22,000 --> 00:04:24,000 which are much shorter. 99 00:04:24,000 --> 00:04:26,000 However, NASA is working hard to reduce the risk. 100 00:04:26,000 --> 00:04:28,000 What are they doing? 101 00:04:28,000 --> 00:04:30,000 They're developing better shielding materials 102 00:04:30,000 --> 00:04:32,000 that will prevent the radiation from reaching the astronauts in the spacecraft. 103 00:04:32,000 --> 00:04:34,000 And high exposures can also come from very intense events, 104 00:04:34,000 --> 00:04:36,000 like solar flares. 105 00:04:36,000 --> 00:04:38,000 Isn't that when the sun has a solar storm? 106 00:04:38,000 --> 00:04:40,000 Very good. 107 00:04:40,000 --> 00:04:42,000 If you can monitor the sun for solar storms that produce these flares, 108 00:04:42,000 --> 00:04:44,000 then you can warn the astronauts to avoid spacewalks. 109 00:04:44,000 --> 00:04:46,000 And to enter specially shielded storm shelters in their spacecraft. 110 00:04:46,000 --> 00:04:48,000 Is there anything that can help the body handle the effects of radiation exposure? 111 00:04:48,000 --> 00:04:50,000 Well, NASA is looking at how a healthy lifestyle, 112 00:04:50,000 --> 00:04:52,000 including dietary vitamin supplements, might provide protection. 113 00:04:52,000 --> 00:04:54,000 They are also looking at the role that age, gender, 114 00:04:54,000 --> 00:04:56,000 and or genetic factors play in how the body responds to radiation. 115 00:04:56,000 --> 00:04:58,000 Wow. 116 00:04:58,000 --> 00:05:00,000 If radiation is such a problem for astronauts, 117 00:05:00,000 --> 00:05:02,000 why don't we have to worry about it on Earth? 118 00:05:02,000 --> 00:05:04,000 We do have some radiation on Earth, 119 00:05:04,000 --> 00:05:06,000 but we're protected from most of it by something the astronauts don't have, 120 00:05:06,000 --> 00:05:08,000 an atmosphere. 121 00:05:08,000 --> 00:05:10,000 Yes. 122 00:05:10,000 --> 00:05:12,000 I learned a month ago that the atmosphere on Mars 123 00:05:12,000 --> 00:05:14,000 blocks a lot of the ultraviolet light from getting to Earth. 124 00:05:14,000 --> 00:05:16,000 Well, that's correct, 125 00:05:16,000 --> 00:05:18,000 and it also absorbs a lot of X-rays, gamma rays, 126 00:05:18,000 --> 00:05:20,000 and high-energy particles. 127 00:05:20,000 --> 00:05:22,000 Charged particles, like cosmic rays and protons from the sun, 128 00:05:22,000 --> 00:05:24,000 are deflected by Earth's magnetic field, 129 00:05:24,000 --> 00:05:26,000 and Earth itself acts like a big shield. 130 00:05:26,000 --> 00:05:28,000 I'm glad that we have some protection. 131 00:05:28,000 --> 00:05:30,000 Radiation sounds pretty serious. 132 00:05:30,000 --> 00:05:32,000 Yes, it is. 133 00:05:32,000 --> 00:05:34,000 So don't forget you should always wear sunscreen 134 00:05:34,000 --> 00:05:36,000 when you're working or playing outside. 135 00:05:36,000 --> 00:05:38,000 Don't worry, I will. 136 00:05:38,000 --> 00:05:40,000 Thanks, Mr. Weiland. 137 00:05:40,000 --> 00:05:42,000 You've been a big help. 138 00:05:42,000 --> 00:05:44,000 You're welcome, Katherine, and good luck. 139 00:05:46,000 --> 00:05:48,000 Hi, guys. 140 00:05:48,000 --> 00:05:50,000 It looks like you've been working hard 141 00:05:50,000 --> 00:05:52,000 on the unmanned missions. 142 00:05:52,000 --> 00:05:54,000 Along with research, we've been working with LEGO 143 00:05:54,000 --> 00:05:56,000 to build possible Mars explorers. 144 00:05:56,000 --> 00:05:58,000 Cool. 145 00:05:58,000 --> 00:06:00,000 Of course, we read all of your reports on the Internet. 146 00:06:00,000 --> 00:06:02,000 Having access to the Internet is a wonderful thing. 147 00:06:02,000 --> 00:06:04,000 Speaking of the Internet, 148 00:06:04,000 --> 00:06:06,000 you can always find great tools for research 149 00:06:06,000 --> 00:06:08,000 on the NASA SciFiles website. 150 00:06:08,000 --> 00:06:10,000 Ready to go to the next level? 151 00:06:10,000 --> 00:06:12,000 What do you mean? 152 00:06:12,000 --> 00:06:14,000 Well, we've been working on different aspects of space travel, 153 00:06:14,000 --> 00:06:16,000 but there's one area that we haven't explored. 154 00:06:16,000 --> 00:06:18,000 Like what? 155 00:06:18,000 --> 00:06:20,000 Dr. Herb Waite from the University of California, 156 00:06:20,000 --> 00:06:22,000 Santa Barbara, just sent us an email. 157 00:06:22,000 --> 00:06:24,000 Doesn't he research bio-inspired nanotechnology? 158 00:06:24,000 --> 00:06:26,000 Right. He referred us to Ms. Dana Novak. 159 00:06:26,000 --> 00:06:28,000 She's helping him in his research. 160 00:06:28,000 --> 00:06:30,000 Here she is now. 161 00:06:30,000 --> 00:06:32,000 Hi, you must be the treehouse detectives. 162 00:06:32,000 --> 00:06:34,000 Dr. Waite sent you a call. How can I help you? 163 00:06:34,000 --> 00:06:36,000 We are researching space technology 164 00:06:36,000 --> 00:06:38,000 and space exploration. 165 00:06:38,000 --> 00:06:40,000 What does bio-inspired mean? 166 00:06:40,000 --> 00:06:42,000 Well, it simply refers to any technology 167 00:06:42,000 --> 00:06:44,000 inspired by biology. 168 00:06:44,000 --> 00:06:46,000 For example, when George DeMestrel 169 00:06:46,000 --> 00:06:48,000 took his dog for a walk one day, 170 00:06:48,000 --> 00:06:50,000 he saw that they both had burrs stuck to them. 171 00:06:50,000 --> 00:06:52,000 He looked at a burr under a microscope 172 00:06:52,000 --> 00:06:54,000 and saw hooks and loops. 173 00:06:54,000 --> 00:06:56,000 That inspired him to invent Velcro. 174 00:06:56,000 --> 00:06:58,000 What a great invention. 175 00:06:58,000 --> 00:07:00,000 I use Velcro all the time. 176 00:07:00,000 --> 00:07:02,000 What plants or animals do you look at for inspiration? 177 00:07:02,000 --> 00:07:04,000 Right now, we're investigating 178 00:07:04,000 --> 00:07:06,000 muscle threads and bloodworm 179 00:07:06,000 --> 00:07:08,000 and clamworm jaws. 180 00:07:08,000 --> 00:07:10,000 Uh, muscles, clamworms, 181 00:07:10,000 --> 00:07:12,000 and bloodworms? 182 00:07:12,000 --> 00:07:14,000 Sounds interesting, but why exactly 183 00:07:14,000 --> 00:07:16,000 are you interested in worm jaws 184 00:07:16,000 --> 00:07:18,000 and muscles? 185 00:07:18,000 --> 00:07:20,000 If we're going to explore the moon, Mars, 186 00:07:20,000 --> 00:07:22,000 and beyond, then we need new, 187 00:07:22,000 --> 00:07:24,000 advanced, and self-healing materials 188 00:07:24,000 --> 00:07:26,000 for spacecraft construction. 189 00:07:26,000 --> 00:07:28,000 What do you mean by self-healing? 190 00:07:28,000 --> 00:07:30,000 Think about what happens when you accidentally cut yourself. 191 00:07:30,000 --> 00:07:32,000 It's amazing to watch 192 00:07:32,000 --> 00:07:34,000 how quickly your body acts to mend the wound. 193 00:07:34,000 --> 00:07:36,000 Like this model, we're trying 194 00:07:36,000 --> 00:07:38,000 to understand how to give composite 195 00:07:38,000 --> 00:07:40,000 materials those same qualities. 196 00:07:40,000 --> 00:07:42,000 This model demonstrates how two 197 00:07:42,000 --> 00:07:44,000 different types of bonds within a material 198 00:07:44,000 --> 00:07:46,000 work together to self-heal. 199 00:07:46,000 --> 00:07:48,000 And why is that important? 200 00:07:48,000 --> 00:07:50,000 One weakness of current composite materials 201 00:07:50,000 --> 00:07:52,000 is that they tend to form tiny hairline 202 00:07:52,000 --> 00:07:54,000 cracks, which can lead to 203 00:07:54,000 --> 00:07:56,000 major damage over time. 204 00:07:56,000 --> 00:07:58,000 In long-distance space exploration, 205 00:07:58,000 --> 00:08:00,000 repairs won't be easy. 206 00:08:00,000 --> 00:08:02,000 Right, there won't be a spare parts 207 00:08:02,000 --> 00:08:04,000 store we can stop at while in space. 208 00:08:04,000 --> 00:08:06,000 Nope, there won't. However, 209 00:08:06,000 --> 00:08:08,000 with new, high-performance 210 00:08:08,000 --> 00:08:10,000 materials, such as the self-healing 211 00:08:10,000 --> 00:08:12,000 materials, we will be taking the 212 00:08:12,000 --> 00:08:14,000 first step in building spacecraft 213 00:08:14,000 --> 00:08:16,000 capable of traveling millions of 214 00:08:16,000 --> 00:08:18,000 miles from Earth that can fix themselves. 215 00:08:18,000 --> 00:08:20,000 That's awesome, 216 00:08:20,000 --> 00:08:22,000 but I still don't understand what muscles 217 00:08:22,000 --> 00:08:24,000 and worm jaws have to do with it. 218 00:08:24,000 --> 00:08:26,000 Nature specializes in how to put 219 00:08:26,000 --> 00:08:28,000 materials together in the most 220 00:08:28,000 --> 00:08:30,000 effective and efficient ways. 221 00:08:30,000 --> 00:08:32,000 We look at the muscle threads because they're 222 00:08:32,000 --> 00:08:34,000 very strong, yet thin and lightweight. 223 00:08:34,000 --> 00:08:36,000 It's amazing how much we can learn 224 00:08:36,000 --> 00:08:38,000 just by looking at nature. 225 00:08:38,000 --> 00:08:40,000 We can learn how to make materials that 226 00:08:40,000 --> 00:08:42,000 recover quickly from stress. Think about 227 00:08:42,000 --> 00:08:44,000 when you buy a six-pack of soda. 228 00:08:44,000 --> 00:08:46,000 When you take a can out of the plastic loop, 229 00:08:46,000 --> 00:08:48,000 the plastic stretches but is 230 00:08:48,000 --> 00:08:50,000 difficult to break. Nature 231 00:08:50,000 --> 00:08:52,000 inflicts damage on the muscle threads just like 232 00:08:52,000 --> 00:08:54,000 you do on the plastic. We call 233 00:08:54,000 --> 00:08:56,000 this damage creep, and it is 234 00:08:56,000 --> 00:08:58,000 undesirable. However, 235 00:08:58,000 --> 00:09:00,000 in nature, many materials that 236 00:09:00,000 --> 00:09:02,000 experience creep recover from it, 237 00:09:02,000 --> 00:09:04,000 and we're studying the muscle threads 238 00:09:04,000 --> 00:09:06,000 to learn how. What about 239 00:09:06,000 --> 00:09:08,000 the blood and clam worm jaws? 240 00:09:08,000 --> 00:09:10,000 The jaws appear to be just as resistant 241 00:09:10,000 --> 00:09:12,000 to abrasion as the tiles on the 242 00:09:12,000 --> 00:09:14,000 space shuttle, yet they have 243 00:09:14,000 --> 00:09:16,000 only half the weight per equal volume. 244 00:09:16,000 --> 00:09:18,000 We learned in the case of the 245 00:09:18,000 --> 00:09:20,000 challenging flight that weight is a very important 246 00:09:20,000 --> 00:09:22,000 factor. The lighter the airplane or spacecraft, 247 00:09:22,000 --> 00:09:24,000 the less fuel it needs. 248 00:09:24,000 --> 00:09:26,000 That's right, and we hope to learn 249 00:09:26,000 --> 00:09:28,000 not only how to make very lightweight 250 00:09:28,000 --> 00:09:30,000 spacecraft materials, but also 251 00:09:30,000 --> 00:09:32,000 tougher ones. Why do the materials 252 00:09:32,000 --> 00:09:34,000 need to be tougher? The materials 253 00:09:34,000 --> 00:09:36,000 used for spacecraft are subjected 254 00:09:36,000 --> 00:09:38,000 to enormous stress, so it's 255 00:09:38,000 --> 00:09:40,000 crucial that they be tough 256 00:09:40,000 --> 00:09:42,000 as well as self-healing. Sounds like 257 00:09:42,000 --> 00:09:44,000 this research is exciting. 258 00:09:44,000 --> 00:09:46,000 Thanks, Ms. Novak. You're welcome. 259 00:09:46,000 --> 00:09:48,000 Keep up the investigation and 260 00:09:48,000 --> 00:09:50,000 call me back if you have any other questions. 261 00:09:50,000 --> 00:09:52,000 Bye! That was impressive. 262 00:09:52,000 --> 00:09:54,000 Never thought that setting muscles and 263 00:09:54,000 --> 00:09:56,000 worms could help us learn about traveling through space. 264 00:09:56,000 --> 00:09:58,000 But I'm still trying to figure out how we're 265 00:09:58,000 --> 00:10:00,000 going to do it. I mean, what will our future 266 00:10:00,000 --> 00:10:02,000 space vehicles look like? I'm not sure. 267 00:10:02,000 --> 00:10:04,000 Maybe Bianca can help us. 268 00:10:04,000 --> 00:10:06,000 Well, she's been training down at Space Camp, 269 00:10:06,000 --> 00:10:08,000 but I don't think their program includes future 270 00:10:08,000 --> 00:10:10,000 spacecraft. No, but they are 271 00:10:10,000 --> 00:10:12,000 close to NASA Marshall Space Flight Center. 272 00:10:12,000 --> 00:10:14,000 I emailed her last night. She wrote back 273 00:10:14,000 --> 00:10:16,000 and said she was meeting with Mr. Cook. 274 00:10:16,000 --> 00:10:18,000 Way to go, Catherine. Have you heard from Dr. D yet? 275 00:10:18,000 --> 00:10:20,000 No. Wasn't he working with 276 00:10:20,000 --> 00:10:22,000 you and Tony? Well, we talked to him a couple 277 00:10:22,000 --> 00:10:24,000 days ago, but we haven't heard from him. 278 00:10:24,000 --> 00:10:26,000 Maybe Bianca gave him a new 279 00:10:26,000 --> 00:10:28,000 fitness program to work on, too. 280 00:10:28,000 --> 00:10:30,000 Well, if so, maybe we should call his house. 281 00:10:30,000 --> 00:10:32,000 He may need some help. 282 00:10:34,000 --> 00:10:36,000 Mr. Cook agreed to meet me 283 00:10:36,000 --> 00:10:38,000 at NASA Marshall Space Flight Center 284 00:10:38,000 --> 00:10:40,000 where they test rocket engines for spacecraft. 285 00:10:40,000 --> 00:10:42,000 They call it the Propulsion 286 00:10:42,000 --> 00:10:44,000 System Component Testing Facility. 287 00:10:44,000 --> 00:10:46,000 Of course, I had lots of questions. 288 00:10:46,000 --> 00:10:48,000 So, how is NASA 289 00:10:48,000 --> 00:10:50,000 researching new spacecraft for the future? 290 00:10:50,000 --> 00:10:52,000 One way is through propulsion. 291 00:10:52,000 --> 00:10:54,000 With a new exploration vision, 292 00:10:54,000 --> 00:10:56,000 we will need propulsion systems that 293 00:10:56,000 --> 00:10:58,000 will be low-cost and will enable 294 00:10:58,000 --> 00:11:00,000 rapid, safe, and reliable 295 00:11:00,000 --> 00:11:02,000 access to, in, and 296 00:11:02,000 --> 00:11:04,000 from space. So why do we need new propulsion 297 00:11:04,000 --> 00:11:06,000 systems? Aren't the old ones good 298 00:11:06,000 --> 00:11:08,000 enough? Most U.S. propulsion systems 299 00:11:08,000 --> 00:11:10,000 are based on 1950s and 60s 300 00:11:10,000 --> 00:11:12,000 technology. They are high-risk 301 00:11:12,000 --> 00:11:14,000 and expensive. Right now, it costs 302 00:11:14,000 --> 00:11:16,000 $10,000 per pound 303 00:11:16,000 --> 00:11:18,000 to put payload into Earth's orbit. 304 00:11:18,000 --> 00:11:20,000 Wow, that's a lot of money. 305 00:11:20,000 --> 00:11:22,000 Exactly. So for us to carry 306 00:11:22,000 --> 00:11:24,000 out the exploration vision, missions 307 00:11:24,000 --> 00:11:26,000 must be affordable, the reliability 308 00:11:26,000 --> 00:11:28,000 must be increased, and we must find a way 309 00:11:28,000 --> 00:11:30,000 to rapidly and safely take us 310 00:11:30,000 --> 00:11:32,000 beyond Earth's orbit to the Moon, 311 00:11:32,000 --> 00:11:34,000 Mars, and beyond. What types of propulsion 312 00:11:34,000 --> 00:11:36,000 systems are being researched? 313 00:11:36,000 --> 00:11:38,000 The primary ones for exploration are chemical, 314 00:11:38,000 --> 00:11:40,000 like these here, 315 00:11:40,000 --> 00:11:42,000 nuclear, electric, and propellant-less 316 00:11:42,000 --> 00:11:44,000 propulsion systems. What's a propellant-less 317 00:11:44,000 --> 00:11:46,000 propulsion system? One type 318 00:11:46,000 --> 00:11:48,000 is a system that uses solar sails. 319 00:11:48,000 --> 00:11:50,000 These are sails much like those found on 320 00:11:50,000 --> 00:11:52,000 a ship. Solar sails are made 321 00:11:52,000 --> 00:11:54,000 from thin layers of mylar and act like a 322 00:11:54,000 --> 00:11:56,000 very large mirror. As photons 323 00:11:56,000 --> 00:11:58,000 of sunlight strike the sail and bounce off, 324 00:11:58,000 --> 00:12:00,000 they gently push the sail along. 325 00:12:00,000 --> 00:12:02,000 How does electrical propulsion work? 326 00:12:02,000 --> 00:12:04,000 You can't have an extension cord 327 00:12:04,000 --> 00:12:06,000 in space. No, it 328 00:12:06,000 --> 00:12:08,000 uses electrical energy from a solar 329 00:12:08,000 --> 00:12:10,000 array to accelerate a propellant. 330 00:12:10,000 --> 00:12:12,000 There are three types of electric propulsion 331 00:12:12,000 --> 00:12:14,000 systems. Electrothermal, 332 00:12:14,000 --> 00:12:16,000 which uses electrical heat. 333 00:12:16,000 --> 00:12:18,000 Electromagnetic, which creates thrust 334 00:12:18,000 --> 00:12:20,000 using a magnetic field. 335 00:12:20,000 --> 00:12:22,000 And electrostatic, which uses charged particles 336 00:12:22,000 --> 00:12:24,000 in an electric field. 337 00:12:24,000 --> 00:12:26,000 Don't we currently use chemical rockets? 338 00:12:26,000 --> 00:12:28,000 Yes, and they have been the primary means for 339 00:12:28,000 --> 00:12:30,000 transportation in space because of the very 340 00:12:30,000 --> 00:12:32,000 large amounts of thrust they generate that are 341 00:12:32,000 --> 00:12:34,000 needed to overcome Earth's gravity. 342 00:12:34,000 --> 00:12:36,000 As fuels become more advanced, chemical 343 00:12:36,000 --> 00:12:38,000 propulsion will continue to play a vital role 344 00:12:38,000 --> 00:12:40,000 in space transportation. 345 00:12:40,000 --> 00:12:42,000 That sounds great, but isn't one propulsion 346 00:12:42,000 --> 00:12:44,000 system better than the other? 347 00:12:44,000 --> 00:12:46,000 Well, there are pros and cons to each system. 348 00:12:46,000 --> 00:12:48,000 The choice of propulsion system depends on 349 00:12:48,000 --> 00:12:50,000 the energy requirements of the mission, 350 00:12:50,000 --> 00:12:52,000 its duration and destination, and whether 351 00:12:52,000 --> 00:12:54,000 it is robotic or human. 352 00:12:54,000 --> 00:12:56,000 I can't wait to travel through space. 353 00:12:56,000 --> 00:12:58,000 It's so exciting. Yes, it is. 354 00:12:58,000 --> 00:13:00,000 So keep studying your math and science. 355 00:13:00,000 --> 00:13:02,000 Don't worry, I will. Oh, by the way, 356 00:13:02,000 --> 00:13:04,000 Dr. D called. He said he wanted to meet you 357 00:13:04,000 --> 00:13:06,000 over at the Neutral Buoyancy Laboratory. 358 00:13:06,000 --> 00:13:08,000 Dr. D at space camp? 359 00:13:08,000 --> 00:13:10,000 That's strange. 360 00:13:10,000 --> 00:13:12,000 Well, it is Dr. D. 361 00:13:14,000 --> 00:13:16,000 Attach stabilizer into position 362 00:13:16,000 --> 00:13:18,000 on both the array 363 00:13:18,000 --> 00:13:20,000 and the bomb auxiliary power panel 364 00:13:20,000 --> 00:13:22,000 and lock into place. 365 00:13:34,000 --> 00:13:36,000 Fully deploy array by 366 00:13:36,000 --> 00:13:38,000 rotating handle counterclockwise. 367 00:13:38,000 --> 00:13:40,000 Roger. 368 00:13:50,000 --> 00:13:52,000 Dr. D, 369 00:13:52,000 --> 00:13:54,000 is that you? 370 00:13:54,000 --> 00:13:56,000 You bet. I'm training for a spacewalk 371 00:13:56,000 --> 00:13:58,000 going on this underwater 372 00:13:58,000 --> 00:14:00,000 solar array. 373 00:14:00,000 --> 00:14:02,000 Of course. We learned from Dr. Utley 374 00:14:02,000 --> 00:14:04,000 in the case of the Inhabitable Habitat 375 00:14:04,000 --> 00:14:06,000 that astronauts learn to work in the weaknesses 376 00:14:06,000 --> 00:14:08,000 of space by diving into a huge 377 00:14:08,000 --> 00:14:10,000 tank of water called the Neutral Buoyancy 378 00:14:10,000 --> 00:14:12,000 Laboratory. 379 00:14:16,000 --> 00:14:18,000 That's what I love about space camp. 380 00:14:18,000 --> 00:14:20,000 We get to practice, 381 00:14:20,000 --> 00:14:22,000 they emphasize the importance of teamwork, 382 00:14:22,000 --> 00:14:24,000 and of course I'm looking forward to the simulators. 383 00:14:24,000 --> 00:14:26,000 Simulators are great. 384 00:14:26,000 --> 00:14:28,000 They allow you to experience what space is really 385 00:14:28,000 --> 00:14:30,000 like. Let's go check them out. 386 00:14:30,000 --> 00:14:32,000 This is the 387 00:14:32,000 --> 00:14:34,000 Space Shot. Great. 388 00:14:34,000 --> 00:14:36,000 It simulates liftoff. 389 00:14:38,000 --> 00:14:40,000 Doesn't liftoff make astronauts feel heavy? 390 00:14:40,000 --> 00:14:42,000 We'll see. 391 00:14:54,000 --> 00:14:56,000 You just experienced four times the force 392 00:14:56,000 --> 00:14:58,000 of gravity, just like the Apollo astronauts 393 00:14:58,000 --> 00:15:00,000 at liftoff. Can we do it again? 394 00:15:00,000 --> 00:15:02,000 Sure. 395 00:15:02,000 --> 00:15:04,000 Three, two, one. 396 00:15:14,000 --> 00:15:16,000 Dr. D, 397 00:15:16,000 --> 00:15:18,000 I also felt weightless for a few seconds 398 00:15:18,000 --> 00:15:20,000 at the top. It was because you were 399 00:15:20,000 --> 00:15:22,000 freely falling. 400 00:15:24,000 --> 00:15:26,000 It's not quite 401 00:15:26,000 --> 00:15:28,000 free fall, but if you go to the moon, 402 00:15:28,000 --> 00:15:30,000 you only weigh one-sixth of what you do on the Earth. 403 00:15:30,000 --> 00:15:32,000 That's a great weight loss program. 404 00:15:32,000 --> 00:15:34,000 Let's see how 405 00:15:34,000 --> 00:15:36,000 you do, weighing only slightly more 406 00:15:36,000 --> 00:15:38,000 than two gallons of milk. 407 00:15:44,000 --> 00:15:46,000 Buzz Aldrin said that 408 00:15:46,000 --> 00:15:48,000 galloping like a horse was easier than 409 00:15:48,000 --> 00:15:50,000 jogging, but why don't you 410 00:15:50,000 --> 00:15:52,000 try the bunny hop? 411 00:15:52,000 --> 00:15:54,000 Awesome! 412 00:15:58,000 --> 00:16:00,000 Training like this 413 00:16:00,000 --> 00:16:02,000 before going to the moon is a great idea. 414 00:16:06,000 --> 00:16:08,000 Now that you've experienced 415 00:16:08,000 --> 00:16:10,000 walking on the moon, you need to train 416 00:16:10,000 --> 00:16:12,000 for re-entry into the Earth's atmosphere. 417 00:16:16,000 --> 00:16:18,000 This is the multi-axis trainer, 418 00:16:18,000 --> 00:16:20,000 and trainers like this were used by our country's 419 00:16:20,000 --> 00:16:22,000 first astronauts in the Mercury program 420 00:16:22,000 --> 00:16:24,000 to prepare for the possibility of a 421 00:16:24,000 --> 00:16:26,000 tumble spin during re-entry. 422 00:16:26,000 --> 00:16:28,000 Oh, I almost forgot. 423 00:16:28,000 --> 00:16:30,000 You've got to contact the other Treehouse 424 00:16:30,000 --> 00:16:32,000 detectives. They don't know where you are. 425 00:16:32,000 --> 00:16:34,000 Well, that's right. I didn't tell them. 426 00:16:34,000 --> 00:16:36,000 I'll get on it right away, just after I become 427 00:16:36,000 --> 00:16:38,000 disoriented. 428 00:16:42,000 --> 00:16:44,000 Dear Treehouse detectives, 429 00:16:44,000 --> 00:16:46,000 sorry about the quick departure. 430 00:16:46,000 --> 00:16:48,000 I had some important work to do at space camp. 431 00:16:48,000 --> 00:16:50,000 I saw Bianca. 432 00:16:50,000 --> 00:16:52,000 I'm sure she will fill you in. 433 00:16:54,000 --> 00:16:56,000 Looking good. Made us a little longer 434 00:16:56,000 --> 00:16:58,000 than I can handle. 435 00:17:00,000 --> 00:17:02,000 So what's up? 436 00:17:02,000 --> 00:17:04,000 Will Bianca survive the rigors of training? 437 00:17:04,000 --> 00:17:06,000 Who will be the next generation of 438 00:17:06,000 --> 00:17:08,000 explorers to go to Mars? 439 00:17:08,000 --> 00:17:10,000 Would you like to walk on Mars someday? 440 00:17:10,000 --> 00:17:12,000 Stay tuned for the exciting conclusion 441 00:17:12,000 --> 00:17:14,000 of The Case of the Great Space 442 00:17:14,000 --> 00:17:16,000 Exploration.