1 00:00:00,000 --> 00:00:09,900 My Outro For My 20th Birthday 2 00:00:30,000 --> 00:00:42,600 Coming up on Destination Tomorrow, see how solar sails are being developed for deep space 3 00:00:42,600 --> 00:00:43,600 exploration. 4 00:00:43,600 --> 00:00:48,340 We'll also see how NASA technology is being used to help protect some of America's most 5 00:00:48,340 --> 00:00:49,680 important documents. 6 00:00:49,680 --> 00:00:55,400 Plus, we'll take a look at how the next generation of reusable launch vehicles is being developed. 7 00:00:55,400 --> 00:00:59,280 And Johnny Alonzo finds out exactly how GPS works. 8 00:00:59,280 --> 00:01:07,240 All this and more next on Destination Tomorrow. 9 00:01:07,240 --> 00:01:08,240 Hello everyone. 10 00:01:08,240 --> 00:01:09,240 I'm Steele McGonigal. 11 00:01:09,240 --> 00:01:10,400 And I'm Kara O'Brien. 12 00:01:10,400 --> 00:01:12,360 Welcome to Destination Tomorrow. 13 00:01:12,360 --> 00:01:16,560 This program will uncover how past, present and future research is creating today's knowledge 14 00:01:16,560 --> 00:01:19,360 to answer the questions and solve the challenges of tomorrow. 15 00:01:19,360 --> 00:01:24,420 Up first, we look at a new way for spacecraft to travel to distant destinations. 16 00:01:24,420 --> 00:01:29,660 New lightweight solar sails might soon become the standard mechanism to power spacecraft. 17 00:01:29,660 --> 00:01:34,460 These reflective structures use energy from the sun rather than rocket power to move through 18 00:01:34,460 --> 00:01:35,460 space. 19 00:01:35,460 --> 00:01:39,100 These sails are not only less expensive than current rocket-powered spacecraft, but can 20 00:01:39,100 --> 00:01:41,900 potentially be four to six times faster. 21 00:01:41,900 --> 00:01:46,100 This increased speed and cost savings could change the way we study deep space. 22 00:01:46,100 --> 00:01:50,260 Jennifer Pulley spoke with Dr. Keith Belvin at NASA Langley Research Center to find out 23 00:01:50,260 --> 00:01:51,260 more. 24 00:01:51,260 --> 00:02:00,060 Throughout humankind's early history, the quest for greater knowledge and understanding 25 00:02:00,060 --> 00:02:02,660 fueled the need for exploration. 26 00:02:02,660 --> 00:02:07,780 For centuries, the vehicle most early explorers used to achieve this exploration was a ship 27 00:02:07,780 --> 00:02:09,340 with sails. 28 00:02:09,340 --> 00:02:14,380 But because these ships depended on wind pushing against the sails for forward motion, they 29 00:02:14,380 --> 00:02:18,580 were generally very slow, unpredictable and often very dangerous. 30 00:02:18,580 --> 00:02:23,900 Today, with the multitude of ways that humans now possess to travel, the sail, with all 31 00:02:23,900 --> 00:02:29,140 of its limitations, has been relegated to recreational status rather than a serious 32 00:02:29,140 --> 00:02:31,500 tool for exploration. 33 00:02:31,500 --> 00:02:34,860 But a new idea might change the way we think about sails. 34 00:02:34,860 --> 00:02:40,100 NASA researchers are actually developing a new type of sail that will use the sun's light 35 00:02:40,100 --> 00:02:42,980 to propel spacecraft deep into space. 36 00:02:42,980 --> 00:02:47,940 These solar sails are so promising that someday they may replace slower, more costly propulsion 37 00:02:47,940 --> 00:02:50,260 systems for deep space exploration. 38 00:02:50,260 --> 00:02:55,220 I spoke with Dr. Keith Belvin at NASA Langley Research Center to find out more. 39 00:02:55,220 --> 00:02:58,540 The idea for solar sails has been around for a very long time. 40 00:02:58,540 --> 00:03:03,780 Maxwell back in 1873 predicted the existence of solar pressure lights. 41 00:03:03,780 --> 00:03:07,700 So we've known about solar pressure for a long time. 42 00:03:07,700 --> 00:03:11,540 But it wasn't until recently that we were able to build solar sails with the lightweight 43 00:03:11,540 --> 00:03:13,780 materials and structures that are needed. 44 00:03:13,780 --> 00:03:16,020 Tell me about these lightweight materials and structures. 45 00:03:16,020 --> 00:03:17,020 How are they being used? 46 00:03:17,020 --> 00:03:23,020 Well, the key to building a solar sail is of course to make it very large and very lightweight. 47 00:03:23,020 --> 00:03:29,340 For a useful solar sail, it has to have a weight of less than 10 grams per square meter. 48 00:03:29,340 --> 00:03:34,060 For example, copier paper has a weight of 70 grams per square meter. 49 00:03:34,060 --> 00:03:37,500 So we're talking about some materials that are much lighter than that. 50 00:03:37,500 --> 00:03:41,820 One of the things that NASA has done over the last decade is to work on materials that 51 00:03:41,820 --> 00:03:47,980 can be processed to just a couple microns, that's a couple millionths of a meter thick. 52 00:03:47,980 --> 00:03:52,820 And these lightweight, thin materials then are made space durable so they can withstand 53 00:03:52,820 --> 00:03:55,380 the radiation and temperatures of space. 54 00:03:55,380 --> 00:03:58,420 Dr. Belvin, tell me how a solar sail works. 55 00:03:58,420 --> 00:04:03,140 The basic principle is much like a ship on the sea that uses sails to capture the wind. 56 00:04:03,140 --> 00:04:08,340 The sun is constantly emitting light, or photons, in all directions. 57 00:04:08,340 --> 00:04:13,820 Since the photons have mass and are in motion, their momentum produces a pressure when reflected 58 00:04:13,820 --> 00:04:14,820 by a surface. 59 00:04:14,820 --> 00:04:21,300 When a spacecraft uses a solar sail for propulsion, the sail's reflective surface transfers a 60 00:04:21,300 --> 00:04:26,740 continuous force from the photons to propel the craft through space, much like a sailing 61 00:04:26,740 --> 00:04:30,140 ship uses wind to push it across the water. 62 00:04:30,140 --> 00:04:34,980 Since the pressure being emitted from the photons is very low, the force is small. 63 00:04:34,980 --> 00:04:40,340 But because the sail will have a constant source of energy, it is continuously accelerating 64 00:04:40,340 --> 00:04:45,100 and can reach speeds upwards of 155,000 miles per hour. 65 00:04:45,100 --> 00:04:50,380 This speed could cut years off travel time during long duration interstellar flights. 66 00:04:50,380 --> 00:04:55,580 In addition, the constant propulsive force provided by the sun's light allows the spacecraft 67 00:04:55,580 --> 00:04:59,980 to travel in orbits that are not affordable using conventional propulsion. 68 00:04:59,980 --> 00:05:02,660 So can solar sails be used on all types of missions? 69 00:05:02,660 --> 00:05:08,180 Well, in addition to solar sails having to be lightweight for various missions, the spacecraft 70 00:05:08,180 --> 00:05:10,660 they're propelling has to be very lightweight. 71 00:05:10,660 --> 00:05:15,580 But there are many missions where, with the miniaturization of electronics, that the spacecraft's 72 00:05:15,580 --> 00:05:18,660 science sensors are very small and lightweight. 73 00:05:18,660 --> 00:05:23,140 And those systems are very amenable to being propelled by a solar sail. 74 00:05:23,140 --> 00:05:28,260 For example, we're looking at missions in the future where we do interstellar transfer 75 00:05:28,260 --> 00:05:32,020 of science instruments using solar sails. 76 00:05:32,020 --> 00:05:36,020 So do we see solar sails only being used in deep space? 77 00:05:36,020 --> 00:05:41,820 Well, there are missions where solar sails can be used close to the Earth's orbit. 78 00:05:41,820 --> 00:05:45,380 They don't all have to be long duration interstellar type missions. 79 00:05:45,380 --> 00:05:50,540 The constant acceleration that a solar sail produces gives it an orbit trajectory that 80 00:05:50,540 --> 00:05:53,460 is not achievable by some other means. 81 00:05:53,460 --> 00:06:00,380 For example, we can fly a science payload to measure the magnetic storms emanating from 82 00:06:00,380 --> 00:06:01,380 the sun. 83 00:06:01,380 --> 00:06:04,340 How do you deploy such a large structure into space? 84 00:06:04,340 --> 00:06:07,180 To deploy a solar sail in space is quite a challenge. 85 00:06:07,180 --> 00:06:13,140 First of all, the sail has to be packaged in a small size to fit into the launch vehicles. 86 00:06:13,140 --> 00:06:19,100 Near-term sail missions are on the order of 70 meters to up to 150 meters in size. 87 00:06:19,140 --> 00:06:23,460 So it's a real challenge to package those tightly and then deploy in space. 88 00:06:23,460 --> 00:06:27,140 Two aspects probably are most important for deploying a solar sail. 89 00:06:27,140 --> 00:06:31,500 The first is deploying the booms that hold the membranes in place. 90 00:06:31,500 --> 00:06:37,100 We're using inflation to push the booms out and to the right location. 91 00:06:37,100 --> 00:06:40,020 And then we cool the booms to rigidize them. 92 00:06:40,020 --> 00:06:45,460 The second aspect is deploying the sail, the thin film membranes that we've talked about. 93 00:06:45,460 --> 00:06:49,500 Those will incorporate rip-stop so that if there's a small tear, it doesn't propagate 94 00:06:49,500 --> 00:06:50,500 very far. 95 00:06:50,500 --> 00:06:56,060 In addition, we have to deploy those so that we don't affect the sail's reflective performance. 96 00:06:56,060 --> 00:07:00,180 And so special measures are taken to maintain the integrity of that sail. 97 00:07:00,180 --> 00:07:01,900 What is the future of this program? 98 00:07:01,900 --> 00:07:06,220 I would say within the next dozen years or so, solar sails will be used routinely to 99 00:07:06,220 --> 00:07:08,420 propel spacecraft. 100 00:07:08,420 --> 00:07:13,340 Continual improvements in the sail technology will allow them to be used for extreme environments 101 00:07:13,340 --> 00:07:15,220 like near-sun missions. 102 00:07:15,220 --> 00:07:20,260 Over the next 20 years, most importantly, we'll have the technology in hand to do interstellar 103 00:07:20,260 --> 00:07:22,060 missions. 104 00:07:22,060 --> 00:07:26,900 These are kilometer-sized solar sails that weigh only one to two grams per square meter. 105 00:07:26,900 --> 00:07:31,500 The technology being developed today at NASA is going to enable us to unlock a lot of the 106 00:07:31,500 --> 00:07:33,460 secrets of the universe. 107 00:07:33,460 --> 00:07:38,580 Not only will we be able to look at distant places using telescopes, we'll actually be 108 00:07:38,580 --> 00:07:44,380 able to send science instruments to some of those locations using solar sails. 109 00:07:44,540 --> 00:07:47,660 The researchers at NASA are continuing to improve the materials used for solar sails 110 00:07:47,660 --> 00:07:51,060 every day, making them stronger and lighter. 111 00:07:51,060 --> 00:07:55,380 Coming up, we find out how some NASA detective work helped preserve the Declaration of Independence, 112 00:07:55,380 --> 00:07:58,620 the Bill of Rights, and the Constitution. 113 00:07:58,620 --> 00:08:03,180 But first, did you know that the inspiration for solar sail technology came from the 17th 114 00:08:03,180 --> 00:08:05,700 century astronomer Johannes Kepler? 115 00:08:05,700 --> 00:08:10,020 Kepler deduced that winds blew objects around in space after he observed comet tails blown 116 00:08:10,020 --> 00:08:13,140 by what appeared to be a solar breeze. 117 00:08:13,140 --> 00:08:17,180 Kepler suggested that eventually, ships might navigate through space using sails that could 118 00:08:17,180 --> 00:08:19,900 catch this wind. 119 00:08:19,900 --> 00:08:24,180 The Constitution, the Bill of Rights, and the Declaration of Independence, also known 120 00:08:24,180 --> 00:08:28,960 as the Charters of Freedom, are obviously three of the most important American documents 121 00:08:28,960 --> 00:08:29,960 ever written. 122 00:08:29,960 --> 00:08:34,640 They not only guide and guarantee liberties for all Americans, but have also been modeled 123 00:08:34,640 --> 00:08:37,660 by dozens of other countries around the world. 124 00:08:37,660 --> 00:08:42,700 So when signs of premature deterioration began to show on the documents, conservators became 125 00:08:42,700 --> 00:08:43,700 very alarmed. 126 00:08:43,700 --> 00:08:48,540 To help find out what was causing the deterioration and how it could be stopped, the National 127 00:08:48,540 --> 00:08:51,980 Archives turned to NASA researchers for an answer. 128 00:08:51,980 --> 00:08:57,980 Tonya St. Romain finds out more. 129 00:08:57,980 --> 00:09:02,860 In the late 1700s, three of the world's most important documents were written here in the 130 00:09:02,860 --> 00:09:04,460 United States. 131 00:09:04,460 --> 00:09:09,580 Now called the Charters of Freedom, the Declaration of Independence, the Constitution, and the 132 00:09:09,580 --> 00:09:14,500 Bill of Rights were conceived and written by early Americans who believed that tyrannical 133 00:09:14,500 --> 00:09:19,660 rule and oppression should be replaced by individual liberties and freedom. 134 00:09:19,660 --> 00:09:24,820 Until the mid-20th century, these documents were proudly displayed for the general public, 135 00:09:24,820 --> 00:09:29,700 but the years of inadequate preservation left them a bit faded and brittle. 136 00:09:29,700 --> 00:09:35,540 This all changed in 1951, when the documents were placed in specially adapted encasements 137 00:09:35,540 --> 00:09:39,500 which were designed to slow down the deterioration process. 138 00:09:39,500 --> 00:09:44,100 These glass encasements were filled with inert helium, which would protect the documents 139 00:09:44,100 --> 00:09:48,900 from the harmful chemically corrosive effects of air, keeping them safe for generations 140 00:09:48,900 --> 00:09:49,900 to come. 141 00:09:49,900 --> 00:09:54,740 But in the late 1990s, conservators began noticing that the documents were, in fact, 142 00:09:54,740 --> 00:09:57,340 still showing signs of deterioration. 143 00:09:57,340 --> 00:10:03,220 Mysterious small white spots were appearing inside the encasements and on the documents. 144 00:10:03,220 --> 00:10:08,180 To help determine the cause of the deterioration and how to fix the problem, the National Archives 145 00:10:08,180 --> 00:10:13,940 asked researchers at NASA to perform a series of tests on the atmosphere inside the encasements. 146 00:10:13,940 --> 00:10:19,540 I spoke with Dr. Joel Levine at NASA Langley Research Center to find out more. 147 00:10:19,540 --> 00:10:25,020 In 1951, the National Bureau of Standards, which is now NIST, the National Institute 148 00:10:25,020 --> 00:10:31,900 of Standards and Technology, was asked by the National Archives to preserve these very 149 00:10:31,900 --> 00:10:37,380 important documents, the Declaration of Independence, the U.S. Constitution, and the Bill of Rights. 150 00:10:37,380 --> 00:10:45,700 It became apparent several years prior to 1998 that some mysterious white spots appeared 151 00:10:45,700 --> 00:10:51,420 in all encasements, and over time, over several years, they increased in number. 152 00:10:51,420 --> 00:10:57,300 The National Archives conservators wanted to know if we had technology that could determine 153 00:10:57,300 --> 00:11:02,100 the chemical composition of the encasements non-invasively. 154 00:11:02,100 --> 00:11:05,140 Non-invasively means without extracting air. 155 00:11:05,140 --> 00:11:06,700 We didn't want to touch the air. 156 00:11:06,700 --> 00:11:08,660 We didn't want to touch the encasement. 157 00:11:08,660 --> 00:11:14,820 We wanted to come up with some technique that could tell us the answer without disturbing 158 00:11:14,820 --> 00:11:18,860 the contents of the encasement, both the documents and the atmosphere. 159 00:11:18,860 --> 00:11:25,700 After considerable discussion, we decided we should use a technique called laser spectroscopy. 160 00:11:25,700 --> 00:11:33,100 What the laser did is provide energy at the very wavelength that water vapor absorbs, 161 00:11:33,100 --> 00:11:38,220 and as we looked at the absorption, we could determine what the background gas was. 162 00:11:38,220 --> 00:11:43,300 We're interested in not the document, but the atmosphere in the encasement that's protecting 163 00:11:43,300 --> 00:11:44,460 the document. 164 00:11:44,460 --> 00:11:49,900 What we found is that the gas that was sealed 50 years ago was still there. 165 00:11:49,900 --> 00:11:54,860 When the laser studies were done, NASA researchers conclusively determined that helium in the 166 00:11:54,860 --> 00:11:57,660 encasements had not leaked out. 167 00:11:57,660 --> 00:12:03,780 This determination only increased concerns over the origin of the mysterious white spots. 168 00:12:03,780 --> 00:12:07,660 Most conservators believed that chemically corrosive air had leaked into the encasements, 169 00:12:07,660 --> 00:12:09,220 causing the damage. 170 00:12:09,220 --> 00:12:12,900 With this belief dispelled, the puzzle only intensified. 171 00:12:12,900 --> 00:12:18,180 So in some instance, we actually went back to step one because we still had the problem. 172 00:12:18,180 --> 00:12:21,500 The problem is what is responsible for these white spots. 173 00:12:21,500 --> 00:12:27,820 We eliminated air as a corrosive agent, and the next thing the National Archives asked 174 00:12:27,820 --> 00:12:35,020 us is could we tell them non-invasively how much water vapor was in the encasement. 175 00:12:35,020 --> 00:12:39,460 Because the documents were written on sheepskin, which requires a small amount of water vapor 176 00:12:39,460 --> 00:12:44,260 for stability, the relative humidity inside the encasements was originally set between 177 00:12:44,260 --> 00:12:46,100 25 and 35 percent. 178 00:12:46,100 --> 00:12:50,300 To determine if the humidity levels had changed, the NASA researchers needed to measure the 179 00:12:50,300 --> 00:12:53,460 relative humidity inside the sealed encasement. 180 00:12:53,460 --> 00:12:57,820 The first technique considered involved placing the encasements in a freezer to cause the 181 00:12:57,820 --> 00:13:02,020 condensation of gaseous water vapor to liquid water droplets. 182 00:13:02,020 --> 00:13:06,660 This idea was rejected due to the distinct possibility that the documents inside could 183 00:13:06,660 --> 00:13:09,260 be damaged by the condensed water. 184 00:13:09,260 --> 00:13:14,420 It was later decided that the humidity could be checked by using a very inexpensive device 185 00:13:14,420 --> 00:13:17,020 called a thermal electro-cooler. 186 00:13:17,020 --> 00:13:20,940 This device would sample only a small area of the encasements, keeping the documents 187 00:13:20,940 --> 00:13:21,940 inside safe. 188 00:13:21,940 --> 00:13:26,940 I called up the archives and I said we just have to freeze a small part of it at the edge 189 00:13:26,940 --> 00:13:30,860 where there is no document, no ink, and we can solve your problem. 190 00:13:30,860 --> 00:13:34,860 When the humidity levels were checked, it was found that the levels inside the encasement 191 00:13:34,860 --> 00:13:40,160 were 60 to 65 percent, twice the expected relative humidity. 192 00:13:40,160 --> 00:13:46,220 This is because when the documents were originally sealed in 1951, the relative humidity in Washington, 193 00:13:46,420 --> 00:13:48,460 D.C. was very high. 194 00:13:48,460 --> 00:13:52,700 The backing paper that the documents were laid upon had actually soaked up water vapor 195 00:13:52,700 --> 00:13:54,460 like a sponge. 196 00:13:54,460 --> 00:13:59,220 Once the documents were encased, the water vapor inside the backing paper could not escape, 197 00:13:59,220 --> 00:14:04,100 so it remained in the encasement's atmosphere, causing the humidity to rise. 198 00:14:04,100 --> 00:14:11,180 The white spots were basic or alkaline chemicals that were pulled out of the glass because 199 00:14:11,180 --> 00:14:14,380 of the presence of high levels of water vapor. 200 00:14:14,380 --> 00:14:20,420 And now, when the National Archives opens with its new encasements, we are all sure 201 00:14:20,420 --> 00:14:28,220 that the documents will be stable for many centuries, and in some small part, NASA scientists 202 00:14:28,220 --> 00:14:33,780 and NASA technology help preserve these documents for many generations to come. 203 00:14:33,780 --> 00:14:44,540 To better understand aerodynamic forces, early pilots and engineers pushed aircraft's 204 00:14:44,540 --> 00:14:49,660 tolerances to the limit, but by pushing the limits, some pilots experienced a very frightening 205 00:14:49,660 --> 00:14:52,900 aerodynamic phenomenon called a flat spin. 206 00:14:52,900 --> 00:14:58,300 In an effort to better understand this phenomenon, NASA's predecessor, NACA, developed a unique 207 00:14:58,300 --> 00:15:01,900 wind tunnel called the 20-foot vertical spin tunnel. 208 00:15:01,900 --> 00:15:05,740 This tunnel was designed to not only study the unique flight conditions of an aircraft 209 00:15:05,740 --> 00:15:11,340 in spin, but also teach pilots recovery techniques to avoid a fatal crash. 210 00:15:11,340 --> 00:15:15,700 The research performed at this tunnel would have a direct impact on virtually every American 211 00:15:15,700 --> 00:15:19,820 aircraft from World War II through today. 212 00:15:19,820 --> 00:15:25,180 Early in 1941, the National Advisory Committee for Aeronautics, or NACA, completed its new 213 00:15:25,180 --> 00:15:27,660 20-foot vertical spin tunnel. 214 00:15:27,660 --> 00:15:32,060 This tunnel tested a very different type of flight situation than the tunnels researchers 215 00:15:32,060 --> 00:15:33,860 were accustomed to using. 216 00:15:33,860 --> 00:15:38,260 The traditional way to test aircraft in a wind tunnel is by mounting an aircraft in 217 00:15:38,260 --> 00:15:42,380 the wind stream to evaluate the aircraft's flight characteristics. 218 00:15:42,380 --> 00:15:47,660 This type of testing is very effective when testing an aircraft in normal flight situations. 219 00:15:47,660 --> 00:15:51,700 But data from a traditional wind tunnel could not adequately account for unusual flight 220 00:15:51,700 --> 00:15:54,180 conditions, like a flat spin. 221 00:15:54,180 --> 00:15:58,820 As a plane enters a flat spin, air is not moving over the control surfaces as it should, 222 00:15:58,820 --> 00:16:02,140 which renders the plane's controls virtually useless. 223 00:16:02,140 --> 00:16:06,780 To help find ways for aircraft to recover from these dangerous spins, researchers test 224 00:16:06,780 --> 00:16:09,380 small-scale models in the spin tunnel. 225 00:16:09,380 --> 00:16:12,460 The idea behind the spin tunnel is simple. 226 00:16:12,460 --> 00:16:16,340 A large fan pulls a column of air up through the middle of the tunnel. 227 00:16:16,340 --> 00:16:20,700 Then a researcher launches an airplane model directly into the airflow by hand. 228 00:16:20,700 --> 00:16:25,420 As the model spins downward, the operator increases wind speeds until the model's fall 229 00:16:25,420 --> 00:16:28,540 is just balanced by the uprushing air. 230 00:16:28,540 --> 00:16:33,180 Then the control surfaces of the model are systematically activated electromagnetically 231 00:16:33,180 --> 00:16:37,220 to find out which ones allow the model to recover from a spin. 232 00:16:37,220 --> 00:16:42,300 This same basic technique that was used in 1941 is still being used today, but researchers 233 00:16:42,300 --> 00:16:46,140 now use computers to track unique markers on the bottom of the plane to measure the 234 00:16:46,140 --> 00:16:48,560 aircraft's spin characteristics. 235 00:16:48,800 --> 00:16:54,080 With these measurements, researchers can determine design modifications and pilot training procedures 236 00:16:54,080 --> 00:16:59,800 which can help pull a plane out of a spin, saving the plane and the pilot from a catastrophic 237 00:16:59,800 --> 00:17:01,120 accident. 238 00:17:01,120 --> 00:17:04,520 This simple system has worked especially well over the years. 239 00:17:04,520 --> 00:17:10,520 During World War II, every fighter, light bomber, attack plane and trainer, over 300 240 00:17:10,520 --> 00:17:13,480 designs in all, were tested in the spin tunnel. 241 00:17:13,480 --> 00:17:17,880 Subsequently, over half of these aircraft were modified in some way to ensure that their 242 00:17:17,880 --> 00:17:21,240 controls would be able to pull them out of a spin. 243 00:17:21,240 --> 00:17:26,000 Today the spin tunnel is still testing many different types of designs, from small general 244 00:17:26,000 --> 00:17:29,960 aviation planes to the Mars sample return capsules. 245 00:17:29,960 --> 00:17:35,280 Since it opened for business in 1941, nearly every American military fighter has been tested 246 00:17:35,280 --> 00:17:36,440 in this tunnel. 247 00:17:36,440 --> 00:17:41,320 However, with 10 percent of all military air accidents still occurring due to the flat 248 00:17:41,320 --> 00:17:47,040 spin, the NASA Langley 20-foot vertical spin tunnel will undoubtedly continue to save lives 249 00:17:47,040 --> 00:17:49,840 for many years to come. 250 00:17:49,840 --> 00:17:54,200 Before the spin tunnel was built, researchers sometimes tested aircraft's spin characteristics 251 00:17:54,200 --> 00:17:57,520 by simply dropping airplane models from high buildings. 252 00:17:57,520 --> 00:18:01,840 Coming up, we find out about the next generation of reusable launch vehicles. 253 00:18:01,840 --> 00:18:06,000 But first, did you know that Lieutenant Francis Evans became one of the first aviators to 254 00:18:06,000 --> 00:18:08,640 develop an effective spin recovery technique? 255 00:18:08,640 --> 00:18:13,440 In 1917, while attempting to get his pontoon plane into a loop, Lieutenant Evans inadvertently 256 00:18:13,440 --> 00:18:14,940 went into a spin. 257 00:18:14,940 --> 00:18:19,340 As he maneuvered out of the spin, he realized that he had unwittingly discovered an effective 258 00:18:19,340 --> 00:18:21,020 spin recovery maneuver. 259 00:18:21,020 --> 00:18:25,060 He was awarded the Distinguished Flying Cross nearly 20 years later for his life-saving 260 00:18:25,060 --> 00:18:27,780 discovery. 261 00:18:27,780 --> 00:18:31,980 Reusable launch vehicles like the Space Shuttle are a vital type of spacecraft for close-Earth 262 00:18:31,980 --> 00:18:33,460 operations. 263 00:18:33,460 --> 00:18:38,420 With the International Space Station providing a platform for unique scientific experiments, 264 00:18:38,420 --> 00:18:42,580 a reliable multi-use craft like the Space Shuttle is needed. 265 00:18:42,580 --> 00:18:46,860 Since the early 90s, researchers at NASA have been developing new types of reusable 266 00:18:46,860 --> 00:18:50,740 launch vehicles which will replace the aging Space Shuttle. 267 00:18:50,740 --> 00:18:55,660 These new spacecraft will be safer, less expensive, and much more durable. 268 00:18:55,660 --> 00:18:59,700 Stephanie Sy spoke with Charlie Cockrell at NASA Langley Research Center to find out what 269 00:18:59,700 --> 00:19:10,420 the future holds for the next generation of reusable spacecraft. 270 00:19:10,420 --> 00:19:15,260 The ability to travel into space is still a relatively recent event in human history. 271 00:19:15,260 --> 00:19:19,940 To get to space, early astronauts traveled in very expensive space capsules which were 272 00:19:19,940 --> 00:19:22,780 only used once before being retired. 273 00:19:22,780 --> 00:19:27,100 These systems worked well, but it was realized that a reusable system should be implemented 274 00:19:27,100 --> 00:19:29,620 over the single-use capsule system. 275 00:19:29,620 --> 00:19:34,780 So in the early 1980s, the world's first and only reusable launch vehicle, the Space Shuttle, 276 00:19:34,780 --> 00:19:36,180 came into service. 277 00:19:36,180 --> 00:19:41,140 With the Shuttle in service, spaceflight became much more accessible and less expensive, while 278 00:19:41,140 --> 00:19:45,740 also truly expanding technological and scientific exploration. 279 00:19:45,740 --> 00:19:51,740 But in a continued effort to make spaceflight even less expensive and much safer for astronauts, 280 00:19:51,740 --> 00:19:55,740 NASA researchers have been looking toward the next generation of reusable space launch 281 00:19:55,740 --> 00:19:56,880 vehicles. 282 00:19:56,880 --> 00:20:01,620 To help develop the next generation of spacecraft, NASA researchers have been developing and 283 00:20:01,620 --> 00:20:04,700 testing a lot of new vehicle technologies. 284 00:20:04,700 --> 00:20:09,460 Some of these new vehicles are so revolutionary that they may soon change the way we all think 285 00:20:09,460 --> 00:20:10,460 of space travel. 286 00:20:10,460 --> 00:20:15,540 I spoke with Charlie Cockrell at NASA Langley Research Center to help explain the next generation 287 00:20:15,540 --> 00:20:17,580 of space vehicles. 288 00:20:17,580 --> 00:20:22,900 NASA's goal is to make space travel safer, more reliable and more cost effective. 289 00:20:22,900 --> 00:20:27,980 One of the goals of the Next Generation Launch Technology Program is to provide routine access 290 00:20:27,980 --> 00:20:33,460 to the International Space Station, provide a safer way for crew return from the space 291 00:20:33,460 --> 00:20:38,900 station, and to also look at other opportunities in space and be able to do that on a routine 292 00:20:38,900 --> 00:20:39,900 basis. 293 00:20:39,900 --> 00:20:43,900 Charlie, how are these new spacecraft so different from the Space Shuttle we're used to seeing? 294 00:20:43,900 --> 00:20:49,620 Our vision is to really move towards spacecraft that look and operate more like conventional 295 00:20:49,620 --> 00:20:50,620 aircraft. 296 00:20:50,620 --> 00:20:54,180 So we want to do things like have less turnaround time in between missions. 297 00:20:54,180 --> 00:20:58,340 They're going to be more reliable to operate, less repairs that will have to take place 298 00:20:58,340 --> 00:21:00,420 in between missions. 299 00:21:00,420 --> 00:21:04,540 One of the chief differences between the Space Shuttle and the vehicles that you're going 300 00:21:04,540 --> 00:21:09,060 to see in the future is we're looking at more advanced types of propulsion systems. 301 00:21:09,060 --> 00:21:12,420 So they're going to look and operate much differently than the Shuttle. 302 00:21:12,420 --> 00:21:15,420 So what are some of the technologies you're using to develop these new vehicles? 303 00:21:15,420 --> 00:21:19,300 Well, in addition to the advanced propulsion systems, we are developing a number of different 304 00:21:19,300 --> 00:21:23,540 vehicle technologies that are going to be directly applicable to the next generation 305 00:21:23,540 --> 00:21:24,980 set of launch vehicles. 306 00:21:24,980 --> 00:21:30,420 One of NASA's major requirements is to develop new technologies and vehicles to transport 307 00:21:30,420 --> 00:21:34,740 crews and cargo to and from the International Space Station. 308 00:21:34,740 --> 00:21:39,700 Because the space station is relatively close to Earth and needs to be resupplied frequently, 309 00:21:39,700 --> 00:21:43,300 the most logical choice is a reusable spacecraft. 310 00:21:43,300 --> 00:21:49,480 One idea under consideration is an air-breathing craft rather than a rocket-propelled spacecraft. 311 00:21:49,480 --> 00:21:55,560 To break Earth's gravitational field, a craft needs to reach about 17,500 miles per hour. 312 00:21:55,560 --> 00:21:59,880 Currently, this is being accomplished through the use of a series of rockets. 313 00:21:59,880 --> 00:22:05,200 These rockets not only carry large amounts of fuel, but must also carry liquid oxygen 314 00:22:05,200 --> 00:22:08,280 to mix with the fuel for maximum thrust. 315 00:22:08,280 --> 00:22:12,960 Although this system is effective, it is very expensive and can be dangerous. 316 00:22:12,960 --> 00:22:17,720 The benefit of an air-breathing craft is that it would not need to carry its own oxygen. 317 00:22:17,720 --> 00:22:23,440 It would scoop oxygen from the Earth's atmosphere into a special engine called a scramjet. 318 00:22:23,440 --> 00:22:27,440 This system would allow the craft to reach the speed required to break the pull of the 319 00:22:27,440 --> 00:22:31,100 gravitational field, sending it into space. 320 00:22:31,100 --> 00:22:36,840 Because the craft is not carrying its own oxygen, the weight will be reduced by up to 50 percent. 321 00:22:36,840 --> 00:22:41,480 This could reduce spaceflight costs by a factor of 10, bringing current payload costs from 322 00:22:41,480 --> 00:22:46,320 about $10,000 per pound to about $1,000 per pound. 323 00:22:46,320 --> 00:22:49,240 So is scramjet technology the only concept you're looking at? 324 00:22:49,240 --> 00:22:53,840 No, we're actually studying a wide range of technologies that include different configuration 325 00:22:53,840 --> 00:23:00,040 shapes, different numbers of stages in the vehicle, different types of propulsion systems. 326 00:23:00,040 --> 00:23:04,820 Most of the longer-term applications do use scramjets, but we're also looking at something 327 00:23:04,820 --> 00:23:09,000 that we would call combined cycle propulsion, which would actually take elements of rocket 328 00:23:09,000 --> 00:23:14,120 propulsion, scramjets, high-speed turbojet engines, and maybe other advanced propulsion 329 00:23:14,120 --> 00:23:18,580 cycles so that we can use the benefits of those at different points in the flight. 330 00:23:18,580 --> 00:23:22,320 So where will this program be in the next 10, 15, 20 years? 331 00:23:22,320 --> 00:23:26,440 I think we're going to be well on our way to developing a next-generation reusable launch 332 00:23:26,440 --> 00:23:27,760 vehicle system. 333 00:23:27,760 --> 00:23:31,600 Whether or not we will actually have an operational system in the next 10 to 15 years is going 334 00:23:31,600 --> 00:23:36,720 to be dependent on what the nation's needs are and how we address that as an overall 335 00:23:36,720 --> 00:23:37,720 strategy. 336 00:23:37,720 --> 00:23:41,160 But we are developing technologies that can not only be included in a vehicle that would 337 00:23:41,160 --> 00:23:45,600 be developed in, say, the next 10 to 15 years, but we're also developing a lot more advanced 338 00:23:45,600 --> 00:23:49,960 technologies that would be good for vehicles that are going to be developed in, say, the 339 00:23:49,960 --> 00:23:51,760 next 20 to 30 years. 340 00:23:51,760 --> 00:23:55,920 And we're doing all of that by utilizing all of the unique capabilities that we have at 341 00:23:55,920 --> 00:23:58,400 our NASA field centers across the country. 342 00:23:58,400 --> 00:24:02,820 One of the most useful developments for professional pilots, drivers, and seamen in recent years 343 00:24:02,820 --> 00:24:04,920 has been the GPS receiver. 344 00:24:04,920 --> 00:24:10,240 These receivers are also being used by hikers, golfers, and fishermen for recreational purposes. 345 00:24:10,320 --> 00:24:16,040 However, many people who use this technology still don't know exactly how it works. 346 00:24:16,040 --> 00:24:20,880 Our own Johnny Alonzo finds out how this complex system helps keep many of us on track and 347 00:24:20,880 --> 00:24:21,880 on schedule. 348 00:24:21,880 --> 00:24:31,040 Trying to figure out where you are and where you're going has always been a challenge. 349 00:24:31,040 --> 00:24:33,960 Navigation and positioning are crucial to so many activities, and yet the process has 350 00:24:33,960 --> 00:24:35,280 not always been easy. 351 00:24:35,280 --> 00:24:39,520 Thankfully, the days of navigating by celestial means or landmarks are long gone since the 352 00:24:39,520 --> 00:24:42,560 introduction of GPS, or the Global Positioning System. 353 00:24:42,560 --> 00:24:44,680 So what is GPS? 354 00:24:44,680 --> 00:24:49,720 For some answers, I spoke with Dr. Kevin Dutton at NASA Langley to find out how it works. 355 00:24:49,720 --> 00:24:55,680 GPS stands for the Global Positioning System, and like the name suggests, it's a system 356 00:24:55,680 --> 00:25:00,720 to find your location anywhere on the Earth or near the Earth's surface, and the way it 357 00:25:00,720 --> 00:25:05,560 does that is by using radio frequency broadcast from orbiting satellites. 358 00:25:05,560 --> 00:25:07,920 Can you tell me why GPS was originally developed? 359 00:25:07,920 --> 00:25:13,080 It was developed by the Defense Department to meet all of their navigational needs. 360 00:25:13,080 --> 00:25:21,120 For example, aircraft, ships at sea, and now even individual soldiers carry little receivers 361 00:25:21,120 --> 00:25:23,840 like this in the field to find out where they are. 362 00:25:23,840 --> 00:25:27,640 The Global Positioning System consists of a constellation of 24 satellites and their 363 00:25:27,640 --> 00:25:29,800 ground stations working together. 364 00:25:29,800 --> 00:25:34,200 GPS uses these man-made stars as reference points to calculate positions accurate to 365 00:25:34,200 --> 00:25:37,360 a matter of meters, and in some cases centimeters. 366 00:25:37,400 --> 00:25:41,600 As long as you have a GPS receiver and a clear view of the sky and a map, you'll never be 367 00:25:41,600 --> 00:25:42,600 lost again. 368 00:25:42,600 --> 00:25:49,600 Today, GPS is finding its way into cars, boats, planes, construction equipment, farm machinery, 369 00:25:49,600 --> 00:25:51,960 and even laptop computers. 370 00:25:51,960 --> 00:25:53,520 So how does the system work? 371 00:25:53,520 --> 00:25:58,680 Let's say you're backpacking and you have a receiver with you, you're going to turn 372 00:25:58,680 --> 00:25:59,680 on that receiver. 373 00:25:59,680 --> 00:26:06,020 Now the GPS satellites are constantly broadcasting a signal, all 24 of them, but above you at 374 00:26:06,020 --> 00:26:10,260 any one time there's only 12 available, and then the other 12 are on the other side of 375 00:26:10,260 --> 00:26:11,260 the Earth. 376 00:26:11,260 --> 00:26:16,180 So your receiver is going to listen and try to find at least four of these satellites 377 00:26:16,180 --> 00:26:21,860 directly above you, and then it's going to determine a range for each satellite, and 378 00:26:21,860 --> 00:26:27,380 it's going to use those ranges and the known locations of the satellites, and it's going 379 00:26:27,380 --> 00:26:32,300 to do some mathematical calculations and a process called trilateration, and it's going 380 00:26:32,300 --> 00:26:35,060 to figure out where that GPS receiver is. 381 00:26:35,100 --> 00:26:39,700 And it'll also give you altitude, and it'll give you speed and the direction that you're 382 00:26:39,700 --> 00:26:40,700 traveling in. 383 00:26:40,700 --> 00:26:45,100 A standard GPS receiver will not only place you on a map at any particular location, but 384 00:26:45,100 --> 00:26:48,180 will also trace your path across a map as you move. 385 00:26:48,180 --> 00:26:52,100 If you leave your receiver on, it can stay in constant communication with GPS satellites 386 00:26:52,100 --> 00:26:54,420 to see how your location is changing. 387 00:26:54,420 --> 00:26:58,020 With this information and this built-in clock, the receiver can give you several pieces of 388 00:26:58,020 --> 00:27:03,340 valuable information like how far you've traveled, how long you've been traveling, your current 389 00:27:03,340 --> 00:27:05,740 speed and your average speed. 390 00:27:05,740 --> 00:27:09,060 Also the estimated time of arrival at your destination, if you maintain your current 391 00:27:09,060 --> 00:27:10,060 speed. 392 00:27:10,060 --> 00:27:13,820 There's a lot of uses that they hadn't really thought about when they developed the system. 393 00:27:13,820 --> 00:27:19,300 For example, later on it was discovered that if you put multiple antennas on a vehicle 394 00:27:19,300 --> 00:27:22,940 like an aircraft, for instance, you could actually get attitude. 395 00:27:22,940 --> 00:27:28,260 You could figure out its orientation, whether it was rolling or pitching or yawing. 396 00:27:28,260 --> 00:27:33,220 Other things that they didn't realize they could really do were, for instance, seismologists 397 00:27:33,220 --> 00:27:38,260 use it for earthquake detection to find out when tectonic plates are actually shifting 398 00:27:38,260 --> 00:27:39,260 apart. 399 00:27:39,260 --> 00:27:40,260 It's that good. 400 00:27:40,260 --> 00:27:41,260 Something else. 401 00:27:41,260 --> 00:27:42,260 Yeah. 402 00:27:42,260 --> 00:27:43,260 Very interesting. 403 00:27:43,260 --> 00:27:44,260 Sure. 404 00:27:44,260 --> 00:27:46,100 So that's how it works. 405 00:27:46,100 --> 00:27:48,900 So the next time you want to know where you are or where you're going, don't reach for 406 00:27:48,900 --> 00:27:49,900 a map. 407 00:27:49,900 --> 00:27:50,900 Reach for your GPS. 408 00:27:50,900 --> 00:27:58,340 How much button is it here to press for a date for tonight's gathering? 409 00:27:58,340 --> 00:28:00,540 That's all for this edition of Destination Tomorrow. 410 00:28:00,540 --> 00:28:01,540 Thank you for joining us. 411 00:28:01,540 --> 00:28:02,840 I'm Steele McGonigal. 412 00:28:02,840 --> 00:28:04,020 And I'm Kara O'Brien. 413 00:28:04,020 --> 00:28:18,620 For all of us here at NASA, we'll see you next time.