1 00:00:01,167 --> 00:00:04,167 [rocket rumbling] 2 00:00:04,167 --> 00:00:07,133 [percussive music] 3 00:00:14,968 --> 00:00:15,968 - HEY, THERE. 4 00:00:15,968 --> 00:00:17,434 WELCOME TO "NASA LAUNCHPAD." 5 00:00:17,434 --> 00:00:19,400 I'M YOUR HOST, AMBER WHALEN. 6 00:00:19,400 --> 00:00:21,133 OKAY, SO YOU KNOW THAT MASS 7 00:00:21,133 --> 00:00:23,133 IS THE AMOUNT OF MATTER IN AN OBJECT. 8 00:00:23,133 --> 00:00:25,133 KIND OF A SIMPLE CONCEPT, RIGHT? 9 00:00:25,133 --> 00:00:28,200 AN OBJECT'S MASS DOESN'T CHANGE DUE TO GRAVITATIONAL PULL. 10 00:00:28,200 --> 00:00:29,467 THAT'S WEIGHT. 11 00:00:29,467 --> 00:00:31,567 BUT THE MASS OF AN OBJECT DOES HAVE RELEVANCE 12 00:00:31,567 --> 00:00:33,200 TO SEVERAL OTHER PROPERTIES. 13 00:00:33,200 --> 00:00:34,934 AND THOSE PROPERTIES ARE CALLED-- 14 00:00:34,934 --> 00:00:37,200 WAIT FOR IT-- MASS PROPERTIES. 15 00:00:37,200 --> 00:00:40,267 NOW, WHAT ARE THESE PROPERTIES, AND WHAT DO THEY MEAN? 16 00:00:40,267 --> 00:00:41,701 WELL, TO ANSWER THAT QUESTION, 17 00:00:41,701 --> 00:00:44,133 WHO BETTER TO TURN TO THAN AMANDA CUTRIGHT? 18 00:00:44,133 --> 00:00:46,701 SHE IS THE MASS PROPERTIES WORKING GROUP LEAD 19 00:00:46,701 --> 00:00:48,701 SUPPORTING THE ORION FLIGHT TEST OFFICE 20 00:00:48,701 --> 00:00:52,367 THROUGH THE ABORT FLIGHT TEST FLIGHT-TEST ARTICLES PROJECT. 21 00:00:52,367 --> 00:00:54,167 THAT WON'T FIT IN THE LOWER-THIRD TITLE, 22 00:00:54,167 --> 00:00:57,100 SO WE'RE GOING TO CALL HER A MECHANICAL ENGINEER, 23 00:00:57,100 --> 00:00:59,701 WHICH SHE IS ALSO. 24 00:00:59,701 --> 00:01:01,701 - WHEN I MENTION MASS PROPERTIES, 25 00:01:01,701 --> 00:01:04,167 THERE ARE A LOT OF DIFFERENT PROPERTIES CONTAINED IN THERE. 26 00:01:04,167 --> 00:01:06,434 THE ONES MOST COMMONLY KNOWN ARE THE MASS. 27 00:01:06,434 --> 00:01:08,300 AND THERE'S ALSO THE CENTER OF GRAVITY, 28 00:01:08,300 --> 00:01:10,200 SO THAT'S KIND OF THE POINT WHERE 29 00:01:10,200 --> 00:01:13,634 THAT MASS COULD BE REFLECTED IN ONE POINT, 30 00:01:13,634 --> 00:01:15,734 SO IF YOU'RE BALANCING IT ON A KNIFE, 31 00:01:15,734 --> 00:01:17,601 THAT CENTER OF GRAVITY IS WHAT YOU NEED 32 00:01:17,601 --> 00:01:19,701 TO PUT OVER THAT KNIFE TO MAKE IT BALANCED. 33 00:01:19,701 --> 00:01:21,367 AND THERE'S ALSO AN INERTIA COMPONENT, 34 00:01:21,367 --> 00:01:25,834 WHICH IS A FUNCTION OF THE MASS AND HOW FAR AWAY THAT MASS IS 35 00:01:25,834 --> 00:01:27,267 FROM THE CENTER OF GRAVITY, 36 00:01:27,267 --> 00:01:30,567 OR THE POINT THAT YOU WANT THE INERTIAS ABOUT. 37 00:01:30,567 --> 00:01:32,801 - SO LET'S RECAP REAL QUICK. 38 00:01:32,801 --> 00:01:36,067 THE TWO BIG PROPERTIES THAT AMANDA MENTIONED BESIDES MASS 39 00:01:36,067 --> 00:01:38,400 ARE INERTIA AND THE CENTER OF GRAVITY. 40 00:01:38,400 --> 00:01:40,100 GO BACK TO NEWTON'S FIRST LAW. 41 00:01:40,100 --> 00:01:42,067 AN OBJECT AT REST STAYS AT REST 42 00:01:42,067 --> 00:01:43,901 AND AN OBJECT IN MOTION STAYS IN MOTION 43 00:01:43,901 --> 00:01:45,734 AT THE SAME SPEED AND DIRECTION 44 00:01:45,734 --> 00:01:47,868 UNLESS SOME NEW FORCE COMES ON THE SCENE. 45 00:01:47,868 --> 00:01:50,701 LET'S FACE IT; THE ONLY WAY YOU'RE GONNA GET OFF THAT COUCH 46 00:01:50,701 --> 00:01:53,534 IS WHEN SOME OUTSIDE FORCE DRIVES YOU TO DO SO, 47 00:01:53,534 --> 00:01:55,601 LIKE HUNGER, YOUR MOTHER YELLING AT YOU, 48 00:01:55,601 --> 00:01:56,934 OR NATURE CALLING. 49 00:01:56,934 --> 00:01:58,467 THAT'S BECAUSE ALL OBJECTS 50 00:01:58,467 --> 00:02:00,067 REALLY HATE TO CHANGE WHAT THEY'RE DOING 51 00:02:00,067 --> 00:02:01,300 WITHOUT A GOOD REASON. 52 00:02:01,300 --> 00:02:03,467 AND THAT SOMETHING SCIENTISTS CALL INERTIA 53 00:02:03,467 --> 00:02:05,200 OR THE RESISTANCE OF AN OBJECT 54 00:02:05,200 --> 00:02:07,133 TO MAKE CHANGE IN THE STATE OF MOTION. 55 00:02:07,133 --> 00:02:09,434 BUT THE HIGHER THE INERTIAL MASS OF AN OBJECT, 56 00:02:09,434 --> 00:02:12,133 THE LARGER THE RESISTANCE TO CHANGING ITS STATE OF MOTION. 57 00:02:12,133 --> 00:02:15,033 SO IF YOU HAD TWO OBJECTS WITH DIFFERENT MASSES, 58 00:02:15,033 --> 00:02:16,567 THE OBJECT WITH THE LARGER MASS 59 00:02:16,567 --> 00:02:18,467 WILL EXPERIENCE A SMALLER ACCELERATION, 60 00:02:18,467 --> 00:02:20,033 AND THE OBJECT WITH THE SMALLER MASS 61 00:02:20,033 --> 00:02:22,100 WILL EXPERIENCE A BIGGER ACCELERATION. 62 00:02:22,100 --> 00:02:24,701 THE CENTER OF GRAVITY IS ANOTHER IMPORTANT PROPERTY. 63 00:02:24,701 --> 00:02:26,567 REMEMBER THAT GRAVITY IS PULLING EQUALLY 64 00:02:26,567 --> 00:02:28,434 AT ALL PARTS OF AN OBJECT. 65 00:02:28,434 --> 00:02:30,067 SO AN OBJECT'S CENTER OF GRAVITY 66 00:02:30,067 --> 00:02:32,834 IS THE POINT IN WHICH THE SYSTEM'S WEIGHT IS BALANCED. 67 00:02:32,834 --> 00:02:34,267 BUT KEEP IN MIND, 68 00:02:34,267 --> 00:02:36,400 THE CENTER OF GRAVITY DOESN'T ALWAYS CORRESPOND 69 00:02:36,400 --> 00:02:38,200 WITH THE GEOMETRIC CENTER OF AN OBJECT. 70 00:02:38,200 --> 00:02:40,634 FOR EXAMPLE, THE CENTER OF GRAVITY IN SPORTS CARS 71 00:02:40,634 --> 00:02:42,567 WOULD BE DESIGNED LOW TO THE GROUND 72 00:02:42,567 --> 00:02:44,701 TO MAKE FOR EASIER HANDLING ON SHARP TURNS 73 00:02:44,701 --> 00:02:47,567 WHILE THE CENTER OF GRAVITY IN A BIG TRUCK IS MUCH HIGHER, 74 00:02:47,567 --> 00:02:49,834 MAKING SUDDEN TURNS A PROBLEM. 75 00:02:49,834 --> 00:02:51,667 WHERE DO YOU THINK THE CENTER OF GRAVITY IS 76 00:02:51,667 --> 00:02:53,234 IN SOME OF THESE THINGS? 77 00:03:00,667 --> 00:03:03,901 BUT HOW DO THOSE PROPERTIES AFFECT HOW SOMETHING FLIES? 78 00:03:03,901 --> 00:03:06,667 HERE'S AMANDA AGAIN TO EXPLAIN. 79 00:03:06,667 --> 00:03:08,634 - THOSE SPECIFIC PROPERTIES AFFECT FLIGHT 80 00:03:08,634 --> 00:03:11,167 FROM A LOT OF DIFFERENT PERSPECTIVES. 81 00:03:11,167 --> 00:03:13,434 PROBABLY THE MAIN ONES ARE THE AERODYNAMICS 82 00:03:13,434 --> 00:03:14,834 AND THE FLIGHT DYNAMICS, 83 00:03:14,834 --> 00:03:17,334 SO THE PATH, OR TRAJECTORY, THE OBJECT IS GOING TO TAKE, 84 00:03:17,334 --> 00:03:19,801 WHICH ALSO THEN GOES INTO THE AVIONICS, 85 00:03:19,801 --> 00:03:22,634 OR FLIGHT CONTROL SYSTEMS, THAT GO INTO THE ARTICLE, 86 00:03:22,634 --> 00:03:25,267 AND IT ALSO GETS INVOLVED 87 00:03:25,267 --> 00:03:27,767 FROM A STRUCTURE AND LOAD STANDPOINT, 88 00:03:27,767 --> 00:03:29,834 SO THAT MASS AND THAT CENTER OF GRAVITY 89 00:03:29,834 --> 00:03:32,234 AFFECTS HOW MUCH LOAD IS GOING TO BE APPLIED 90 00:03:32,234 --> 00:03:35,234 TO CERTAIN COMPONENTS OF THE SYSTEM. 91 00:03:35,234 --> 00:03:37,234 - BUT ARE THOSE PROPERTIES GOING TO BE THE SAME 92 00:03:37,234 --> 00:03:38,601 IN A FLIGHT-TEST ARTICLE? 93 00:03:38,601 --> 00:03:42,100 FOR EXAMPLE, IN THE ARES I-X FLIGHT-TEST ARTICLE, 94 00:03:42,100 --> 00:03:43,734 CERTAIN COMPONENTS AREN'T GOING TO HAVE 95 00:03:43,734 --> 00:03:45,901 ALL THE SAME INTERNAL SYSTEMS AND STRUCTURES 96 00:03:45,901 --> 00:03:48,567 THAT WILL GO INTO THE FINAL ARES I VEHICLE. 97 00:03:48,567 --> 00:03:50,801 AND OF COURSE, THERE WON'T BE ANY ASTRONAUTS 98 00:03:50,801 --> 00:03:52,334 GOING UP IN THE ARES I-X. 99 00:03:52,334 --> 00:03:54,901 THIS SEEMS TO BE A CHALLENGE FOR ENGINEERS. 100 00:03:54,901 --> 00:03:58,801 SO HOW DO YOU HANDLE THAT? AMANDA? 101 00:03:58,801 --> 00:04:00,634 - SO AS A MASS PROPERTIES ENGINEER, 102 00:04:00,634 --> 00:04:02,200 A QUESTION THAT COMES UP A LOT IS, 103 00:04:02,200 --> 00:04:05,467 ARE WE ACCURATELY REPRESENTING IN OUR FLIGHT-TEST ARTICLES 104 00:04:05,467 --> 00:04:07,834 WHERE THE ASTRONAUTS ARE SITTING AND WHERE THEIR BEDS ARE 105 00:04:07,834 --> 00:04:09,934 AND ALL THE DIFFERENT COMPONENTS? 106 00:04:09,934 --> 00:04:12,467 SO THE ANSWER TO THAT QUESTION IS THAT 107 00:04:12,467 --> 00:04:17,567 THE OPERATIONAL VEHICLE WILL HAVE ALL THOSE SYSTEMS IN THERE, 108 00:04:17,567 --> 00:04:19,601 THE ASTRONAUTS IN THERE, AND THEREFORE, 109 00:04:19,601 --> 00:04:22,734 IT HAS A RESULTING MASS AND CENTER OF GRAVITY POINT. 110 00:04:22,734 --> 00:04:24,334 FOR OUR FLIGHT-TEST ARTICLES, 111 00:04:24,334 --> 00:04:27,534 WE HAVE TO END UP WITH THE SAME MASS AND CENTER OF GRAVITY POINT, 112 00:04:27,534 --> 00:04:29,200 BUT WE HAVE A DIFFERENT STRUCTURE 113 00:04:29,200 --> 00:04:30,868 AND DIFFERENT SUBSYSTEMS IN THERE. 114 00:04:30,868 --> 00:04:34,133 SO IN OUR PARTICULAR CASE FOR THE PAD-ABORT 1 FLIGHT TEST 115 00:04:34,133 --> 00:04:37,234 AS WELL AS THE NEXT FLIGHT TEST, WHICH WILL BE ASCENT-ABORT 1, 116 00:04:37,234 --> 00:04:40,300 WE HAVE THOUSANDS OF POUNDS OF BALLAST THAT WE USE 117 00:04:40,300 --> 00:04:44,767 TO GET TO THAT MASS AND CG REQUIREMENT. 118 00:04:44,767 --> 00:04:46,868 - SO IF THEY'RE PUTTING BALLAST IN, 119 00:04:46,868 --> 00:04:48,834 OR SOME RANDOM HEAVY MATERIAL 120 00:04:48,834 --> 00:04:50,868 ADDED TO HELP STABILIZE THE OBJECT, 121 00:04:50,868 --> 00:04:53,434 THAT'S GOT ME WONDERING HOW THESE FLIGHT-TEST ARTICLES 122 00:04:53,434 --> 00:04:55,467 COMPARE TO THEIR FINAL COUNTERPARTS. 123 00:04:55,467 --> 00:04:56,968 WELL, IT DEPENDS. 124 00:04:56,968 --> 00:04:58,100 DIFFERENT FLIGHT TESTS 125 00:04:58,100 --> 00:04:59,934 HAVE DIFFERENT GOALS AND OBJECTIVES, 126 00:04:59,934 --> 00:05:01,934 SO NOT ALL PARTS OF THE FLIGHT-TEST ARTICLE 127 00:05:01,934 --> 00:05:03,167 NEED TO BE IDENTICAL. 128 00:05:03,167 --> 00:05:04,367 AND IN SOME CASES, 129 00:05:04,367 --> 00:05:06,834 THE MATERIALS USED MAY NOT EVEN BE THE SAME. 130 00:05:06,834 --> 00:05:09,234 LET'S LET AMANDA EXPLAIN. 131 00:05:09,234 --> 00:05:11,000 - SO WHAT YOU SEE BEHIND ME IS THE HEAT SHIELD 132 00:05:11,000 --> 00:05:12,801 FOR THE ASCENT-ABORT 1 FLIGHT TEST, 133 00:05:12,801 --> 00:05:15,234 AND I'LL USE THAT AS AN EXAMPLE FOR SOMETHING THAT WE DO 134 00:05:15,234 --> 00:05:17,868 ON ALL THE COMPONENTS THAT GO INTO THE FLIGHT TESTS. 135 00:05:17,868 --> 00:05:19,601 WE HAVE A CAD MODEL THAT REPRESENTS-- 136 00:05:19,601 --> 00:05:20,934 COMPUTER AIDED DESIGN MODEL-- 137 00:05:20,934 --> 00:05:23,067 THAT REPRESENTS THE IDEAL HEAT SHIELD, 138 00:05:23,067 --> 00:05:25,300 SO THE DENSITY AND THE SHAPE 139 00:05:25,300 --> 00:05:26,968 OF THAT PARTICULAR PART, 140 00:05:26,968 --> 00:05:29,434 BUT WE ACTUALLY TAKE A MEASUREMENT 141 00:05:29,434 --> 00:05:30,901 OF WHAT THAT ACTUALLY WEIGHS, 142 00:05:30,901 --> 00:05:33,133 AND WE COMPARE IT TO THE ANALYTICAL MODEL. 143 00:05:33,133 --> 00:05:35,334 SO FOR MASS PROPERTIES, WE HAVE BOTH ESTIMATES 144 00:05:35,334 --> 00:05:37,868 THAT COME FROM A VARIETY OF AREAS 145 00:05:37,868 --> 00:05:42,133 AS WELL AS THE ACTUALS FOR EACH COMPONENT. 146 00:05:42,133 --> 00:05:44,234 - THANKS, AMANDA, FOR ALL THE INFORMATION. 147 00:05:44,234 --> 00:05:45,834 TESTING AND RETESTING, 148 00:05:45,834 --> 00:05:47,801 LOOKING FOR THE BEST ANSWERS. 149 00:05:47,801 --> 00:05:51,200 AND YOU THOUGHT DRAFT VERSIONS ENDED WITH FRESHMAN ENGLISH. 150 00:05:51,200 --> 00:05:53,267 WELL, THAT'S IT FOR THIS EPISODE. 151 00:05:53,267 --> 00:05:55,100 I'M AMBER WHALEN, AND WE'LL CATCH YOU NEXT TIME 152 00:05:55,100 --> 00:05:56,501 ON "NASA LAUNCHPAD."