1 00:00:04,667 --> 00:00:10,601 [dramatic percussion music] 2 00:00:18,667 --> 00:00:21,100 - HEY, WELCOME TO "NASA LAUNCHPAD." 3 00:00:21,100 --> 00:00:23,133 I'M YOUR HOST, VINCE WHITFIELD. 4 00:00:23,133 --> 00:00:25,000 NOW, WHEN YOU THINK OF AN ENGINE, 5 00:00:25,000 --> 00:00:26,267 WHAT COMES TO MIND? 6 00:00:26,267 --> 00:00:29,334 PROBABLY A CAR WITH ITS RECIPROCATING GAS ENGINE 7 00:00:29,334 --> 00:00:30,801 OR MAYBE EVEN A JET ENGINE. 8 00:00:30,801 --> 00:00:32,367 OR LET'S GO OLD-SCHOOL. 9 00:00:32,367 --> 00:00:33,934 HOW ABOUT A STEAM ENGINE? 10 00:00:33,934 --> 00:00:37,067 NOW, ALL OF THESE PRODUCE ROTATIONAL ENERGY, 11 00:00:37,067 --> 00:00:40,200 OR THE KINETIC ENERGY CREATED BY THE ROTATION OF AN OBJECT. 12 00:00:40,200 --> 00:00:42,133 AND OF COURSE, YOU REMEMBER THAT ENERGY 13 00:00:42,133 --> 00:00:45,267 IS SIMPLY THE CAPACITY OR ABILITY TO DO WORK. 14 00:00:45,267 --> 00:00:47,667 BUT IF I TELL YOU TO THINK OF A NASA ENGINE, 15 00:00:47,667 --> 00:00:48,934 WHAT COMES TO MIND? 16 00:00:48,934 --> 00:00:50,901 YEAH, PROBABLY A ROCKET, RIGHT? 17 00:00:50,901 --> 00:00:52,734 AND THE ENERGY IS WHAT'S NEEDED 18 00:00:52,734 --> 00:00:54,501 TO GET THAT MASSIVE ROCKET OFF THE LAUNCHPAD 19 00:00:54,501 --> 00:00:55,534 AND INTO ORBIT. 20 00:00:55,534 --> 00:00:56,634 BUT GET THIS. 21 00:00:56,634 --> 00:00:58,634 A ROCKET ENGINE IS FUNDAMENTALLY DIFFERENT 22 00:00:58,634 --> 00:01:00,000 THAN OTHER TYPES OF ENGINES, 23 00:01:00,000 --> 00:01:02,367 AND IT CAN BE BOTH SIMPLER AND MORE COMPLEX 24 00:01:02,367 --> 00:01:03,601 AT THE SAME TIME. 25 00:01:05,667 --> 00:01:08,367 ON THE ONE HAND, A ROCKET ENGINE IS VERY SIMPLE. 26 00:01:08,367 --> 00:01:11,067 IN FACT, YOU CAN BUILD AND FLY MODEL ROCKETS FOR YOURSELF. 27 00:01:11,067 --> 00:01:12,734 TO FIND OUT WHY ROCKETS WORK, 28 00:01:12,734 --> 00:01:14,767 LET'S LOOK AT NEWTON'S THIRD LAW: 29 00:01:14,767 --> 00:01:16,300 FOR EVERY ACTION, 30 00:01:16,300 --> 00:01:18,501 THERE IS AN EQUAL AND OPPOSITE REACTION. 31 00:01:18,501 --> 00:01:19,767 AND THAT'S BASICALLY IT. 32 00:01:19,767 --> 00:01:21,734 THE ROCKET'S EXHAUST CREATES FORCE, 33 00:01:21,734 --> 00:01:24,167 AND THE ROCKET MOVES IN THE OPPOSITE DIRECTION. 34 00:01:28,033 --> 00:01:29,400 BUT ON THE OTHER HAND, 35 00:01:29,400 --> 00:01:32,133 THE PRACTICAL APPLICATION OF ROCKETS IS VERY COMPLICATED. 36 00:01:32,133 --> 00:01:34,801 I MEAN, COME ON, THEY CALL IT "ROCKET SCIENCE." 37 00:01:34,801 --> 00:01:36,567 SURE, THE CONCEPT IS SIMPLE, 38 00:01:36,567 --> 00:01:38,133 BUT AS YOU CAN SEE BY THIS PICTURE 39 00:01:38,133 --> 00:01:41,434 OF THE SPACE SHUTTLE'S SOLID ROCKET BOOSTERS, OR SRBs, 40 00:01:41,434 --> 00:01:43,601 THESE ROCKETS ARE PRETTY COMPLEX. 41 00:01:43,601 --> 00:01:45,133 LET'S TALK FUEL. 42 00:01:45,133 --> 00:01:46,801 WHAT KIND OF FUEL DOES A CAR TAKE? 43 00:01:46,801 --> 00:01:48,400 YEAH, OF COURSE, GASOLINE. 44 00:01:48,400 --> 00:01:50,367 BUT THE SRBs DON'T USE GASOLINE. 45 00:01:50,367 --> 00:01:52,334 THEY USE SOMETHING WITH A LITTLE BIT MORE KICK. 46 00:01:52,334 --> 00:01:53,734 LIKE THEIR NAME SUGGESTS, 47 00:01:53,734 --> 00:01:55,901 THEY ACTUALLY USE SOLID FUEL AS A PROPELLANT 48 00:01:55,901 --> 00:01:58,000 RATHER THAN A LIQUID LIKE GASOLINE. 49 00:01:58,000 --> 00:02:02,634 EACH SOLID ROCKET MOTOR CONTAINS MORE THAN 450,000 KILOGRAMS, 50 00:02:02,634 --> 00:02:04,868 OR 1 MILLION POUNDS, OF PROPELLANT, 51 00:02:04,868 --> 00:02:06,234 WHICH, WHEN IT'S CURED, 52 00:02:06,234 --> 00:02:08,868 LOOKS AND FEELS LIKE A HARD RUBBER ERASER. 53 00:02:08,868 --> 00:02:11,400 THE FUEL IS ACTUALLY MADE UP OF POWDERED ALUMINUM. 54 00:02:11,400 --> 00:02:13,334 YEAH, ALUMINUM, KIND OF LIKE THE FOIL 55 00:02:13,334 --> 00:02:14,767 YOU MIGHT FIND IN YOUR KITCHEN. 56 00:02:14,767 --> 00:02:17,801 BUT IN ITS POWDERED FORM, IT IS EXTREMELY FLAMMABLE 57 00:02:17,801 --> 00:02:20,067 AND IS EXPLOSIVE WHEN MIXED WITH AIR. 58 00:02:20,067 --> 00:02:23,033 SO STICK IN A CATALYST OR SOME CHEMICAL SUBSTANCE 59 00:02:23,033 --> 00:02:25,100 THAT CAN ACTUALLY START OR SPEED UP A REACTION 60 00:02:25,100 --> 00:02:27,167 WITHOUT INTERFERING WITH THE REACTION ITSELF, 61 00:02:27,167 --> 00:02:28,400 A CURING AGENT, 62 00:02:28,400 --> 00:02:30,200 AND A BINDER THAT HOLDS THE MIXTURE TOGETHER, 63 00:02:30,200 --> 00:02:31,501 THEN ADD AN OXIDIZER-- 64 00:02:31,501 --> 00:02:33,133 IN THIS CASE, AMMONIUM PERCHLORATE-- 65 00:02:33,133 --> 00:02:35,100 AND YOU GET THE REST OF THE PROPELLANT MIXTURE. 66 00:02:35,100 --> 00:02:36,501 BUT HOW DOES IT WORK? 67 00:02:36,501 --> 00:02:39,834 WELL, TO GET THE PICTURE, WE NEED TO FOCUS ON TWO THINGS: 68 00:02:39,834 --> 00:02:41,534 THE FUEL AND THE OXIDIZER. 69 00:02:41,534 --> 00:02:42,868 HERE'S DR. RICHARD BYLES 70 00:02:42,868 --> 00:02:44,334 OF THE VIRGINIA AIR AND SPACE CENTER 71 00:02:44,334 --> 00:02:47,734 WITH A SMALL-SCALE DEMONSTRATION OF HOW SOLID-FUEL ROCKETS WORK. 72 00:02:47,734 --> 00:02:51,968 - NOW, THIS IS THE BASIC OF ALL ROCKET MOTORS THAT ARE SOLID, 73 00:02:51,968 --> 00:02:53,934 FIREWORKS AND EVERYTHING ELSE, IS, 74 00:02:53,934 --> 00:02:56,634 YOU HAVE TO HAVE AN OXIDIZER, WHICH THIS STUFF IS. 75 00:02:56,634 --> 00:02:58,601 THIS IS A POWERFUL OXIDANT. 76 00:02:58,601 --> 00:03:00,667 AND YOU HAVE TO HAVE SOME FUEL SOURCE. 77 00:03:00,667 --> 00:03:03,334 AND WHAT HAPPENS WITH THE FUEL SOURCE IS, 78 00:03:03,334 --> 00:03:05,133 IN SOLID ROCKET BOOSTERS 79 00:03:05,133 --> 00:03:08,100 ON THE SPACE SHUTTLE, FOR EXAMPLE, 80 00:03:08,100 --> 00:03:11,367 THEY USE A FUEL SOURCE THAT IS SOLID 81 00:03:11,367 --> 00:03:13,834 AND HAS THE OXIDIZER MIXED WITH IT. 82 00:03:13,834 --> 00:03:16,267 AND IT'S NOT UNTIL THEY IGNITE IT FIRST 83 00:03:16,267 --> 00:03:17,968 THAT IT GOES OFF. 84 00:03:17,968 --> 00:03:20,067 IT'S STABLE AT ITS TEMPERATURE. 85 00:03:20,067 --> 00:03:21,334 AS SOON AS IT HEATS UP, 86 00:03:21,334 --> 00:03:23,934 THEN IT STARTS BURNING AND FLAMING, 87 00:03:23,934 --> 00:03:25,767 AND THAT'S WHAT TAKES THE SPACE SHUTTLE UP 88 00:03:25,767 --> 00:03:28,133 FOR THE FIRST TWO MINUTES, ALONG WITH THE MAIN ENGINE. 89 00:03:28,133 --> 00:03:30,868 - SO BASICALLY, WHAT WE'VE GOT HERE IS SODIUM CHLORATE 90 00:03:30,868 --> 00:03:32,167 AS OUR OXIDIZER 91 00:03:32,167 --> 00:03:33,968 AND A GUMMY BEAR AS OUR FUEL. 92 00:03:33,968 --> 00:03:36,601 NOW, WE PUT THE OXIDIZER INTO THE TEST TUBE 93 00:03:36,601 --> 00:03:38,067 AND THEN THE FUEL, 94 00:03:38,067 --> 00:03:39,834 JUST LIKE TEST TUBE IS A SOLID ROCKET BOOSTER. 95 00:03:39,834 --> 00:03:42,567 NEXT, WE APPLY HEAT AND WAIT FOR THE REACTION. 96 00:03:42,567 --> 00:03:44,901 AND WE HAVE IGNITION. 97 00:03:44,901 --> 00:03:46,701 THAT FLAME COMING FROM THE BURNING GUMMY BEAR 98 00:03:46,701 --> 00:03:48,467 IS A PRETTY GOOD APPROXIMATION OF WHAT YOU SEE 99 00:03:48,467 --> 00:03:50,033 WHEN THE SHUTTLE TAKES OFF, RIGHT? 100 00:03:50,033 --> 00:03:51,400 AND THE GUMMY BEAR DOES THAT 101 00:03:51,400 --> 00:03:53,501 BECAUSE IT'S MADE UP PRIMARILY OF SUGAR, 102 00:03:53,501 --> 00:03:55,634 AND SUGAR OXIDIZES VERY WELL. 103 00:03:55,634 --> 00:03:58,200 NOW, THE SHUTTLE'S SOLID ROCKET BOOSTERS 104 00:03:58,200 --> 00:03:59,667 ARE RELATIVELY INEXPENSIVE 105 00:03:59,667 --> 00:04:01,334 COMPARED TO OTHER FORMS OF PROPULSION, 106 00:04:01,334 --> 00:04:02,601 AND THEY'RE REUSABLE. 107 00:04:02,601 --> 00:04:03,901 BUT THEY'RE NOT PERFECT. 108 00:04:03,901 --> 00:04:05,267 FOR ONE THING, 109 00:04:05,267 --> 00:04:07,400 ONCE YOU START THE REACTION AND THE SRBs HAVE IGNITED, 110 00:04:07,400 --> 00:04:08,801 YOU CANNOT STOP THEM. 111 00:04:08,801 --> 00:04:11,367 AND IT'S ALSO NOT EASY TO ADJUST THE AMOUNT OF FUEL USED 112 00:04:11,367 --> 00:04:12,534 THROUGHOUT THE BURN ON THE FLY. 113 00:04:12,534 --> 00:04:13,734 THAT'S ALL DETERMINED 114 00:04:13,734 --> 00:04:15,501 IN THE MIXING AND PACKING OF THE PROPELLANT. 115 00:04:15,501 --> 00:04:18,467 DIFFERENT CONCENTRATIONS OF FUEL, OXIDIZER, ET CETERA, 116 00:04:18,467 --> 00:04:20,000 DETERMINE HOW MUCH ENERGY WILL BE USED 117 00:04:20,000 --> 00:04:21,300 THROUGHOUT THE FLIGHT. 118 00:04:21,300 --> 00:04:23,100 IN OTHER WORDS, IT'S NOT LIKE DRIVING A CAR, 119 00:04:23,100 --> 00:04:24,734 WHERE YOU CAN STOMP ON THE GAS PEDAL 120 00:04:24,734 --> 00:04:27,634 OR SLAM ON THE BRAKE TO SPEED UP OR SLOW DOWN THE CAR AT WILL. 121 00:04:27,634 --> 00:04:29,300 BUT HEY, THAT'S OKAY. 122 00:04:29,300 --> 00:04:30,834 REMEMBER, LIKE RICHARD SAID, 123 00:04:30,834 --> 00:04:32,400 THE SRBs ONLY ADD BOOST 124 00:04:32,400 --> 00:04:33,868 TO THE MAIN ENGINES OF THE SHUTTLE 125 00:04:33,868 --> 00:04:35,501 FOR THE FIRST TWO MINUTES OF FLIGHT. 126 00:04:35,501 --> 00:04:37,934 AND THOSE FIRST TWO MINUTES ARE ALL ABOUT GETTING LIFT 127 00:04:37,934 --> 00:04:39,567 AND PROPELLING THE SHUTTLE UPWARD. 128 00:04:39,567 --> 00:04:41,701 AFTER THAT, THE SRBs ARE JETTISONED 129 00:04:41,701 --> 00:04:43,934 AND RETRIEVED TO BE REPACKED FOR OTHER FLIGHTS. 130 00:04:48,400 --> 00:04:50,534 EVEN THE NEXT-GENERATION ARES SYSTEMS 131 00:04:50,534 --> 00:04:53,834 IN NASA'S CONSTELLATION PROGRAM WILL USE SOLID ROCKET BOOSTERS 132 00:04:53,834 --> 00:04:56,701 DERIVED FROM THE SPACE SHUTTLE PROGRAM FOR ITS LAUNCHES. 133 00:04:56,701 --> 00:04:58,734 ARES 1 WILL USE AN SRB 134 00:04:58,734 --> 00:05:00,567 ONLY FOR THE ROCKET'S FIRST STAGE. 135 00:05:00,567 --> 00:05:03,133 ARES V, WHICH WILL BE HAULING THE CARGO AND EQUIPMENT, 136 00:05:03,133 --> 00:05:04,601 MAY NEED A BIT MORE ENERGY. 137 00:05:04,601 --> 00:05:07,167 SO ITS FIRST STAGE WILL BE A COMBINATION OF THE TWO-- 138 00:05:07,167 --> 00:05:09,601 COUNT THEM, TWO-- SOLID ROCKET BOOSTERS 139 00:05:09,601 --> 00:05:13,000 AND A CRYOGENIC ENGINE. 140 00:05:13,000 --> 00:05:14,000 NOW, WAIT A MINUTE. 141 00:05:14,000 --> 00:05:15,434 WE'VE ONLY TALKED ABOUT 142 00:05:15,434 --> 00:05:17,534 THE FIRST TWO MINUTES OF THE SPACE SHUTTLE'S FLIGHT. 143 00:05:17,534 --> 00:05:18,701 WHAT HAPPENS AFTER THAT? 144 00:05:18,701 --> 00:05:20,667 I DID SAY ROCKET SCIENCE WAS COMPLEX. 145 00:05:20,667 --> 00:05:21,968 STAY TUNED TO FIND OUT. 146 00:05:21,968 --> 00:05:22,968 THAT'S IT FOR NOW. 147 00:05:22,968 --> 00:05:24,100 I'M VINCE WHITFIELD, 148 00:05:24,100 --> 00:05:26,234 AND THANKS FOR WATCHING "NASA LAUNCHPAD." 149 00:05:26,234 --> 00:05:27,400 I'LL CATCH YOU NEXT TIME.