1 00:00:00,000 --> 00:00:04,000 Hi, I understand you'd like to know more about propulsion systems. 2 00:00:04,000 --> 00:00:07,000 Yes, we're trying to design an out-of-this-world vacation, 3 00:00:07,000 --> 00:00:10,000 and realize because of the great distances in space, 4 00:00:10,000 --> 00:00:12,000 we might need to get there a different way. 5 00:00:12,000 --> 00:00:14,000 But how do we currently travel to space? 6 00:00:14,000 --> 00:00:19,000 We use chemical rockets that produce a jet of exhaust gases, 7 00:00:19,000 --> 00:00:22,000 and these gases propel the ship forward. 8 00:00:22,000 --> 00:00:24,000 How long would it take a spaceship to reach Mars? 9 00:00:24,000 --> 00:00:26,000 About ten months. 10 00:00:26,000 --> 00:00:28,000 Ten months is not that long. 11 00:00:28,000 --> 00:00:30,000 So why aren't chemical rockets good enough? 12 00:00:30,000 --> 00:00:34,000 To an astronaut, ten months in space is a long time. 13 00:00:34,000 --> 00:00:39,000 Persistent radiation of space will weaken your immune system 14 00:00:39,000 --> 00:00:41,000 and also damage your bones, 15 00:00:41,000 --> 00:00:45,000 so you would like to go there as fast as you can. 16 00:00:45,000 --> 00:00:47,000 Yes, we learned a little about physiological losses 17 00:00:47,000 --> 00:00:49,000 from Beth Shepard in our last case. 18 00:00:49,000 --> 00:00:52,000 What will the propulsion systems in the future be like? 19 00:00:52,000 --> 00:00:56,000 Instead of using the heat from a chemical reaction, 20 00:00:56,000 --> 00:00:59,000 future rockets will use something called a plasma. 21 00:00:59,000 --> 00:01:01,000 What's plasma? 22 00:01:01,000 --> 00:01:05,000 Plasma is a gas which has been superheated to millions of degrees. 23 00:01:05,000 --> 00:01:09,000 It is even hotter than the interior of our sun. 24 00:01:09,000 --> 00:01:10,000 That's hot. 25 00:01:10,000 --> 00:01:13,000 How will the rocket not burn up with such a high temperature? 26 00:01:13,000 --> 00:01:17,000 Since there is no known material that can take those temperatures, 27 00:01:17,000 --> 00:01:19,000 we will not use materials. 28 00:01:19,000 --> 00:01:22,000 We are going to use an invisible force field 29 00:01:22,000 --> 00:01:27,000 that will hold this plasma and prevent it from touching any surrounding material. 30 00:01:27,000 --> 00:01:28,000 How will it work? 31 00:01:28,000 --> 00:01:32,000 The magnetic field is like an invisible tube 32 00:01:32,000 --> 00:01:37,000 that will contain and guide the plasma to provide a much hotter exhaust. 33 00:01:37,000 --> 00:01:39,000 Where will you get the energy to heat the plasma? 34 00:01:39,000 --> 00:01:42,000 We will get the energy from electricity 35 00:01:42,000 --> 00:01:46,000 generated by an onboard nuclear power plant. 36 00:01:46,000 --> 00:01:50,000 Will plasma rockets be used to travel outside of our solar system? 37 00:01:50,000 --> 00:01:53,000 Actually, plasma rockets will become even more powerful 38 00:01:53,000 --> 00:01:59,000 where the energy of the plasma will be generated by an internal source, 39 00:01:59,000 --> 00:02:02,000 a thermonuclear reaction called fusion. 40 00:02:02,000 --> 00:02:05,000 I've heard of fusion. It sounds fast. 41 00:02:05,000 --> 00:02:08,000 Fusion rockets will be so fast 42 00:02:08,000 --> 00:02:13,000 that it will be possible for people to travel to the farthest reaches of the solar system 43 00:02:13,000 --> 00:02:16,000 and be able to return to their families within a couple of years. 44 00:02:16,000 --> 00:02:19,000 How long before we have this type of space travel? 45 00:02:19,000 --> 00:02:22,000 It's hard to tell. One never knows about progress. 46 00:02:22,000 --> 00:02:25,000 It could be as long as 50 years, 47 00:02:25,000 --> 00:02:27,000 but then again, it could be less. 48 00:02:27,000 --> 00:02:29,000 Why so long? 49 00:02:29,000 --> 00:02:32,000 Developing new technology takes time, 50 00:02:32,000 --> 00:02:34,000 and we do want to make sure it's safe. 51 00:02:34,000 --> 00:02:37,000 I know NASA is very cautious and always puts safety first. 52 00:02:37,000 --> 00:02:41,000 Thanks, Dr. Chang-Diaz, for giving us a lot to look forward to in the future. 53 00:02:41,000 --> 00:02:42,000 You're welcome. 54 00:02:42,000 --> 00:02:46,000 And don't forget to have fun designing your vacation. 55 00:02:46,000 --> 00:02:49,000 And be sure to call if you need anything else.