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NASA Connect video containing four segments as described following. First segment of Rocket to the Stars defines work and energy using the concepts of force, motion, distance, mass, height, and gravity. The work and energy segment covers the Gravitational Potential energy,and Kiinetic Energy equations. The Work and Energy segment next provides a problem that involves the calculation of the Kinetic Energy of 2 different rovers on the planet Mars. Second segment of Rocket to the Stars contains a preview of the Program's Hands on Activity which allows students to investigate the relationship between height a marble is released and distance a milk carton will travel once the marble hits the milk carton. Third segment of Rocket to the Stars describes Nuclear Energy and how NASA Scientists will use this energy in space exploration. Fourth segment of Rocket to the Stars describes a new rocket propulsion technology called Variable Specific Impluse Magnetoplasma Rocket or VASIMR for short.
Hey, hey, hey. I'm Kenan Thompson, but I play Fat Albert in the live action film based
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on Bill Cosby's hit show. On this episode of NASA Connects, you'll learn about the
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science concepts of work and energy. You'll also see how we can use algebra to help explain
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both concepts. NASA engineers and scientists will introduce you to exciting and innovative
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space propulsion technologies of the future. And in your classroom, you'll apply your math
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and science skills by conducting a really cool hands-on activity. So stay tuned as host
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Jennifer Pulley takes you on another exciting episode of NASA Connects. Rocket to the stars.
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Hi, I'm Jennifer Pulley, and welcome to NASA Connect, the show that connects you to math,
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science, technology, and NASA. Imagine it's the year 2040. You and a team of international
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scientists are part of the exploration crew that will begin construction of the first
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human base on Mars. You are laying the groundwork for the next generation of explorers to explore
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Mars and beyond. It's not an easy task, but you are up to the challenge. All your years
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of schooling, training, and hard work have finally paid off. Does it sound like a fantasy
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to you? Actually, it's not. NASA is ready to make the next step to exploring the solar
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system and beyond, and they need your help. NASA is looking for bright, young engineers,
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scientists, and researchers who will make the new vision for space exploration a reality.
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For you, it starts right now in the classroom. Now, during the course of this program, you
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will be asked to answer several inquiry-based questions. After the questions appear on the
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screen, your teacher will pause the program to allow you time to answer and discuss the
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questions. This is your time to explore and become critical thinkers. Students working
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in groups take a few minutes to answer the following questions. One, what comes to mind
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when you think of work? Two, how are work and energy related? Three, what are some forms
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of energy? Briefly describe them and give examples of each. It is now time to pause
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the program and answer the questions. So, guys, how did you do with the questions? Great
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job. Okay, let's get started. So, what is work? Well, most people would say they are
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working when they do anything that requires a physical or a mental effort. Now, in scientific
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terms, work is the use of force to move an object a certain distance. More specifically,
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to do work on an object, some part of the force you exert must be in the same direction
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as the object's motion. Let's look at the following two examples. On the left side,
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Norbert is lifting a stack of textbooks from the floor. And on the right side, he is carrying
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the stack of textbooks. Note the direction of the applied force and motion for each
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example. In which example is Norbert actually doing work? If you said the left side, you
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are correct. Why isn't Norbert doing work in the example on the right? Well, because
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no part of the applied force is in the same direction as the object's motion. When the
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force is in the same direction as the motion, we can determine the amount of work being
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done on an object by multiplying force times distance. What are the units for work? You
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know that force is measured in newtons and distance can be measured in meters. The product
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of a force measured in newtons and the distance measured in meters is a measurement called
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a newton meter or the joule. The joule is the standard unit used to measure work. One
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joule of work is done when a force of one newton moves an object one meter. Do you have
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any idea how much a joule of work is? I know. Let's take an apple, which weighs about one
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newton. Now, if you lift the apple from the floor to your waist, which is about one meter,
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you do one joule of work on the apple. But what happens if I want to lift 100 apples?
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For me, that would take a lot of force and I don't think I have enough energy to do that.
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Let's go back to our example with the apple. Now, I easily have enough energy to lift this
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apple from the floor to my waist and I know I'm doing work on the apple as I lift it. So,
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there must be a relationship between work and energy, right? When I lifted the apple from the
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floor, I caused a change. In this case, the change is in the position of the apple. An object that
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has energy has the ability to cause change or the ability to do work. When I worked on the apple,
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some of my energy was transferred to the apple. You can think of work then as the transfer of
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energy. As I lifted the apple from the floor to my waist, the apple gained energy. You know,
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guys, energy has many forms and we'll get to your list in just a few minutes. But first,
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let's focus on two forms of energy, potential energy and kinetic energy. Let's take a look
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at each. If I hold the apple still in my hand, does the apple have energy? Careful, not all forms
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of energy involve movement. Well, this apple has stored energy. We call it potential energy. Holding
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the apple like this gives the apple the potential to fall to the ground. Now, if I release the apple,
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the apple falls. The potential energy changes into kinetic energy. It is pretty obvious when
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an object has kinetic energy. As long as the object is moving, it's said to have kinetic
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energy. What's more difficult to determine is how much potential energy an object has. Let's go back
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to our example with the apple. The potential energy of this apple really depends on height.
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How high or low my hand is from the ground. We call this type of potential energy gravitational
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potential energy. Gravitational potential energy depends on mass, gravitational acceleration and
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height near the Earth's surface. Gravitational potential energy, or GPE, is equal to the
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product of mass, gravitational acceleration and height. Remember that G is the acceleration caused
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by Earth's gravity, which at sea level equals 9.8 meters per second squared. Let me show you an
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example. Suppose a satellite has a mass of 293 kilograms and we lift it to the top of Mount
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Everest. What is the gravitational potential energy of the satellite? Well, what do we know?
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We know mass is equal to 293 kilograms. Gravitational acceleration is equal to 9.8
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meters per second squared. And we know the height of Mount Everest, which is approximately 8,850
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meters. Let's write the equation for gravitational potential energy. GPE equals MGH. Substituting
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in our values for mass, acceleration due to gravity, and height, we get GPE equals the product of 293
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kilograms, 9.8 meters per second squared, and 8,850 meters. The answer turns out to be approximately
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25 million. Don't forget, I need to assign a unit to that number. Units are very important when
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explaining scientific concepts. Do you have any idea what the unit for energy is? Let's figure it
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out. The original equation for GPE is MGH. Mass times gravity is equal to weight. And weight is
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measured in newtons. Remember, weight is a force. Therefore, the unit for gravitational potential
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energy is the newton meter. Do you remember from earlier in the program what a newton meter is
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equivalent to? Well, if you said one joule, you're on the ball. One newton meter is equivalent to one
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joule. Wait a minute. Work is also measured in joules. I think we just showed mathematically how
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energy and work are related to each other. Now let's go back to kinetic energy. How much kinetic
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energy do you think an object, say like a rocket, depends on? The kinetic energy of an object depends
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on both its mass and its velocity. The mathematical relationship between kinetic energy, mass, and
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velocity is KE equals 1 half MV squared. Notice that the velocity is squared in the equation. Remember
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guys, the number two is called an exponent. The exponent tells you how many times a number or base
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is used as a factor. For example, two squared is equal to two times two, which equals four. Three
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squared is equal to three times three, which equals nine, and so on. The term V squared equals V times
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V. So, are you ready to try a problem involving kinetic energy? Here's one for you. Norbert's
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Mars rover, with a mass of 210 kilograms, is traveling on the surface of Mars at a speed of
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six meters per second. Zot's rover, with a mass of 170 kilograms, is traveling on the surface of Mars
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at eight meters per second. Predict which rover has more kinetic energy, then verify your prediction
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mathematically. You may now pause the program. So, did you make the correct prediction? Let's
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double check your work. Solving for the kinetic energy of Norbert's rover, we have kinetic energy
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is equal to one half times 210 kilograms times six meters per second quantity squared. The kinetic
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energy of Norbert's rover is equal to 3780 joules. Solving for the kinetic energy of Zot's rover,
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we have kinetic energy is equal to one half times 170 kilograms times eight meters per second
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quantity squared. The kinetic energy of Zot's rover is equal to 5440 joules. So, comparing the
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two values, we see that the kinetic energy for Zot's rover is greater than the kinetic energy
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for Norbert's rover. We now know that an object may possess both kinetic energy and potential
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energy at the same time. Let's go back to our example with the apple. Any object that rises and
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falls experiences a change in its kinetic and potential energy. Let's look at this energy
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transformation as I toss the apple into the air. When the apple moves, it possesses kinetic energy.
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As it rises, it slows down. Its kinetic energy decreases. Because the height increases, its
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potential energy increases. At the highest point, the apple actually stops moving. At this point,
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it no longer has kinetic energy, but it has maximum potential energy. As the apple falls,
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the kinetic energy increases and the potential energy decreases. No matter how energy is
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transformed or transferred, all of the energy is still present somewhere in one form or another.
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This statement is known as the law of conservation of energy. As long as you account for all the
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different forms of energy involved in any process, you will find that the total amount of energy
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never changes. In other words, energy cannot be created or destroyed. It just changes form.
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So, do you think you have a pretty good idea of what work and energy, specifically potential and
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kinetic energy, are all about? Well, good, because now it's time to preview this program's hands-on
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activity. The NASA Explorer School students from Martinsville Middle School in Martinsville,
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Virginia, will preview this program's hands-on activity. Hi, NASA Connect asked us to show you
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this program's hands-on activity. In this activity, students will do an inquiry investigation on the
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relationship between the height from which a marble on a ramp is released and the distance
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a milk carton at the end of the ramp is moved along the floor after the ball collides with the
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carton. You can download a copy of the educator's guide from the NASA Connect website for directions
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and a list of materials. Before you start the activity, your teacher will ask you to answer
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and discuss several critical thinking questions based on the experimental setup. Set up the ramp
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by using tape to mark one end 0.7 meters high and place an empty milk carton at the other end of
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the ramp so that it will catch the marble after it rolls down the ramp. You will roll a marble
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from five different measured heights. Line up a meter stick on the floor along the distance that
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the milk carton will travel after being hit by the marble. Starting at the first height marked
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on the ramp, release the marble down the ramp. On the data collection chart under trial one, record the
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linear distance that the milk carton travels after the marble hit it. You will conduct four more
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trials. Record the distance the milk carton travels. Calculate and record the average distance the milk
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carton traveled. Continue the experiment by increasing the height from which you drop the
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marble by 0.1 meter each time. Students will analyze their data by calculating the potential
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energy that the marble has at each height and the kinetic energy that the marble has at the end of
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each roll. Now is your chance to put your algebra skills to the test. Keep in mind that for this
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activity, you will need to ignore energy lost because of friction. Based on the data you collect,
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you will graphically show the relationship between the height from which the marble is dropped and
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the distance the carton is moved. From the graph, select another designated height and predict how
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far the milk carton will move if the marble is released. Go ahead and test your prediction.
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Were you correct? Don't forget to check out the web activity for this program.
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You can download it from the NASA Connect website.
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Now that you have a basic understanding of energy, let's hear about some innovative propulsion
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technologies that NASA is developing for future space exploration. And don't forget, you are the
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future explorers. Thanks, Jennifer. Space is big. Distances to Mars and beyond are so large
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that when using today's spacecraft technology, we can only send relatively small spacecraft.
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In other words, distance affects the mass that we can send. NASA is working on a new way of
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powering space vehicles that will enable us to send more complex spacecraft to Mars, Jupiter,
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and beyond, and may even shorten the travel time. The new program is called Prometheus. It will
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provide a giant leap in our ability to explore our solar system. The program focuses on using
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nuclear power in long-distance spacecraft. The nuclear power system will create electricity
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that will be used for two things. One job will be to propel the spacecraft. The other will be to
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provide power for the instruments on board. This capability will let NASA send spacecraft to places
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that we currently want to reach. It would also allow us to do more scientific work when the
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spacecraft reaches its destination and could even help speed up travel through the solar system.
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Many space missions have used nuclear power. The farthest known man-made object is the nuclear
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powered spacecraft called Voyager 1. This probe has been used for over 26 years. It is now over
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8 billion miles away. That's more than twice the distance from the sun to Pluto. Remember earlier
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in the program, Jennifer asked you to list some forms of energy. On my list, I have mechanical
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energy, thermal energy, chemical energy, electromagnetic energy, and nuclear energy.
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Project Prometheus will be using nuclear energy to help power the spacecraft. Nuclear energy is
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the energy stored in the nucleus of an atom. In a nuclear reaction, a tiny portion of an atom's
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mass is turned into energy. Scientists are studying two different ways of using the energy stored
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within the nucleus of an atom. The first approach is to take an atom that is naturally very unstable,
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which means that the atom wants to change into a different, more stable atom. During this change,
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the atom releases tiny particles causing the material to heat up. This process is known as
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radioactive decay. The released particles are called radiation. The heat that is released can
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be harnessed and converted to electrical energy. This energy can then be used to power the spacecraft
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systems. It is called radioisotope decay. The second approach is to break apart the nucleus
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of the atom to release even more energy than radioactive decay. This process is called
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nuclear fission. It is used in nuclear power plants all around the world to produce electricity.
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Nuclear fission systems can generate large amounts of power. Think of this comparison.
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A radioisotope power system could create enough power to light a few light bulbs.
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A nuclear fission power system could create enough energy to power a laundromat.
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This increased amount of energy means that a nuclear fission energy system could do more than
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just power a spacecraft's scientific instruments. It could also be used to run the engines that
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propel the rocket. NASA hopes to use this technology soon. In fact, it's already working
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on the first probe to use this technology. This probe is the Prometheus 1 mission. This mission
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will use a nuclear fission system. This system would provide energy for both spacecraft electrical
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power and propulsion. Prometheus 1 would orbit three of the larger moons of Jupiter, Callisto,
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Ganymede, and Europa. Europa is one of our solar system's most fascinating celestial bodies.
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Europa's surface is completely covered in ice, but scientists believe that the solar system's
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largest oceans could be hidden under that ice. If oceans are indeed present, there is a possibility
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that life could be found there. The Prometheus 1 mission will be finding answers to the mysteries
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of these moons. One day, the same power and propulsion systems used on Prometheus 1 could
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be used to send probes to other far-off places. These systems will even be used to support human
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missions to explore the solar system and beyond. Back to you, Jennifer.
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Thanks, Anita. Sounds pretty cool. You know, NASA is working on another propulsion technology.
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It's called VASIMR. Dr. Franklin Chang-Diaz can tell us more about that technology.
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Thank you. My name is Franklin Chang-Diaz, and I'm an astronaut and director of the Advanced Space
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Propulsion Laboratory. I would like to share with you another possible advanced space propulsion
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technology that we've been working on for many years. It is called the Variable Specific Impulse
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Magnetoplasma Rocket, or VASIMR for short. This new engine would allow for much faster space travel
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than what we can do today. VASIMR is a plasma-based propulsion system. Do you remember the
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four states of matter? They are solid, liquid, gas, and plasma. You can go from one state to the other
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by adding or subtracting heat from the material. Take water, for example. Its solid state is ice.
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Add heat, and you get liquid. Add more heat, and you get gas or vapor. If you add even more heat
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to the gas, the atoms in it get torn or broken. Remember, each atom is sort of like an egg.
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It has a central nucleus, the yolk, with positive particles in it called protons,
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and a blanket, the white, of negative charged particles called electrons in it.
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When the atom gets torn, these charges are free to roam around every which way.
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Scrambled eggs. Such a mixture of charged particles is called plasma.
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Plasmas are very hot, with temperatures of hundreds of thousands to millions of degrees.
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The sun and the stars are made of plasma. Plasmas are very good conductors of electricity
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and they respond very well to electric and magnetic fields. We use these properties to heat them
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and also to confine them and use their extreme heat to produce awesome rocket propulsion.
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Electric fields heat the plasma and speed it up. Magnetic fields direct the plasma in the right
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direction as it is pushed out of the engine. This creates thrust for the spacecraft.
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Possible fuels for the VASIMR engine could include hydrogen, deuterium, helium, nitrogen,
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and others. The use of hydrogen as a fuel for the project would also have other benefits.
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Hydrogen can be found all throughout space. This means we are likely to find plentiful supplies
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of fuel everywhere we go and we could refuel the spacecraft for the return trip to Earth.
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Also, strong magnetic fields and liquid hydrogen make for great radiation shields.
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This means the hydrogen fuel for the VASIMR engine, as well as the magnet technology we
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are developing for it, could both also be used to protect the astronaut crew
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from dangerous radiation exposure during the flight. This is how technology developed for one
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thing can also be used for another equally important purpose. To heat and accelerate the
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plasma in deep space flights, VASIMR will use electricity from nuclear power. VASIMR is still
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years away from transporting humans and cargo to Mars and beyond. Remember the scenario that
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Jennifer gave you at the beginning of the program. Our team can only take this advanced technology
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so far, and then it will be up to you. Your generation will make this space propulsion
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system a reality. Some of you may one day fly on it and become the astronauts that will build the
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first base on Mars. I've been in space seven times, but you will be the astronauts who will get a
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chance to explore the Moon, Mars, and beyond. You are the next generation of explorers, so good luck.
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Back to you, Jennifer.
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My thanks to Dr. Chang Diaz. You know, I can't wait for the day when we receive the first
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transmission from people on Mars, and maybe you'll be one of them. Well, that wraps up another episode
00:27:16
of NASA Connect. We'd like to thank everyone who helped make this program possible. Got a comment,
00:27:23
question, or suggestion? Well, email them to connect at larc.nasa.gov. And don't forget to
00:27:29
check out this program's student challenge. You can find it on the NASA Connect website.
00:27:37
So until next time, stay connected to math, science, technology, and NASA, and maybe we'll see you on Mars.
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♪♪♪
00:27:53
♪♪♪
00:28:23
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- NASA LaRC Office of Education
- Subido por:
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- Licencia:
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- Visualizaciones:
- 521
- Fecha:
- 28 de mayo de 2007 - 16:54
- Visibilidad:
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- Enlace Relacionado:
- NASAs center for distance learning
- Duración:
- 28′ 34″
- Relación de aspecto:
- 4:3 Hasta 2009 fue el estándar utilizado en la televisión PAL; muchas pantallas de ordenador y televisores usan este estándar, erróneamente llamado cuadrado, cuando en la realidad es rectangular o wide.
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