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Destination Tomorrow - Episode 15
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NASA Destination Tomorrow Video containing three segments as described below. NASA Destination Tomorrow Segment exploring the function of aerobraking and how this helps reduce costs and create more room in aircraft. NASA Destination Tomorrow Segment exploring new materials technology development and how it has revolutionized the world of science and technology. NASA Destination Tomorrow Segment exploring a newly discovered moon called Titan that revolves around the planet Saturn.
My Outro For My 20th Birthday
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Coming up on Destination Tomorrow, find out about one of Saturn's moons that has one
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of the best chances for life to exist outside of Earth.
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We'll also see how spacecraft are placed into orbit around faraway planets.
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And Johnny Alonzo finds out how advanced materials are keeping us safer.
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All this and more next on Destination Tomorrow.
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Hello everyone, I'm Brad Breckenridge filling in for Steel McGonagall.
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And I'm Kara O'Brien, welcome to Destination Tomorrow.
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This program will uncover how past, present, and future research is creating today's knowledge
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to answer the questions and solve the challenges of tomorrow.
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We begin with a look at a fascinating moon called Titan, which is orbiting around the
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planet Saturn.
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This moon has become the subject of much scientific speculation in recent years since
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it was discovered to have an atmosphere roughly four times thicker than Earth's.
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About half the size of Earth, this small planet-like moon has an atmosphere that contains large
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amounts of nitrogen and carbon.
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This is important because these chemicals are considered by many scientists to be the
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building blocks for life as we know it.
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Little is known about Titan's surface because its thick atmosphere hides it from view.
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To help us learn more about Titan, NASA scientists have launched an intriguing mission to explore
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this distant moon.
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This mission, called Cassini-Huygens, was launched from Kennedy Space Center on October
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15, 1997.
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Once at Saturn, the Cassini-Huygens spacecraft will not only study Saturn's atmosphere and
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its other moons, but will also drop a small lander onto the surface of Titan.
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While Cassini-Huygens will dramatically boost our knowledge of Titan, it will likely lead
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to more questions about this interesting moon.
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Tonya St. Romain spoke with researcher Dr. Marianne Rudisil to find out more about the
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current mission and possible future missions to Titan.
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One of NASA's stated goals is to search for life and life-enabling conditions such as
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water and life-like chemistry throughout the universe.
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In recent years, the task of searching for life has become much easier with the development
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of tools like the Hubble Space Telescope and advanced sensors aboard spacecraft.
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With these technology advancements, NASA scientists are now able to better identify so-called
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hotspot locations in the universe.
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A hotspot location is simply a celestial body, that is, a planet or a moon, that may have
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conditions that are conducive to the origin and existence of life.
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Scientists have located a number of potential hotspots in our solar system, though one of
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the most intriguing is a moon orbiting the planet Saturn named Titan.
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Titan is very exciting because unlike most moons in our solar system, it actually has
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an atmosphere.
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In fact, many scientists believe that Titan's atmosphere closely resembles early Earth's
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atmosphere three and a half billion years ago, when life was just beginning on our planet.
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The chemicals that make up Titan's thick, hazy atmosphere include nitrogen and carbon,
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elements considered by scientists to be the building blocks or raw materials for life
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as we know it.
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With this in mind, NASA and European Space Agency scientists are working on a mission
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called Cassini-Huygens, which will study Saturn and some of its moons, including Titan.
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The Huygens probe will descend into the thick Titan atmosphere to study its composition
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and look for signs of prebiotic chemistry.
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I spoke with Dr. Mary Ann Rudisill at NASA Langley Research Center to find out why this
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distant moon is such an important place to study.
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Titan's a really interesting place to explore for a number of reasons.
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It's a very large moon.
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It's larger than two of our planets, Mercury and Pluto.
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But the most interesting thing about it actually is that Titan has a very dense atmosphere
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and this atmosphere has a lot of chemistry, interesting chemistry going on.
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Most of the atmosphere at Titan is nitrogen, a lot like Earth's.
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It has methane, but it also has a lot of complex organic types of molecules going on.
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And it has weather as well.
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And so we think that potentially there are actually clouds on Titan that kind of rain
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organic molecules down onto the surface and kind of lay out an organic sludge along the
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surface of Titan.
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So a lot of scientists believe that in some important ways Titan might actually be very
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much like what Earth was like in its early days prior to life on our planet.
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So it's an interesting place to go to, to kind of look at those processes and understand
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how life originated on our planet in that type of physical environment.
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One of the reasons Titan is of great interest to scientists is because it's the only moon
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in the solar system known to have clouds and a thick, planet-like atmosphere.
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Because Titan's atmosphere contains nitrogen and high percentages of smog-like chemicals
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such as methane and ethane, it may actually rain gasoline-like liquids onto the surface,
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forming shallow, methane-filled lakes.
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Although the smog-like atmosphere would be harmful to humans and other forms of complex
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life on our planet, the organic nature of Titan's atmosphere is much like the prebiotic
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environment from which life arose here on Earth.
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Simply put, these conditions may actually be laying the foundation for life on Titan
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sometime in the future.
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Dr. O'Doussell, is there potential for life on Titan?
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Well, that's a really interesting question, actually, and maybe yes and maybe no.
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And I say that because of this.
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Maybe yes, because Titan has, as I said, some really interesting and complex organic chemistry
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going on.
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But the problem is that chemistry isn't all that it takes to have life.
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Titan is very far away from our sun, and so it's a very, very cold place.
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So the problem is that everything is ice.
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And life, as we know, it needs access to liquid water.
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And it also needs a source of energy.
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So on the one hand, yes, the chemistry could potentially support early life on Titan, but
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it's not warm enough.
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It's too cold, and it doesn't have access to water and energy that it would need.
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But you could speculate about some other ways, perhaps, that it could have liquid water.
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We know, for example, that meteorites have come to Titan and hit the surface, generating
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heat and bringing energy with it.
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And perhaps for certain amounts of time, then that would mean that there could be pools
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of liquid water there.
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So it's really interesting to think about and speculate about the possibility of life
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in other parts and other locations of our solar system.
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And Titan is a very interesting place to look into those questions, and that's why we're
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going there.
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Once the spacecraft gets to Saturn, how will it collect data?
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Will it use rovers like the Mars rovers?
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No, actually, it's going to be rather different from the Mars mission.
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We're not sending rovers like Spirit and Opportunity.
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It won't be trundling around on the surface like we did on Mars.
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First, we're sending the Cassini spacecraft, and it's an orbiter.
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And when it reaches Saturn, it'll actually spend the next four years there kind of doing
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a grand tour through a Saturn system.
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And one of the things it will do is about 40 flybys near Titan and collect information,
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kind of a big-picture view of Titan.
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But then in addition to that, we have a Titan probe, a Huygens probe, and that was developed
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by the European Space Agency.
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And it'll drop down through Titan's dense atmosphere, and all the way down, the instruments
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will be taking all kinds of measurements like the density of the atmosphere and the temperature
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and altitude and things of that sort.
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And of course, it's going to be taking a lot of data, a lot of information about the chemistry
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of Titan's atmosphere, what kinds of things are there and how much.
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And it'll take about two to two-and-a-half hours to get all the way down through a dense
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atmosphere.
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We don't know what it will land in, but it will be able to stay on the surface and then
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in its local area kind of take some measurements and also radio that information back to the
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orbiter and back to Earth.
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The next generation of science missions to Titan will probably be much different than
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the missions of today.
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Because little is known about the moon's geology, one type of mission concept recently developed
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by NASA would rely on a dirigible-type craft to move through Titan's atmosphere, taking
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multiple measurements over time.
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This blimp would float above the surface and deploy a small probe to sample Titan's atmosphere,
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methane crater lakes, and crater rim ice.
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The probe would be able to analyze the samples on the spot and then relay the information
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to scientists back on Earth.
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With Earth nearly 800 million miles away, the probe would need to be almost completely
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autonomous.
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This type of craft could conceivably float through Titan's atmosphere for many months,
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gathering valuable evidence about Titan's chemistry and geology and what that means
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for us back on Earth.
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NASA Jet Propulsion Laboratory, California Institute of Technology
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Realistically, what are your expectations?
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Are you expecting to find life on Titan?
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Scientists try to be very objective, you know, and only have attitudes and opinions based
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upon what we know, of course.
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And so I think a lot of people are holding back and saying, I don't expect to find life
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there.
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It's too cold.
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Even though we have extremophiles here on our planet that can live in very dry or very
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cold conditions, it's really cold out there, you know, and there isn't liquid water.
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So we're not expecting to see anything there.
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But the nice thing would be is if we could find, I think a lot of people would be very,
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very happy if we saw some serious complex organic chemistry going on.
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Prebiotic, you know, clearly prebiotic chemistry would just be wonderful.
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Going to other destinations in our solar system and then gathering this kind of information
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could really help us understand how our planet formed and how life originated on our planet.
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And these were really profound questions, not just to scientists, but to everyone.
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And so I think it's really interesting and great that NASA can send spacecraft and gather
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these kinds of data to help us answer those kinds of questions.
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Many astrobiologists are skeptical as to whether life as we know it exists on Titan.
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Although many of the building blocks for life are there, temperatures average a numbing
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minus 290 degrees Fahrenheit.
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However, Titan might provide a habitat for life if scattered sources of heat from geysers
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or volcanoes are discovered.
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Coming up, we'll find out how NASA has been using a technique called aerobraking to insert
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spacecraft into extraplanetary orbits.
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First, did you know that Saturn's density is the lowest in the solar system?
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Although Saturn has a diameter of about 75,000 miles, it's made up of primarily hydrogen
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and helium gases.
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The presence of these gases makes Saturn's specific gravity at about 0.7, less than that
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of water.
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In fact, Saturn's density is so low that if it were placed in an imaginary gigantic
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bathtub, it would float.
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In the past, entering into orbit around a planet or moon required precise navigation
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and the ability to slow a spacecraft with thrusters.
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Of course, thrusters require large amounts of fuel to slow the craft down to orbital
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speeds.
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The fuel carried on these missions takes up valuable space, which can be used to store
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science instruments.
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To help reduce costs and create more room, NASA researchers have developed an alternative
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to using fuel to slow the craft, called aerobraking.
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Aerobraking uses the atmosphere of the target planet as both a brake and a steering wheel
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to slow the craft.
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Jennifer Pulley spoke with Dr. Mary Kay Lockwood to find out more about aerobraking and how
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NASA is using this technique in space travel.
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The sight of spacecraft flying out of the atmosphere on the way to a distant destination
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is a familiar one to most of us.
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In order to break free of the Earth's gravitational field, a typical spacecraft needs to be traveling
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at speeds close to 25,000 miles per hour.
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Once the spacecraft does break free, it is able to continue traveling to its destination
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at high speeds because there is very little friction to slow it down.
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Once the craft reaches its destination, the craft must decelerate from very high speeds
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to much lower speeds in a relatively short period of time.
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In the past, additional thrusters would be fired to help the craft decelerate as it approached
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its target.
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But a major problem with this method is that the fuel needed for these thrusters takes
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up valuable space and weight, which could be used to house additional science instruments.
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More recently, NASA has been using an aero-assist technique called aerobraking, which adds the
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use of atmospheric drag to slow the craft, rather than using thrusters alone.
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This technique allows additional science instruments to be delivered to a distant target, while
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also reducing costs.
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I spoke to Dr. Mary Kay Lockwood at NASA Langley Research Center to find out more.
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Well, when we first approach a planet on a trajectory from Earth, we do a small firing
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of the thrusters and capture into a very large elliptical orbit about that planet.
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We then do several passes through the upper atmosphere of that destination to slow the
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spacecraft down into the final science orbit.
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Aerobraking is accomplished when a vehicle makes multiple passes around a planet or moon
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and uses the atmosphere to slow down the vehicle.
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This process is very slow, sometimes taking several months, because the vehicle is only
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exposed to the upper layers of the atmosphere.
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This procedure is very similar to how a rock reacts when it is skimmed across the top of
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water.
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With each skip, the rock slows down until it finally stops.
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The spacecraft is similar, because with each pass through the atmosphere, it slows down
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more and more until it finally reaches the appropriate orbital speed.
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Has the aerobraking technique ever been flown on a mission?
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Well, aerobraking was first demonstrated in the Magellan mission at the very end of the
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mission at Venus, and it has since flown in two successful Mars missions, both the
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Mars Global Surveyor mission and Mars Odyssey.
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It's also going to be used in the future on the Mars Reconnaissance Orbiter mission.
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Once a vehicle nears its destination, how does the atmosphere slow it down?
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Well, an atmosphere slows a vehicle down in the same way that if you were to put your
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hand out the window of a car while it's moving, you can feel the force of the air on your
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hand, and that is the same force that's slowing the spacecraft down when it passes through
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the atmosphere.
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Aerobraking is a good way to slow a vehicle down at a destination and capture into an
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orbit, but we're also looking at another approach called aerocapture.
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Aerocapture is similar to aerobraking because it uses the atmosphere to slow a vehicle down.
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But unlike aerobraking, which only skims the top layers of the atmosphere, the aerocapture
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technique allows the vehicle to go deep inside the atmosphere of the target.
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The vehicle maneuvers through the atmosphere using drag to decelerate to the desired orbital
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speed.
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After the vehicle exits the atmosphere, a very small thruster firing occurs to achieve
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the desired orbit around the target planet or moon.
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One of the major differences between aerobraking and aerocapture is that for aerocapture we
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need an aeroshell, and an aeroshell is very much the same as the aeroshell used on the
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Mars Exploration Rover missions you may be familiar with.
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But for aerocapture, of course, we're maneuvering through the atmosphere and then exiting the
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atmosphere and finally achieving an orbit at a destination, where with the Mars Exploration
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Rovers we were landing on the surface of that destination.
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For aerobraking you do not need an aeroshell because you're passing through the very upper
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part of the atmosphere, so the heating environment on the vehicle is not nearly as severe as
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it is with aerocapture.
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So do different planets need different shaped aeroshells, or will one design work in all
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situations?
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The aeroshell shape for the aerocapture missions at places like the Earth or at Mars or at
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Titan can be very similar to those that are used with the Mars Exploration Rover missions.
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But if we're going to destinations such as Neptune, that would require a different vehicle
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shape, different aeroshell shape, and that would be more shaped like a bullet that flies
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at an angle.
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To achieve a successful aerocapture we have to stay within a very narrow corridor.
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If we don't stay within that corridor we would have a flyby, we wouldn't capture into the
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orbit, or on the other side we would land.
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So it's very important to stay within a particular corridor through that destination.
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At Neptune the corridor is narrower.
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It's kind of like a little highway.
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It's like a little highway.
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And so at Neptune in order to make the highway bigger we need to have a different shape.
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So Dr. Lockwood, in addition to aeroshells, what are some other techniques that can be
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used to slow a vehicle down?
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We're looking at other techniques that might be second generation techniques that would
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use an inflatable aeroshell or even a balut.
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A balut basically looks like a giant donut.
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It's got tethers similar to a parachute, but it has a giant ring behind it and that allows
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a spacecraft to fly shallower in the atmosphere to still slow down.
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We are always working to achieve the science and exploration goals for NASA and being able
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to reduce the cost of these systems and being able to improve the performance of the systems
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is a very important part of achieving that goal.
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It's very exciting and challenging work.
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Coming up, we'll find out how specialized materials are saving lives, but first, did
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you know that aerobraking was first tested on the Magellan mission to Venus in 1994?
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Although the Magellan mission used propulsion to slow the craft, aerobraking was tested
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at the end of the mission to validate the theory.
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With the success of this test, NASA researchers decided to use aerobraking as the primary
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deceleration method on one of its next missions, the Mars Global Surveyor.
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On February 4, 1999, history was made when the Mars Global Surveyor successfully obtained
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stable circular orbit of Mars using aerobraking as the primary method of deceleration.
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Researchers at NASA have a long and significant history of materials technology development.
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With an impressive list of new lubricants, lightweight alloys and composites, these materials
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have revolutionized our world.
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Since the 1960s, the process of creating new materials has rapidly advanced.
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Today, NASA scientists are continuing to develop new materials that are hundreds of times stronger
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than steel at a fraction of the weight.
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These advanced materials are becoming so strong and lightweight, they can stop bullets and
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even keep debris from puncturing space vehicles.
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But how are these materials made and what else can they be used for?
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Our own Johnny Alonzo finds out how it works.
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Specialized protective clothing has been around for thousands of years.
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From ancient warriors to medieval knights, protective garments were worn to help prevent
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injuries and save lives.
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The materials that were used to make these types of clothing, like metal and leather,
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worked well in those early days, but as weapons became more sophisticated, the usual materials
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began offering less protection.
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The types of materials that were used to make protective clothing remained relatively unchanged
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until about the mid-1960s, when a research scientist named Stephanie Qualik introduced
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a revolutionary new material called Kevlar.
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This material was not only lightweight and durable, but was about five times stronger
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ounce for ounce than steel.
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With this development, the world of protective materials changed forever.
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Today, stronger, lighter synthetic structures have opened up new and exciting avenues in
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the development of protective materials.
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These materials are being used in everything from sporting goods to space applications.
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To help shed some light on how these materials have changed our lives, I spoke with Dr. Jeffrey
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Hinckley at NASA Langley Research Center to find out how it works.
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If you look at the history of materials in humankind, you see the Stone Age, the Bronze
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Age, and then the Age of Steel, which is sort of the Industrial Revolution.
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We're in the course of another revolution now of high-performance materials that combine
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the strength, the stiffness of steel with other properties, electrical conductivity,
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the ability to be formed in plastically and to even stop bullets.
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Another example is Kevlar, which is used in armor protection for our troops.
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And of course, glass fiber is familiar to some people and glass fiber boats and so on.
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So we talk about Kevlar.
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How does a thin material like that stop bullets?
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We have here the flexibility of a fine fiber, a very tough, resilient material, and twice
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as strong as steel at a fifth the weight.
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And Kevlar is also a good material for penetration resistance, cut resistance.
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Because of the way it's fabricated, actually, the molecules that make up the polymer are
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stretched and aligned such that in order to break this material, you actually have to
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break the molecules.
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To understand how a flexible material like Kevlar can stop bullets, just think of a net
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on a soccer goal.
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The net strands are interlaced together, which are in turn attached to the frame of the goal.
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When the ball is kicked into the goal, each tether extends from one side of the frame
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to the other, dispersing the energy from the point of impact over a wide area.
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This forces the ball to stop.
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The same basic principle applies to bulletproof vests.
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The vest is made up of layers of fabric containing incredibly strong fibers.
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When a bullet hits this material, the energy is dissipated, forcing it to stop before it
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can penetrate the vest.
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Why is NASA interested in using these materials?
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Kevlar as a bulletproof vest material is essential to protecting the astronauts and the equipment,
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for example, on the space station.
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Space is a very hostile environment.
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Extreme temperatures, radiation, and small meteorites can make working there very dangerous.
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For example, the International Space Station is orbiting the Earth at close to 18,000 miles
00:24:19
per hour.
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At these speeds, even a piece of debris the size of a grain of sand can damage the station.
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To help decrease the chance of an object penetrating the outer skin, the space station wears a type
00:24:29
of bulletproof vest.
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Layers of aluminum, ceramic fabrics, and Kevlar form a blanket around each module's aluminum
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shell.
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If an object strikes the station, this blanket of protective materials helps to dissipate
00:24:41
the energy of the object, helping to keep the crew safe inside.
00:24:46
I know that composite materials are still relatively new.
00:24:49
How do you think they will change in the future?
00:24:53
Maybe one of the most exciting examples is carbon nanotubes.
00:24:55
These are pure carbon and unbelievably small, but they're in the form of a fiber.
00:25:00
This is a material that was discovered in the 1990s and is probably stronger than anything
00:25:07
we've known up until now.
00:25:13
It's perhaps stronger than diamond.
00:25:15
The trick is to figure out how to make something useful out of these tiny, tiny tubes.
00:25:19
This is 10,000 times smaller than the human hair.
00:25:23
And so the trick is to use this material, which, even under a microscope, just looks
00:25:28
like soot, into a strong, lightweight composite material.
00:25:33
And so our chemists are working on that.
00:25:40
An idea that's really on the drawing boards is the idea of a self-healing material.
00:25:42
You can imagine a spacecraft that's going to be in orbit for 20 years, it would be nice
00:25:47
not to have to service it.
00:25:51
So we conceived the idea of a material that would heal itself after it was damaged.
00:25:53
And I have an example here.
00:26:00
This is sort of a conventional plastic material that was struck by a 9mm bullet.
00:26:03
And as you can see, it shattered and left a hole that's just a little over 9mm in diameter.
00:26:10
This is a new material that was invented here at NASA.
00:26:17
And this also was struck by a 9mm bullet.
00:26:20
The bullet went right through, the bullet was not stopped.
00:26:23
But there's no hole.
00:26:27
We can imagine that self-healing materials would be useful on aircraft, too.
00:26:29
Right now, when an aircraft is brought in for service, they look all around it for cracks.
00:26:32
And they're looking for a critical crack, which on some commercial jets might be as
00:26:38
much as 4 inches long.
00:26:42
When they get to the critical crack size, they can repair it.
00:26:44
Well, we can imagine a composite material made with a self-healing matrix, a self-healing
00:26:47
plastic, that could heal itself and the cracks would never grow.
00:26:52
The exciting thing about working for NASA is that it is always something new.
00:26:56
And we get to sometimes see the results of our work coming into commercial use.
00:27:01
So the next time you hear about somebody getting their life saved by a bulletproof vest, you
00:27:06
know how it works.
00:27:09
I wonder if these things work well with paintballs.
00:27:11
That's all for this edition of Destination Tomorrow.
00:27:14
Thank you for joining us.
00:27:16
I'm Brad Breckenridge.
00:27:17
And I'm Kara O'Brien.
00:27:18
For all of us here at NASA, we'll see you next time.
00:27:19
1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15.
00:28:10
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- Idioma/s:
- Niveles educativos:
- ▼ Mostrar / ocultar niveles
- Nivel Intermedio
- Autor/es:
- NASA LaRC Office of Education
- Subido por:
- EducaMadrid
- Licencia:
- Reconocimiento - No comercial - Sin obra derivada
- Visualizaciones:
- 719
- Fecha:
- 28 de mayo de 2007 - 17:05
- Visibilidad:
- Público
- Enlace Relacionado:
- NASAs center for distance learning
- Duración:
- 28′ 32″
- 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.
- Resolución:
- 480x360 píxeles
- Tamaño:
- 166.11 MBytes
