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Destination Tomorrow - Episode 20

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Subido el 28 de mayo de 2007 por EducaMadrid

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NASA Destination Tomorrow video containing four segments as described below. First segment of episode 20 that contains the Behind the Scenes segment in which Scott Striepe discusses how the Mars Reconnaissance Orbiter (MRO) will pave the way for future missions to Mars. The first segment of episode 20 discusses the technology behind the MRO and how aerobraking will be used to decrease the amount of fuel necessary for the mission. The Mars Reconnaissance Orbiter segment ends with a Did You Know? segment describing the concern NASA scientists have with Martian dust. Second segment of episode 20 contains the TechWatch segment which describes how NASA research has been the driving force behind new medical technology. The second segment of episode 20 begins with a brief flashback of how the practice of medicine has evolved from X rays to current Cat scans. The Advances in Medical Tech segment describes how the ARTEMIS technology combines CAT scans with virtual imaging technology to provide doctors with greater precision in their operations. Third segment of episode 20 contains the Retrospective segment which describes the development and history of reusable vehicles for space. The Space Shuttle Program covers the history, testing, and achievements of the Space Shuttles and their crew. The Space Shuttle Program segment ends with a Did You Know? segment on the Space Shuttle Enterprise. Fourth segment of episode 20 contains the How It Works segment which describes NASA research on sonic booms. The Sonic Booms segment describe the research underway aimed at making super sonic over land flight possible.

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My Outro For My 20th Birthday 00:00:00
Coming up on this episode of Destination Tomorrow, we take a look at a new device that may help 00:00:30
give doctors a type of x-ray vision. We'll also find out about a unique spacecraft designed 00:00:42
to help scout out locations on Mars for future human missions. And we take a look back at 00:00:47
the history of the Space Shuttle. Plus, Johnny Alonzo finds out how sonic booms work. All 00:00:52
this and more next on Destination Tomorrow. 00:00:58
Hello everyone, I'm Kara O'Brien and welcome to this edition of Destination Tomorrow. For 00:01:10
many years now, NASA planners have been sending different types of spacecraft to Mars to answer 00:01:15
basic questions about the Martian atmosphere, mineralogy, and of course, to find out if 00:01:20
life exists there. Although these missions have been very successful in answering key 00:01:25
scientific questions, it has been determined that we need to change our focus towards issues 00:01:30
relating to human factors. With the agency's new push to have human crews at Mars by around 00:01:35
2030, there's a need to begin looking at the challenges associated with getting crews there. 00:01:40
Researchers will need to spend a great deal of time looking for suitable landing sites 00:01:46
that are free of dangerous obstacles, have sufficient amounts of water, and are scientifically 00:01:49
interesting. To help in this task, a spacecraft called the Mars Reconnaissance Orbiter has 00:01:54
been designed to help pave the way. Jennifer Pulley finds out more. 00:01:59
Although the first planned human missions to Mars probably won't take place until about 00:02:07
the year 2030, NASA planners are already beginning to gear up for them. Literally millions of 00:02:11
key decisions are now being made to help ensure the success of human flights to Mars in the 00:02:17
future. Of course, one of the most important decisions that must be determined early on 00:02:21
is where to land our crews. Planners need to find a landing site that is not only free 00:02:26
of dangerous obstacles like boulders and craters, but there must also be scientifically valuable 00:02:31
points of interest. And of course, water close by is a definite plus. 00:02:37
To help prepare the way for these human missions, NASA planners have developed a unique spacecraft 00:02:41
called the Mars Reconnaissance Orbiter, or MRO. Now, this spacecraft will use advanced 00:02:47
science instruments and high-resolution cameras to scout locations of interest and possible 00:02:53
landing sites for these human missions. To help us understand how the Mars Reconnaissance 00:02:59
Orbiter will work, I spoke with Scott Streepy here at the NASA Langley Research Center to 00:03:03
find out more. Well, the Mars Reconnaissance Orbiter is a 00:03:08
multipurpose spacecraft that's designed and built for the next NASA mission to Mars. Basically, 00:03:11
the orbiter will continue NASA's exploration theme of Follow the Water. It will be on a 00:03:17
very small science orbit. It will be looking for water ice, vapor, and liquid water on 00:03:21
the surface, in the atmosphere, and even below the surface. Also, it will be able to take 00:03:27
some of the highest resolution pictures ever taken of Mars. And from that, NASA scientists 00:03:32
can evaluate potential landing sites for future robotic and human missions. Also, after the 00:03:36
primary science mission is completed, it will become a communication relay for future 00:03:42
Mars missions. So how is the MRO mission different from other 00:03:47
missions to Mars? Well, this particular mission has a high-resolution 00:03:51
camera on board. It will take more detailed pictures than we've ever been able to take 00:03:55
before. Carrying the most powerful telescopic camera 00:03:58
ever flown to another planet, the Mars Reconnaissance Orbiter will be able to show surface features 00:04:01
on Mars as small as a kitchen table. This high-resolution camera will provide a wealth 00:04:07
of information about possible landing sites by photographing the Martian surface in unprecedented 00:04:11
detail. Now, how is this high-resolution camera different 00:04:17
from other cameras used on other missions? Well, this will be able to show things on 00:04:20
a much smaller scale than we've ever been able to get on Mars. You can get details of 00:04:25
boulders and surface features that we've not been able to take with pictures. For example, 00:04:29
they'll leave me investigations to try to go and find the Mars rovers that are currently 00:04:34
there and maybe even look for some of the spacecraft that we lost previously to see 00:04:38
if we can better understand why those didn't complete successfully. 00:04:42
Because the camera and five other science instruments will produce huge amounts of data 00:04:46
every day, the MRO has been designed to send information at ten times the rate of any previous 00:04:49
Mars mission. An added benefit to the MRO is that it will continue to be used as a communications 00:04:55
platform for robotic missions of the future, long after its initial 24-month science phase 00:05:00
is complete. It also has a new suite of instruments that 00:05:06
we've never brought, except for some instruments that will continue to look at the weather 00:05:09
patterns of Mars to understand how the weather impacts the motion of the water on the surface 00:05:13
and in the atmosphere. Now, Scott, what is your role in the Mars 00:05:19
Reconnaissance Orbiter mission? Well, I lead a team of NASA engineers that 00:05:22
supports the Jet Propulsion Laboratory's navigation team during the aerobraking phase. Here at 00:05:26
NASA Langley, we have unique capabilities in aerodynamics, aerothermodynamics, thermal 00:05:30
analysis and flight mechanics. We're bringing all that in to help the Mars Reconnaissance 00:05:34
Orbiter mission during that critical aerobraking phase. 00:05:38
Aerobraking sounds like aeronautics and braking. I'm assuming this has something to do with 00:05:41
slowing the vehicle down? Aerobraking is a technique that you can reduce 00:05:44
the size of a spacecraft's orbit without using very much fuel. And in fact, the Mars Reconnaissance 00:05:48
Orbiter, when it arrives at Mars, will use its engines to put itself into a fairly large 00:05:54
elliptical orbit. Instead of using additional fuel to make that a smaller orbit, what it 00:05:57
will do is skim the upper atmosphere of Mars over a period of six months. And every time 00:06:03
it goes through the atmosphere, it'll lose some of its orbital energy through atmospheric 00:06:07
drag. But you have to be careful because if you go too deep in the atmosphere, you could 00:06:11
cause major components to overheat and thus damage them. By using aerobraking at Mars, 00:06:15
MRO is able to save hundreds of pounds of fuel. And what that means is we don't have 00:06:19
to send all that weight from Earth to Mars. And we can use maybe a smaller rocket or use 00:06:23
that weight for something else like the science instruments. 00:06:28
So Scott, what is the expected length of this mission? 00:06:30
Well, after aerobraking finishes, the primary science mission lasts one Martian year, which 00:06:33
is about 24 Earth months. After that's completed, that's when it will become a communication 00:06:38
relay for future missions. 00:06:43
Now, the term reconnaissance means that you're looking for something. You said you're looking 00:06:44
for water. What else are you searching for? 00:06:47
It'll help the NASA scientists investigate future potential landing sites for other robotic 00:06:49
missions, but also for the human missions that are coming. 00:06:54
So Scott, finally, what are your overall expectations for the MRO mission? 00:06:57
I'm really excited about the MRO mission. Not only do you have subsurface radar, very 00:07:01
high resolution images, the search for water in all three forms, looking at the weather 00:07:05
patterns and the ability to send detailed information to and from future landers. I 00:07:10
think MRO is uniquely positioned to be able to not only expand our knowledge of Mars, 00:07:15
but also continue our recent success at Mars. 00:07:20
The Mars Reconnaissance Orbiter is scheduled to take about seven months to reach Mars and 00:07:23
an additional 21 months to take its measurements, but researchers believe that it will continue 00:07:28
to be a valuable communications platform for many years to come. Coming up, we'll find 00:07:33
out about a new device that may give doctors a form of X-ray vision. But first... 00:07:38
Did you know that one big concern for future human missions to Mars is the Martian dust? 00:07:43
Because Mars has a very thin atmosphere and has about one-third the gravity of Earth, 00:07:48
the dust on Mars reacts differently to wind than the dust here on our home planet. The 00:07:53
smallest dust grains on Mars are as fine as cigarette smoke and can simply hang in the 00:07:57
air, potentially causing breathing problems for astronauts if it gets introduced into 00:08:03
the spacecraft. This dust can also form into tornado-like dust devils that can reach as 00:08:07
high as five miles, producing huge storms that can engulf the entire planet. 00:08:12
NASA is known for its breakthrough technology in aeronautics and space, but few people realize 00:08:20
how important NASA research has been in advancing medical technologies. Although this research 00:08:26
rarely specifically attempts to develop these technologies, many of its discoveries are 00:08:31
spun off and used in the creation of new medical devices. One of the latest inventions that 00:08:36
has benefited from research performed at NASA is something called Artemis. This new device 00:08:42
has the potential to make some surgeries much safer and will help to save lives. I had the 00:08:47
opportunity to visit the laboratory at Analytical Mechanics Associates to help understand how 00:08:52
Artemis will work. 00:08:58
The history of medicine has a somewhat checkered past. From its earliest history until just 00:09:03
before the beginning of the 20th century, many of the earliest practitioners were only 00:09:07
able to provide the crudest forms of medical assistance to patients. For years, spiritual 00:09:12
healing, bloodletting, and herbal remedies were generally the only form of medical help 00:09:17
available to the average person. But this began to change in the late 1800s as advancements 00:09:21
in medical practices began to move at a rapid pace. Perhaps one of the most important advancements 00:09:27
during that time was the development of the x-ray in 1895. With this device, doctors finally 00:09:33
had the ability to peer inside the human body without having to perform surgery. Since 00:09:39
that time, this unique machine has proven to be invaluable, allowing doctors a two-dimensional 00:09:44
view inside of the patient. Although this technology has been a revolution, the two-dimensional 00:09:50
pictures were not appropriate for all types of soft tissue imaging, such as those used 00:09:56
in cancer diagnosis and in heart procedures. So, in 1973, the introduction of the CAT scan 00:10:00
again revolutionized the way doctors could see inside patients. This device, for the 00:10:07
first time, allowed doctors a three-dimensional view of the body and was especially helpful 00:10:13
in looking at soft tissue. So what's the next revolution? Currently, researchers using NASA 00:10:18
technology are developing a device that could give doctors a type of x-ray vision. Using 00:10:23
a CAT scan in conjunction with virtual reality, researchers have developed the augmented reality 00:10:29
technology for minimally invasive surgery, or ARTEMIS. This system may soon be helping 00:10:35
to make surgeries much safer and much less invasive. I spoke with Bishan Shanoas of Analytical 00:10:41
Mechanics Associates to help us find out how ARTEMIS may be used in the future. ARTEMIS 00:10:47
is a state-of-the-art technology that fuses augmented reality technology with fiber optic 00:10:52
shape sensing. The augmented reality part takes 3D images of a person's anatomy and 00:10:57
superimposes it over the real patient itself. So this enables doctors and physicians to 00:11:03
be able to take these 3D images and look at them exactly where they are on the real patient. 00:11:09
The fiber optic shape sensing portion allows the doctor to see the shape, and hence the 00:11:15
tip, of the needle or the RF catheter or whatever device he chooses to insert into the patient. 00:11:20
So can you explain to me exactly how this will work? The patient goes into a CAT scan 00:11:27
machine. You get CAT scans of the patient. You assemble that into a 3D model. You then 00:11:31
take the 3D model and project it onto the screen. You then register the 3D model over 00:11:39
the actual patient, and then the doctor can see where exactly the organs are. You then 00:11:48
stick the needle in with this fiber optic shape sensing technology from Lunar Innovations. 00:11:53
You insert it into the patient. Once the doctor inserts the needle into the patient, the doctor 00:11:57
can see where the needle's going. The doctor guides the needle to the exact spot, burns 00:12:02
out the tumor, extracts the tissue, does whatever the procedure demands. 00:12:07
What are the issues these days with the way doctors are using CAT scans in some surgeries 00:12:10
today? 00:12:15
The problem today is that the doctor has to look away from the screen and look at the 00:12:15
CAT scans or 3D images without looking directly at the patient. So he's trying to poke the 00:12:20
patient, but he's looking at something else. If you ever try to do something while looking 00:12:25
at something else, you'll kind of realize what the difficulty is. But that's the general 00:12:29
problem is that you cannot see where you're going. You cannot look at what your target 00:12:33
lesion is or what your target organ is, and you cannot look at, you cannot see your needle 00:12:37
once it's been inserted. It's kind of like, it's pretty much groping in the dark. 00:12:42
The Artemis system holds great promise for use in minimally invasive surgeries. Because 00:12:46
these surgeries generally use probes, catheters, and needles to perform the work, the real-time 00:12:52
virtual look inside the body will improve the quality, safety, and efficiency of procedures. 00:12:57
With tens of thousands of minimally invasive surgeries being performed each year, the addition 00:13:03
of the Artemis system will undoubtedly save time, reduce cost, and most importantly, help 00:13:08
save lives. 00:13:14
This device gives the doctor direct x-ray vision into the patient. So the glasses are 00:13:15
what you use to see the stereo image. What happens is the system draws one image as if 00:13:20
it's being seen with your left eye. It draws another image as if it's being seen with your 00:13:25
right eye. And it shutters it fast enough and the glasses shutter in sync so that you're 00:13:30
looking at your right eye, you're looking at your left eye, and your right eye. And 00:13:35
when you look at them together, it does it so fast and it syncs it together. That way 00:13:37
it looks like you're looking at a 3-D image in real life. 00:13:40
Now what types of NASA technology was used to help you develop this? 00:13:44
As you know, with NASA, we've used virtual reality and visualization for ergonomic design 00:13:48
of the space shuttle and for different other types of aerospace concepts. We've decided 00:13:53
to take that technology and extend it to the realm of augmented reality and apply that 00:13:57
to medicine. 00:14:03
We're very excited about this technology. It's actually, we're pretty sure that it can 00:14:04
actually make minimally invasive surgical procedures a lot safer. It's going to make 00:14:09
medical care, from that perspective, a lot less expensive. It's going to minimize the 00:14:14
time for people to wait and the time for these operating procedures. And we envision that 00:14:19
at some point it can be applied to things such as beating heart surgery. That's kind 00:14:24
of like the holy grail. So there's so many things that we're looking forward to actually 00:14:28
doing with this and we're very excited over here. 00:14:30
Towards the end of the Apollo program, NASA officials were already thinking about what 00:14:38
would be next for the American space program. At that time, the rockets used to place astronauts 00:14:46
and equipment into space were designed to be used only once. Although effective, NASA 00:14:51
planners decided that they needed a system that was less expensive, reliable, and perhaps 00:14:56
most of all, reusable. The idea of a reusable space shuttle that could launch like a rocket 00:15:01
and land like an airplane was appealing and would soon change the way astronauts were 00:15:07
traveling into space. The space shuttle was born on January 5, 1972, when President Richard 00:15:11
Nixon authorized the development of reusable vehicles for space exploration. The project 00:15:18
became known officially as the Space Transportation System, or STS. It was based on a piloted 00:15:23
spacecraft boosted into orbit by a reusable launch vehicle that could return to Earth 00:15:30
like an airplane, ready to be used again on short notice. This new vehicle consisted 00:15:35
of three primary elements, a delta-winged orbiter spacecraft, two solid rocket boosters, 00:15:41
and one external fuel tank. Over a 10-year span, five orbiters were built, including 00:15:54
the test vehicle named Enterprise and the four space orbiters Columbia, Discovery, Atlantis, 00:16:02
and Challenger. On April 12, 1981, after years of testing and construction, the first shuttle, 00:16:12
Columbia, reached orbit piloted by astronauts John Young and Robert Crippen. The first four 00:16:20
shuttle flights were collectively called the Orbital Flight Test Program and demonstrated 00:16:27
how the spacecraft performed under real spaceflight conditions. During these first four flights, 00:16:31
NASA tested the shuttle as a launch vehicle, habitat for crew members, freight handler, 00:16:37
instrument platform, and aircraft. After the fourth landing, NASA declared the shuttle 00:16:42
ready for operation. Since that time, the shuttle program has performed well over the 00:16:48
last 100 missions and has accomplished a number of monumental achievements. In June 00:16:56
1983, Sally Ride became the first American woman in space. The shuttle launched the Magellan 00:17:02
spacecraft to Venus, the Galileo spacecraft to Jupiter, and the Ulysses spacecraft to 00:17:08
study the sun. The shuttle also has deployed the Hubble Space Telescope, the Gamma Ray 00:17:13
Observatory, and the Upper Atmosphere Research Satellite. Another key milestone came in 1998 00:17:19
when astronaut John Glenn, the first American to orbit the Earth, returned as the oldest 00:17:25
man ever to reach space as a member of the crew of Discovery on a nine-day mission. The 00:17:30
shuttle has also been instrumental in constructing and outfitting the International Space Station 00:17:35
while also being used to carry large payloads to and from orbit and perform servicing missions 00:17:40
on satellites. The design, now approaching its third decade, is still state-of-the-art 00:17:45
in many areas, including computerized flight control, airframe design, electrical power 00:17:50
systems, thermal protection systems, and main engines. Even though the sophisticated shuttle 00:17:55
program suffered the devastating losses of the Columbia and the Challenger, its successful 00:18:01
missions have made great strides in space travel and exploration during its short history. 00:18:06
More than 100 documented NASA technologies from the space shuttle are now incorporated 00:18:11
into the tools we use, the foods we eat, and the biotechnology and medicines used to 00:18:16
improve health. Although plans are now in the works to retire the fleet, the space shuttle 00:18:21
program will forever hold a special place in the history of space travel, not only for 00:18:26
its unique design, but for the history and technologies it brought to all of us. 00:18:31
The space shuttle has been one of the most valuable and important tools in our quest 00:18:37
to increase our understanding of space. It is scheduled to go out of service in the near 00:18:41
future, being replaced by the new Crew Exploration Vehicle. Up next, we'll find out exactly 00:18:45
how sonic booms work. But first... 00:18:51
Did you know Enterprise, the first space shuttle test vehicle, was originally to be named 00:18:54
Constitution in honor of the U.S. Constitution's Bicentennial? However, viewers of the 00:18:59
popular TV science fiction show Star Trek started a write-in campaign urging the White 00:19:04
House to change the name to Enterprise. Designated OV-101, the newly named Enterprise was 00:19:09
rolled out of the assembly facility on September 17, 1976 to begin its work as a flying test bed. 00:19:15
Although it never flew in space, the Enterprise flew eight captive flights attached to the 00:19:22
747 shuttle carrier and five free flights that landed at Edwards Air Force Base. The 00:19:27
Enterprise was enormously successful helping test and prove technologies that would be 00:19:32
needed in future space shuttles. In November 2003, Enterprise was moved to the 00:19:37
Smithsonian Stephen F. Udvar-Hazy Center near Washington Dulles Airport, where it is now 00:19:42
on permanent public display. 00:19:48
Today in our busy world, one of the key prerequisites for many people in personal and 00:19:53
business life is speed. This is especially true when it comes to aviation. Although air 00:19:57
travel is almost always the fastest means of travel, many would like it to become even 00:20:02
faster. Though the technology exists for aircraft to fly at speeds faster than the speed of 00:20:07
sound, today's aircraft don't because of the problem with sonic booms. To help lessen the 00:20:12
impact of these booms, NASA researchers are attempting to find a way to help aircraft 00:20:17
move faster without causing disruptions on the ground. Our own Johnny Alonzo spoke with 00:20:22
researcher Dr. Kevin Shepard at NASA Langley Research Center to learn what a sonic boom 00:20:27
is and find out how it works. 00:20:32
In the early days of flight, having an aircraft that could fly even as fast as 30 miles per 00:20:39
hour seemed revolutionary. But a goal that pushed virtually every aircraft designer, 00:20:43
engineer and pilot at that time was to find a way to increase the speeds of their aircraft. 00:20:48
As new designs began to emerge, aircraft were continually getting stronger, safer and, above 00:20:53
all, faster. By the mid-1940s, aircraft technology had advanced to the point that breaking the 00:20:58
sound barrier was finally in sight. After numerous attempts and failures, the world's first 00:21:03
sonic boom was heard on October 14, 1947, when Chuck Yeager flew the X-1 aircraft into 00:21:08
history over the desert near Edwards, California. From that point on, military and civilian 00:21:13
test pilots were regularly breaking the sound barrier in fighter aircraft and in specialized 00:21:18
test vehicles like the X-15. But it wasn't until 1976 that civilian passengers finally 00:21:22
got their chance to fly supersonically with the introduction of the famed Concorde. 00:21:27
The Concorde had the ability to fly at over 11 miles high, 1,350 miles per hour, and travel 00:21:32
from Paris to New York in only three and a half hours. Unfortunately, one of the major 00:21:38
drawbacks from the Concorde's incredible speed was the amount of noise it produced. 00:21:43
Not only was it noisy when taking off and landing, but once it reached supersonic speeds, 00:21:47
it created a very loud sonic boom. 00:21:51
Sonic booms are so disconcerting to most people on the ground that commercial aircraft have 00:21:54
only been given the clearance to break the sound barrier over water. 00:21:58
So, are we just relegated to flying below the speed of sound? Well, maybe not. 00:22:01
To help us understand what causes a sonic boom and if there's anything we can do to 00:22:06
lessen its impact, I spoke with Dr. Kevin Shepard at NASA Langley Research Center to 00:22:09
find out how it works. 00:22:13
Any vehicle traveling faster than the speed of sound creates a sonic boom. 00:22:15
What actually happens is shockwaves, which are pressure rises, develop near the airplane. 00:22:19
And as those travel to the ground, what we perceive as a noise, in fact, is this sudden 00:22:25
pressure jump, much like a rifle crack or a balloon popping. 00:22:29
In fact, what you hear are two booms closely separated in time, boom, boom. 00:22:34
And you could visualize it as two rifle cracks or as two claps of thunder. 00:22:39
Sure. 00:22:44
Closely spaced in time. 00:22:45
What is the speed of sound? And how do you measure the speed of sound? 00:22:46
We like to say Mach 1 is supersonic. Everyone knows that expression. 00:22:50
Mach 2 is twice the speed of sound. Mach 3, three times and so forth. 00:22:54
The actual speed depends on the atmospheric conditions. 00:22:58
So, if you're near the surface where it's typically quite warm, speed of sound is 700, 00:23:01
750 miles an hour. 00:23:07
When you're at altitude where airplanes fly, it's a little lower, maybe 600 miles an hour. 00:23:09
So, for example, Concorde traveled at Mach 2, 1200 miles an hour is roughly the speed it traveled at. 00:23:14
A common misconception about the sound barrier is once it has been broken, 00:23:20
there is just one quick noise, and then the noise dissipates. 00:23:23
One reason this misconception is so prevalent is that most people hear a sonic boom 00:23:26
when they're standing in a stationary position on the ground. 00:23:30
What actually happens is when the aircraft breaks the sound barrier, 00:23:33
it continues to break it as long as it's flying supersonically. 00:23:36
Any observer on the ground hears the airplane go by. 00:23:39
If you picture a boat in the middle of a creek and the bow wave from the boat, 00:23:43
you watch the boat go by. A little while later, that bow wave passes you on the riverbank. 00:23:48
People further down the riverbank have the exact same experience. 00:23:54
So what's happening is, in the case of the airplane, 00:23:57
it's dragging this boom carpet behind it all the way across the country. 00:24:00
Depending on weather and altitude, the sonic boom created by the aircraft 00:24:04
can be heard in a path of about 60 miles wide for the entire distance of the flight. 00:24:07
So, if an aircraft is flying from New York to Los Angeles, 00:24:11
the sonic boom will be heard consistently across the country in a 60-mile-wide path. 00:24:14
This is the foremost reason supersonic flights are not allowed to fly over land in the United States. 00:24:18
Yeah, most people find the sonic boom unacceptable. 00:24:23
There's the two loud sounds. They're startling. They're annoying. 00:24:26
They tend to shake buildings, rattle windows. 00:24:31
And so, based on experience with Concorde, for example, it just doesn't happen. 00:24:34
There is no commercial overland supersonic flight. 00:24:38
But revolutionary steps now being taken by NASA may change that in the future. 00:24:41
So, Dr. Shepard, are we stuck with the fact that we'll never be able to fly over land at supersonic speed? 00:24:45
We're hopeful that's not the case. 00:24:50
The current programs we're working on are aimed at allowing supersonic overland flight. 00:24:52
The hope we have is based on a recent flight test, 00:24:58
which demonstrated that we can, in fact, shape the airplane in such a way that we can shape the sonic boom 00:25:01
and it sound different, sound more acceptable. 00:25:06
This has been known in theory for 40-plus years, 00:25:09
but it was only demonstrated in the last couple of years with a real flight vehicle. 00:25:12
Now, that's part of the story. 00:25:16
The real issue is can we get the boom low enough for people to find it acceptable? 00:25:18
We think we can reduce it. Can we reduce it enough? 00:25:23
We're hopeful, and we're hoping we'll have a flight demonstrator within the next few years. 00:25:26
So, Dr. Shepard, how do you test sonic booms? 00:25:30
I mean, is it always in flight, or can you also test it on land? 00:25:33
We'd love to do it in flight. 00:25:37
But building vehicles, as you can imagine, is very expensive, and you don't get to do it very often. 00:25:39
So if you've got a theory that this kind of vehicle will make a different kind of boom than this, 00:25:43
yeah, we'd like to build the vehicles, but that's not going to happen. 00:25:47
So in terms of figuring out what people might find acceptable, 00:25:50
we simulate the sonic booms using ground-based simulators, 00:25:53
which are basically loudspeaker systems where we can produce the sounds 00:25:57
that would be developed by certain vehicle types. 00:26:01
And that's the simulators that we have here at Langley. 00:26:04
They're being used for that because we hope that will guide the design of the airplanes 00:26:06
to ultimately lead to an acceptable sonic boom. 00:26:10
Can you give me some examples of what you test in these simulators? 00:26:13
These simulators are basically loudspeaker-based systems, so we can make sounds, 00:26:16
and we can design them to make sounds that sound very much like real sonic booms. 00:26:20
We bring in human test subjects, members of the public, and in essence they give us their opinion. 00:26:26
You know, this sonic boom versus another, which actually corresponds to one airplane versus another 00:26:31
because we're trying to design airplanes to give us the right sonic boom. 00:26:35
And so the characteristics of the boom is what they're assessing with their ears. 00:26:39
If we can solve the sonic boom problem, then we can have supersonic flight over land. 00:26:43
People and goods can get from place to place quicker because our overall aim here 00:26:47
is to make the air transportation system more efficient, safer, in this case faster, 00:26:51
but also environmentally acceptable. 00:26:56
That way we save time, we save money, we have a more efficient system. 00:26:58
That's it for this edition of NASA's Destination Tomorrow. 00:27:03
I'm Kara O'Brien. 00:27:06
For all of us here at NASA, we'll see you next time. 00:27:07
NASA Jet Propulsion Laboratory, California Institute of Technology 00:27:10
NASA Jet Propulsion Laboratory, California Institute of Technology 00:27:40
NASA Jet Propulsion Laboratory, California Institute of Technology 00:28:10
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949
Fecha:
28 de mayo de 2007 - 17:05
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Enlace Relacionado:
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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.
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