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Radiation, Spacecraft Materials and Propulsion

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Subido el 28 de mayo de 2007 por EducaMadrid

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In the third segment of the Case of the Great Space Exploration the tree detectives learn about the types of space radiation, new materials to create spacecrafts and propulsion systems that will be used in future missions.

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So what's up? What else do the treehouse detectives need to know about space? 00:00:00
How will humans overcome the harshness of space for travel to Mars? 00:00:05
How will robots help lead the way to Mars? 00:00:09
All this and more when the NASA Sci-Files continues. 00:00:12
Don't forget to look for the answers to the following questions. 00:00:15
What are galactic cosmic rays? 00:00:19
Explain how spacecraft will be self-healing in the future. 00:00:22
Why does NASA need new propulsion systems? 00:00:27
Houston, how do you read us? 00:00:34
Roger, Houston. We're at Mach 10.5 and everything looks okay. 00:00:36
Guys, I'm reviewing protocols for an upcoming mission. 00:00:42
It's so cool because you work directly with Mission Control to troubleshoot and solve problems throughout the entire mission simulation. 00:00:45
Right now, I'm reviewing re-entry and landing procedures after successfully launching a new satellite to track RJ's exercise program. 00:00:52
The counselors monitor your progress closely, and they even introduce problems into the mission simulation for the teams to solve. 00:00:59
You really have to be prepared. Keep up the good work, RJ. Over and out. 00:01:06
It kind of goes against the whole idea of working out, doesn't it? 00:01:12
No, that's the beauty. 00:01:16
No fat, frozen yogurt with sugarless sauce and toppings, and it even has fresh fruit. 00:01:18
It's totally healthy. 00:01:22
I'll just stick with the water. 00:01:24
I have to admit, Bianca's right. 00:01:26
Ever since we started exercising, I feel great. 00:01:29
We're not quite ready to go into space, but we're getting there. 00:01:32
Dr. V's comments on the potential danger of space travel do have me a little concerned. 00:01:35
Me too. I've been going over all our research, and the radiation problem seems critical. 00:01:39
So what do we do next? 00:01:43
Time for the problem board. 00:01:45
We know that space is an extreme environment. 00:01:47
And NASA trains astronauts to live safely in that environment. 00:01:49
And astronauts will also need to learn to live on the Moon and Mars. 00:01:52
So what do we need to know? 00:01:55
We need to know more about how astronauts will deal with radiation in space. 00:01:57
Katherine mentioned in her report that she might be able to meet with Mr. Mark Whalen at the NASA Johnson Space Center to learn more about radiation. 00:02:00
Good idea. 00:02:05
We might even be able to learn how to send a triage detective to Mars. 00:02:07
Excellent idea. 00:02:10
Wait, what? Send someone to Mars? 00:02:12
Are you crazy? 00:02:14
I'm fine. 00:02:16
Corinne is going to stop by the Mars Society's remote habitat in Utah. 00:02:18
It actually simulates what working and living will be like on Mars. 00:02:21
That is really cool. 00:02:24
Where are you going? 00:02:26
To see Dr. D? 00:02:28
No, Dr. D isn't home. 00:02:30
I'm going to get another banana split. 00:02:32
You're kidding. 00:02:34
No. 00:02:36
When you eat the light version, sometimes you have to eat twice as much to fill up. 00:02:38
You'll never learn. 00:02:40
Hi, Mr. Whalen. 00:02:48
Hi, Katherine. 00:02:50
I'm glad you could stop by. 00:02:52
I understand you want to learn more about radiation in space. 00:02:54
Yes. 00:02:56
We've read that radiation is very dangerous. 00:02:58
But we're not exactly sure what it is. 00:03:00
Well, radiation is one of the top biological concerns for our astronauts. 00:03:02
There's two basic types of radiation, light and particles. 00:03:04
How is light dangerous? 00:03:06
Light comes in many different forms. 00:03:08
The low-energy visible light that you're familiar with isn't dangerous. 00:03:10
But light comes in a high-energy form called ultraviolet. 00:03:12
Isn't that what causes sunburn? 00:03:14
Well, that's right. 00:03:16
X-rays and gamma rays are ultraviolet. 00:03:18
X-rays and gamma rays are another form of light with more energy than ultraviolet. 00:03:20
And they can cause serious damage to your body's cells. 00:03:22
What about the particles? 00:03:24
Very fast-moving particles are considered to be radiation. 00:03:26
One example is high-energy protons, which are released by flares on the sun. 00:03:28
Another, even more dangerous type of radiation are galactic cosmic rays, or GCRs. 00:03:30
What's a galactic cosmic ray? 00:03:32
GCRs are extremely fast-moving protons 00:03:34
and nuclei of elements such as iron, silicon, and other elements 00:03:36
that come from outside our solar system. 00:03:38
Why are they so dangerous? 00:03:40
Well, GCRs are extremely fast-moving protons 00:03:42
and nuclei of elements such as iron, silicon, and other elements 00:03:44
that come from outside our solar system. 00:03:46
Why are they so dangerous? 00:03:48
They can penetrate more than 100 centimeters into materials 00:03:50
and can cause a lot of cell damage. 00:03:52
They are also very difficult to shield against 00:03:54
and they can even create additional radiation 00:03:56
when they collide with metal spacecraft. 00:03:58
Wow! 00:04:00
I've heard that radiation can increase your chances of getting cancer. 00:04:02
Is that true? 00:04:04
That's correct. 00:04:06
The greater the radiation exposure, the greater the risk of getting cancer 00:04:08
and other effects such as cataracts, which is a clouding of the eye lens. 00:04:10
What determines how much exposure you get? 00:04:12
The length of the mission is one of the most important factors. 00:04:14
A mission to Mars could take several years. 00:04:16
Longer missions mean greater health risk from radiation exposure, 00:04:18
especially compared to space shuttle missions, 00:04:20
which are much shorter. 00:04:22
However, NASA is working hard to reduce the risk. 00:04:24
What are they doing? 00:04:26
They're developing better shielding materials 00:04:28
that will prevent the radiation from reaching the astronauts in the spacecraft. 00:04:30
And high exposures can also come from very intense events, 00:04:32
like solar flares. 00:04:34
Isn't that when the sun has a solar storm? 00:04:36
Very good. 00:04:38
If you can monitor the sun for solar storms that produce these flares, 00:04:40
then you can warn the astronauts to avoid spacewalks. 00:04:42
And to enter specially shielded storm shelters in their spacecraft. 00:04:44
Is there anything that can help the body handle the effects of radiation exposure? 00:04:46
Well, NASA is looking at how a healthy lifestyle, 00:04:48
including dietary vitamin supplements, might provide protection. 00:04:50
They are also looking at the role that age, gender, 00:04:52
and or genetic factors play in how the body responds to radiation. 00:04:54
Wow. 00:04:56
If radiation is such a problem for astronauts, 00:04:58
why don't we have to worry about it on Earth? 00:05:00
We do have some radiation on Earth, 00:05:02
but we're protected from most of it by something the astronauts don't have, 00:05:04
an atmosphere. 00:05:06
Yes. 00:05:08
I learned a month ago that the atmosphere on Mars 00:05:10
blocks a lot of the ultraviolet light from getting to Earth. 00:05:12
Well, that's correct, 00:05:14
and it also absorbs a lot of X-rays, gamma rays, 00:05:16
and high-energy particles. 00:05:18
Charged particles, like cosmic rays and protons from the sun, 00:05:20
are deflected by Earth's magnetic field, 00:05:22
and Earth itself acts like a big shield. 00:05:24
I'm glad that we have some protection. 00:05:26
Radiation sounds pretty serious. 00:05:28
Yes, it is. 00:05:30
So don't forget you should always wear sunscreen 00:05:32
when you're working or playing outside. 00:05:34
Don't worry, I will. 00:05:36
Thanks, Mr. Weiland. 00:05:38
You've been a big help. 00:05:40
You're welcome, Katherine, and good luck. 00:05:42
Hi, guys. 00:05:46
It looks like you've been working hard 00:05:48
on the unmanned missions. 00:05:50
Along with research, we've been working with LEGO 00:05:52
to build possible Mars explorers. 00:05:54
Cool. 00:05:56
Of course, we read all of your reports on the Internet. 00:05:58
Having access to the Internet is a wonderful thing. 00:06:00
Speaking of the Internet, 00:06:02
you can always find great tools for research 00:06:04
on the NASA SciFiles website. 00:06:06
Ready to go to the next level? 00:06:08
What do you mean? 00:06:10
Well, we've been working on different aspects of space travel, 00:06:12
but there's one area that we haven't explored. 00:06:14
Like what? 00:06:16
Dr. Herb Waite from the University of California, 00:06:18
Santa Barbara, just sent us an email. 00:06:20
Doesn't he research bio-inspired nanotechnology? 00:06:22
Right. He referred us to Ms. Dana Novak. 00:06:24
She's helping him in his research. 00:06:26
Here she is now. 00:06:28
Hi, you must be the treehouse detectives. 00:06:30
Dr. Waite sent you a call. How can I help you? 00:06:32
We are researching space technology 00:06:34
and space exploration. 00:06:36
What does bio-inspired mean? 00:06:38
Well, it simply refers to any technology 00:06:40
inspired by biology. 00:06:42
For example, when George DeMestrel 00:06:44
took his dog for a walk one day, 00:06:46
he saw that they both had burrs stuck to them. 00:06:48
He looked at a burr under a microscope 00:06:50
and saw hooks and loops. 00:06:52
That inspired him to invent Velcro. 00:06:54
What a great invention. 00:06:56
I use Velcro all the time. 00:06:58
What plants or animals do you look at for inspiration? 00:07:00
Right now, we're investigating 00:07:02
muscle threads and bloodworm 00:07:04
and clamworm jaws. 00:07:06
Uh, muscles, clamworms, 00:07:08
and bloodworms? 00:07:10
Sounds interesting, but why exactly 00:07:12
are you interested in worm jaws 00:07:14
and muscles? 00:07:16
If we're going to explore the moon, Mars, 00:07:18
and beyond, then we need new, 00:07:20
advanced, and self-healing materials 00:07:22
for spacecraft construction. 00:07:24
What do you mean by self-healing? 00:07:26
Think about what happens when you accidentally cut yourself. 00:07:28
It's amazing to watch 00:07:30
how quickly your body acts to mend the wound. 00:07:32
Like this model, we're trying 00:07:34
to understand how to give composite 00:07:36
materials those same qualities. 00:07:38
This model demonstrates how two 00:07:40
different types of bonds within a material 00:07:42
work together to self-heal. 00:07:44
And why is that important? 00:07:46
One weakness of current composite materials 00:07:48
is that they tend to form tiny hairline 00:07:50
cracks, which can lead to 00:07:52
major damage over time. 00:07:54
In long-distance space exploration, 00:07:56
repairs won't be easy. 00:07:58
Right, there won't be a spare parts 00:08:00
store we can stop at while in space. 00:08:02
Nope, there won't. However, 00:08:04
with new, high-performance 00:08:06
materials, such as the self-healing 00:08:08
materials, we will be taking the 00:08:10
first step in building spacecraft 00:08:12
capable of traveling millions of 00:08:14
miles from Earth that can fix themselves. 00:08:16
That's awesome, 00:08:18
but I still don't understand what muscles 00:08:20
and worm jaws have to do with it. 00:08:22
Nature specializes in how to put 00:08:24
materials together in the most 00:08:26
effective and efficient ways. 00:08:28
We look at the muscle threads because they're 00:08:30
very strong, yet thin and lightweight. 00:08:32
It's amazing how much we can learn 00:08:34
just by looking at nature. 00:08:36
We can learn how to make materials that 00:08:38
recover quickly from stress. Think about 00:08:40
when you buy a six-pack of soda. 00:08:42
When you take a can out of the plastic loop, 00:08:44
the plastic stretches but is 00:08:46
difficult to break. Nature 00:08:48
inflicts damage on the muscle threads just like 00:08:50
you do on the plastic. We call 00:08:52
this damage creep, and it is 00:08:54
undesirable. However, 00:08:56
in nature, many materials that 00:08:58
experience creep recover from it, 00:09:00
and we're studying the muscle threads 00:09:02
to learn how. What about 00:09:04
the blood and clam worm jaws? 00:09:06
The jaws appear to be just as resistant 00:09:08
to abrasion as the tiles on the 00:09:10
space shuttle, yet they have 00:09:12
only half the weight per equal volume. 00:09:14
We learned in the case of the 00:09:16
challenging flight that weight is a very important 00:09:18
factor. The lighter the airplane or spacecraft, 00:09:20
the less fuel it needs. 00:09:22
That's right, and we hope to learn 00:09:24
not only how to make very lightweight 00:09:26
spacecraft materials, but also 00:09:28
tougher ones. Why do the materials 00:09:30
need to be tougher? The materials 00:09:32
used for spacecraft are subjected 00:09:34
to enormous stress, so it's 00:09:36
crucial that they be tough 00:09:38
as well as self-healing. Sounds like 00:09:40
this research is exciting. 00:09:42
Thanks, Ms. Novak. You're welcome. 00:09:44
Keep up the investigation and 00:09:46
call me back if you have any other questions. 00:09:48
Bye! That was impressive. 00:09:50
Never thought that setting muscles and 00:09:52
worms could help us learn about traveling through space. 00:09:54
But I'm still trying to figure out how we're 00:09:56
going to do it. I mean, what will our future 00:09:58
space vehicles look like? I'm not sure. 00:10:00
Maybe Bianca can help us. 00:10:02
Well, she's been training down at Space Camp, 00:10:04
but I don't think their program includes future 00:10:06
spacecraft. No, but they are 00:10:08
close to NASA Marshall Space Flight Center. 00:10:10
I emailed her last night. She wrote back 00:10:12
and said she was meeting with Mr. Cook. 00:10:14
Way to go, Catherine. Have you heard from Dr. D yet? 00:10:16
No. Wasn't he working with 00:10:18
you and Tony? Well, we talked to him a couple 00:10:20
days ago, but we haven't heard from him. 00:10:22
Maybe Bianca gave him a new 00:10:24
fitness program to work on, too. 00:10:26
Well, if so, maybe we should call his house. 00:10:28
He may need some help. 00:10:30
Mr. Cook agreed to meet me 00:10:34
at NASA Marshall Space Flight Center 00:10:36
where they test rocket engines for spacecraft. 00:10:38
They call it the Propulsion 00:10:40
System Component Testing Facility. 00:10:42
Of course, I had lots of questions. 00:10:44
So, how is NASA 00:10:46
researching new spacecraft for the future? 00:10:48
One way is through propulsion. 00:10:50
With a new exploration vision, 00:10:52
we will need propulsion systems that 00:10:54
will be low-cost and will enable 00:10:56
rapid, safe, and reliable 00:10:58
access to, in, and 00:11:00
from space. So why do we need new propulsion 00:11:02
systems? Aren't the old ones good 00:11:04
enough? Most U.S. propulsion systems 00:11:06
are based on 1950s and 60s 00:11:08
technology. They are high-risk 00:11:10
and expensive. Right now, it costs 00:11:12
$10,000 per pound 00:11:14
to put payload into Earth's orbit. 00:11:16
Wow, that's a lot of money. 00:11:18
Exactly. So for us to carry 00:11:20
out the exploration vision, missions 00:11:22
must be affordable, the reliability 00:11:24
must be increased, and we must find a way 00:11:26
to rapidly and safely take us 00:11:28
beyond Earth's orbit to the Moon, 00:11:30
Mars, and beyond. What types of propulsion 00:11:32
systems are being researched? 00:11:34
The primary ones for exploration are chemical, 00:11:36
like these here, 00:11:38
nuclear, electric, and propellant-less 00:11:40
propulsion systems. What's a propellant-less 00:11:42
propulsion system? One type 00:11:44
is a system that uses solar sails. 00:11:46
These are sails much like those found on 00:11:48
a ship. Solar sails are made 00:11:50
from thin layers of mylar and act like a 00:11:52
very large mirror. As photons 00:11:54
of sunlight strike the sail and bounce off, 00:11:56
they gently push the sail along. 00:11:58
How does electrical propulsion work? 00:12:00
You can't have an extension cord 00:12:02
in space. No, it 00:12:04
uses electrical energy from a solar 00:12:06
array to accelerate a propellant. 00:12:08
There are three types of electric propulsion 00:12:10
systems. Electrothermal, 00:12:12
which uses electrical heat. 00:12:14
Electromagnetic, which creates thrust 00:12:16
using a magnetic field. 00:12:18
And electrostatic, which uses charged particles 00:12:20
in an electric field. 00:12:22
Don't we currently use chemical rockets? 00:12:24
Yes, and they have been the primary means for 00:12:26
transportation in space because of the very 00:12:28
large amounts of thrust they generate that are 00:12:30
needed to overcome Earth's gravity. 00:12:32
As fuels become more advanced, chemical 00:12:34
propulsion will continue to play a vital role 00:12:36
in space transportation. 00:12:38
That sounds great, but isn't one propulsion 00:12:40
system better than the other? 00:12:42
Well, there are pros and cons to each system. 00:12:44
The choice of propulsion system depends on 00:12:46
the energy requirements of the mission, 00:12:48
its duration and destination, and whether 00:12:50
it is robotic or human. 00:12:52
I can't wait to travel through space. 00:12:54
It's so exciting. Yes, it is. 00:12:56
So keep studying your math and science. 00:12:58
Don't worry, I will. Oh, by the way, 00:13:00
Dr. D called. He said he wanted to meet you 00:13:02
over at the Neutral Buoyancy Laboratory. 00:13:04
Dr. D at space camp? 00:13:06
That's strange. 00:13:08
Well, it is Dr. D. 00:13:10
Attach stabilizer into position 00:13:14
on both the array 00:13:16
and the bomb auxiliary power panel 00:13:18
and lock into place. 00:13:20
Fully deploy array by 00:13:34
rotating handle counterclockwise. 00:13:36
Roger. 00:13:38
Dr. D, 00:13:50
is that you? 00:13:52
You bet. I'm training for a spacewalk 00:13:54
going on this underwater 00:13:56
solar array. 00:13:58
Of course. We learned from Dr. Utley 00:14:00
in the case of the Inhabitable Habitat 00:14:02
that astronauts learn to work in the weaknesses 00:14:04
of space by diving into a huge 00:14:06
tank of water called the Neutral Buoyancy 00:14:08
Laboratory. 00:14:10
That's what I love about space camp. 00:14:16
We get to practice, 00:14:18
they emphasize the importance of teamwork, 00:14:20
and of course I'm looking forward to the simulators. 00:14:22
Simulators are great. 00:14:24
They allow you to experience what space is really 00:14:26
like. Let's go check them out. 00:14:28
This is the 00:14:30
Space Shot. Great. 00:14:32
It simulates liftoff. 00:14:34
Doesn't liftoff make astronauts feel heavy? 00:14:38
We'll see. 00:14:40
You just experienced four times the force 00:14:54
of gravity, just like the Apollo astronauts 00:14:56
at liftoff. Can we do it again? 00:14:58
Sure. 00:15:00
Three, two, one. 00:15:02
Dr. D, 00:15:14
I also felt weightless for a few seconds 00:15:16
at the top. It was because you were 00:15:18
freely falling. 00:15:20
It's not quite 00:15:24
free fall, but if you go to the moon, 00:15:26
you only weigh one-sixth of what you do on the Earth. 00:15:28
That's a great weight loss program. 00:15:30
Let's see how 00:15:32
you do, weighing only slightly more 00:15:34
than two gallons of milk. 00:15:36
Buzz Aldrin said that 00:15:44
galloping like a horse was easier than 00:15:46
jogging, but why don't you 00:15:48
try the bunny hop? 00:15:50
Awesome! 00:15:52
Training like this 00:15:58
before going to the moon is a great idea. 00:16:00
Now that you've experienced 00:16:06
walking on the moon, you need to train 00:16:08
for re-entry into the Earth's atmosphere. 00:16:10
This is the multi-axis trainer, 00:16:16
and trainers like this were used by our country's 00:16:18
first astronauts in the Mercury program 00:16:20
to prepare for the possibility of a 00:16:22
tumble spin during re-entry. 00:16:24
Oh, I almost forgot. 00:16:26
You've got to contact the other Treehouse 00:16:28
detectives. They don't know where you are. 00:16:30
Well, that's right. I didn't tell them. 00:16:32
I'll get on it right away, just after I become 00:16:34
disoriented. 00:16:36
Dear Treehouse detectives, 00:16:42
sorry about the quick departure. 00:16:44
I had some important work to do at space camp. 00:16:46
I saw Bianca. 00:16:48
I'm sure she will fill you in. 00:16:50
Looking good. Made us a little longer 00:16:54
than I can handle. 00:16:56
So what's up? 00:17:00
Will Bianca survive the rigors of training? 00:17:02
Who will be the next generation of 00:17:04
explorers to go to Mars? 00:17:06
Would you like to walk on Mars someday? 00:17:08
Stay tuned for the exciting conclusion 00:17:10
of The Case of the Great Space 00:17:12
Exploration. 00:17:14
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Idioma/s:
en
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Autor/es:
NASA LaRC Office of Education
Subido por:
EducaMadrid
Licencia:
Reconocimiento - No comercial - Sin obra derivada
Visualizaciones:
1631
Fecha:
28 de mayo de 2007 - 15:34
Visibilidad:
Público
Enlace Relacionado:
NASAs center for distance learning
Duración:
17′ 16″
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:
103.44 MBytes

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