JSC: What is Microgravity?
- NASA
Sherri Jurls is speaking
on the screen.
View of the Johnson Space
Center from the air.
Sherri: The astronaut corps
building, you can see in the back of your picture there, there's some
blue, that represents water. We are just at the coast of the Gulf of Mexico,
so just in the horizon area, that you are looking at.
Back to Sherri.
Well again, this is a Web
cast being broadcast to you from Johnson Space Center and today we're
going to be talking about the topic of microgravity, so I hope all of
you have jumped into the chat room and submitted your questions. We have
a very special guest with us here today who will be able to answer all
of your questions and give us extra information.
His name is Dr. John Charles.
Welcome Dr. Charles.
Sherri and Dr. Charles
are on the screen.
Dr. Charles: Glad to be here,
Sherri.
Sherri: Will you take a moment
and tell us a little bit about your background and what you do here at
Johnson Space Center?
Dr. Charles: I'd be glad
to Sherri.
Dr. Charles is speaking
on screen.
I'm a cardiovascular physiologist
by training. I now work not so much in the laboratory anymore, cardiovascular
physiology by the way is the study of the heart and the blood vessels.
I have a Ph.D. in that area but true to typical government service, I'm
now working in an area that I'm not trained in and that is I'm helping
to plan future space missions, space station missions, space shuttle missions.
I'm actually what's called a mission scientist for an upcoming space shuttle
flight this July. That'll be a research mission in orbit.
Note that I am not an astronaut,
I'm a mission scientist, I'm not a mission specialist. I've not flown
in space, but I've imagined myself in space many times and I hope we can
talk about some of those imaginings and some of the things I've learned
along the way here during our chat today.
Sherri and Dr. Charles
on screen.
Sherri: Great. Well are there
any special projects that you hope to work on some day? What kind of things
do you look forward to in your career?
Dr. Charles is speaking
on screen.
Dr. Charles: Well I joined
NASA back in the dark ages of the early 1980s. My goal was to join the
program that was heading off to the Moon and off to Mars. The work I'm
doing now is planning investigations that will support people moving out
into space and I'm hopeful that before I retire in the next 15 or 20 years,
we will actually have a program to send astronauts beyond the space station,
to the Moon and off to Mars or wherever the appropriate destination is.
We find in the life sciences,
the problems are pretty much the same whether you're in orbit around the
Earth or heading off to the Moon or off to Mars. But it will be exciting
to be involved in the exploration program like that.
Sherri speaking on screen.
Sherri: Well I couldn't agree
more. It will be very exciting for me as well to see us go out that far.
Well let's go ahead and start our program off today. Our topic again is
microgravity. Let's go ahead and define what microgravity is so that we
make sure we're all on the same page as we're discussing this topic today.
Is it true that it's the
same thing or not the same thing as Zero G?
Sherri and Dr. Charles
shown on screen.
Dr. Charles: It depends on
who you ask. Microgravity is strictly defined as one-millionth of one
G, that's sort of a breakeven point for what we call the microgravity
science of the fluids and the crystals and the physics experiments that
need something like weightlessness. They're very, very sensitive to even
slight jitter, and jitter is what violates your micro G, what breaks the
level.
In terms of biology, micro
G is essentially weightlessness or Zero G. I prefer the term weightlessness
or Zero G
Dr. Charles speaking on
screen.
because as far as biological
specimens like us, or the things I study are concerned, weightlessness
is micro G and there's really not much meaningful difference.
Microgravity or weightlessness
are achieved by being in orbit around the planet. I think this might be
the time to show what the Show and Tell looks like.
Dr. Charles has a model
of a rotating Earth and a space ship orbiting the Earth in his hands.
If I have a planet in my
hand, let's call it Earth, and I have in my hand also a small representation
of a space ship, that space ship is orbiting the planet and here you can
see it orbiting the planet. By doing so, it's going in a large circle
around the planet.
That circle, because of its
velocity, because of the speed given to it by those large rockets on the
launch pad, is exactly balancing -- let's see if I can get it over here
-- the speed around the planet, exactly balances the effect of gravity
pulling it down to the planet. So it doesn't fall because it's going forward
so fast that it essentially falls around the planet. (Let's see if I can
do this well.) Falling around the planet, it falls toward the Earth, but
the Earth also curves away, so the vehicle is falling around the planet
and it continues to do that as long as it's not acted on by another force
or an external force. And that produces, inside that capsule, or inside
that space ship, weightlessness.
Dr. Charles is speaking
on screen.
Weightlessness or microgravity.
The microgravity comes in because of some more esoteric physics. There's
actually a little bit of atmosphere at altitudes, orbital altitudes, and
that atmosphere actually slows the shuttle down so that things inside
are actually sort of moving a little bit toward the end of the shuttle,
toward the nose of the shuttle, not exactly in microgravity. And also
there's some effect because of the shuttle being an extended structure,
not a point mass.
But for our purposes, when
you're in orbit, you're weightless. I think we have a little graphic here
to show you what weightlessness might look like here on the ground. There's
some ways to mimic this on the Earth.
Graphic showing weightlessness.
One is in an elevator. If
you had a high enough elevator and you're brave enough and you push the
down button and just let it go all the way to the bottom and took the
breaks off, as that elevator falls, you fall with it. You're both accelerated
by the force of gravity, 32 feet per second, 9.8 meters per second, per
second here on the ground and if the elevator's falling exactly as fast
as you and your payload, that apple that the woman is holding in that
picture, then you're weightless inside that elevator.
Dr. Charles is speaking
on screen.
That's fine until you reach
the bottom of the elevator shaft, in which case you stop abruptly. Now
the thing about being in orbit is that you don't stop abruptly, you keep
falling around the planet, you're just going forward fast enough that
the planet curves away from underneath you and you keep going until you
fire your retro rockets and come back.
Another way to get the effects
of weightlessness here on the Earth is actually a little bit above the
Earth, it's the NASA's KC135 Zero G aircraft.
Video showing KC135 aircraft
ascending.
Here you see a video of that
aircraft going through its maneuver, its parabola out over the Gulf of
Mexico. I had a chance to fly in this several times. I've enjoyed it immensely.
Screen within a screen
showing passengers on plane in a weightless state.
And here you see the airplane
going for-, I think it's an altitude of about 25,000 feet up to a peak
of about 35,000 feet, and as they reach that 45 degrees nose up, the pilot
chops the throttle back and essentially coasts through that parabola,
so everybody inside is falling exactly as fast as the airplane.
Here we're about 45 degrees
nose down, the pilot resumes the throttle and pulls out of that dive to
go off and do it again.
Dr. Charles is speaking
on screen.
You do about 40 parabolas
on a typical flight. Those parabolas are provocative, that means they
make you-, some people motion sick. The good news is not everybody gets
motion sick and of course the bad news is some people get motion sick
and the flight, the crew chief on board will tell you, "Cheer up,
only 39 more parabolas to go," no matter how sick you are.
So that's, in a nutshell,
what weightlessness or microgravity are all about. I'll be glad to expand
on those definitions a little bit further if anybody has additional questions.
NASA logo on the screen.
Sherri speaking on screen.
Sherri: Well thank you, Dr.
Charles, for explaining to us about the science behind microgravity. I
was unsure whether it was just because you flew up in space you started
floating, but now we know that there is a scientific reason behind that.
And the airplane, that KC135 aircraft you were telling us about, since
it is so provocative and maybe upset some of our stomachs, I know that
it has a nickname that's the airplane of the "Vomit Comet."
Dr. Charles is speaking
on screen.
Dr. Charles: Yeah, the airplane
is called a Vomit Comet usually by-, well by a lot of folks, usually the
folks that have gotten sick on board the airplane. It's such a prevalent
nickname that some people think that's its official name. But in fact
it is a KC135. KC is an Air Force designation. It used to be an Air Force
tanker. It used to refuel other airplanes on maneuvers around the world.
The 135 just means it's a
serial number. It's actually a-, I think it's a Boeing 727 in its first
life.
Sherri and Dr. Charles
are on screen.
Sherri: Okay. Well is the
KC135 aircraft is the only way we can train our astronauts for microgravity
environment? Is there like a room they can go in and start floating or?
Dr. Charles is speaking
on screen.
Dr. Charles: There is no
such thing as weightlessness here on the surface of the Earth. If there
was a zero gravity room, NASA would be a whole lot less expensive to fund
because we'd all be going to that zero gravity room to do our experiments
instead of lining up to fly experiments on a very expensive space shuttle
or on other rockets. And there are ways we can mimic parts of the weightless
experience depending on what you're trying to mimic.
Video showing astronauts
moving around in the neutral buoyancy laboratory.
We have some video here showing
what it looks like to be underwater in something that's called a neutral
buoyancy laboratory, which is just NASA-speak for a very large water tank.
The water tank is large enough that you can actually-, they have actually
built a mock up of the space station inside of it where the astronauts
inside those space suits are buoyed or balanced with lead weights on the
outside such that they are neutrally buoyant. That is they don't sink
or rise inside the water.
When they are positioned
in the water, they stay where they are. That lets them pretend to be weightless
inside that big water tank, so they can do weightless activities that
might be required outside of the space station. Now keep in mind that
they are not weightless inside those suits.
Inside those suits, they
still feel the effects of gravity. They are simply floating much like
you float in a pool. But inside those suits, if they're standing upright
with respect to gravity, their feet are on the soles of the boots and
their heads are down inside their helmets. And if somebody turns them
upside down, or if they go upside down as a maneuver, they are resting
on their shoulders, and the blood is rushing to their head.
So they're only weightless
with respect to the effect of-, with respect to the space station mock
up or the other activities they're doing in the tank. But inside their
bodies, inside those suits, they still feel gravity.
Sherri and Dr. Charles
on screen.
Sherri: Wow, well thank you
for showing us this live footage of the astronauts training right now
and describing to us what we're seeing. Wow! Fascinating.
Sherri is speaking on screen.
Well let's go ahead and start
taking your questions. The first one is from Matt of the Belmont Career
Center in Ohio. And Dr. Charles, Matt wants to know if the feeling of
being in space can become addictive?
Dr. Charles is speaking
on screen.
Dr. Charles: Well it certainly
can. Like I said, my experience on the KC135 where you get 20 seconds
or so of weightlessness and about almost a minute of hypergravity, that's
about 1.5 or 2 Gs repeated periodically for 24 parabolas at a time, or
40 parabolas at a time,
Video showing astronauts
weightless on the KC135.
that experience is perhaps
not addictive in the clinical sense, but it is addictive in the sense
that you enjoy being weightless so much that you don't mind the hypergravity
portions in-between.
Dr. Charles is speaking
on screen.
It's fun to sort of fly through
the cabin if you're allowed to, like Superman. It's fun to immediately
go upside down, which is the first thing I always did in weightlessness
was to put my feet on the ceiling and walk around, or try to walk around.
Being tall like I am, I was able to reach my feet on the ceiling and reach
the floor with my hands, so I could actually push myself against the ceiling
and walk along the length of the airplane.
But you've got to keep in
mind that it's only for 20 seconds, and at the end of that 20 seconds,
when the plane pulls out of that dive, you're going to fall to the floor
with your normal gravity weight or even more. So you want to make sure
that anything that's aimed toward the floor at the end of that parabola
is not fragile, like your head, your neck, or maybe your face if you're
a movie star.
So the deal here is that
it is fun and it's a way to experience weightlessness, and it can be considered
addictive. I certainly miss flying. I don't get a chance to fly much anymore
because I'm not into the management aspects instead of actually doing
the experiments. It's a lot of fun to do it in the aircraft, and I imagine
some folks would consider it addictive. But it's not clinically addictive.
You don't build up a resistance to it or anything like that.
Sherri and Dr. Charles
shown on screen.
Sherri: Well Joanna, Laura,
Nana and Mary, and I hope I said all your names right, from Nightingale
Middle School, write in and they want to know if astronauts get tired
of living in space for such extended periods of time like they are in
the space station right now, four or five months at a time.
Dr. Charles is speaking
on screen.
Dr. Charles: The Russian
space program in the 1980s and 1990s figured out that about a six-month
tour of duty on the Mir station was the right length of time to have people
on the space station. After six months, they started getting jaded or
tired or wore out. And less than six months they didn't feel like they'd
really gotten maximum efficiency. They hadn't really adapted to weightlessness
yet and hadn't been able to apply their training on the ground to the
tasks they were sent up to do.
I don't know if you can really
get tired of it. I think your body does adjust to weightlessness in ways
that are perhaps less than appropriate when you come back to the ground.
But I imagine it depends on the individual. Some people probably would
get tired after a couple of hours or a couple of days on a short flight
and some folks might think six months or even a year or a year and a half
would not be long enough in space.
If we send people off to
Mars some day in the hopefully not-too-distant future, maybe the next
20 years or so, we may be looking at missions that are 2.5 years long.
So our six-month trips in the space station right now would seem like
a weekend jaunt I suspect to those people.
Sherri speaking on screen.
Sherri: Okay, and Joel would
like to know if food tastes any different in a microgravity environment.
Dr. Charles is speaking
on screen.
Dr. Charles: Well Joe, that's
an interesting question too. I'm not an astronaut, I haven't flown, so
I only know what they tell us. But there's a lot of effort made to make
the food as interesting and appealing as possible because of a phenomenon
that you're talking about, and that is there seems to be some blunting
of the taste of food reported by the astronauts in space flight.
It may be because of some
of the changes that occur in the human body in weightlessness. One of
the ones that has been speculated on the most is the headward fluid shift,
that is the distribution of body fluids, the juice inside your body essentially,
from the lower body into the upper body, causing your face to feel puffy
or your upper body to sort of fill out, your legs to get skinnier.
There's been some thought
that perhaps that actually accumulates not just in the head.
Split screen picture showing
on the left side of the screen a human form profile and on the right side
of the screen a hand holding a balloon filled with fluid.
Here you can see a video
of how the fluids are distributed on the ground. You see that balloon
is at 1 G, and now as we go into weightlessness in our KC135, you see
the balloon becomes more spherical and the body fluids are distributed
more into the upper part of the body, especially in the head. That may
fill up your sinuses, may interfere with your sense of smell
Split picture on screen
showing astronaut with regular face on the left side of the screen, and
the astronaut with a puffy face on the right side of the screen.
and some folks have
Here you can see a picture
of an astronaut before flight and in flight and see how puffy his face
gets in flight there.
Dr. Charles speaking on
screen.
If you're a person that depends
heavily on your sense of smell in flight-, or when you enjoy food, then
you may find some changes. Astronauts routinely say that food doesn't
taste the same in flight. We do fly extra condiments for them, extra hot
sauce and salt especially and pepper to sprinkle on the food.
But this looks like an entrée
into talking about food in general. What do you think Sherri?
Sherri and Dr. Charles
on screen.
Maybe we ought to be talking
about food in general.
Sherri: I think that's a great
idea.
Dr. Charles: I'm going to
show you, I'm going to try and raise it up here so the camera can see
it. What a typical meal might look like on the space shuttle.
Sherri: Now I would imagine
it's not very easy trying to eat in space.
Dr. Charles: Well I'm told
it's not that easy, but I suspect they get used to it. Here we have --
let's see if we can get this.
Sherri is holding a packaged
meal and Dr. Charles is demonstrating how it is consumed by the astronauts.
Will you hold that, okay.
There's the typical food. This looks like here's your vanilla instant
breakfast. This is an instant breakfast inside this Mylar aluminized pouch.
You squirt water into it. You knead it to mix it all up and then you suck
it out through the nozzle with a little valve on the end here that allows
you to close off that nozzle so it doesn't keep squirting after you've
finished squeezing.
Sherri: Yeah we don't want
that vanilla instant breakfast all over the shuttle.
Dr. Charles: All over us,
yeah. We also have apple cider. You drink it the same way. You squirt
water into it and then knead it and then suck it out of the little tube
at the end.
Sherri: So you can't just
go get a drink out of the faucet or anything?
Dr. Charles: No, there's
no such thing as a faucet and a glass sitting there waiting for it. You
have to contain your fluids inside pouches of some sort, bags of some
sort.
Sherri: What would water do?
Dr. Charles: Well you saw
that video a second ago of that balloon in weightlessness. The water would
blob up into a sphere and essentially stay wherever you put it or float
wherever you pushed it.
Dr. Charles is speaking
on screen.
Astronauts do like to play
with their food, unlike students and youngsters. Astronauts will play
with the food and float it in the middle of the cabin and attack it and
push it back and forth. They like to play with blobs of drinking fluids
and attack them, sort of sneak up on them like sharks and swallow them.
They like to play with other food items that you might also recognize.
Let me show you one that
you will recognize right away.
Dr. Charles on screen
holding up a clear package of M&Ms.
If you can see that, that
is a package of M&Ms and they're just like M&Ms that you would
buy off the shelf. And my favorite snack too. And who knows how many calories
I've gained eating M&Ms. This is the kind of food that can be-, let's
look at a video here of water floating in the cabin.
Video of water globule
floating in the cabin.
I told you about the beverages
being squirted out of the container. There's what water would look like
floating in the cabin.
Sherri: So it doesn't separate
into droplets I see.
Dr. Charles: It doesn't separate
into droplets because it's held together by surface tension. What you
see inside that blob of water or also bubbles. And you can also put things
here. The Japanese astronaut has put a couple of little flower buds inside
the water to make it more attractive. Sort of a Zero G vase for your flowers.
Video of Japanese astronaut
sucking up water globule.
And here's the astronaut
then sucking up a different, I hope, a different bubble of water. I hope
he hasn't got the flowers inside there.
Dr. Charles speaking on
screen.
Sherri: Okay so what about
the food?
Sherri and Dr. Charles
on screen.
Dr. Charles: Well other food
items do not require the special packaging as the beverages. Here we have
just a plain old sausage patty, just like you might pick up at Bob Evans
or someplace like that. Again it has to be, it's dehydrated. You have
to squirt hot water into it and let it sort of soak up the water and get
up to the temperature you'd like to eat it at.
Dr. Charles speaking on
screen and holding up foods.
Here are scrambled eggs to
go with your sausage, and they are just like camping food you might have
if you go on a camping trip. You squirt hot water in there and knead it
and then cut the bag open and use a spoon and eat it. And also have oatmeal
with-, this is oatmeal with raisins and spice. The same kind of thing
just like you get out of your packet of oatmeal in the morning.
And this for dessert, if
you've been a good-, if you've eaten all your dinner you get pudding.
And pudding is served to you just like it would be off the grocery store
shelf.
Sherri: Now why are you having
to pull these off of the tray?
Sherri and Dr. Charles
on screen demonstrating attaching food to Velcro tray.
Dr. Charles: Well because
we have a zero gravity tray. All of the food may be normal. The environment
is not normal and so if you're going to eat in space, you probably want
to keep all your meal items together and you do that by putting them with
Velcro onto a zero gravity tray table or a table. And this way you keep
all the items together, they don't drift off, you don't have to go chasing
your shrimp cocktail while you're eating it, unless you enjoy doing that
sort of thing.
This tray table can be strapped
to your leg. You see there's a strap on the back so you can just sort
of make a lap table out of it or you can Velcro it to the convenient wall
or whatever suits your fancy in terms of food and how you prefer to eat
it in weightlessness.
Sherri speaking on screen.
Sherri: Well I know we have
a short video clip of our astronauts trying to have a little fun with
their food up in space in this microgravity environment. Let's share it
with our guests out there in worldwide Web land.
Video showing astronauts
eating various foods in weightlessness.
Sherri and Dr. Charles
on screen.
Sherri: I don't know about
you guys, but that looks like a lot of fun. I sure would like to chase
my M&Ms down the inside of the space station.
Sherri speaking on screen.
Well Jeff writes in and
wants to know how microgravity affects our bodily systems, if at all.
Dr. Charles speaking on
screen.
Dr. Charles: Jeff, the answer
to that is a question, that's actually a question I've dedicated my life
and my career to. So we may spend the rest of the hour talking about just
that thing.
Very generally, microgravity
does affect all of our bodily systems, some bodily systems like the sense
of balance -- I'm pointing toward my ears where my vestibular system is,
our blood, our heart, our blood vessels, our heart, the blood in our blood
vessels. All those things are affected by gravity in the short term. I
can show you some video here maybe along the way. Okay.
Also extended weightlessness
will affect things like bones and muscles as well.
Video showing astronauts
exercising on a treadmill in the cabin.
It depends on how much time
you spend in weightlessness, how much of your body is affected and how
drastically your body is affected.
Back to Dr. Charles.
Short flights, like the early
Mercury flights of the 1960s where the astronauts are only in orbit for
a few hours or maybe a day at the most, didn't have as big an effect on
the body as later flights on space stations like the Mir space station
where some astronauts and cosmonauts stayed up for six months or even
a year or longer than a year.
Things happen gradually in
the human body. The vestibular system, the cardiovascular system, those
changes occur fairly quickly within the first several days.
Video showing vestibular
system.
Here's a cut away view of
somebody's skull, showing the vestibular system, the organs of balance
inside the inner ear, with the little stones in your head. You actually
have rocks in your head, they're called otoliths. This is all embedded
in the otoconial membrane, but that's not important.
The important part is as
these little stones inside your inner ear are attached to hair cells,
which are themselves attached to nerve endings, and as those otoliths
are moved by gravity or by acceleration, they signal to the brain which
way you're moving and how fast you're moving and how intense gravity is.
Back to Dr. Charles.
In weightlessness, those
little hair cells are stimulated in a different way. They're still stimulated,
but instead of signaling when your head is tilted, which is what I'm doing
now, I'm tilting my head and my inner ear is signaling to my brain how
my head is tilted. If I do that in weightlessness, my inner ear does not
signal, because it doesn't sense the shifting of those little stones inside
of my inner ear.
It does sense, however the
absence of gravity altogether, and that can confuse, if you pardon the
expression, confuse the brain and require some adjustments, some learning.
Luckily the brain and the vestibular system seem to adapt to weightlessness.
I shouldn't say adapt, but they start getting accustomed to weightlessness
fairly quickly, within the first several hours. Many astronauts feel some
queasiness some discomfort, some motion sickness early, early in flight,
within the first several hours of flight.
Picture of human body
in profile.
But usually after one day
or even at the most two days, that has pretty much gone away.
Picture of human head
and torso showing brain, heart, and kidneys.
They've learned how to move
around and feel normal in weightlessness.
The adaptation continues
for the remainder of the time on flight though.
Back to Dr. Charles.
Also your cardiovascular
system, the system that holds the blood inside the blood vessels, is immediately
affected by weightlessness because the fluid volume inside the body, when
you go into weightlessness, that fluid volume shifts into the upper part
of the body, causing that facial fullness we talked about before and also
filling up the heard and filling up the blood vessels and the lungs.
The body doesn't really --
I hate to say it again, doesn't really care for that. That's not normal
for the body, so the body acts to reduce that filling by other things,
opening up blood vessels so the blood can sort of move throughout the
body more conveniently. By eliminating fluids perhaps through increased
urination or even vomiting. Perhaps the vomiting is part of the fluid
control. And by decreasing your thirst and things like that.
So after several days, your
body has started to reduce its internal blood volume, it's internal fluid
volume. Astronauts that fly flights as short as four or five days come
back to the Earth with a reduced blood volume, about equivalent to one
or two blood donations, depending on how much, depending on individuals.
They haven't lost blood, but they've lost the watery part of the blood.
The water that makes up the plasma has been eliminated through the processes
I have described, which has the effect of concentrating but decreasing
the amount of blood in the body. So the blood is actually reduced and
when you stand up after a space flight, and you need the blood to go to
your head, against the force of gravity, you might find that you've got
a little bit too little blood to make that convenient, to make that function
efficiently.
That process continues, probably
for the first several weeks in flight. After about 30 days or so on space
flights, your cardiovascular system has adapted to weightlessness. But
after 30 days, your bones are only just starting to adapt to weightlessness.
Your bones may lose about 1 or 1.5% of their bone density, of their stuff
every month in flight. Some people think it doesn't really start for the
first month or two, some think it's really 1.5% vs. 1%. The measurements
are very difficult to make and they're very approximate. But the point
is, with extended periods of time in weightlessness, you do lose stuff
out of your bones. You lose the calcium and you lose the protein that
holds the calcium in place and you lose the other molecules like phosphate
that hold the bone in place.
So after a long enough space
flight, you might be at an increased risk for things like fractures. If
you were to spend a really, really long time in space, probably longer
than a Mars flight, you might be at an increased risk for fracture.
What happens though, as soon
as you get into weightlessness, that calcium coming out of the bones does
other things. The calcium that comes out of the bones is a very, very,
very tiny amount, but it doesn't take very much, if it starts accumulating
on certain body areas. And one of the body areas where calcium that leaches
out of the bones ends up is in your kidneys, and you may end up with a
kidney stone, especially if you're prone to kidney stones. And you might
not even know you're prone to kidney stones until you get one.
The risk for kidney stones
increases very early in space flight, even though the risk to the bones
from which the calcium came to make the kidney stone is not increased
for many months in flight. It's a very different story we're talking about.
So you've got your organs of balance, your vestibular system, your heart,
your blood vessels, your bones, your kidneys, your muscles also lose strength
in flight. But it's not as fast as the vestibular system, it's not as
slow as the bones. It's someplace in-between.
And astronauts exercise a
lot. Astronauts will exercise, or at least they're supposed to exercise
two hours a day. That's an hour in the morning and an hour in the afternoon
every day they're in flight. So on a six month space flight you are exercising
twice a day every single day for six months, unless you get a note from
the teacher or a note from your mom or a note from your doctor that says
you don't have to exercise that day. But astronauts generally like to
exercise. For some reason they think exercise is fun and they will exercise
pretty much as much as they need to, especially as the mission comes to
a close and they want to get back into good condition, to look good when
they come off of the space ship at the end of the flight, and be able
to walk around, and squeeze the husband or the wife and hold the kids
up and say hi to mom and dad.
So there's a lot of motivation
for them to exercise and they work very hard at it. But there are changes
and you can tell that do occur in the body. I'll be glad to talk about
those in more detail even now or off-line as appropriate.
Sherri and Dr. Charles
on screen.
Sherri: Well actually we've
had a question come in from Patty when we were talking about the reduction
in blood and everything. She wants to know if microgravity makes your
heart have to work harder.
Dr. Charles is speaking
on screen.
Dr. Charles: In microgravity,
the body's fluids shift into the upper part of the body, the heart is
filled more than it is standing upright or even sitting upright on the
ground. Which causes intrinsic mechanisms, that is the basic mechanism
of the heart to squeeze harder to get rid of that fluid volume. The heart
works in a certain range of preferred contraction sizes.
So your heart doesn't have
to work harder and it doesn't really work less hard either. Your heart
does what it has to do to maintain blood pressure. What happens is that
the body's fluid volume is adjusting and the filling pressure, that is
the amount of blood that's moved into the heart, so the heart sucks up
and squirts out each time it beats, that changes in flight.
I'm not real comfortable
saying the heart doesn't work as hard or the heart has to work harder.
It depends on what you're doing in flight. There may be some tendency
over a long period of time for the heart muscle to atrophy, just like
your muscles in your arms and your legs would atrophy in weightlessness,
because of the other things that happen in your body, especially changes
in blood volume in the body. But generally the heart keeps working as
hard as it has to to keep you conscious and functioning.
Sherri speaking on screen.
Sherri: Okay. Denise writes
in and wants to know if living in microgravity might help some people
who have disabilities?
Back to Dr. Charles.
Dr. Charles: That's a great
question for the distant future. Living in microgravity might indeed help
people that are say burn patients and they need to be floating above the
bed instead of laying on the bed and developing bed sores and ulcers and
impeded healing. It might be a good place to put heart patients that can't
function in gravity anymore. It might be a good place to put people with
muscular dystrophy or other degenerative diseases. But the problem is
you've got to get them there, and getting them there right now requires
a space shuttle or an equivalent kind of rocket which requires high load
at the beginning of the flight.
By that I mean high G loads,
acceleration forces, danger and risk. Plus to fly safely, you have to
be trained to fly safely so you can take care of yourself in an emergency.
We don't have ambulances that go into orbit, we don't have taxis that
go into orbit yet. They're all very complex machines. And then once you
get into space, we don't know enough about what happens to the body. Would
the healing process continue as we hope it would?
For example, having your
burn patient floating in your Zero G burn ward might be good for the discomfort
that would come from putting pressure on the burns, but we don't know
whether burns would then heal, or any injury would heal appropriately
in space.
So there's plusses and minuses
and we're still at too early a stage in our research of the effects of
space flight on the human body to say whether it's a good place to take
people that have injuries or other things like that. But that's the kind
of research that you can spend your time working on and perhaps have an
answer to that question by the time you're my age.
Sherri speaking on screen.
Sherri: We look forward to
having you on, Denise. Sandy writes in and wants to know if microgravity
has any effect upon temperature.
Dr. Charles speaking on
screen.
Dr. Charles: I'm not sure
what Sandy means. Does she mean-, I wonder if she means the body temperature
or does she mean the cabin temperature? The cabin is as warm or as cold
as your thermostat makes it. Weightlessness is different from air and
it's different from temperature. Weightlessness just means that things
are floating inside the cabin instead of falling to the floor. But a weightless
room is not the same as a vacuum chamber or anything like that.
You can pull the air out
of a chamber for example here on the ground, and we do, we have chambers
that are vacuum chambers that are space simulation chambers, to test space
ships and space suits. But there's still the full force of gravity. Gravity
is on the surface of the Earth, and if you just pull air out of a chamber
around, on the surface of the Earth, you're going to have gravity without
air.
You need air or you need
some sort of medium to transmit temperature so of course inside that vacuum
it's going to be whatever temperature vacuums are. Conversely, or inversely,
you can have temperature inside of a weightless environment.
Video of astronauts floating
around in the spaceship.
The space shuttle, you notice
astronauts float around in their shorts and their T shirts or they're
wearing socks or they're wearing short sleeves or they wear long sleeves,
because the temperature inside of a space station or a space shuttle may
be different depending on how close you are to the air duct or the heating
element. Maybe different depending on whether there's lots of people around
you and all of them contributing their body heat, or whether you're off
on and end by yourself. Whether you're on the sunny side of the space
station or the dark side of the space station.
Back to Dr. Charles.
So yes there is temperature
in weightlessness inside the space ship. Outside the spaceship, you're
subject to the temperature of deep space. And on the sunlit side you may
be 250 degrees above zero, and on the dark side, you may be 100 degrees
or so below zero. But that's an effect of being in the vacuum, that's
not-, if you see an astronaut outside in the space shuttle EDA space walk
and you see that part of him is in the shadow
Video of astronauts working
outside of spaceship on docking module.
but the part that's in the
shadow is having sunlight reflected off of it from the space shuttle.
So it's not 100 degrees below zero there either.
You can see a little bit
more of a shadow on that docking module there. But the point is, in direct
sunlight, it's about 250 degrees above zero, and below, in the shade,
it's going to be much colder than that.
Sherri speaking on screen.
Sherri: For those of you just
joining us, we are broadcasting live from the Johnson Space Center with
our very special guest Dr. John Charles answering your questions about
the topic of microgravity today. Take a moment, submit your questions
into the chat room on the Quest Web site. Do tell us where you are, let
us know what state you're in or who's classroom you're in or what school
you go to, and we'll call out your name.
Okay, Patty wants to know,
since you described that the face gets puffy, does that mean that your
legs get skinny?
Dr. Charles speaking on
screen.
Dr. Charles: Patty, that's
exactly what it means. The fluids shift out of the lower body, the legs
and the thighs and even the abdomen into the upper part of the body. Astronauts
will talk about their puffy faces, which is sort of like a very expensive
face lift, because you fill out all the loose tissue in your face, and
any wrinkles you have may sort of get filled in with the body fluids.
And they also like the fact, some astronauts especially it seems to be
the women, I'm not exactly sure why, seem to like the fact that their
legs do get slimmer, even skinny in flight. And you see sometimes in videos,
you see astronauts wearing shorts or like I say, shorter pants or like
that in weightlessness and they do notice things about their bodies. And
they notice those things about each others' bodies.
Split screen showing astronaut's
regular face and astronaut's puffy face.
And talking about faces getting
puffy, here's that picture again showing an astronaut before flight and
in flight with a puffy face. Some people have actually said that they
have difficulty reading each other's emotions or moods, because a puffy
face is more difficult to read.
Dr. Charles speaking on
screen.
They're not accustomed to
it. Here you see somebody's legs in weightlessness. It's supposed to look
like their legs are skinnier.
Astronauts will talk about
the bird legs of space flights. So they do notice that their legs do get
skinnier.
Sherri is speaking on screen.
Sherri: Bird legs. That's
funny. Okay, Maria writes in and wants to know if microgravity or the
effects of microgravity are the same in all parts of the orbit?
Dr. Charles demonstrating
with model globe and space shuttle.
Dr. Charles: Marie, if you're
in orbit, the microgravity is the same throughout the orbit. Now this
is a complicated process and it's going to take some talking, but the
deal is if you're in orbit, presumably you're orbiting very close, and
the space shuttle orbit is essentially very, very close to the surface
of the Earth. About 250 miles up is where the space station is. If you're
in an orbit that takes you much higher, say 1,000 miles around the Earth,
you're still in orbit. The space shuttle is still falling around the planet
and you're still falling around the planet inside that shuttle, so you're
still weightless.
Now this gets complicated
because we scientists like to complicate things and we talk about microgravity
which implies that it's not really weightlessness, there is an additional
phenomenon at play. One of the additional phenomenon at play is especially
in very low orbits, when we have, when you're orbiting a planet at very,
very low altitude, you're still bumping into very few stray molecules
of atmosphere. But at five miles a second, you're bumping into an awful
lot of those.
Now I'm holding up a tennis
ball, it's not going to be easy to see, but you can go out and get a tennis
ball, and if you look at the fuzz on the tennis ball, that's about how
high the shuttle orbits and that's about how high the atmosphere is, with
respect to the Earth. So it's a very, very thin layer of atmosphere, but
the shuttle is orbiting just above your thickest part of that, so it can
stay in orbit.
At that altitude though,
the atmosphere doesn't stop at shuttle altitude. The atmosphere continues
getting thinner and thinner and thinner and thinner and thinner all the
way out, essentially to infinity. At that altitude, the shuttle is bumping
into just a few molecules but it's going so fast and it's so big that
it's bumping into a lot of molecules over time.
If you go up higher, you
bump into fewer and the orbits last longer. If you're down low, you've
heard about things like Sky Lab falling out of orbit or the Mir station
falling out of orbit. It's because eventually it'll bump into so many
molecules in the atmosphere over a period of years, that it slows them
down to the point where they're no longer going at orbital velocity. Then
they fall into hopefully into the ocean someplace.
But we talk about microgravity
because that deceleration, that slowing down, is constantly occurring.
All the time you're in orbit, you're slowing down gradually. And if you're
free-floating inside the shuttle, you're slowly drifting towards the forward
aspect, the forward end of the shuttle, and if you hit it, then you sort
of, you've experienced microgravity.
Also, the effect that --
let's see if I can do this, show you how this looks -- the shuttle, even
in orbit around the planet, is not a point. The shuttle is 100 and some
odd feet. I think it's 120 feet from stem to stern and in the physics
of space flight, that makes a difference. If you're at the exact center
of gravity in the shuttle, right in the middle, then you can be weightless.
But if you're at the nose or at the tail, you're actually in a slightly,
slightly different orbit than the rest of the shuttle, and you're going
to be moving at a very, very slightly different velocity, which has the
effect of causing microgravity.
So at all points in the orbit,
yes, you should be weightless. Neither you nor I could sense with our
senses the differences but very, very precise measuring instruments can
tell the difference, depending on your location and a particular orbit.
In fact experiments do prefer, certain experiments like the microgravity,
the science experiments, prefer to be right in the middle of the shuttle
where the zero gravity is the highest, the microgravity is the lowest.
Back to Sherri.
Sherri: Well you explained
to us that because of microgravity, there's no real up or down and our
neuro-vestibular system gets very confused. Well Shari wants to know how
does food know to go down?
Back to Dr. Charles.
Dr. Charles: Well Shari,
food doesn't go down, it follows the path that it's being pushed. You
actually, when you swallow food, your esophagus is not just letting the
food drop, it's not like you have a stovepipe in your neck that leads
to your stomach, you actually have an esophagus which sort of squeezes
the food down. That's called peristalsis, and that food is squeezed on
down, just like you squeeze toothpaste out of the bottom of the toothpaste
tube.
That works whether you're
right-side up or upside down, you can test it yourself. You can stand
on your head if you're able to. I was never able to, but if you lay on
a chair and hang your head off, you can actually swallow things quite
successfully because your body doesn't need gravity to make food go down.
Same thing for digestion. The stomach squeezes the food up as it digests
it and it squirts it on into the intestine where it's moved around by
peristalsis, coming out you know where.
But the same thing happens
in the blood vessels as well. Blood is not just contained in these big
empty sacs that we call blood vessels. The arteries are actually very
muscular and they open and close depending on what the body is going through,
the veins can actually open and close and sort of squeeze blood as well.
And if the veins are not doing it, the muscles around the veins. The veins
are deeply embedded in the muscles of the arms and legs for example and
every time you move your arm, you're squeezing blood vessels and you're
milking that blood back out of the vein into the upper part of the body
or into the body where it comes back to the heart.
So food doesn't have to go
down by gravity. Food goes down by mechanisms that Mother Nature provided
millions of years ago.
Sherri and Dr. Charles
on screen.
Sherri: That's fascinating.
Alise would like to know if being on Mars would be like experiencing microgravity.
Dr. Charles: On Mars, Alise,
you're going to be feeling what we call hypo-gravity, I call hypo-gravity.
That means less than normal gravity. Normal gravity is Earth's one G.
Picture of Mars from outer
space.
Mars has about one-third,
strictly speaking it's about 38% of Earth's gravity. So if you weighed
100 pounds on Earth, you would weigh on the order of 38 pounds on Mars.
I'm not sure how much you weigh, I weigh much more than 100 pounds, and
I would like to go to Mars to weigh that much less.
But the deal is different
planets may have different gravity, depending on how big they are and
how massive they are. Earth we call the standard, so we refer to normal
gravity as one G, Earth gravity. Mars is a smaller planet, I don't guess
we have a Mars here.
Dr. Charles demonstrating
with the model Earth and a tennis ball.
But let's call this little
tennis ball the Moon, that's almost the right size for the Moon compared
to the Earth. The Moon is much smaller, and it has one-sixth of Earth's
gravity.
Now one-sixth G or one-third
of a G are much, much different than micro G, because micro G means one
one-millionth of a G. So you're still feeling gravity. In fact the Apollo
astronauts on the Moon said that after they got used to being on the Moon,
they felt perfectly comfortable walking around, bouncing around and maneuvering
themselves in the one-sixty gravity.
Picture of astronaut walking
on the Moon.
Here's a picture of an astronaut
on the Moon. So you see he's standing with his feed down on the ground
on the Moon because he feels the effects of gravity. He weighs one-third,
if he was to stand on a bathroom scale, the scale would register one-third
of what it did back on the Earth. He's still got the same amount of mass,
he still has the mass, in his case probably 150 pounds plus 150 pound
space suit or so. But his feet are only having to support one-third, or
one-sixth of that because of the effect of gravity.
Dr. Charles speaking on
screen.
Gravity is going to be a
part of every planet we go to and in fact some folks think that living
on planets is going to be better than living off of planets because the
gravity has some protective effect on the body, it keeps the bones and
the muscles and the heart and the vestibular system and everything else
a little bit more adapted to Earthly life. And we're even talking about
putting artificial gravity into spaceships by perhaps rotating them and
making them like a centrifuge, just like if you were to take a bucket
with some water tied to a rope and sling it around, the water would stay
in the bucket because of something that's like centrifugal force; centrifugal
acceleration.
Picture of inside of space
station module of the future.
That might actually be better
not just for bodies but for engineering as well, because, and this is-,
we're looking down the length of a space station module in the future,
about 2005 or 2006, and this module will added to the space station which
is the centrifuge module. If you look straight down that picture we're
showing you and see that circular feature at the far end. That circular
feature contains a large centrifuge, a 2-meter or about a six-foot radius
centrifuge that we can actually put animals or small specimens on to experience
artificial gravity and weightlessness on the space station. A very important
facility we hope to have added to the space station to help our understanding
of the role of gravity.
Back to Dr. Charles.
We'll then find out whether
we need artificial gravity, partial gravity, fractional gravity. Plus
the engineers might also like that because perhaps it will make plumbing
easier. Imagine building a zero-gravity toilet vs. a 1G toilet. You can
imagine the differences and you can imagine that we already know how to
build toilets that work at 1G, at Earth gravity. Maybe we need to think
about having a rotating space station.
Picture of space shuttle
toilet.
Here's a picture of a space
shuttle toilet which, if you get past the obvious differences, is very
much like an earthly toilet. And I guess I'll save the question I'm sure
is going to come up about using the bathroom. The toilet is a toilet.
You see the seat that you sit on to do your number two and then you can
also see I think off to the side there, you can see a funnel which is
how you do your number one. It's the same, it's a funnel for men and for
women, different shaped cones in the funnel but the process is the same,
and it all uses air flow.
Picture of space station
toilet.
This is the toilet on the
space station, it's a slightly different looking device but the same general
principle. Uses air flow and other things like as a substitute for the
absence of gravity, to collect the body's wastes and process them and
put them where they're supposed to be out of the way of the astronauts.
Sherri speaking on screen.
Sherri: That's fascinating,
thank you. Patty writes in and wants to know if the brain functions differently
in space. And have you had to take any measures to help keep the astronauts
alert?
Back to Dr. Charles.
Dr. Charles: Patty, that's
an interesting question because the brain does seem to function differently
in space and especially in weightlessness. Astronauts will comment that
they do feel differently in space, not just because they're weightless,
but because it's a novel environment. If you're like me, when you go into
a new room or a new building or a new city or a new experience, you sort
of feel overwhelmed. You feel like there's too much going on, I only feel
like I'm only seeing this much of it and there's things going on that
I'm not even noticing.
Imagine if you were in an
environment which is completely different than you've ever experienced
before. Not only is it a new room and a new town and a new city, and a
new state, but the physical properties are different. Like you're no longer
feeling gravity. You're now weightless and things float around you and
if you drop something out of your pocket, you know where to look for it.
You bend over and pick it up and there it is.
In space, if you drop something,
if you let something go, if something pulls off of a restraint, of a Velcro,
it can drift away and you will never see it again until you find out where
it drifted off to in a sort of a random pattern. It's a different environment
entirely.
That affects some people.
In fact, that affects many people, many astronauts in a very profound
sense. They do feel that they're at a disadvantage in space. They're still
able to do their jobs and they're trained to do very complex jobs, but
they do realize that they're at a disadvantage because it's such a different
environment. And so they pay very, very close attention to the procedures,
to the checklist, to the rules, essentially.
You give them a list of procedures
to follow to do any experiment or any activity and you will notice the
astronauts almost always carry those procedures around with them all the
time because they want to make sure they don't forget and do something
that's going to break an experiment or break a piece of the space station
or just look bad. You'd hate to do the wrong thing and be laughed at by
your fellow astronauts and by Mission Control.
But we laugh about it, we
kid about it, but it's a very important part of being an astronaut is
knowing what the instructions are and following the instructions. Some
astronauts say they read the instructions, they read the instruction book,
they look at the switch, they see which way the switch is supposed to
be thrown, up, down, then they look at the instructions again to make
sure they understand it and they look back at the switch, and then they
sort of go up and hold their breath and flip the switch the way they think
it's supposed to be. Because they're just not as confident because of
the novelty of the environment, that they really understand things as
closely, as well as they're used to. And they're all very smart people,
accustomed to being very much in control of their bodies and of the environment.
So it's a different place for them.
Part of the adaptation of
space flight is getting more comfortable in this environment. It could
be something as simple as if you come into a module and say you're on
the space station, you come into a module from another module, and the
floor is not where you expected it to be. You can be completely disoriented.
And the module and the space station seem to be built, especially the
Russian Mir station, was built so that all the floors were at different
angles from each other. So if you left one module and went through the
connecting node into another module, the floor was in a different direction
than the module he just left.
It's almost like it was designed
to be confusing. I think the International Space Station is going to be
a little bit better in that regard. I think all the modules are going
to have pretty much the floor in the same direction. But the floor doesn't
matter, because we store things on the ceiling, on the walls, on the floor.
People may be working on the floor, people may be having their feet on
the ceiling, doing things on the floor, so if you pop into a module and
you see everybody you know upside down, you're going to be disoriented.
Even if the floor is where it's supposed to be, you're going to be confused.
And if you see everybody
at different angles doing different things, you're going to be even more
confused. So there's a lot of mental processing, a lot of higher cognitive
function that's required to function safely and efficiently in space flight.
That's why some astronauts do feel that there is some alteration of their
higher functions, of their efficiency in space, I think.
Sherri and Dr. Charles
on screen.
Sherri: We have about seven
minutes left. I just want to encourage everyone to try and get your last-minute
questions submitted by entering them into the chat room, so we have the
opportunity to answer them here for you.
Sherri speaking on screen.
Dr. Charles, Erica heard
that the fluids in astronauts' bodies float in microgravity and wants
to know if spandex would help that?
Dr. Charles speaking on screen.
Dr. Charles: Well Erica,
that's a great idea. Spandex is in fact one of the things that has been
considered to help astronauts, not counter the effects of space flight,
but to counter the effects of coming back to the ground after a space
flight. Spandex would be a tight fabric that would fit around let's say
the legs and the lower abdomen, sort of like pantyhose.
Video of space shuttle
coming in for a landing.
There are also things like
G suits, anti-gravity suits that the astronauts wear when they land on
the space shuttle, to keep the fluids not from floating around the body,
but from falling to the bottom of their bodies. That's not quite a precise
description, but very briefly, I told you earlier how the body fluids
are reduced in volume. That is you actually have less fluid, less blood
circulating inside the body in space flight because of the normal process
of adaptation.
That fluid volume is sort
of distributed preferentially, it sort of seems to be accumulating in
the upper part of the body. When you come back to the Earth, that reduced
fluid volume now is sort of pulled into the lower body, into the legs,
into the abdomen, which is fine. You need fluids, you need blood down
there, but you'd also like to have blood at the head and the heart.
Back to Dr. Charles.
And if you don't have as
much blood as you did when you launched, then there's a chance you're
going to be light-headed. You're going to have insufficient perfusion
of the brain.
Now Spandex, which has been
tested, or these anti-gravity suits, these G suits which are sort of like
bladders, they're bladders like jet pilots wear, squeeze the lower body
to keep the fluids in the upper part of the body, where the brain and
the heart and the lungs are. Because for that brief period of time, you
don't need to worry about how much fluid is in your feet and your legs
and your abdomen, you need to worry about how much fluid is up in the
brain and the heart and the lungs getting oxygen from the lungs, dropping
off carbon dioxide and then going to the brain to keep your brain working
well.
So Spandex would probably
work for returning back to Earth and it has been attempted. The current
G suit is now this air bladder suit, but that doesn't mean other work
can't be done on things like Spandex to help astronauts make the adaptation
back to the gravitational environment of Earth or another planet.
Back to Sherri.
Sherri: Michael wants to know
how a paper airplane would fly in microgravity environments.
Back to Dr. Charles.
Dr. Charles: Michael, I bet
you if we look hard enough, we probably have some video showing toys in
space. And one of the toys that was tested on a shuttle flight as far
back as 15 or 17 years ago was a paper airplane. In fact I think Jake
Garn was one of the first astronauts that actually had his TV picture
made flying a paper airplane.
The paper airplanes generate
lift by the air flow, or the flow of air across a curved surface, their
wing. And ideally, the tendency of the airplane to settle or to fall in
the air is counteracted by the lift generated as the air goes over the
wing. If you throw a paper airplane in weightlessness, you can expect
that if you've built it perfectly, it will tend to fly up, because there's
not gravity pulling it down, and the lift is continuing, so it will tend
to fly upwards.
Of course, the paper airplanes
I've built never go flat on Earth and they never go without spinning.
So I suspect if I was to throw a paper airplane, it would do one of those
little nose dives and just fall into the far wall there. But lift is an
important phenomenon related to air pressure and air flow and it's going
to be related to the shape of the wing. So a paper airplane could work
and if you did it well, it would work in weightlessness as well.
Back to Sherri.
Sherri: Well thank you. For
those of you who did not have the opportunity to have your questions answered.
There will be a FAQ page posted on the Quest Web site, probably about
a day delay, so give us a little time. But you can also see the archived
event if you want to go back and watch more closely some of the responses
that Dr. John Charles gave, and want to take more accurate notes.
I do want to let you know
I just found out there won't be a FAQ page, so don't be looking for that,
I apologize.
Sherri and Dr. Charles on
screen.
Well Dr. John Charles, do
you have any final words for those of us who might be interested in studying
the kinds of things that you have spent your career doing?
Dr. Charles speaking on
screen.
Dr. Charles: The kind of
things I'd recommend that you do if you were interested in a career in
space life sciences or space research or even an astronaut, which I am
not, but I know people who are. I would recommend that you study things
that interest you, because more than likely you're going to be doing something
related to those things for the rest of your life. Study things that appeal
to you. Don't study science and physics if you hate science, physics,
math. Don't study mathematics thinking that it's going to get you a good
job as an astronaut because the odds against being selected as an astronaut
are extremely high.
It's 400-to-1, after you
make the next-to-final cut. That's still a very, very steep probability
you go up against. Study the things you're interested in. But if you are
interested in space flight, it certainly doesn't hurt to get a good background
in the science, and the mathematics. Any science, biology, chemistry,
physics, astronomy, geology, whatever appeals to you, a good background
in mathematics because mathematics is the language of science and essentially
the language of the universe.
But I also recommend that
you broaden your perspective, that you learn things about things outside
of science. Learn about art, learn about music, learn about culture, learn
about social studies because we are all people in this together, we all
have to work together and the more we understand about the broader perspective,
the better we can do in our space science research jobs. And living together
in space is just like living together on the Earth.
Back to Sherri.
Sherri and Dr. Charles.
Back to Sherri.
Sherri: Well we want to thank
you so much for joining us here today and serving as our subject matter
expert. And for all of you out there in worldwide Web land, we want to
thank you for spending your time with us as well. On behalf of the Ames
Research Center Quest Project and the Distance Learning Outpost here at
Johnson Space Center, we hope you have a great afternoon. Good bye.
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