[rock music] NARRATOR: It promises
to deliver technology. It will carry us ever
farther, ever faster. But it's fraught with
constant and lethal peril. Flying in outer
space is like going through a shooting gallery. [banging] NARRATOR: It will test the
limits of human capacity and human ingenuity. If something goes
wrong, what do you do? Nothing. You just die. NARRATOR: Welcome to
the age of space travel. [dramatic music] In ways scarcely even imagined,
the steady hand of progress is poised to deliver
humanity to the heavens. For ages, the mysterious
splendor of the universe has enticed us from
its remote heights. [blasting] At last, its mysterious
temptations are within reach, and man's destiny
can be fulfilled. I don't know if it's
written in our genes, but anytime you see
something at a distance, it piques your curiosity. The first thing you want
to do is get a closer look. So while telescopes
get you pretty far in this regard, those things
that are close enough to be within the reach of our space
program, why not take the trip? MAN: T-minus 10, 9,
main engine starting. 5, 4, and liftoff of space
shuttle Atlantis to assemble-- NARRATOR: Prying free from
our home planet's grip ranks among the greatest of
human achievements. But no one since 1972 has
ventured beyond the Earth's orbit. Our space program has
been stuck for 30 years. We simply just go
around the planet Earth. It's just like Columbus
exploring the New World for the first time
and then spending the rest of his life
simply puttering around the Spanish coastline. [blasting] What's the problem? There's a dirty little four
letter word, and that is cost. It cost about $10,000 to put a
pound of anything into orbit. Imagine John Glenn
made out of solid gold. That's what it costs to put
John Glenn or you into orbit. It would cost about $20 million
for you to take a weekend trip up to the space station. It would cost about
a half a billion for you to go to the moon. And for you to go to Mars would
probably cost tens of billions of dollars. NARRATOR: One way to reduce the
cost of reaching space would be to find a more efficient way
to overcome Earth's gravity. Remember the story of
"Jack and the Beanstalk"? Jack was the little boy
who climbed the beanstalk into heaven. Well, imagine a
space elevator such that you hit the up
button, and the elevator takes you into the heavens, just
like "Jack and the Beanstalk." NARRATOR: Instead of
building from the ground up, the space elevator would
be built from the top down. A satellite in
geosynchronous orbit would drop a 60,000 mile
cable back to Earth, where it would be
anchored to the surface. Now, we are within
striking distance of being able to create
fibers that could withstand the tension of traveling
at enormous velocities in outer space as the
space elevator rotates with the planet Earth. So it never falls, because
it rotates at the same rate as the planet Earth. NARRATOR: The elevator's
compartment would simply roll up the cable, shuttling
travelers and supplies into orbit, where it would
wait for a spacecraft. This system would entirely
replace a conventional rocket launch. And that might reduce
the cost of space travel by a factor of $1,000. Think about that. Then you begin to realize that
perhaps a trip to outer space may be no worse than
an airplane ticket. NARRATOR: But beyond the limits
of Earth's comforting embrace, exotic menaces await
every space traveler. [dramatic music] Flying in outer space it's
not like taking a nice ride in the country and a car. It's like going through
a shooting gallery. [banging] NARRATOR: To an
unsuspecting voyager, it might seem the universe
is taking aim with a firearm. [rifle bangs] There are particles in space,
even dust-sized particles, pebble-sized particles that
are traveling tens of thousands of miles an hour. And sometimes, even faster. NARRATOR: More than half a
million of these projectiles, measuring over an
inch in diameter, are zipping around
our planet right now. They include pieces of glass
broken off of solar cells, paint chips from space craft,
and debris from rocket booster engines. And in deeper space,
there's more danger from pebble-sized meteors
called micrometeoroids. A small piece of dust
can crack the glass. It can penetrate metal. It can pulverize plastic,
and that does happen in space all the time. NARRATOR: But perhaps an
even more deadly danger, not at all solid, lies in wait. Radiation. The devastating effects
of this invisible energy have been witnessed on
Earth in the aftermath of the atomic bombs
of World War II and the nuclear
fallout of Chernobyl. Distressingly, our
own life-giving sun spews out streams of
poisonous radiation. MICHIO KAKU: So
realize that we've been protected in this cradle. We've been protected by
the atmosphere the Earth. The magnetic field of the Earth
gobbles up most of the flares from the sun to create
the aurora borealis. In outer space, you get the
aurora borealis coming right at you. There's no ozone layer. There's no magnetic
field to protect you. It's just you and the
harshness of outer space. [dramatic music] NARRATOR: At our home planet's
distance from the sun, roughly 90 million miles away,
several million solar particles pass through each
square inch of space every second around our earth. There's high-energy particles
streaming from the sun all the time. But every now and then,
there's an extra dose of these particles. The sun burps up high
energy radiation. That's bad, too. That level of radiation it
is never good for one's DNA. [dramatic music] NARRATOR: Sunspots flare up
these extra doses of energy like a battery of cannons
bombarding the cosmos. There's no way to know
that they're going to be here before they arrive. NARRATOR: Unfortunately, there's
still a risk of radiation, even as we get
farther from the sun. That's because another
invading energy lurks. Known as galactic
cosmic rays, they hail from the distant alien
worlds of exploding stars and black holes. Galactic cosmic
rays are particles that are traveling
at speeds very close to the speed of light. Even a single particle of
iron slamming into your body can have the effect of a Major
League baseball, 200 miles an hour. They can be devastating. [dramatic music] NARRATOR: Although heavy
iron particles are rare, outside of the protection
of a spacecraft, such as when an astronaut
performs a spacewalk, thousands of
galactic cosmic rays do penetrate the
body every second. MAN: [inaudible] copies. NARRATOR: Every 24 hours,
the galactic cosmic rays and solar particles
attack a space traveler with as much radiation as
a surface dweller on Earth receives in six months. [dramatic music] The human body won't immediately
feel the impacting radiation. But in sufficient quantities,
it can be noticed. Even with eyes
closed, the particles spark flashes when they strike
a space traveler's retina. The flashes are not blinding,
and you have to ask yourself, hm.
Did I see something? And then you say, oh, yes. I did. And its appearance is a little
different from time to time. [mellow music] NARRATOR: However,
the human body does feel the shock of this
bizarre weightless existence. I think that the most
dangerous thing going into space is the
loss of gravity. Weightlessness causes almost
every system in your body to start changing, and it
doesn't stop changing until you get back on to a world
where you're pulled down again by its gravity. NARRATOR: One of the first
casualties of zero gravity is a space traveler's
sense of direction. What's up and what's down? Very good question. And first of all, it's
whatever you want it to be. If you want this to
be up, that's fine. But if you want this to be
up, that's just as good. NARRATOR: Most travelers will
suffer from motion sickness for the first few hours. Or most likely, days. But it's just
one of those things that you ought to resign
yourself to facing, that everyone is very likely
to feel a little bit disturbed in terms of orientation. NARRATOR: Here on Earth, scuba
divers floating under water experience the nearest
sensation of prolonged periods without gravity. It is for this very reason
that aspiring NASA astronauts trained to live and work in
a gravity-free environment by subjecting themselves
for up to six hours at a time in a large water tank. Now, scuba equipment, you
still experience the forces of gravity. But it doesn't feel like it,
because your whole body is uniformly buoyed by the
water that holds you up. NARRATOR: And except for the
visual cue of air bubbles floating to the surface,
swimming underwater can mimic the sensation
of disorientation. But as time passes in the
weightlessness of space, the human body
senses it no longer needs to resist the
force of gravity and begins shedding
muscle and bone mass. When you're in
space, your body thinks that you might
as well be lying in bed. And so if you're not careful,
your body will atrophy. NARRATOR: To counter
this, each day in space, an astronaut needs to exercise. The legs are
especially vulnerable, because they are seldom used. In this world,
the arms and hands do most of the work to
move the body around. What would be the toughest
thing to get used to? It might very well be just
how you live in space, where you can't walk across the room. You have to float
everywhere you're going. NARRATOR: The lack of
gravity also slows down the digestive tract, which can
cause problems at mealtime. Your digestive system stops. You can't eat. You can't drink until you
can start digesting again, and that can take anywhere
from hours to days. NARRATOR: Worse still,
zero gravity and radiation can combine in an
especially sinister way. In space, the immune
system is not as effective as it normally is. And many of the bacteria and
viruses that we normally can withstand become more virulent. NARRATOR: Additionally, bacteria
can grow up to 50 times faster, and any virus brought
on board could mutate into a never-before-seen
predator, thanks to the
ever-present radiation. All these difficulties
prey on space travelers in just the first
few hours or days. [whooshing] And what about what about
journeys that need more time? It only gets tougher. The universe is an
unforgiving place. It's open to only the boldest
adventurers, those who have the mettle to trek
deep into an environment swimming with toxic hazards
and unafraid to stray far from the safe and familiar. We take it for granted
that clothing is flexible and machines work
in room temperature. Because implicitly
or explicitly, they're designed for that. You go into the depths of
space, if you're facing the sun, it could be hundreds
of degrees Fahrenheit. If you're facing
away from the sun, it could be hundreds
of degrees below zero. JERRY LINENGER:
Down here on Earth, you take so much for granted. You know, we're
out here, sunshine, the fresh air all around you. Up there, you're in
a closed ecosystem. You have to supply all the
human needs that the Earth just automatically does for us. You have to hope that the
integrity of the whole stays together so you don't
have rapid decompression, quick suffocation. NARRATOR: The same reality
exists for a submarine gliding deep through the ocean. It provides a
life-preserving barrier to protect its inhabitants
from a surrounding alien world. [dramatic music] NEIL COMINS: If there's
damage to the spaceship, air leaks out. You die. Damage to the submarine,
water gets in, you die. So the isolation both physically
and personally between the two seem quite parallel. NARRATOR: The potential for
a catastrophic mishap lurks. When you're out in
the middle of the ocean, you have only yourself and
your colleagues to rely on. And the same thing
applies in space. Things have to hold out. You can't come back. You can't run to
the hardware store. You can't fix the
thing with some part that you didn't bring along. And you're stuck with
human ingenuity, the tools you brought with you. And out there in
space, you truly are just removed from mankind. It is isolation like
I've never felt before. ANNOUNCER: Liftoff. We have liftoff. Often, our efforts
to explore space have been analogized
to the great explorers of the 15th and 16th century. The first two,
across the oceans, going to unknown
territory, having to bring all their
supplies with them, not knowing if
they'll ever return. And I think there's a lot
to say about that analogy. But there's a point where
it breaks down badly. When Cortez landed in South
America, when Columbus hit the Caribbean, there was
still air there for him to breathe, all right? There were fruit on the trees. Supposedly the Apollo 11
astronauts, Neil Armstrong and Buzz Aldrin, land on the
moon and the engine broke. JACK SWIGERT: OK, Houston,
we've had a problem here. What do you do? Nothing. You just die. There's not sort
of an engine tree that they can pluck parts
from to repair their ship. So the hazards
are vastly greater to human health in
space exploration than traveling anywhere
on Earth's surface. [dramatic music] NARRATOR: There won't be
any service stations in case you break down, run out of gas,
or need something to drink. One of the challenges
of space exploration is either carry along
with you all the supplies you need, water, food,
oxygen, or finding some way to manufacture that en route
or at your destination. We're not there yet. We don't know how
to do that yet. And so one hazard is
if something goes wrong and you run out of food, and
water, and shelter, that's bad. You'll die. NARRATOR: Every sip, every
drop of water is precious. On a space voyage, there will
be no such thing as a shower. The only option will
likely be a wet cloth. This is quite a change from
the 130 gallons of water each American consumes
in just one day. The cuisine on board would take
some getting used to as well. For a few days, you
can take fresh fruits, and fresh vegetables,
carrots, and apples, and things like that. For the longer
missions, though, you have to have storable
foods that can stay for long periods of time
without spoiling and going bad. NARRATOR: And yet
astronauts agree that enduring the
myriad of risks is a small price to pay
for the chance to witness the wonder of the
cosmos in person. ASTRONAUT: 1,500. It's 2.3. ASTRONAUT: Right. I know how they felt, because
they report things like, well, you could
hold up your finger, and you could block out
the Earth with your thumb. And it kind of gave them
an entire new perspective of how amazing this little
blue marble, the Earth, is and how precious it is in
this vast solar system. [mellow music] That experience
changed me forever, and I think it would change
anyone that could possibly have that experience in the future. NARRATOR: However, the
length of future voyages might limit the
range of experiences available to space travelers. Distances in our vast universe
can defy comprehension. If our sun were the
size of a basketball, our Earth would be
the size of a pea. If they were placed
in Central Park, the nearest star would be
another basketball almost 5,000 miles away in Hawaii. NEIL DEGRASSE TYSON:
One of the prerequisites you might have for a space
mission is that you're alive when you arrive
at your destination. So you'd want your
space missions to be small compared with a life
expectancy of a human being. And right now, that
pretty much limits us to the planets and possibly
comets and asteroids, if we include those as
places we might visit. NARRATOR: The brutal,
scathing landscapes of the solar system's inner
planets, Mercury and Venus, do not make for tempting
vacation destinations. Temperatures on Venus can
exceed 900 degrees Fahrenheit, and the crushing it pressure is
equivalent to being submerged in 3,000 feet of water. That leaves all
points further out from the sun for
potential exploration. But even trips to our
closest attractions will still take several
months, or even years. [tense music] About 139 million miles separate
the orbits of Earth and Mars. But since each body circles
the sun at different speeds, the distances with respect to
each other change continuously. The problem with going to
Mars is that Mars and the Earth only line up about
once every two years. [rocket blasts] NARRATOR: With current
chemically-propelled rocket technology, a flight leaving
from Earth or the Red Planet in 2018, when the two bodies
are on the same side of the sun, could take 104 days,
less than four months. After a 40-day stay,
the return trip would require a little
more than six months. That's an entire year
to make one round trip. [rocket blasts] But a voyage departing in 2031,
when the earth and Mars are on the opposite
sides of the sun, would demand about 20 months,
nearly two years of travel time. That's one to two years
away from any lifeline. [dramatic music] Comets, those oversized,
dirty snowballs, swoop close enough to Earth
to accommodate a round trip lasting as short
as a few months. Find some comet that's
on its way into the sun, and ride it, and watch the
coma grow and the tail form. And watch the sun first,
slowly, but then rapidly get larger, and
larger, and larger and swing around the
backside and come out. It's got to be the most fun
tour of the solar system you can come up with. It'd be dangerous, because
particles of the comet would fly up and hit you
in the face and things. So apart from all that
which would kill you, it would be a fun trip. [whooshing] NARRATOR: Just beyond
the orbit of Mars, asteroids fly within
range of a few years round trip from Earth. Future travel agencies might
arrange cosmic versions of extreme vacations
by exploiting the unique environments of
these miniature planets. They put you on a
sled and slingshot you into space in such a way
that the weak gravity of the asteroid will
hold you in orbit but won't pull you
back down again. It would be a great ride. NARRATOR: Three times farther
away than Mars, the orbit of Jupiter, with its
crowded moon system, offers dozens of
diverse visions. It may prove tempting
for future travelers, but round trip could
take five years. Saturn is nearly twice
as far as Jupiter, and the thought of
decade-long trips might be too much to bear. But there are
technologies that can slice the time it takes to
visit Mars to just a few days. For mankind ever to venture
into the depths of the cosmos, endeavor to bathe in the
light of an exotic star, or even just a
voyage to the suburbs of our own solar system,
we'll need to find a way to travel much, much faster. What's the fastest
we could travel? Nothing yet observed
by science moves faster than the speed of light,
186,000 miles per second. The speed of light is
the ultimate velocity in the universe. It's Einstein's
cop on the block. The speed of light
is so fast that you could go around the Earth
seven times in just one second. For you to jump to the
moon at the speed of light, you could reach the moon
in about one second. NARRATOR: Compare
that to the three days it takes to get there
with current technology. The problem is that we can't
travel at the speed of light or really, anything
even approaching it. Take the fastest thing
we have ever sent anywhere and ask, how long will that
take to reach the nearest star? That would take 50,000 years. [rocket blasts] NARRATOR: And that is using
current chemical propulsion, which maxes out at about
40,000 miles per hour, the same power source we
use to lift our rockets off of the planet. But getting us to Mars faster
than a few months' time would require a different
kind of propulsion. There are a few ideas for how to
propel us to velocities closer to the speed of light, which
would be fast enough to get us anywhere in the solar
system in under a day, or even to the nearest
stars in less than a decade. One such theory echoes an
ancient earthly propulsion device, wind pushing a sail. It was Kepler, that
great astronomer, who first wrote
down in his notes the possibility of using
sails to sail in outer space. NARRATOR: Light
streaming from the sun mimics gusts of
wind in outer space. This solar wind is what
creates a comet's tail as it nears the sun. However, sunlight scatters
in all directions. And as the distance
from the sun doubles, its power reduces
by a factor of four. With a little help
from the moon, there is a matter
in which light could be focused in one direction. If we have a battery of laser
cannons on the moon firing in synchronization
at a solar sail, we may be able to propel
it to about, perhaps, half the speed of light. Now, lasers do
diffuse this space. For example, if I have
a laser on the Earth and I shine it to the moon,
it does not create a spot on the moon. The spot is about five
miles across on the moon. These sails, however,
would be huge. Now, we're talking about
astronauts, perhaps, spending months in outer space
designing a sail hundreds, maybe even thousands
of miles across, sufficiently light
and durable in order to capture light from a battery
of laser beams on the moon. NARRATOR: But solar sailing
limits space vessels to destinations within
our solar system. One alternative gets
around this problem by tapping into hydrogen,
the most abundant element in the universe, as
a propulsion source. My favorite design
to take us to the stars is the ramjet fusion engine. [upbeat music] The ramjet engine has a gigantic
scoop in the forward direction that gobbles up hydrogen gas
as it moves in deep space. It collects the hydrogen
gas and then fuses it, just like the sun, and
shoots out a huge stream of ions out the other end. And on paper, it
looks fantastic. On paper, it looks as if a
ramjet fusion engine could go on forever, simply using
up the hydrogen that is found naturally in outer space. NARRATOR: Unfortunately,
scientists have not yet been able to achieve a
hydrogen fusion reaction capable of propulsion in tests. But another potential
fuel source, one that seems to come right
out of science fiction, has already been
created in laboratories. It's called antimatter, and
it's the opposite of all that we know. For example, think of
the world on the other side of the looking glass. Just like in Lewis Carroll's
"Alice in Wonderland," we physicists have wondered,
is there another universe on the other end of
the looking glass, a parody-reverse universe
where left becomes right, right becomes left. In an anti-universe,
charges are reversed. So positive charges
become negative. Negative charges
become positive. And when they meet, they
create a burst of energy. So if this universe on the
other side of the looking glass are made out of an
antimatter and I where to touch this
other universe, I would destroy most of the
New York City metropolitan area in a burst of energy. [blasting] So the conversion of
antimatter and matter to energy is 100% percent efficient. It is the ultimate engine,
but there is a catch. There's always a catch. Even though we can create
anti-atoms in the laboratory, the cost is stupendous. It would bankrupt the
United States of America to create a teaspoon
of antimatter. However, it would only take
a few grams of antimatter to take us to Mars, and perhaps
several teaspoons of antimatter to take us to the nearby stars. NARRATOR: But for
us to ever visit a distant star or
another galaxy, we need something
stranger than even Alice could ever dream of
peering through her looking glass. [dramatic music] Scientists continue the
quest for a propulsion method to carry us ever
deeper into space. But even achieving light speed
won't allow us to get very far. Light's fast, but
the universe is huge. So even if we could
ride on a beam of light, if we wanted to cross the
galaxy where they do in all the science-fiction programs,
it would take 100,000 years to do it. [blasting] NARRATOR: And even
at light speed, traveling to the nearest galaxy
would take several million years. And if light speed is
the ultimate speed limit of the universe, it seems
we are doomed to confinement in our galactic neighborhood. What we're desperate for
is some new understanding of the fabric of space time that
will allow us to somehow warp it, distorted so that
you can take shortcuts. And of course, that's what
they do in "Star Trek" when they turn on
their warp drives. If they want to get from
one side of the galaxy to the other, all they do is
invoke the warp drive that warps the fabric of
space, and then they take a little
shortcut right there. They cheat, basically. Everybody knows
Einstein's famous dictum. You cannot go faster
than the speed of light. However, there is
a footnote to it. You see, Einstein left
open the possibility that you can rip all the
fabric of space and time itself so that you
effectively take a shortcut through the universe. Think of a carpet. If you want to go
across the carpet, that's the old-fashioned way. You can also get a lasso. Lasso a table on the
other side of the carpet and then drag the
table toward you so that you collapse the
space in front of you. In a nutshell, Einstein says,
the bigger the mass, the bigger the bending of space and time. If you can concentrate
enormous amounts of energy at a single point
comparable to that of a black hole or a
huge, gigantic star, you are literally warping
the fabric of space and time. You simply hop across
to the nearby stars. So in other words, you did
not really go to the stars. The stars came to you,
because you are compressing the space in front of you. [dramatic music] NARRATOR: The massive
amount of energy or mass needed to create such a
warped curvature of space seems beyond
comprehension, and perhaps, beyond human capability. There may be an alternative. Physicist John Brandenburg is
developing a theory in which a starship of the
future could achieve faster-than-light travel
not by manipulating a vast area of the universe,
but rather, by manipulating only the area around the starship. The trick is to have a starship
imitate a curious particle that, so far, only
exists in theory. It's called a tachyon. JOHN BRANDENBURG:
It's a particle with a different twist. Light itself always
moves at the same speed. Tachyons, on the other hand,
can go infinitely fast. They just can't go slower
than the speed of light. They look at the speed of light
as a lower speed limit that they cannot violate. NARRATOR: If they
do exist, thacyons can outrun the speed of
light, because they have what physicists recognize
as imaginary mass. An imaginary value can
be visualized in the spin of a struck tennis ball. Its spin can cause it to
bend and move in a manner that an observer
might not expect to see from its initial
point of contact. [dramatic music] In the same way, a tachyon
is unseen by the universe and can break its speed limits. Brandenburg proposes altering
the space time surrounding a starship with a powerful
electromagnetic field so that the ship moves
through spacelike a tachyon. It would operate like a stealth
aircraft, invisible to radar, unseen by radar operators. JOHN BRANDENBURG: So if one
can achieve this control of the spacetime
around this ship, one can essentially make
it an imaginary object. In a technical way, that means
it's moving faster than light. You're basically
disconnecting yourself from the rest of the cosmos. NARRATOR: It could grant
the traveler the ability to go anywhere in the universe
in the blink of an eye, as if a multitude of
doorways suddenly appeared. A doorway, you step into,
and then you step out somewhere down the hall so fast that it
didn't seem like you had time to move any place. That's a imaginary
connection in spacetime. And you've changed
yourself, not spacetime. NARRATOR: No one may how fast
or even where such a space vessel could travel. Which door to go into? Which door to come out of? That's the trick. NARRATOR: But voyaging through
the hall of the universe isn't possible without
first overcoming one of its fundamental forces,
the one that shackles us to our home planet. Getting away from the
Earth's gravitational field, that's the first thing
that we have to do. ANNOUNCER: 10, 9, 8, 7, 6-- NARRATOR: For an object
to break away from Earth's gravitational pull-- ANNOUNCER: 3, 2, 1. We have ignition and
liftoff of NASA's new-- NARRATOR: It must
achieve a velocity of 17,500 miles per hour. That's fast enough to streak
from New York to Los Angeles in about eight minutes. JOHN BRANDENBURG:
There's no other way to do it, at least, that we have
now, other than brute force. [dramatic music] NARRATOR: While a theoretical
space elevator can climb away from Earth's
gravitational pull-- [rocket blasts] --a rocket must outrun it
with the brute force provided by the explosive chemical
reaction of burning fuel. NEIL DEGRASSE TYSON:
The chemical power is what drives
today's rocket engine. Every time you burn something,
that's chemical power. Every time a rocket engine
ignites, that's chemical power. Every time you start
your engine in your car, you're using the chemical
energy stored in the gasoline. NARRATOR: The fuel alone can
burden a space-bound craft with up to 90% of
its total weight. [mellow music] If you're carrying all
the fuel you'll ever need, then most of the effort
of the first ignited fuel is to lift the unburned
fuel into orbit. It'd be like trying to
drive from New York City to Los Angeles on
one tank of gas. Well, you would need a
tanker truck behind you. And most of the energy to
accelerate the tanker truck is going into just move the
fuel that's in the tanker truck. NARRATOR: The space
shuttle, its rockets, and the fuel they're carrying
weigh a staggering 4 million pounds, and nothing short
of a bone-rattling eruption could push it up
and away from Earth. MISSION CONTROL: Well, Ben, it
looks like your long wait is over. We wish you all the
best luck in the world. Godspeed, and we'll see you
back here in about two weeks. NARRATOR: A journey
into space today means that space travelers must
ride a controlled detonation into the sky. Whatever the vehicle weighs,
we have to generate about 1 and 1/2 to two times that
thrust in order to get it off the surface of the Earth. [dramatic music] [rocket blasts] NARRATOR: To get
the space shuttle up to speed demands 7
million pounds of thrust. To put that into perspective-- If you can imagine me holding
a one-pound ball in my hand, if I'm holding it here
and I'm holding it steady, I am exerting a pound
of thrust on that ball. So if I lower it down,
I'm clearly not exerting a one-pound. If I pick it up, I'm
exerting more than a pound. So you have to have
a little more thrust than you do the
weight, obviously, or you won't go anywhere. NARRATOR: How a rocket
moves can be illustrated with a blown-up balloon. This works almost
like an engine nozzle. Now, I can hold in place,
and you can control it. You can let it go. And what we do is we try
to inject as much mass through that throat as we can. And as it expands
out the back end, that expansion or that
pressure pushing that way pushes the vehicle this way. [cheering] NARRATOR: When today's
astronauts climb aboard for their journeys
on the space shuttle, they're hitching to
giant containers housing that necessary mass. Millions of pounds of highly
combustible hydrogen and oxygen wait to be ejected. It only takes a spark. ANNOUNCER: T-minus 10, 9. [hissing] [rocket blasts] ROBERT LIGHTFOOT: The main
engine starts six seconds before takeoff. The whole shuttle shakes and
feels like it wants to just rip itself out of the launch pad. ANNOUNCER: Lift off of
space shuttle Endeavor, expanding the international-- It shudders, and
you think, oh my gosh. That's an awful lot of force,
about a million and a half pounds of thrust. [rocket blasts] It's kind of surreal. It's like, this can't
really be happening. It's something
you've been wanting to do for years and years,
and it's really happening. It's like riding a
man-made earthquake. You've spent several million
pounds' worth of fuel to get to the first two
minutes of flight, and then the solid
rocket boosters come off. [blasting] And that's like a trainwreck
when those things come off. It almost feels like you're
just accelerating faster, and faster, and faster as
you burn all the fuel out of the big main tank. So for the next six minutes,
and you're accelerating up to a point where you're
finally feeling about three Gs, three times the force of
gravity of acceleration. So now, it almost feels like
there's a big gorilla sitting on your chest. [upbeat music] [tires squeal] NARRATOR: A drag race who
accelerates from 0 to 100 miles per hour in two seconds will
feel G-forces similar to those experienced by astronauts. As the vehicle
keeps accelerating and you're watching the speed
tick by in thousands of feet per second, until you get to
25 times the speed of sound. Then there's a cutoff, and
then everything's floating. And now, you're in space. So space isn't very far away. It takes about eight minutes
and 30 seconds to get there. NARRATOR: The next model for
venturing into the great beyond and reaching new
worlds will begin first with a visit to an old friend. [mellow music] Although not quite
yet a space elevator, NASA's mission to
return to the moon builds on the idea
of Earth orbit as a base for farther voyagers. NASA's Constellation
Program, a successor to the legendary Apollo Program,
aims to plant boots on the moon by 2020. Two separate rockets form
the foundation of the plan. The unmanned Ares 5 rocket,
towering taller than a football field standing on its end,
will carry the lunar lander, supplies, and an
Earth-departure rocket into orbit, where it will
wait for the astronauts. [upbeat music] [rocket blasts] The Ares 1 rocket
will deliver the crew to orbit aboard a capsule. [upbeat music] [blasting] It will then rendezvous with
the Earth departure rocket and blast to the moon. We can take more supplies,
more commodities to the moon. That's what this tandem
system provides for us. Instead of Apollo,
which only allowed us to go for one or two days
at a time and then come back. [rocket blasting] NARRATOR: Will we
ever find a way to surpass the bold achievements
of the Apollo Program? Will we ever cross the
vast expanse of the cosmos as quickly and effortlessly
as we travel to another city or another continent? We must if we are to
survive as a people. If we stop exploring, we
have learned time and time again throughout history that
those societies basically tend to wither up and die. It's a part of what we are. It's a part of what we
leave to our children and their children. It's who we are,
and it's what we do. [blasting]
