Original subtitles

(tense music)

- [Narrator] An international armada

of science probes is converging on Mars.

(loud rumbling)

They are searching for evidence of past life

(forceful air blowing) (resonant rumbling)

while testing technologies needed

for humans to safely visit this desolate world.

The Red Planet has beckoned generations

of dreamers and space flight pioneers

to imagine crossing the wide gulf between worlds.

Longstanding questions hang in the balance.

What is humanity's future in space?

Could we actually make a second home

on Mars?

(tense music)

Mission planners have long known

it is nearly impossible to land on Mars.

(deep rumbling) (forceful air blowing)

The atmosphere is thick enough to melt spacecraft,

which hit it going more than 16,000 kilometers an hour,

yet it's so thin (wind blowing)

even a wide aero shell

(loud thudding) (wind blowing)

plus a big parachute...

- [Mission controller] The parachute has deployed

and we are seeing significant deceleration.

- [Narrator] Aren't enough to fully break the fall.

(loud thudding)

- [Mission controller] Heat shield's up.

- [Mission controller] Perseverance has now slowed

to subsonic speeds.

(forceful wind blowing) (loud clanging)

(air swooshing)

- [Narrator] Percy, the Mars 2020 Perseverance rover

used an innovative system of rockets

(forceful air blowing)

and an ingenious sky crane...

- [Mission controller] Sky crane maneuver has started.

(forceful air blowing)

- [Narrator] To gently touch down.

- [Mission controller] Tango delta.

- [Mission controller] Touchdown confirmed.

Perseverance safely on the surface of Mars.

(NASA crew cheering)

- [Narrator] But exactly how to land a crew

of astronauts safely is a problem waiting to be solved.

Percy is among the most sophisticated

mobile machines ever made.

It's small companion, Ingenuity, is the ultimate drone,

testing for the first time

controlled flight

on another world.

From the striking images Percy and other probes send down,

it's easy to believe Mars

is very much like the deserts of Earth.

(tranquil music)

For at least a century, visionaries have imagined,

if we could just get there,

it shouldn't be too tough to explore in person

to pioneer a frontier of freedom and prosperity,

and perhaps to make a backup copy of Earth's biosphere

in case of disaster.

But the real Red Planet is a trickster

with a long history of fooling us,

colder than Antarctica,

bone dry,

harsh, toxic grit under foot,

and a constant rain of lethal radiation from above

a tragic world.

The Mars we wish for

has never been the Mars that truly is.

For thousands of years, the bright Amber planet

has been toying with human imagination.

As they orbit,

Earth and Mars come closest together every 780 days or so.

Called a planetary opposition,

it's the best time to observe the Red Planet,

which over a few weeks appears to slow down,

backtrack,

then speed forward again.

Puzzled by this capricious retrograde motion,

Egyptian sky watchers saw Mars

as a hawk-headed humanoid deity,

flying back and forth between the realms of the living

and the dead.

From its odd motion,

Babylonian astrologers believe Mars

to be a quick, impulsive, volatile god.

On May 4th,

357 BCE,

the Greek natural philosopher Aristotle

observed the half full moon passing

in front of the Red Planet

and realized that Mars must be farther away than the moon,

but he would have been surprised by how much.

Mars is about 200 times more distant.

(forceful air blowing)

Chemical rockets that take

around three days to get to the moon

would take nearly seven months to reach Mars.

(suspenseful music)

Future nuclear thermal rockets

might cut that trip to less than three months.

(suspenseful music)

That's still a very long time

to spend confined in a small spacecraft

(suspenseful music)

and you can't just return home in a few hours or days

if there's a problem.

(suspenseful music)

Astronauts in microgravity must exercise often.

(fast-paced music)

Bones become brittle.

Heart muscles get lazy.

And about one-third Earth's gravity,

how will Mars affect human health over the long-term?

(fast-paced music)

Around 150 AD,

Greek mathematician and astrologer, Claudius Ptolemy,

proposed at Mars and the other four wandering stars

must circle Earth on a set of spheres,

but

700 years later,

Islamic astronomers began to find problems

with Ptolemy's so-called epicycles.

In 1543,

Copernicus of Poland put the sun at the center of motion

and Mars looping behavior finally made sense.

(tranquil music)

About 40 years later,

wealthy, obsessive Danish astronomer Tycho Brahe

wanted to accept Copernicus geometry,

but he couldn't quite let go of Ptolemy.

Tycho insisted that the immensely heavy Earth

must be too lazy to orbit,

(tranquil music)

but massive worlds do move.

In the early solar system

the huge planet Jupiter may have migrated

inward toward the sun,

about as far as Mars' present day orbit.

(energetic music)

Plowing through the solar nebula,

Jupiter gobbled up much of the dust and gas,

robbing Mars of its potential to grow larger.

The stunted planet could attain

only about half Earth's diameter

and barely 11% its mass.

As Jupiter and Saturn continued to migrate,

they displaced billions of tons of icy rocks,

flinging them inward,

(ambient music)

a deluge of debris lasting three million years,

the late heavy bombardment.

Today, the high country of Mars' southern hemisphere

has one very large hole punched in it,

the Hellas Basin,

the third largest impact crater in the solar system,

but the little planet may have been hit

by something even bigger.

As you fly from south to north,

Mars' terrain sinks.

From red and orange highlands

down to green and blue valleys,

Mars whole northern hemisphere is a giant sunken ellipse

draping over 40% of the planet.

If this is an impact site,

the incoming object would have been

about the size of dwarf planet Pluto.

(loud rumbling)

It would have totally remade Mars,

probably shutting off its internal dynamo,

erasing its protective magnetic field

and killing the chances for a life-sustaining atmosphere.

When groups of would-be settlers do set sail for Mars,

they must accept that they will never again

take a breath outside their helmets or habitats.

They will have spent months crossing the void

to a desolate world

with a lethal environment.

In September of 1610, Galileo Galilei recorded

the first telescopic observation of Mars.

26 years later,

Francisco Fontana made the first known drawing of the planet

saying it looked like a very black pill.

By 1649,

the Dutch brothers Christiaan and Constantijn Huygens

had developed much better optics.

Christiaan sketched an irregular mark on Mars.

Living in the wetlands of Holland,

he thought it looked like a big bog.

So it became known as the Great Marsh,

Syrtis Major.

Huygens timed that rotating feature,

finding the day length on Mars to be like Earth.

Seven years later,

Giovanni Domenico Cassini refined that figure

to 24 hours plus 40 minutes,

very close to what astronomers measure today.

Cassini also logged the first observation

of Mars' south polar cap.

Watching the changing faces of Mars,

Cassini imagined it must be quite similar to Earth.

(tense music)

Three billion years ago,

Mars may indeed have been Earth-like,

volcanoes building the atmosphere,

(water flowing)

steam and mist and flowing water filling early seas

with more fluid than the Arctic ocean on Earth.

In 1997,

Sojourner, NASA's first Mars rover,

found the outflow of a cataclysmic flood.

(tense music)

Beginning in 2004,

the Mars exploration rovers Spirit and Opportunity

found stacked strata of rock

laid down by flowing water over thousands of years

and little rounded iron-rich concretions

nicknamed blueberries that must've formed in pockets of silt

lying under salty water.

But what of water on modern Mars?

NASA's Phoenix found evidence in 2008.

(forceful air blowing) (loud scraping)

Soft landing at a high northern latitude,

its rocket plumes blew away surface dust,

exposing some white material.

Digging a shallow trench, the little probe revealed more,

which disappeared within a day.

And on the lander's legs

drops of liquid appeared,

then changed.

(soft rattling)

In August of 2012,

the Mars Science lab, Curiosity, began to roll,

trekking through dry stream beds

between the banks of ancient watercourses

and across the alluvial fan

at the mouth of a long dead river.

Perseverance joined Curiosity in 2021.

Landing in a once-flooded crater,

finding the clay-rich rocks of an ancient river delta,

these hardy robot geologists found layered terrains

each built by episodes of flowing mud

with dry times in between,

but these wet periods ended long ago.

Today's Mars seems a lifeless desert,

(soft rattling)

a lonely landscape

crying out for company.

In 1698,

Christiaan Huygens did not think Mars was so desolate.

His last book,

"Cosmotheoros"

imagined that the worlds of the solar system

must harbor plants and animals.

Though they would be different from those on Earth,

they probably led comparable lives.

Huygens saw no reason that life on the planets

should not be intelligent.

And he also pointed out

how important water would be to those creatures.

(tranquil music)

The moon is rich in aluminum, titanium,

silicon and magnesium.

Asteroids add carbon, cobalt,

platinum, molybdenum, nickel, and other elements.

Mars has all of these,

plus abundant iron and other metals,

especially near its enormous volcanoes,

but Mars' key ingredient is water ice,

which can be split to make breathable oxygen

and hydrogen fuel.

Percy is testing this idea right now,

breathing in carbon dioxide

and electrochemically breaking out the oxygen.

Water from beneath the surface

plus carbon dioxide from its atmosphere

can be rearranged to make methane and oxygen.

Use that oxygen to burn the methane,

and you can launch rockets.

(forceful air blowing)

By making propellant on Mars,

the cost of getting back to Earth drops

by at least a factor of five.

To conjure up space-based civilization,

we can bring with us only tools and talent,

small factories and power generators.

We must hunt and gather the rest.

(ambient music)

In 1704,

Giacomo Filippo Maraldi

guessed that dark rings around Mars poles

might be melt lines.

Could the poles be ice caps, he wondered.

80 years later, Frederick William Herschel declared,

"Yes, Mars poles are water ice."

And he thought that the broad dark equatorial patches

must be oceans.

Herschel daydreamed what it might be like

to sail those waters.

(tranquil music)

Mars probably lost its oceans before life emerged

out of the seas on Earth.

The northern desert lowlands,

the flattest topography on any known planet,

look like the floor of an ancient sea.

Up to four kilometers deep,

Mars' polar ocean may have covered a third of the planet.

In 1785,

Herschel speculated that Martians

probably enjoy a situation similar to our own,

but he realized the Martian atmosphere must be very thin.

It is thin.

The planet is enveloped in sparse carbon dioxide.

There's very little water in the air,

but there is methane

which could be coming from hot underground geology,

but the methane levels sometimes rapidly blooms

then quickly disappears.

And that has a lot of experts wondering,

might something be living below the surface?

In 1788,

Johann Hieronymus Schroeter proposed

that Mars has no solid surface at all,

just drifting clouds and misty rain,

but Schroeter's shifting scene was probably just due

to the unstable air of Earth above his big telescope.

The true story of Mars atmosphere is becoming clearer.

(tense music)

Going back at least a billion years,

intense ultraviolet radiation from the sun

and the sputtering solar wind bombarded the small planet.

With its low gravity and frail global magnetic field,

Mars could not hold on to its protective gas envelope.

Most of its air was lost to space

and the rest of its water absorbed into the ground.

Back in 1830,

none of this dreadful history was known.

Johann Heinrich Madler and Wilhelm Beer

crafted the first fairly accurate Mars maps.

They placed their zero longitude line through a feature

that will later be named Sinus Meridiani,

Meridian Bay.

This is what Meridian bay looks like from the ground.

The Opportunity rover explored it for 13 and a half years,

sending home images of the stark, withered land escape.

It's easy to imagine standing on Mars yourself,

gazing at the intricately weathered rocks.

Nearly everywhere our probes look,

they see evidence of past liquid water.

(tranquil music)

Though there are no oceans today,

there's plenty of hidden ice.

The Mars reconnaissance orbiter recorded eroded cliff faces

exposing compacted, frozen water,

in some places more than a hundred meters thick.

(tranquil music)

On passes over the poles,

MROs radar revealed up to two kilometers of ice.

It's been laid down in layers,

suggesting that Mars climate may cycle

between warm and cool times

Zooming in from orbit,

we can see dark streaks

that appear and disappear seasonally

on the slopes of steeper craters.

They look a lot like desert rain gullies on Earth,

and many researchers thought

they might be flowing salty water.

New analysis suggests that the larger ones at least are dry,

streams of rounded sand grains tumbling over one another

flowing like liquid in the low gravity of Mars,

but the small ones

seem truly wet.

In 1862,

astronomer Camille Flammarion

picked up the idea of intelligent aliens,

publishing the first of his eight books

about life on the planets.

"The Plurality of Inhabited Worlds"

became an all-time bestseller.

Charles Darwin's notion that species develop

in response to their environment

led Flammarion to speculate that various planets

would cause creatures there to be unlike those of Earth.

Drilling into the rocks,

Mars rovers have shown the building blocks of life

to be plentiful.

(tranquil music)

Clay minerals would have filtered salts and harsh compounds

from the primeval flowing waters.

Many types of microbes now living on Earth

almost surely could have survived on ancient Mars,

but no photos,

fossils or direct chemical evidence of life

have yet turned up.

Around

1864,

the Vatican became concerned

about the state of grace of the Martians.

Father Pietro Angelo Secchi of the Roman College Observatory

began to chart where they might live.

He renamed Huygens' Syrtis Major feature,

calling it the Atlantic Canale.

That word simply means channel.

Secchi intended no reference to intelligent design,

but his term canale

would cause much confusion over the following years.

At the same time, in England,

astronomer William Dawes made Mars maps of his own.

Dawes was extremely nearsighted,

but his charts were more detailed than any before.

Sensing a great story,

science writer, Richard Anthony Proctor

blasted the Dawes maps out to the public.

(melancholic music)

The Suez canal was completed in November of 1869,

making news around the world.

The Panama canal was in the planning stages

and many people made a connection between the straight

canale on Mars maps

and these great works of engineering on Earth.

There are many ancient water channels all over Mars,

but there's no evidence of technology in their shapes.

Mars came again into opposition

in 1877.

Nathaniel Green, an artist by day

and astronomer by night,

painted the most accurate Mars chart yet.

Over in America,

the self-taught astronomer, Asaph Hall,

noticed something no one else had,

two tiny moons.

Phobos and Deimos

may be bits of Mars

flung into orbit by giant impacts long ago,

or they may be asteroids captured by the planet's gravity.

With Mars particularly close,

within just 56 million kilometers of Earth,

Giovanni Schiaparelli began to map it.

Though he, like Dawes, was near-sighted and colorblind,

Schiaparelli was somehow able to extract more

from the telescope than others.

He too called the lines he saw on Mars canale,

giving them whimsical names from classical literature

that are still used today.

Some Mars oppositions are closer than others.

While Earth's orbit around the sun is nearly circular,

Mars orbit is much more elliptical.

(ambient music)

During Mars southern autumn and winter,

that hemisphere is tipped away from the sun

and the whole planet is farther away,

making those seasons longer and colder.

(ambient music)

With the next close opposition, in 1879,

Schiaparelli came to believe

he was seeing pairs of straight canale.

(ambient music)

Harvard College Observatory's William Henry Pickering

declared that martian canals were only visible

because plants were growing along their banks.

(ambient music)

All speculation about large engineering projects

by smart Martians

was put to rest

of the night of July 14th, 1965

as NASA's Mariner 4 flew by Mars.

In the probes' 21 images,

Mars looked much more like the moon than the Earth.

Worse,

Mariner couldn't find a protective magnetic field.

Harsh solar wind and cosmic radiation

would have been scouring the planet for millennia.

It's tough to imagine how even primitive life

could survive here.

But back in 1892,

Camille Flammarion was still filling

his imaginary Martian canals with water.

He speculated they were the rectification of old rivers

by the inhabitants for the purpose

of general water distribution

and that the actual habitation of Mars

by beings superior to our own is very probable.

Pouring more into Flammarion's illusory waterworks,

Pickering asserted that he had observed up to 40 lakes.

At about the same time,

a wealthy world-traveling American diplomat

was feeling like he needed a career change

and a personal passion project.

Percival Lowell had read Flammarion's books

and he made plans to look for Martians

during the coming opposition of 1894.

Pickering helped lowering two telescopes

on a hilltop in Flagstaff, Arizona.

The new Lowell Observatory

stared at Mars all summer long.

But Lowell, an untrained observer,

saw only what he believed.

He sketched a planet-wide irrigation system

transporting billions of gallons of melted polar snow

to equatorial oases,

the irrigated agriculture projects of an advanced race.

But during the same opposition,

astronomer Edward Barnard,

wielding the California Lick Observatory's

larger refracting telescope,

could not find a single straight line anywhere on Mars.

And when the Lick's William Campbell examined Mars

with a spectroscope, he saw not a trace of water.

English astronomer, Edward Maunder

demonstrated how straight lines on Mars

could easily be optical illusions.

Undeterred,

Percival Lowell sprinted across America

on a lecture tour in 1895,

promoting his book named simply "Mars".

A story-thirsty public bought his tales

of Martian waterworks by the thousands.

The real Mars is a parched planet.

Though tilted rocks tell us there were lakes here long ago,

today, dust devils swirl across the barren terrain.

The Spirit rover caught one in the act

486 Martian days after landing.

Curtains of desiccated grit

sweep up into the hazy sky from rugged canyon cliffs.

Dry, sandy landslides garnish steep crater walls

and clump on the floors.

Percival Lowell began observing

with an even bigger refractor in 1896,

but still could not see his glaring error.

Lowell carried on for 20 more years,

hallucinating over 450 canals with vegetation,

seduced by the drama of a desperate civilization

bravely combating global climate change

as their dying world dried to a planetary desert.

(ambient music)

In fact,

Mars' climate did change radically,

but it happened long before Lowell's time.

Without the large moon to stabilize it,

Mars wobbles tens of degrees

over hundreds of thousands of years,

much more wildly than Earth.

When Mars points a pole toward the sun,

billions of tons of CO2 might be released,

unleashing epics of greenhouse warming.

This might melt some surface ice,

letting the water flow,

(tranquil music)

but the temperate times

can never last.

(tranquil music)

In his 1899 novel "The War of the Worlds,"

H. G. Wells found drama in the doomed planet.

An advanced race of Martians comes to conquer Earth

and enslave humans as work animals.

(tense music)

In 1976,

Earth sent two Viking landers,

not to subjugate, but to investigate.

- [Mission controller] Brace for dismount.

- [Mission controller] ACS is green,

1.5 degrees per second max, 0.2 Gs.

- [Mission controller] Eight feet per second.

- [Mission controller] Touchdown, we have touchdown.

(NASA crew cheering)

- [Mission controller] We have touchdown.

(cheering drowns out speaker)

- [Narrator] They found very active,

intriguing surface chemistry,

but evidently,

no life.

Back in 1905,

the idea of a living Mars

captured Lowell Observatory's Carl Lampland.

He claimed to have photographed 38 canals.

Now, it's vital to remember,

most of these observers were good astronomers,

wielding the best telescopes of their day,

yet they saw what wasn't there,

a lesson perhaps for those who, today,

dream of settling Mars.

In 1909, at the Meudon Observatory near Paris,

astronomer Eugene Antoniadi could find no linear canals,

yet the public had been seduced

by the idea of an alien civilization.

American novelist Edgar Rice Burroughs

released the first of his 11-volume tale

depicting heroic John Carter on a fictional Mars,

the desert planet Barsoom.

Today's Mars rovers are finding a desert world too.

Curiosity trekked around a wide field of dark sand dunes.

Rolling like waves on an ocean,

the Sandy mounds slowly migrate across the terrain.

The orbiting high-rise camera caught Curiosity at work

in what's known as the Bagnold Dune Sea.

In 1921,

Mount Wilson Observatory astronomers

measured surface temperatures on Mars,

finding them to swing wildly

from 15 Celsius at midday

to a lethal minus 85 Celsius just before sunrise.

(ambient music)

Astronomer Walter Sydney Adams

found only vanishingly tiny quantities of oxygen and water.

(ambient music)

At the Yerkes Observatory,

Girard Kuiper showed the Martian air

to be nearly all unbreathable carbon dioxide,

yet Mars continued to entice explorers.

In 1949,

rocket pioneer Wernher von Braun wrote "Project Mars".

It was a sci-fi novel,

but full of factual engineering

and a familiar plot,

a multinational crew from Earth

visits intelligent humanoid Martians

as they desperately try to save their world a year.

A year later,

Ray Bradbury's "Martian Chronicles"

placed a human colony on Mars

to escape a nuclear war devastated Earth.

(bomb exploding)

The first thermonuclear bomb was tested in 1952.

(suspenseful music)

In the same year,

Von Braun published an enhanced "Das Marsprojekt,"

adding a broad technical workup

for a large scale space program.

(energetic music)

After nearly a thousand launches of people,

propellant and parts,

a flotilla of 10 spaceships and 70 crew members

would journey across the gulf between planets to spend

444 days on Mars.

(energetic music)

"Das Marsprojekt" was a rough draft

for what would become NASA's Mercury,

Gemini and Apollo projects.

(ambient music)

In 1955,

Paramount Pictures released "Conquest of Space,"

modeled on Von Braun's adventurous plans.

- I can give you confounded little reason

for this attempt to reach Mars

and no assurance at all that it will even be successful.

(suspenseful music)

- [Narrator] To successfully reach the Red Planet quickly,

engineers realized, might take more power

than chemical rockets can produce.

At the U.S. Los Alamos National Lab,

Project Rover began an effort

to harness atomic fission to drive spaceships.

(ambient music)

The astronauts' crew capsule

will be placed many meters from the radioactive engines.

Getting to Mars faster would cut astronauts dose

of solar and cosmic radiation.

Project Orion, (loud pulsing)

a different approach to nuclear rockets started, in 1958.

The idea: detonate nuclear bombs behind a ship

to push it along.

(loud pulsing)

It's called pulsed plasma wave propulsion.

(loud pulsing)

Outrageous as it seems,

this method could offer rapid transport

to Mars and the rest of the solar system.

(loud pulsing)

By 1961,

the U.S. Nuclear Rocket Engine NERVA program

had accumulated 17 hours of engine testing.

(inspiring music)

In the Soviet Union, engineers were working

on nuclear thermal rockets of their own.

(inspiring music)

(ambient music)

As late

as 1962,

the U.S. Air Force was still making Mars maps

with straight canal lines.

(ambient music)

- [Man] Someday, a manned trip to Mars and return

may become the mission assignment.

- [Narrator] To accomplish that assignment,

Krafft Ehricke, a visionary German American engineer,

introduced the idea of ganging together

clusters of nuclear rockets.

He thought his modular approach

could bring Mars and Venus within reach

as early as the 1970s.

And he identified the most efficient launch windows

to reach these planets.

Ehricke passionately believed that human expansion

throughout the solar system is a fundamental right,

(tranquil music)

and that we are at our most dignified

when we apply the laws of physics

to elevate and protect our individual freedoms.

Ehricke's and Von Braun's visions

would drive the Boeing Company

to propose the integrated manned

interplanetary spacecraft concept in 1968.

(ambient music)

It bundled up to five nuclear thermal stages

to propel astronauts and probes to the nearest planets.

It would have caused half, again,

as much as the Apollo Moon Program,

but it might have delivered the first crew to Mars by 1986.

(suspenseful music)

The U.S. put boots on the moon in July, 1969.

Humans had finally touched another world.

(suspenseful music)

With the moon landings fresh in mind,

many people expected the United States

to next target sending astronauts to Mars.

- [Astronaut] Houston, we've had a problem here.

- [Mission controller] Say it again please.

- [Astronaut] Houston, we've had a problem.

(tense music)

- [Narrator] But President Richard Nixon

during the political consequences

of a catastrophic mission failure

would support only a space shuttle.

Though four subsequent U.S. presidents

would ask for various Mars programs,

human space activities would remain confined

to low Earth orbit

for more than half a century.

By 1990,

some planners realized that cumbersome

bring-everything-with-you space programs were not workable.

(energetic music)

To remedy this,

engineers Robert Zubrin and David A. Baker

proposed the Mars Direct concept.

It's motto: travel light

and live off the land.

(energetic music)

By making rocket fuel from the planet itself,

explorers could ensure themselves a ride home.

(loud rumbling)

By 1993,

key ideas from Mars Direct

had found their way into NASA's

Mars Design Reference Mission,

but consistent congressional support for humans to Mars

never materialized.

In recent years,

giant aerospace companies and small private startups

have all adopted bits of Mars Direct.

(ambient music)

Boeing's affordable Mars mission

would send a solar electric sailing ship

to reconnoiter from low orbit.

(ambient music)

Astronauts would descend

(forceful air blowing)

protected by an inflated arrow shell,

touching down like the Apollo missions

to find a previously landed habitat waiting.

(forceful air blowing)

They'd returned to orbit like last century's moonwalkers

for the long trip home.

In contrast,

Lockheed-Martin proposes a Mars-orbiting base camp.

(ambient music)

It's conservatively built by stacking pairs of modules,

(ambient music)

two tank farms,

two habitats,

two rocket propulsion units,

redundancy for safety far from Earth.

(ambient music)

Astronauts make sorties to the surface

with a single stage lander,

(forceful air blowing)

but this surface-to-orbit shuttle craft

doesn't depend on fuel made on Mars.

(ambient music)

Younger, more aggressive companies are thinking bigger.

Elon Musk's Space Exploration Company

is developing

Starship.

(loud rumbling)

It's designed to transport massive payloads

and many people across Earth

and to orbit,

and eventually,

bring millions of tons of material

to the surfaces of planets, moons, and asteroids.

Like Von Braun and Ehricke before him,

Musk is focused on solving transportation

around the solar system.

SpaceX's eventual goal: (forceful air blowing)

make Earth life multiplanetary

by building civilization

on Mars.

(ambient music)

In friendly competition with SpaceX,

Blue Origin,

led by Amazon founder Jeff Bezos,

is quietly developing large boosters of its own.

Blue Origin's vision

is also to extend civilization into space

to preserve Earth's climate

and maintain it as a flourishing biosphere

by moving heavy industry and power generation

off the planet.

And eventually,

constructing city-sized free-flying habitats

from materials already in space

on the moon,

asteroids,

and comets.

(tranquil music)

(air swooshing)

(forceful air blowing)

Video game makers too

began to promote the adventure of populating Mars

(tranquil music)

and the rest of the solar system

(tranquil music)

and some visionaries foresee

the eventual terraforming of Mars,

warming it up,

making it as Earth-like as possible.

But to do this,

these world builders must find enough greenhouse gases

to heat the planet,

then continuously replenish its thick atmosphere

and constantly restore its water

as the vapor escapes to space.

(tranquil music)

Still more challenges lurk on the trickster planet.

Mars surface is everywhere loaded

with toxic caustic perchlorates,

up to 1% of the sands,

putting astronauts at high risk

for thyroid problems and cancer.

Other invisible dangerous cascade from the sky

unhindered by the thin atmosphere,

the constant rain of cosmic rays from interstellar space

and highly energetic particles from solar flares

pelting the planet.

(tranquil music)

Despite the many intriguing renderings

of domed cities on Mars,

settlers for many generations to come

will have to spend most of their time

in thickly roofed shelters

or underground.

Yet there may be hope.

The rise of autonomous machines,

advanced robotics,

artificial intelligence,

and augmented reality

can extend human senses to the surface of the Red Planet.

And someday we may send devices

to terraform Mars on their own.

Human emigres from Earth

could eventually build communities

on a ready-made planet.

(tranquil music)

(energetic music)

In 2033,

Mars will come into a particularly favorable position

for launching human cruise,

but who will go

and why?

Mars has seduced so many seeking notoriety,

promising an entire new world to explore

or exploit.

Ingenious engineering may find elegant solutions

for how to get us to Mars,

but what becomes of us

once we get there?

(pensive music)