How the Universe Works

NASA has set its sights on Mars.

Its goal is to send humans to the red planet

in the next 20 years.

Looking up at Mars in the sky,

I really do feel like I'm looking at a place

that someday there will be people walking around on it.

It feels so much like earth in so many ways,

and it's a place that really captures my imagination

as a result.

It's the most earthlike environment

we see in our solar system.

So we're not going to leave it alone.

We're going to try to do this.

But conquering our planetary neighbor

is a tougher challenge than we ever thought possible.

It's an isolated environment

where a million things can go wrong,

where there's absolutely no hope of rescue.

There are so many hurdles to overcome

for human exploration of Mars, and it makes it quite difficult.

Sure, we can get there, but are we going to be in one piece?

Sometimes it feels like Mars is designed to keep us away.

Are we doomed to fail in this endeavor?

captions paid for by discovery communications

The red planet... earth's neighbor

and the destination of NASA's most ambitious mission to date.

But this expedition will be harder

than we ever thought possible.

It hurts to think of how hard it is.

It's the farthest a human being has ever been from the earth.

We got to take every precaution

as NASA's astronauts arrive at Mars,

they'll face a huge obstacle.

Landing on the planet is a daunting task.

In the past, Mars hasn't always rolled out the welcome mat.

Mars is kind of like a graveyard for spacecraft.

It's actually really hard to send something from earth

and land it on Mars.

This is how the European space agency

hoped its $250 million Schiaparelli lander

would touch down in 2016...

...but the lander's systems got it wrong.

The parachute detached early, sending the craft into free fall

for 33 seconds.

Schiaparelli smashed into the surface

at 335 miles an hour,

leaving a deep, black scar on the martian landscape.

It turns out that Mars is actually

a particularly difficult planet to land on.

Even humanity's most brilliant engineers,

we've got about a 50% success rate

when it comes to landing on Mars.

The red planet is littered with dead spacecraft

that didn't stick the landing.

And for NASA's first crewed descent to Mars,

the space agency must learn from these mistakes.

But as the crew hurdles toward the surface

they're battling the same problem

as all the landers that failed before.

The martian atmosphere

is 100 times thinner than earth's

so it can't provide the drag needed

to slow a spacecraft down.

So it's not like the earth, where you can have

these big, giant parachutes

that gently glide you down to the surface.

You can use some of the air, but it's hard.

The red planet's thin atmosphere

is a problem that's been billions of years in the making.

Mars doesn't have a large atmosphere

because it's constantly being peeled away

due to the lack of protection of a magnetic field.

The solar wind can strip away an atmosphere.

On earth, a liquid metal core creates a magnetic field

which shields the planet and helps maintain the atmosphere.

Mars is different.

4.5 billion years ago,

Mars and earth formed from dust and gas in space.

Mars forms where building materials were scarce.

Its growth was stunted.

So Mars is much smaller than the earth.

It's a factor of 10 smaller than the earth,

and that factor of 10 in mass is important.

All of that extra mass allows the inside of the earth

to stay warm and to have a core that's rotating,

which generates a magnetic field.

4 billion years ago, the churning heart of Mars

started to cool and solidify.

With no hot core, there's no magnetic field being generated.

All of the high-velocity charged particles coming from the sun

pick away at the atmosphere and slowly tear it away.

We know it's losing atmosphere every second

due to the solar wind.

So, you know, bye-bye atmosphere.

With little martian atmosphere to work with,

NASA had to be creative to get its crewless landers

to the martian surface.

In 2012, the revolutionary sky crane

landed the curiosity rover using parachutes and retro rockets.

Previous missions have used both a parachute

and something else like a bouncy ball

inflated around the spacecraft.

I don't think a human crew is going to be too pleased

if they're gonna be bouncing onto the surface

in an airbag, rolling to a stop, right?

To land people on Mars, NASA will need some new tricks.

The 2020 rover will overcome the challenge with the advanced

supersonic parachute inflation research experiment,

a.s.p.i.r.e.

It will rapidly slow down the craft

with the force of an airplane jet engine.

This is fine for the rover.

It's actually gonna work no problem.

But it's not going to work for people.

A human lander will weigh far more

than the 2,300-pound rover.

Not even supersonic parachutes

could land a crew safely on Mars.

NASA will need a new plan.

One idea is to use the thin martian atmosphere

in a unique way.

There's an idea of coming in really fast,

getting to the thick part of the atmosphere,

and then going horizontal to the ground

and gliding and losing your momentum that way.

As the astronauts descend,

they tilt the nose of the lander towards the martian surface

aiming for the thickest part of the atmosphere

close to the ground.

Then they pull up at the last second

using friction from the atmosphere to slow the craft.

Descent engines switch on for the final touchdown.

Is this a crazy idea?

I mean, yeah, it's a little bit weird.

I don't know if we'd really think about it,

doing something like this,

but, I mean, you've got to think outside the box sometimes.

Right now, NASA's plans for landing a craft on Mars

are still on the drawing board.

But even if they can get astronauts onto the surface,

the thin atmosphere isn't done with them yet.

It causes swirling dust storms

that cover the planet's entire surface.

Mars doesn't just have dust devils.

It has dust hell.

And these towering clouds have killed before.

If NASA's astronauts arrive on Mars as planned, in 2035,

the settlers will find one of the red planet's

biggest challenges is its dust.

It's sticky,

basically, light from the sun

can give the stuff a static charge

and then it clings to stuff.

So it's not just a matter of, like, you know,

standing on a doormat outside your your space habitat

and shaking yourself off.

It's gonna get in your space suit.

It's gonna coat your visor.

It's going to cover your solar panels.

If you get it in your lungs, it's not a good thing.

We have to figure out how to clear this stuff out.

300 feet.

Through the '60s and '70s,

Apollo astronauts walked on the moon.

When they returned to their landing module,

they brought moon dust back with them.

The lunar dust clogged seals, caused equipment to overheat,

and resulted in false instrument readings.

It even made the astronauts sick.

You don't want to be breathing in fine, dusty material

by itself, you can get things like silicosis.

It's, you know, almost basically a lung cancer

that you can get just from breathing the dust itself.

You don't want to do that.

The red planet is covered in sticky dust,

and new research suggests it all came from one place...

...the Medusae Fossae formation.

When the 600-mile-long volcanic deposit formed

3 billion years ago,

it was around half the size of the United States,

but the martian winds have eroded this structure

and spread the dust across the entire planet.

When the wind whips up this dust,

it can have disastrous consequences.

The real problem is just that all these fine particles

get lofted into the atmosphere,

and it takes a really long time for them to settle back out.

And what the dust does is it just gets up in the sky

and it sits there and sits there and sits there.

As more material gets lifted into the atmosphere,

it forms huge dust storms.

The storms are so large they block out the sunlight

and cool the martian surface...

...creating a temperature difference

between the ground and atmosphere

that causes winds to increase and the storms to grow.

And NASA's opportunity rover knows firsthand

the dangers of being trapped in one.

Opportunity was a NASA rover sent to Mars

to hunt for signs of past water on the surface