Our lives depend

on a world we can't see.

Think about your week so far.

Have you watched TV, used GPS,

checked the weather or even ate a meal?

These many things
that enable our daily lives

rely either directly or indirectly

on satellites.

And while we often take for granted

the services that satellites provide us,

the satellites themselves
deserve our attention

as they are leaving a lasting mark

on the space they occupy.

People around the world
rely on satellite infrastructure every day

for information, entertainment
and to communicate.

There's agricultural
and environmental monitoring,

Internet connectivity, navigation.

Satellites even play a role

in the operation of our financial
and energy markets.

But these satellites that we rely on

day in and day out

have a finite life.

They might run out of propellant,

they could malfunction,

or they may just naturally
reach the end of their mission life.

At this point, these satellites
effectively become space junk,

cluttering the orbital environment.

So imagine you're driving down the highway
on a beautiful, sunny day

out running errands.

You've got your music cranked,

your windows rolled down,

with the cool breeze
blowing through your hair.

Feels nice, right?

Everything is going smoothly

until suddenly
your car stutters and stalls

right in the middle of the highway.

So now you have no choice
but to abandon your car

where it is on the highway.

Maybe you were lucky enough

to be able to move it out of the way
and into a shoulder lane

so that it's out of the way
of other traffic.

A couple of hours ago,

your car was a useful machine
that you relied on in your everyday life.

Now, it's a useless hunk of metal

taking up space in a valuable
transportation network.

And imagine international roadways
all cluttered with broken down vehicles

that are just getting in the way
of other traffic.

And imagine the debris
that would be strewn everywhere

if a collision actually happened,

thousands of smaller pieces of debris

becoming new obstacles.

This is the paradigm
of the satellite industry.

Satellites that are no longer working

are often left to deorbit
over many, many years,

or only moved out of the way
as a temporary solution.

And there are no
international laws in space

to enforce us to clean up after ourselves.

So the world's first satellite, Sputnik I,

was launched in 1957,

and in that year, there were
only a total of three launch attempts.

Decades later and dozens of countries
from all around the world

have launched thousands
of more satellites into orbit,

and the frequency of launches
is only going to increase in the future,

especially if you consider
things like the possibility

of 900-plus satellite
constellations being launched.

Now, we send satellites
to different orbits

depending on what they're needed for.

One of the most common places
we send satellites

is the low Earth orbit,

possibly to image the surface of Earth

at up to about 2,000 kilometers altitude.

Satellites there are naturally buffeted
by Earth's atmosphere,

so their orbits naturally decay,

and they'll eventually burn up,

probably within a couple of decades.

Another common place we send satellites

is the geostationary orbit

at about 35,000 kilometers altitude.

Satellites there remain in the same place
above Earth as the Earth rotates,

which enables things like communications
or television broadcast, for example.

Satellites in high orbits like these
could remain there for centuries.

And then there's the orbit
coined "the graveyard,"

the ominous junk or disposal orbits,

where some satellites
are intentionally placed

at the end of their life

so that they're out of the way
of common operational orbits.

Of the nearly 7,000 satellites
launched since the late 1950s,

only about one in seven
is currently operational,

and in addition to the satellites
that are no longer working,

there's also hundreds of thousands
of marble-sized debris

and millions of paint chip-sized debris

that are also orbiting around the Earth.

Space debris is a major risk
to space missions,

but also to the satellites
that we rely on each and every day.

Now, because space debris and junk
has become increasingly worrisome,

there have been some national
and international efforts

to develop technical standards

to help us limit the generation
of additional debris.

So for example, there are recommendations

for those low-Earth orbiting spacecraft

to be made to deorbit in under 25 years,

but that's still a really long time,

especially if a satellite
hasn't been working for years.

There's also mandates
for those dead geostationary spacecraft

to be moved into a graveyard orbit.

But neither of these guidelines
is binding under international law,

and the understanding is that they will be
implemented through national mechanisms.

These guidelines are also not long-term,

they're not proactive,

nor do they address
the debris that's already up there.

They're only in place
to limit the future creation of debris.

Space junk is no one's responsibility.

Now, Mount Everest is actually
an interesting comparison

of a new approach to how
we interact with our environments,

as it's often given the dubious honor

of being the world's highest garbage dump.

Decades after the first conquest
of the world's highest peak,

tons of rubbish left behind by climbers

has started to raise concern,

and you may have read in the news
that there's speculation

that Nepal will crack down on mountaineers

with stricter enforcement
of penalties and legal obligations.

The goal, of course,
is to persuade climbers

to clean up after themselves,

so maybe local not-for-profits will pay
climbers who bring down extra waste,

or expeditions might organize
voluntary cleanup trips.

And yet still many climbers feel

that independent groups
should police themselves.

There's no simple or easy answer,

and even well-intentioned
efforts at conservation

often run into problems.

But that doesn't mean
we shouldn't do everything in our power

to protect the environments
that we rely and depend on,

and like Everest, the remote location
and inadequate infrastructure

of the orbital environment

make waste disposal a challenging problem.

But we simply cannot reach new heights

and create an even higher garbage dump,

one that's out of this world.

The reality of space

is that if a component
on a satellite breaks down,

there really are limited
opportunities for repairs,

and only at great cost.

But what if we were smarter
about how we designed satellites?

What if all satellites,

regardless of what country
they were built in,

had to be standardized in some way

for recycling, servicing

or active deorbiting?

What if there actually were
international laws with teeth

that enforced end-of-life
disposal of satellites

instead of moving them out of the way

as a temporary solution?

Or maybe satellite manufacturers
need to be charged a deposit

to even launch a satellite into orbit,

and that deposit would only be returned

if the satellite was disposed of properly

or if they cleaned up
some quota of debris.

Or maybe a satellite
needs to have technology on board

to help accelerate deorbit.

There are some encouraging signs.

The UK's TechDemoSat-1,
launched in 2014, for example,

was designed for end-of-life disposal

via a small drag sail.

This works for the satellite
because it's small,

but satellites that are higher
or in larger orbits

or are larger altogether,
like the size of school buses,

will require other disposal options.

So maybe you get into things
like high-powered lasers

or tugging using nets or tethers,

as crazy as those sound in the short term.

And then one really cool possibility

is the idea of orbital tow trucks
or space mechanics.

Imagine if a robotic arm

on some sort of space tow truck

could fix the broken components
on a satellite,

making them usable again.

Or what if that very same robotic arm

could refuel the propellant tank
on a spacecraft

that relies on chemical propulsion

just like you or I would refuel
the fuel tanks on our cars?

Robotic repair and maintenance

could extend the lives of hundreds
of satellites orbiting around the Earth.

Whatever the disposal
or cleanup options we come up with,

it's clearly not just a technical problem.

There's also complex space laws
and politics that we have to sort out.

Simply put, we haven't found a way
to use space sustainably yet.

Exploring, innovating
to change the way we live and work

are what we as humans do,

and in space exploration,

we're literally moving
beyond the boundaries of Earth.

But as we push thresholds
in the name of learning and innovation,

we must remember that accountability
for our environments never goes away.

There is without doubt congestion
in the low Earth and geostationary orbits,

and we cannot keep
launching new satellites

to replace the ones that have broken down

without doing something about them first,

just like we would never
leave a broken down car

in the middle of the highway.

Next time you use your phone,

check the weather, or use your GPS,

think about the satellite technologies
that make those activities possible,

but also think about the very impact

that the satellites have
on the environment surrounding Earth,

and help spread the message
that together we must reduce our impact.

Earth orbit is breathtakingly beautiful

and our gateway to exploration.

It's up to us to keep it that way.

Thank you.

(Applause)