- [Astronaut] Oh, great, we have a lost tool.

- [Reporter] In 2023, an astronaut dropped a bag of tools outside the International Space Station, and it slowly floated away.

If you drop something on earth, you just pick it up, but when you drop something in space, it becomes space junk, and it's now traveling faster than a bullet.

- [Astronaut] You see it?

- [Control] Yeah, we see it.

- When Donald Kessler was at NASA in the '60s, little did he know his name would later become synonymous with space junk.

He predicted that over time, nations would launch so many satellites and spacecraft into space the remains of those objects would create enough space debris to put operational satellites and even astronauts lives in danger.

- You end up with an exponential growth.

- [Reporter] It's now estimated there are more than 26,000 pieces of space junk larger than 10 centimeters orbiting the earth, from old satellite antenna to rocket thrusters as big as a school bus.

Add to that total, the more than 190 million other pieces smaller than five centimeters and even smaller than that.

This includes lost screws, cables, or other things broken off from collisions or age.

- And initially, they just let it build up.

It just remained in orbit because it would be placed at a high enough in orbit that it would take 'em, in cases some years, hundreds to thousands of years, before the natural decay would bring them back down.

- [Reporter] Kessler started as an astrophysicist at the Johnson Space Center at Houston, where his first job was to figure out how to protect spacecraft from meteoroids flying in from outer space, some of the remnants of the creation of planets and stars, that arrive in our solar system at incredible speeds and smash into each other in the process, creating more and smaller versions of themselves.

- And I said, "Well, if that's goin' on in the solar system, "why wouldn't this also happen from the objects "that we're placing in earth orbit?"

- [Reporter] He wrote a paper in 1978.

That paper postulated there would be a cascading effect from satellites smashing into each other that would put future orbital launches at risk.

His prediction would later become known as the Kessler Syndrome.

- This debris belt was exactly like the asteroid belt.

- [Reporter] Think of a spacecraft trying to avoid a beltway of space junk orbiting at thousands of miles per hour above the earth.

The Kessler Syndrome and the dangers posed by space junk events would over time weave their way into the mainstream, that would inspire the screenplay behind the Oscar winning film "Gravity," where chaos follows astronauts after their spacecraft is hit by space debris.

He even got the nod from director Tim Burton when his name was borrowed for a scientist in the movie "Mars Attacks."

- We're speaking with Professor Donald Kessler.

- [Donald] Hey Don, "We're goin' to this movie, "we want you to come with us."

[Donald laughs] - [Reporter] Kessler says satellites are like any piece of machinery.

They get old and break apart from collisions or wear and tear.

They must then be either repaired or be replaced.

Trouble is, there aren't any galactic landfills available that will take that trash.

So how did we get here?

The United States launched its first satellite in 1958, called Explorer One.

- [TV Anchor] The story of Sputnik One dominated the front page.

- [Reporter] This was one year after the Soviet Union launched Sputnik.

Many say that marked the beginning of the space race, and it also marked the beginning of the space debris pile-up.

Over the years, the US and other countries would send up satellites for weather, telecommunications, and defense.

Right now, there are about 8,400 active satellites in orbit, but this doesn't include all the satellites launched over the past 50 years that no longer work.

- [Donald] There was a source of just paint flakes.

Like paint on your house will eventually fall off.

- [Announcer] Main gear touchdown.

- [Reporter] To give an idea of how dangerous space junk is, a paint fleck, yes, a paint fleck that had peeled off an old satellite hit the space shuttle as it was reentering the atmosphere in 1983.

- [Announcer] Nose gear touchdown.

- [Reporter] Years later, in 2009, a satellite called Iridium 33 collided with an old and defunct stage of a Russian military satellite called Cosmos 2251.

It was a first time an active satellite had been impacted by a piece of space debris.

There have been attempts to get rid of old satellites by space agencies and even various militaries.

The Russians, in fact, worked up a system that would be seated on a rocket and shoot objects with pellets.

- "That just won't happen."

I mean, that's what they actually told me in front of a huge audience, that that just won't happen, it'll just make a clean hole through it.

And I said, "No, that's not the way it works."

- [Reporter] Kessler says all options for reducing space junk are very expensive, and at the moment, NASA can't afford them.

Those ideas include capturing satellites with nets and even harpooning them at high velocities, as seen in this NC State demonstration.

So for now, the best option is to better protect astronauts, and that was done by simulating what happens when your spacecraft is hit by debris flying at high orbital velocity.

- Things are traveling so fast in space that even a small thing can cause a lotta damage.

They shot up this particle, that's smaller than a BB, at a velocity of over six kilometers per second, and it made this large crater, and then it also made this what's called a spall.

- [Reporter] And using that data, scientists were then able to create new materials to absorb impacts, a technology that's still in use today by NASA.

- [Donald] It melted the particle till it was a vapor, and it actually just vaporized and deposited the melted material onto the back surface.

- [Reporter] Meanwhile, it looks like space debris overhead is something earth will need to live with for a very long time.

How it will impact future launches might just come down to our will to invest in a solution.

- [Donald] When I talk to the people within NASA about the only thing that they can come up with is that we just have to take the most economic approach to space.

There's no real simple economic solution to it.

- [Announcer] Payload separation confirmed.