Do you remember when Elon Musk launched a car into space? It is still out there, but it might
not be in the best shape. It's not just peacefully drifting through a vacuum. It is hurtling around
the sun at 63,592 miles per hour, being bombarded by solar radiation. That car might be in pieces.
But not the same pieces it would be in if it was down here on Earth. The environment of
space breaks stuff down differently. And the space debris a little closer to us,
all the stuff that we humans have blasted into space and just left there in orbit?
Yeah, the unusual environment of space means that it too breaks down and degrades differently than
it would have if it was just down here on Earth. But how long does it take to break down? And does
it all break down? And how is that car looking right about now? Today we're talking space trash.
In space pants. Look at my space pants, very excited about that.
There are a few different types of space debris. First you have natural meteoroids. These are
hunks of rock or iron in orbit around the sun, but sometimes pieces of them can get stuck in Earth's
orbit too. There's also orbital debris. This is defined by NASA as any human made object in orbit
around the Earth that no longer serves a useful function. These could include old satellites,
abandoned launch stages from rockets, paint chips and stuff left behind by space missions,
or even pieces left behind when all of these things start to crash into one another. Orbital
debris can be made up of all different kinds of materials, including things like polymers,
like paints and plastics, metals and their alloys, oxides, sulfides,
halides, carbides. Anything that we send up in space could be out there. And a lot of it is in
low Earth orbit or LEO, where many satellites and the International Space Station also hang out.
Now it's a bit hard to conceptualize how much of a problem space debris
is because space is really big and a lot of this debris is pretty small.
The majority of mission-ending threats come from debris between 1mm and 1 cm in
diameter…but estimates suggest there could be over 100 million pieces of it out there.
And as of June 2022, the Space Surveillance Network is currently tracking nearly
40,000 objects larger than a softball. Softball.
But no matter the size, you got to remember that this stuff is traveling at
17,500 miles per hour, zipping around us.
If you launch a rocket into the path of a 17,500 mile per hour softball,
you are going to have problems. That's one hell of a pitch.
And past collisions have caused damage to satellites and spacecraft. In the past
space shuttle windows had to be replaced after collisions with debris as small as paint chips.
Things like the ISS even have to move sometimes to avoid crashing into debris.
Just recently in June of 2022, the mirror of the James Webb Space Telescope was struck by
a micro-meteoroid. Thankfully it's built to withstand that and many more because
we know that collisions happen in space. Also sometimes whole satellites can just
crash into one another, which feels like a thing that shouldn't happen. In 2009,
two communication satellites called Iridium 33 and Cosmos 2251 collided at 11.7 kilometers per
second. That is 26,000 miles per hour. The Space Surveillance Network tracked over 2000 pieces of
debris from that one crash alone. Since Cosmos 2251 wasn't active at the time, it's one of the
events that has caused the space community to call for organizations to remove their old satellites
from orbit when they've hit the end of their life. If it's not there, it can't crash into anything.
And every collision that happens between debris can just lead to more debris.
In 1978, Donald Kessler proposed a theory that describes, "a self-sustaining cascading
collision of space debris in LEO," or low Earth orbit. That just sounds really bad.
This theory is now referred to as the Kessler Syndrome or collision cascading.
It describes a situation where debris collisions create more debris,
which creates more collisions, and on and on and on. The fear was that if this happened,
the continued buildup of debris could make certain orbital spaces useless, dangerous, debris fields.
Thankfully, we don't seem to be headed in that direction
quite yet. Now some of the debris just falls out of orbit, burning up in our atmosphere,
but depending on how far out into orbit it is, it can take a while for that to happen.
Orbital debris less than 370 miles up usually falls back to Earth in a few years,
but things over 620 miles up could orbit us for more than a century. And we're putting
more stuff up there all the time, faster than the rate that it is falling back down to Earth.
Now, if you leave trash just sitting out on Earth it'll break down over time.
So let's take a car, for example. If you let a car sit in a field for a century
it would look pretty rough at the end of it. Bugs might eat away at the leather interior.
Rain and fog would cause any iron parts to rust and crumble. The sun would slowly fade and then
break down plastics. But there aren't bugs or rain in space so the car wouldn't rust up in orbit,
right? Surprisingly, wrong. There isn't water out there with the orbital debris,
but up to 700 kilometers up there is oxygen. And at that altitude, it exists as atomic
oxygen rather than the O2 that we breathe down here. Atomic oxygen is just a single O, which is
very reactive. So reactive, in fact, that things can start to rust even with no water around.
The typical chemical reaction for rust looks something like this.
You need iron, oxygen, and water, but the atomic oxygen doesn't need water around
to start reacting with metals and creating oxides or rust. The oxygen atoms can react
directly with metals on the surface of the debris. Things like aluminum and steel will
form layers of oxides on their surface that cling on top and prevent further corrosion.
An Earth orbiting car with a steel frame would likely be okay for a while, but iron and silver
oxides can flake or break off and allow the metal underneath to keep corroding, eventually wearing
away the surface. Depending on the conditions a silver surface could lose between 11.5 and
300 micrometers of metal a year. That's around a hair's width a year. In the case of space debris,
this wearing away could be a good thing since it could eventually remove the object from orbit.
But for active satellites, this corrosion can be really damaging. So one way to protect components
is to cover them in gold since atomic oxygen won't break down that gold. Plastic can also be broken
down by atomic oxygen, so they too are often coated in more resistant silicone paints. And
this is incredible, there is so much fast moving atomic oxygen and other reactive species
crashing into objects in LEO, that the collisions cause the emission of lots of short lived, excited
state species that emit visible radiation around the surface of whatever they're crashing into.
Basically stuff up there glows. This phenomena was first observed by astronauts aboard early
space shuttle missions, giving it the nickname of shuttle glow. And it's honestly really beautiful.
One of the most likely chemical players here is nitric oxide on the surface of the shuttle.
Is this laughing gas we're talking about? When fast moving atomic oxygen hit nitric
oxide on the shuttle surface, it may have created excited nitrogen dioxide molecules.
Those could then release their energy as light and then become regular old NO2. Okay, total aside
here. When trying to figure out how new materials will respond to the damaging environment of space,
scientists can just stick them out into space and see how they do. And they do so on delightful
little trays that look like this, each material in its own little cutout ready to be compared before
and after flight. And I find it so satisfying because it is both incredibly orderly and also
wildly chaotic considering that they're being bombarded by reactive oxygen and
solar radiation. Just love this so much. And that's another thing that a car orbiting
around the Earth would have to deal with, radiation. Down here on Earth our car sitting
in a field has all of the atmosphere and Earth's magnetic field to protect it from solar radiation.
But out in orbit, above the atmosphere, orbiting debris is left unprotected. This can break apart
carbon-carbon bonds and organic materials like fabrics and leather, some polymers and
carbon fiber. And that last one is important for our orbiting car because that Tesla Roadster up
in space, it has a carbon fiber frame. So either orbiting around the Earth or orbiting around the
Sun, it is likely that its frame is looking a little worse for wear these days. In fact,
at the time of launch one scientist estimated that it would likely start to break down within a year.
Atomic oxygen and radiation aren't the only things that space debris encounters.
They also have to deal with things like temperature changes, vacuum conditions,
and charged particles. There's a lot going on up there. And another weird thing that can happen to
debris up in orbit is called cold welding. Here I have two pieces of metal. This is indium. If I
press them together really tightly and turn them, they stick together, but it is more than just
sticking. With nothing between them some of the indium molecules from one hunk of metal have bound
to some of the indium molecules from the other hunk of metal. They don't know that they're not
from the same hunk of metal anymore. This is cold welding. When two surfaces made out of the same
material collide and there's nothing in between them, not even air molecules, say, like in the
vacuum of space, they can cold weld together. Sometimes this can cause problems when surfaces
on two pieces of a spacecraft stick together. This can be referred to as adhesion, sticking, or,
hilariously, stiction. Thankfully, this actually doesn't happen a lot by chance in space
since most stuff has a layer of oxides all over it, either from before launch or due
to all of that atomic oxygen just flying around. So chemistry is breaking down some space debris,
but it's doing it really slowly, a lot slower than we're putting more debris up there. So there
are some physical solutions to space debris that have been proposed, things like satellites with
grappling hooks to pull debris out of orbit or big spinning magnets to move it around.
All right, so finally, back to the Roadster. Currently, it is way out of LEO and orbiting way
past Mars at the moment. So it's definitely out of the range of all of that oxygen. No corrosion fear
there. When it launched a bunch of articles came out saying that the radiation would rip lots of
it to pieces, just like we talked about, tearing through those carbon-carbon bonds in things like
leather and fabric and plastics, as well as its carbon fiber frame. And some people predict that
the tires, paint, and plastic are potentially already deteriorated by radiation as well.
But while there are a lot of processes breaking down materials in space, they're all pretty
slow. So some experts have stated that the overall car will probably still be recognizable
as a car for about a million years, as it slowly breaks down. Unfortunately, the battery powering a
loop of Bowie songs has long since died. There's no charging station up in space quite yet.
Hey, no. No, we are not getting a copyright strike. We turn that off.
We don't need that here. We don't want that on our channel. None of those vibes. I mean,
we want the Bowie, we just don't want the copyright strikes. Take Bowie any day.