Hey guys! We’ve just hit 4 million subscribers, and we wanted to thank you for all the support over the years.
And for this special occasion, we’re going to continue to do what we do best
and break down the science we know you all love so much! Thanks again for all the support!
In recent years, rocket launches have recaptured
the public’s imagination.
Thanks to incredible footage of reusable rockets like Space-X’s Falcon 9 and Blue Origin’s
New Shepard making almost unreal-looking landings on landing pads and drone ships, a rocket
launch has become must-see Internet TV.
They even pull zany stunts, like Elon Musk launching an electric car into space and announcing
he hopes to put a million people on Mars.
That’s a lofty goal, pun intended, and to achieve it, we’re going to have to launch
a lot of rockets, much more than the 80 or 90 we currently do each year.
If rate of launches climbs, pun intended again, has anyone considered what all those rockets
are doing to our environment?
Rockets work by burning propellant, and lots of it.
Instead of like the engine in your car, which burns fuel to make gasses expand, which pushes
a piston which turns a shaft which ultimately turns your wheels, rockets skip all that middle
stuff and just jump straight to lighting fuel on fire, pushing themselves forward using the expanding
gases that are shooting out the back.
As you might imagine, this uses tons of fuel.
So much so that over 95% of the mass of most rockets is just fuel.
What does burning that much fuel mean for something like global warming?
How much CO2 does one rocket launch emit?
We could actually figure that out with the power of math.
No don’t go, I promise it’ll be simple.
Let’s take the most powerful rocket there is right now, SpaceX’s Falcon Heavy, which
is basically 3 Falcon 9’s duct-taped together.
Falcon Heavys use liquid oxygen and a rocket fuel called RP-1, which is highly refined
kerosene.
Nearly 86% of RP-1's mass is carbon, and SpaceX doesn’t publish specifics, but a rough estimate of
a full tank of gas for the Falcon Heavy is about 425 metric tons of RP-1.
That’s about 365 tonnes of carbon per launch.
Let’s assume all that carbon combines with oxygen to form CO2.
Carbon makes up 27% of the mass of CO2, so divide that 365 tonnes of carbon by 0.27 and you
get nearly 1,352 tonnes of carbon dioxide per launch, give or take.
By comparison, a typical passenger car emits 4.6 tonnes of CO2 annually, so one rocket
launch is the equivalent of nearly 294 cars on the road for a year.
That… doesn’t seem so bad actually.
Even if we launched one Falcon Heavy, the most powerful rocket currently flying remember,
every day for a year that would still emit less CO2 than 110,000 cars.
There are over 270 million registered vehicles in the U.S. alone, so that’s a drop in the
bucket.
And that’s assuming all the fuel is used completely.
The real environmental issue is rockets aren’t that efficient.
RP-1 that doesn’t completely burn forms chains of hydrogen and carbon.
These dark sooty particles are known as black carbon, and in the atmosphere they can trap
incoming heat.
In the stratosphere, this heat can speed up reactions and lead to the breakdown of ozone
particles, depleting the ozone layer and exposing us down here to more UV radiation.
Along with black carbon, RP-1 produces nitric oxide and nitrogen dioxide, which are highly
reactive and further break down ozone.
But before you get mad at Elon Musk, just remember that different fuels produce different
pollutants, and some are much worse for the ozone layer.
The chlorine-based fuel used in the Space Shuttle’s solid rocket boosters utterly
obliterates ozone.
Solid propellants also produce more alumina, which is a shiny particulate that could reflect
heat back into space, but could also trap outgoing heat from the planet’s surface,
so we don’t know the impact it would have on climate.
That’s really the theme here, we just don’t know enough to say for sure what mass rocket
launches would do to our planet.
Companies keep rocket data confidential, so the data we have is mostly from lab experiments,
modeling, and a few sensor-equipped planes that flew through rocket plumes about 20 years
ago.
We may feel that we don’t launch enough rockets to be concerned with their pollution,
but that’s what we thought about space junk before it became a major problem.
If we have more research and better data, we’ll have a better understanding of our
impact on the planet.
Some scientists are calling for just that before we make a final say on just how much
rocket launches affect the environment.
So the next time you watch another live launch and impressive landing, just keep in the back
of your mind that more research is needed.
Thanks for watching don’t forget to subscribe because we have more videos, like Maren’s
about just how big our atmosphere is.
Does the impact of rocket launches worry you or do you think our focus should be on other
environmental problems?
Let us know in the comments and I’ll see you next time on Seeker.