
How much do rockets pollute? - dpifke
https://everydayastronaut.com/rocket-pollution/
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redis_mlc
Injecting combustion products into the upper atmosphere is something we really
need to study more.

I supported the Ozone Hole studies in the mid 80's, and we found CFCs
destroyed a protective part of our atmosphere. That recovered over time, but
there are some rogue manufacturers using CFCs again, and leaking massive
quantities.

We know airborne nuclei like soot cause localized precipitation, so that does
change weather (it's called cloud seeding.)

We really need to know more about the effect of rockets at high altitudes, and
airliner jet engines at 30,000'.

I have a strong feeling airliners have a significant effect due to the volume
of air traffic and how dirty burning jet fuel is.

To see how jet engines could have a significant effect, there are around
10,000 airliners worldwide, which are in the air more than 12 hours each per
day typically.

The break in air travel due do corona virus is an excellent time to compare
atmospheric samples before and after the pause.

~~~
t0mas88
The data does not support the common opinion that airplanes are terrible for
the environment. Their total contribution to for example CO2 is tiny compared
to industry and electricity generation.

Somehow the climate activists have decided to make a lot of noise about flying
but it's mostly unfounded. They go as far as using very old models of planes
in their calculations (e.g. a 737-400 model) and claiming that's the amount of
CO2 per passenger of all air travel. While that model is out of use by the
airline for at least 15 years already. It was designed in 1985.

So beware of the data and tricks like this when you're told flying is so bad
for the environment.

~~~
leoedin
I think the reason flying is so often vilified is because it represents a huge
proportion of an individual's emissions.

The reason flying represented only 2.5% of global emissions is because most
people never do it. There's a small subset of people, mainly in the West, who
do the vast majority of flying.

As this BBC article makes clear, a return flight from London to San Francisco
represents half the emissions of the average London resident. If you fly a
couple of return long haul trips a year, they'll emit the same as everything
else you do for the rest of the year.

[https://www.bbc.com/future/article/20200218-climate-
change-h...](https://www.bbc.com/future/article/20200218-climate-change-how-
to-cut-your-carbon-emissions-when-flying)

Looking at old aircraft will make the figures seem worse, but it's not like
new aircraft are an order of magnitude more efficient.

The best case budget airlines (high seat density and high seat utilisation)
today get about 2.27L/100km for each seat. The 737-300 was about 3.46L/100km -
so about 65% of what it used to be. Better for sure, but not "we've fixed the
problem" better. I'm not sure to what extent those figures take into account
changing seat density and utilisation.

[https://en.m.wikipedia.org/wiki/Fuel_economy_in_aircraft](https://en.m.wikipedia.org/wiki/Fuel_economy_in_aircraft)

~~~
Retric
The average London resident emits unusually low amounts of CO2. A 5,369 miles
flight, which is extremely long, at ~100MPG = 54 gallons of fuel. A 30 MPG car
driven 15,000 miles per year is 500 gallons of fuel.

A far more common round trip London to Paris flight is ~6 gallons of fuel. So,
someone doing that _every weekend_ is still using 38% less fuel per year is
using our 15,000 mile driver.

Flying only emits 2.5% of global CO2 because it’s surprisingly efficient and
most people don’t travel ultra long distances frequently. LA to London takes a
~10 hour travel day each way making it unappealing to do frequently.

~~~
nine_k
15000 miles per year is 41 miles a day _every day_. If we see it as a work
commute (plus some grocery shopping on the way), it's about 56 miles a day. Is
this realistic in UK? (I can imagine it can be that bad in some parts of the
US.)

~~~
heavenlyblue
People don’t do that in the UK. Public transport is much more convenient.

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DennisP
I was pretty surprised to see that Starship flying point-to-point is only
about twice as bad on emissions per passenger as a 747.

~~~
mrfusion
Zero drag for 99% of your trip is pretty awesome.

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ecoled_ame
something that tends to annoy me about hydrogen fuels - people emphasize that
the combustion product is water. okay .. so that step is clean.

but how was the hydrogen in the fuel cell produced in the first place? i guess
it’s an energy consuming process that produces a decent level of pollution,
whether it’s by electrolysis, heating of a chemical in the presence of a
catalyst, etc.

~~~
willis936
Electrolysis does not produce pollution. If you are suggesting a mechanism by
which it does, I would love to hear it.

[https://en.wikipedia.org/wiki/Electrolysis_of_water](https://en.wikipedia.org/wiki/Electrolysis_of_water)

[https://en.wikipedia.org/wiki/Water_splitting](https://en.wikipedia.org/wiki/Water_splitting)

~~~
mac01021
The power generation mechanism you use to get the electric current for
electrolysis may or may not be clean.

~~~
willis936
That’s entirely the point of hydrogen fuel. The process of producing or using
hydrogen does not pollute. You have decoupled pollution from energy storage.

Hydrocarbons pollute by their very nature. In order to have a carbon neutral
hydrocarbon cycle you need an impractical number of CO2 capture facilities.

~~~
TheSpiceIsLife
> The process of producing or using hydrogen does not pollute.

There’s no way this can be correct.

You can’t use hydrogen to produce the electricity used in hydrogen
electrolysis, because that’s not permitted in this universe.[1]

Therefore the electricity has to come from some other source, which all
generate life-cycle carbon emissions.[2]

1\.
[https://en.wikipedia.org/wiki/Second_law_of_thermodynamics](https://en.wikipedia.org/wiki/Second_law_of_thermodynamics)

2\. [https://en.wikipedia.org/wiki/Life-cycle_greenhouse-
gas_emis...](https://en.wikipedia.org/wiki/Life-cycle_greenhouse-
gas_emissions_of_energy_sources)

~~~
mac01021
In theory you could produce the H2 off planet.

Also, that tidal power looks pretty good...

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bryanlarsen
Elon Musk plans on refueling his rockets on Mars using locally produced
methane. Using solar power, he'll create methane and liquid oxygen from CO2
and water. If he then burns the methane and liquid oxygen in a rocket engine
you get your CO2 and water back. Thus the process is carbon neutral.

Before he does it on Mars he'll have to perfect it on Earth first. I hope he
does more than that and starts using carbon neutral methane for all his
Starship flights on Earth.

~~~
DennisP
Yep, the article talks about that.

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orbital-decay
The article implies that rockets burn 100% of their fuel, which is an
oversimplification for most thrusters. There's also a fair amount of residual
fuel and oxidizer in the piping, at least part of which is dumped into the
environment. While it isn't that scary for something like kerolox, it's a
concern for hypergolics.

~~~
efreak
Actually, this is mentioned in the article, in the "HOW MUCH DO DIFFERENT
ROCKETS EMIT?" section, and gets more into it in the linked raptor article[1]

> Although all rocket engines do run fuel rich for the right balance of heat
> management and performance, so there is likely going to be unburnt fuel
> expelled regardless of the cycle type, but much more when it is an open
> cycle engine.

1: [https://everydayastronaut.com/raptor-
engine/](https://everydayastronaut.com/raptor-engine/)

