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WeylandsWings t1_j7ck4sy wrote

Reply to comment by marketrent in New review finds that rocket emissions in the upper atmosphere can affect the ozone layer but are not regulated — Global annual launches grew from 90 to 190 in the past 5 years, and an upsurge in rocket launches may potentially undo decades of work to save the ozone layer by marketrent

> A new fuel is methane, which is used in multiple rocket engines under development by major launch companies. The emissions products of methane are as yet poorly understood.

????? What? The combustion byproducts of a methalox rocket is mostly H2O and CO2.

And it isn’t poorly characterized. The report authors just don’t look into it. NASA has a wonderful piece of software/web site that you can run Computational Chemical Equilibrium simulations, even simulated rocket engines. And it is pretty accurate.

And for a 300 bar , sea level methalox engine it spits out the following mass fractions of various species at the Comustion Chamber, the throat, and most importantly for this discussion the Exit. (Forgive the formatting, on mobile)

Species. Chamber Throat Exit

*CO 0.22048 0.20984 0.13790

*CO2 0.27689 0.29368 0.40681

COOH 0.00009 0.00005 0.00000

*H 0.00071 0.00060 0.00001

HCO 0.00004 0.00002 0.00000

HO2 0.00028 0.00016 0.00000

*H2 0.00681 0.00644 0.00695

HCOOH 0.00002 0.00001 0.00000

H2O 0.41879 0.42748 0.44829

H2O2 0.00008 0.00004 0.00000

*O 0.00481 0.00356 0.00000

*OH 0.04585 0.03779 0.00005

*O2 0.02515 0.02032 0.00000

So as you can see, the vast majority of the exhaust is Water, Carbon Dioxide, and Carbon Monoxide. Now there will be other trace components because the system assumes the LOX and Methane are totally pure, but even then those will be trace.

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BigBrainedReader t1_j7e99zc wrote

As you have shown the percentages can you also give us a link to the mass of the fuel reflected in these percentages. I think that would help in quantifying the amount of admission being dumped into the different layers of our atmosphere.

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der_innkeeper t1_j7eewnh wrote

Each launch is roughly the equivalent of a 747's worth of fuel (kerosene or methane).

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WeylandsWings t1_j7fe8qh wrote

About 650 kg/s for the inputs according to Wikipedia. 510 kg/s of LOX and 140 kg/s of CH4 for a Raptor engine.

But it really depends on the engine in question and the throttle level.

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