A reference to Merlin's CH4-LOX mixture made me contemplate the atmospheric effects of the various by-products of different rocket fuels. As usual, I'll bow out and offer others to perform the calculations (so gracious of me, I know. I cannot help myself from being so charitable).
I think the relevant question should be couched along the lines of "For a given amount of thrust, how many moles of { CO2; uncombusted CH4; ____?____ } are produced? Another way to present the data would be "In order to bring { X tons of cargo } to { LEO / Lunar Mission / etc. }, how many moles of...?"
Any such byproducts should be compared against the combustion products of alternative fuels such as
Kerosene-LOX
N2O4 - MMH or UDMH
and so on. I think we can neglect the currently rejected fuels, such as the wonderful bromine pentafluoride (BrF5) we used in grad school. My suspicion is that what outgassed from our laboratory probably damaged the earth's ozone layer more than all the propellants and refrigerants from the rest of North America's bathrooms, kitchens and automobiles combined, and maybe the entire planet's. Not sure about their GHG effects.
A rigorous analysis of the combustion products need account for the location of all such combustion, as near-surface effects of any GHG are different to when the gases emanate in the upper atmosphere, troposphere, "outer" space, and so on.
Then, as a follow-on, a full cost analysis should include the dollar-cost including negative externalities of a given fuel OR a given launch, etc. This of course brings us immediately to having to broach the topic of what a carbon tax should be. $50 per ton-equivalent of CO2? $100?
This is in NO WAY casting aspersion on rocketry. Mr Musk himself has famously said that...well, read my sig-line. It does, however, represent a fuller comparison of various fuels AND it offers a way for the space industry to compare its work against other human activities. It also allows hard number to be offered against those who will - if not now, later - challenge space exploration to defend themselves.
Is anyone up to performing these calculations?
I think the relevant question should be couched along the lines of "For a given amount of thrust, how many moles of { CO2; uncombusted CH4; ____?____ } are produced? Another way to present the data would be "In order to bring { X tons of cargo } to { LEO / Lunar Mission / etc. }, how many moles of...?"
Any such byproducts should be compared against the combustion products of alternative fuels such as
Kerosene-LOX
N2O4 - MMH or UDMH
and so on. I think we can neglect the currently rejected fuels, such as the wonderful bromine pentafluoride (BrF5) we used in grad school. My suspicion is that what outgassed from our laboratory probably damaged the earth's ozone layer more than all the propellants and refrigerants from the rest of North America's bathrooms, kitchens and automobiles combined, and maybe the entire planet's. Not sure about their GHG effects.
A rigorous analysis of the combustion products need account for the location of all such combustion, as near-surface effects of any GHG are different to when the gases emanate in the upper atmosphere, troposphere, "outer" space, and so on.
Then, as a follow-on, a full cost analysis should include the dollar-cost including negative externalities of a given fuel OR a given launch, etc. This of course brings us immediately to having to broach the topic of what a carbon tax should be. $50 per ton-equivalent of CO2? $100?
This is in NO WAY casting aspersion on rocketry. Mr Musk himself has famously said that...well, read my sig-line. It does, however, represent a fuller comparison of various fuels AND it offers a way for the space industry to compare its work against other human activities. It also allows hard number to be offered against those who will - if not now, later - challenge space exploration to defend themselves.
Is anyone up to performing these calculations?
