LNG is 85-95% methane, typically, with ethane making up most of the rest. It contains small amounts of propane and butane.
I hadn't known that SpaceX was using a special grade of ~100% liquefied CH4 as nickik says above.
EDIT: shale gas is richer in ethane and higher hydrocarbons than traditional sources of natural gas. Maybe SpaceX is sticking to 100% methane just so they don't have to ponder variability of composition depending on how gas is being extracted.
Methane can be synthesized from CO2 and hydrogen. More complex hydrocarbons are way more difficult to produce. So pure methane based engine is a better method for using on other planets.
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LNG is 85-95% methane, typically, with ethane making up most of the rest. It contains small amounts of propane and butane.
I hadn't known that SpaceX was using a special grade of ~100% liquefied CH4 as nickik says above.
EDIT: shale gas is richer in ethane and higher hydrocarbons than traditional sources of natural gas. Maybe SpaceX is sticking to 100% methane just so they don't have to ponder variability of composition depending on how gas is being extracted.
Methane can be synthesized from CO2 and hydrogen. More complex hydrocarbons are way more difficult to produce. So pure methane based engine is a better method for using on other planets.