3 ms·
I'm not sure about Raptors specifically, but usually liquid rocket engines run rich (or, as Russians say, "sweet", rather than "sour", or lean), which means tha
by avmich 3y ago
I'm not sure about Raptors specifically, but usually liquid rocket engines run rich (or, as Russians say, "sweet", rather than "sour", or lean), which means that there's excess of methane in the exhaust. Methane is a powerful (comparing to CO2) greenhouse effect agent, which fortunately doesn't have as long atmospheric life as CO2.
- MPSimmons 3y agoThis is a closed cycle, so I would expect it to be cleaner, but I don't know for sure.
- p1mrx 3y agoRaptor (Starship) is closed cycle, and BE-4 (Vulcan) is oxygen rich, so neither should be dumping unburned methane during normal operation.
- mr_toad 3y agoBE-4 has oxygen rich pre-burners, while Raptor is full-flow. However both engines use a fuel rich mix in the main combustion chamber. But the pollution from either is far less than from a solid fuel engine.
- p1mrx 3y agoInteresting. Then I wonder how the GHG emissions of methalox/kerolox engines actually compare? Methalox emits less CO2, but unburned methane is 30X worse than CO2.
- mr_toad 3y agoAt least some of the unburnt gas in the exhaust plume will ‘afterburn’ when it mixes with oxygen in the atmosphere. Aside from CO2, methalox engines produce noticeably less soot than kerolox.