Which is why you don’t use oxygen, at least in the traditional way. That’s my point. Interestingly you can inject the oxygen into the exhaust to act as a high-

Which is why you don’t use oxygen, at least in the traditional way. That’s my point. Interestingly you can inject the oxygen into the exhaust to act as a high-thrust, low-Isp afterburner. That’s the LANTR concept.