07-19-2010, 09:47 AM
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Launching since 1970.
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Join Date: Mar 2005
Location: Southern California
Posts: 2,188
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Quote:
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Originally Posted by Solomoriah
Carbon dioxide gas extracted from the atmosphere should be a zero carbon footprint (you put back exactly what you take out). Discounting the energy cost of extraction and compression, of course.
Is there a reason we don't use CO2 for this? Does it have to be liquified to work?
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It has to be a liquid that is a liquid under pressure and turns to a gas at standard pressure. The rocket thrust is generated by the liquid turning to a gas and the gas is at increased pressure. As it changes state, it gets cold. It's a thermodynamics thing. |