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starfhury
Guest
From what I am reading here, the assumption is that the CEV will be cable of at least two things. A return to earths surface from LEO or lunar orbit or even more radical, a return to earth after landing on the moon! That might explain the additional mass requirement Griffin wants. Is 30 - 40 tons enough to allow the CEV to land on the moon, boost back to orbit and then aerobrake and land again on the earth? Looked at long term, that might not be such a bad idea. Sure it makes the CEV heavier and possible bigger than it really could have been, but it would also eliminate developing a separate lunar lander. Right there is a cost reduction they can achieve by parts reduction and integration of functionality. <br /><br />This allows the option of a TLI stage to which the CEV attaches itself. The TLI stage will also return the CEV to earth orbit and partially slow it down for a combined rocket/aerobrake manuever back to earth. This only requires us to have a barebones TLI stage of nothing more than prop tanks and motors. This will allow NASA to sort of go the Shuttle route again. They would build 4 or 5 resuable CEVs to establish a fleet of them so that the core parts are not thrown away. This brings up an another interesting question. Would a stick launched CEV be able to achieve LEO with a rocket motor also capable of ascending from the lunar surface? It seems to me they might be going for a lot of integration. If that's the case the CEV might be more intersting that I originally thought. Could a second stage rocket motor attached to the CEV achieve earth orbit, and if it can can it not also achieve lunar orbit after landing on the moon? If both are true then NASA has a potential winner in my book. With this new insight, I have to go rethink what I thought about CEV, but the plans I've seen so far don't actually support it. <div class="Discussion_UserSignature"> </div>