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Old October 14 2012, 11:50 PM   #234
gturner
Admiral
 
Location: Kentucky
Re: Envisioning the world of 2100

newtype_alpha wrote: View Post
Not hoping for, that's just the way it is. HLVs simply don't have the work history to justify the kind of money NASA has been ordered to spend on them, even if they had a coherent plan for how to USE them, and they don't.
I just did an interesting first pass calculation based on an Apollo mission using lithium aluminum hexahydride/H2O2 instead of Aerozene-50/N2O4.

http://www.sps.aero/Key_ComSpace_Art...plications.pdf

With a 500 psi chamber pressure it has a vacuum ISP of 469, whereas everything above the S-IVB on Apollo had an ISP of 311 to 314.

Holding the dry mass of the lunar ascent module, descent module, command module, and service module consant would still result in a required LEO mass of 57 tonnes, instead of 130 tonnes. Using it the 3rd stage would reduce that stage's dry weight, too, meaning you'd only need one launch on a Falcon 9H to fly the same mission.
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