Re: FT3, details of needed changes

Excerpts from FT: 7-Oct-96 RE: FT3, details of needed .. by Oerjan
Ohlson@nada.kth.s 
> > There was some guy at NASA who had some research done on this,
> > and big rockets worked out cheaper and more efficient than
> > smaller ones. 
>  
> Appearently not when it comes to lifting off from planets; or else we 
> wouldn't have any problems in launching huge space stations... I
think.
> (I don't think air resistance would be that important - would it?)

Um, yes it would; you get air friction on the way up, too.  For most
craft it's not a problem, but something large & unaerodynamic (as most
stations are) is gonna hurt.

I'm not actually sure that the original poster (the quote above
Oerjan's) is correct; I think he may be referring to Truax at Aerojet
General in the sixties.  He did some research and discovered that
development costs actually decrease with increasing size -- take Agena
vs. Thor.  Thor was several times larger than Agena, but cost far less
to develop.  Ditto on the Titan I two-stage launch vehicle; the smaller
upper stage cost more than twice as much to develop than the lower
stage, in spite of the fact that the upper stage was a virtual copy,
just re-scaled down from the lower stage.

Basically, the cheapest rockets are big dumb boosters (BDBs) that don't
push the state of the art, are reusable (though with a big enough
production base, and enough launches, they don't have to be), don't push
safty margins, and do *not* mix people and cargo.  If you need to lauch
people, make something small and reusable and expensive and safer than
anything, but lauch the cargo in the BDB.

Anyway, if anyone wants a copy of an article on this, just let me know. 
(Or I could post it; it's only 4-5K or so.)

Later,

		    Aaron Teske
		    Mithramuse+@cmu.edu