[AR] Re: Saturns (was Re: APCP ...)

  • From: Henry Spencer <hspencer@xxxxxxxxxxxxx>
  • To: Arocket List <arocket@xxxxxxxxxxxxx>
  • Date: Sat, 29 Apr 2023 20:36:27 -0400 (EDT)

On Sat, 29 Apr 2023, roxanna Mason wrote:

Well this was assuming low risk open cycle engines like F-1 and H-1 which 4 stages would have been necessary...

Come now, at least you should assume that upper-stage engines would be based on the Atlas *sustainer*, which had a vacuum-Isp advantage of nearly 30s over the H-1. But I would expect better than that -- the only reason better upper-stage kerosene engines weren't seriously pursued was that everybody thought LH2 made them unnecessary.

The Russian N-1 had 4 stages and used closed cycle NK-33 engines. 

But, as I noted, quite heavy tanks. Especially compared to the S-IC, whose mass ratio was impressively good and could certainly have been improved further.

Henry

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