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Old October 13 2012, 12:29 AM   #224
gturner
Admiral
 
Location: Kentucky
Re: Envisioning the world of 2100

publiusr wrote: View Post
gturner wrote: View Post

Um, that's idiocy nested several levels deep...
That wasn't the arguement I was making mind you, that was the letter writers.' From what I understand Falcon can fly depressed trajectory in addition to having engine out capability, so it is number one in my book. My concern is that a lot of negativity that Ares/ Constellation faced (and that SLS faces now) will be turned against Musk.
It won't matter to him. In "The Avengers" we saw how much Iron Man cared for the opinions and objectives of SHIELD, and as even Robert Downey Jr. admitted, Elon Musk is Tony Stark.

gturner wrote: View Post
The RD-180 uses a mixture ratio of 2.7:1, but it makes the pre-burner difficult to make because it has to run in a high temperature oxidizing environment.
And if there is one thing you want to avoid, its hot oxygen. From what I understand, RD-180 is the two nozzle half-strength version of the Zenit first stage/Energiya strap-on's RD-170 series engine of Glushko. He liked hypergolics but wanted time to perfect kerolox designs and Korolev [sic] pushed him, leading to the falling out--among other things (Kolyma).
Yes, the RD-180 is a half-RD-170. Interestingly, the RD-170's higher specific impulse compared to the F-1 means a Saturn V with 4 RD-170's would outperform one with five F-1's.

To me, that is not a problem in that hydrogen's trouble of having low density and high volume just leads to a wider HLLV shroud and all the advantage that comes with that.
If we had a high power RP-1 engine (like the RD-170 or Musk's 1.8m lbs proposal), they could use the SLS first stage as a second stage, ala Saturn V on steroid. The configuration they have now is a Shuttle-derived version of North American's Saturn II INT-17 proposal, which strapped Titan SRB's to the Saturn S-II stage, with an S-IVB on top, to give them a payload capability in between the Saturn IB and Saturn V.

I'm a big believer in engine-out capability--and this proves that a failure in a densely packed aft section need not lead to fratricide. Now I understand that Musk wants to move the engines out around the outer 'rim' of the rocket. I wonder if that might actually make things worse.
It should improve the mass ratio because the force will be more in line with the load-bearing skin, and it should also increase stability at the expense of slightly more base drag.

I'm not sure the seperation would have much affect on debris, but you shouldn't have birds nesting in there anyway.
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