[AR] Re: shuttle SRBs (was Re: Re: Phenolic regression rate)

  • From: Henry Spencer <hspencer@xxxxxxxxxxxxx>
  • To: arocket@xxxxxxxxxxxxx
  • Date: Sun, 4 Feb 2018 23:06:11 -0500 (EST)

On Sun, 4 Feb 2018, George William Herbert wrote:

...the US doesn't currently have any big LOX/kerosene engines on hand. The RS-27A (Delta II core) is the biggest that's been in US production recently, and it's rather small for the job. ...

On the other hand, Falcon clustering Merlins isn't a big deal, and they're (M1D) ~ 140,000 LBT at sea level.

The RS-27A was about 200klb at sea level, and could probably be uprated further with a bit of development. Clustering them should be no great problem either -- they are minor derivatives of the H-1 (in fact, the original RS-27s were rebuilt H-1s), eight of which powered the Saturn IB.

However, what is really wanted for an SRB replacement is something more in the league of the F-1, or better yet the F-1A (1.8Mlb and considered ready for flight). A shuttle SRB is about 2.7Mlb -- the one good thing about big solids is that it's easy to get high thrust. The Energia strap-ons were minor variants of the Zenit first stage, using the RD-170, which delivers about 1.6Mlb.

(Unfortunately, not only does the RD-170 share the RD-180's problems of being Russian, but the rest of the Zenit first stage is Ukrainian, so it gets hit by unfavorable politics from both sides.)

Serial production. Can be had preintegrated into in a fully reusable stage, even...

Definitely a potentially useful package, even if one could wish it were larger for such applications.

Henry

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