"Greg \(Strider\) Moore" wrote on Wed,
1 Aug 2018 20:38:32 -0400:

"Jeff Findley" wrote in message
...


Aerojet Rocketdyne progressing towards six-engine RS-25 production run
written by Philip Sloss July 31, 2018
https://www.nasaspaceflight.com/2018...ne-six-engine-
rs-25-run/

From the above article:

As the design is being certified through ground testing, work
will be continuing to complete production and delivery of the
flight engines. "We get to a final certification engine, I
believe it's in the early to mid-2021 time-frame and then the
six production engines will follow right behind that," Adamski
said.

NASA began the procurement process for production of subsequent
Core Stage Engines (CSE) with a "sources sought request for
information (RFI)" earlier this year.

"The RFI that you're talking about was for eighteen engines at
four per year, with the first flight set delivered in July of
2025," he said. "Right now we could accommodate that and we
responded to that RFI also."

So, there you go. After the round of 6 new engines (which is the
current contract), the follow-on contract will deliver engines at a rate
of four per year.

And how quickly is SpaceX producing Merlins... Oh rate, claiming up to 400 a
year (though looks like they're hitting closer to 250... still huge
difference.)


AND much less important, since unlike SLS, Falcon is not throwing away
the engines with every launch.


And not quilt building Raptors in a production line just yet but... somehow
I'm guessing they'll do more than 4-6 a year :-)


Well, they're talking about orbital flights within the next year or so
and Mars missions by the first half of the 2020's. How many engines
does that take? You need a tanker plus a ship plus a booster for
each.



This means that the flight rate of SLS will actually be about one per
year with perhaps a few years that have two launches instead of one.

Nah, this simply means they'll have enough engines for that rate...
doesn't say a thing about actual payloads, missions or even money! :-(


Last plan I saw had them shooting one about every other year with a
surge rate of one per year.


This program is an absolute money suck with nothing to show for it as of
yet. No one in their right mind would ever use the RS-25E in anything
but SLS due to its high cost. Despite the changes to reduce
manufacturing costs, this engine is still going to be ridiculously
expensive to produce with a production rate that tops out at one engine
per quarter.

They aren't producing them, they're hand-crafting them. And that's a huge
problem.


AND they're throwing them away with every launch, which is an even
bigger problem given the cost of the engines and the low production
rate.


--
"The reasonable man adapts himself to the world; the unreasonable
man persists in trying to adapt the world to himself. Therefore,
all progress depends on the unreasonable man."
--George Bernard Shaw