In article ,
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Yeah, the ULA "solution" seems like what I'd expect from a traditional
vendor.

I mean they're right, physically the engines are the most expensive
components. And I'm not surprised their reaction is, "Let's work on the
most expensive HARDWARE" and not really look at it from an entire systems
POV like SpaceX and Blue Horizon has, which is the entire system.
Sure, you get the engines back... but you need an expensive aircraft for
every recovery. SpaceX only needs a drone ship for some of their
recoveries. I'd be curious to see which is cheaper to operate. The
helicopter only needs to be in flight for a couple of hours, but aircraft
hours are very expensive. The drone ships are probably very cheap to operate
on an hourly basis, but need to be in operation for more hours.

Don't forget the expensive separation system to get the engines with all
their plumbing, electrical connections, structure, and etc. to cleanly
separate. That's going to be hard to develop, complex to operate, and
prone to "little" failures. All those connections had better separate
cleanly (especially the plumbing). Anything that's not a clean
separation means higher refurbishment costs at best and loss of the
engine(s) at worst.

But then once you get back the engines vs. booster, you've got more stacking
operations. I can't see that being cheap. Touch labor gets expensive and it
SpaceX seems to be well aware of that (e.g. I bet the titanium fin-grates
are more expensive upfront, but if you don't have to touch them for 10
flights, you've reduced your touch costs and probably saved money.)

Even military aircraft don't like to drop parts when flying. Drop tanks
for fuel are cheap in theory, but aren't so cheap when you have to do it
operationally. During WWII the British started making drop tanks out of
paper! These paper tanks were single use since the fuel would slowly
dissolve the glue used to make them. These were developed so that metal
could be conserved. Metal being a precious commodity during WWII in
Brattain.

I think ULA is going to win this fight. At least with Vulcan.
Blue Horizon is still an unknown quantity.

I think ULA might survive only because Vulcan would give the US
Government the two "proven" launch suppliers that it "needs". Blue
Origin is not entirely an unknown quantity, IMHO. Its New Shepard
suborbital launch vehicle has successfully flown several times proving
out the LH2/LOX BE-3 engine as well as their VTVL technology. Right now
they're working on BE-4 (which ULA wants to use on Vulcan) as well as
their New Glenn orbital launch vehicle (which will use the proven BE-3
engine in its upper stage).

Blue Origin is further ahead than ULA is with Vulcan, IMHO. ULA still
hasn't officially chosen between BE-4 and AR-1 for its first stage
engine. The former being liquid methane which will require cryogenic
fuel tanks and the latter being kerosene which won't. This, and other
differences between the engines, greatly impacts the first stage design
of Vulcan. Vulcan is much more "paper rocket" than New Glenn because of
this very large development uncertainty.

Jeff
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