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Old October 27th 17, 06:21 PM posted to sci.space.policy
Greg \(Strider\) Moore
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Default Were liquid boosters on Shuttle ever realistic?

"Fred J. McCall" wrote in message
...

"Greg \(Strider\) Moore" wrote:

"Fred J. McCall" wrote in message
. ..

There is no such thing as assembly line production 'spewing out'
rocket engines. It made sense to use Merlin engines because the idea
was to have three identical cores for Falcon Heavy, sort of like what
Delta IV Heavy does. In the event, Musk found they couldn't do that
and that they couldn't just use three Falcon 9 cores for Falcon Heavy.
The side boosters are now different from the central 'core'.


What are the differences? Last I knew the side boosters for the primary
flight are B1023.2 and B1025.2 (i.e 2nd flight for those two boosters)


It's mostly got to do with mechanical loading. The side boosters are
close (but not an exact match) for what they fly on Falcon 9. They're
only slightly modified so as to be able to take structural loading
from the attachment points on the sides rather than straight down
through the center of the core.


I can see that. As you say, must be fairly slight. Interesting though.

The center booster requires a lot
more structural work to stand loads, both the side loads from the two
attached boosters and the increased load on the front of the booster
from the second stage and payload.


Yeah, I figured the central core would be different.

Musk himself has said that he
doesn't necessarily expect the first launch attempt to reach orbit and
would consider it getting far enough away to avoid pad damage a win.


Yeah, he's doing a good job of lowering expectations. I'm pretty sure he's a
lot more confident than that, or else he wouldn't risk a launch.

Look at how many Falcon 9 launches failed before they got a success.


You mean 0?
Landing took some tries, but the launches were successful.


According to Musk, Falcon Heavy was "shockingly difficult" to develop.
It was originally supposed to use fuel cross-feed among the three
cores, but that proved too difficult and was dropped.


Yeah. That I knew. And makes sense. Gets some advantages, but it's a feature
that can be added on later.

It was
originally supposed to be three 'standard' Falcon 9 cores (with Falcon
9 eating the additional structure) but now the center booster is
different from the side boosters. Yes, it really is rocket science...


Ayup.
Or at least rocket engineering.



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