JF Mezei writes:

markus baur wrote:

btw - did you catch that little tidbit about fuel crossfeed form
boosters to core stage - i believe that one is new ..

Pardon my ignorance, what is the advantage of this ?

Is it just a question of shifting tank weight from the core to the
strap-ons so that once you shed the boosters, you end up with lighter
vehicle since the main tank is smaller ?

Rather the other way around, I think. If you have boosters that are
identical to the core and all fire from the launch on, all you get is a
way to lift a larger/heavier second stage (since the core and the
boosters will burn out at the same time). But if you can crossfeed
propellants from the boosters to the core you can separate the empty
boosters earlier and then still have a full (or nearly full) core stage
to continue on. This is like launching an Falcon 9 from already above
the atmosphere and from a launch pad travelling with a few km/s.


Jochem

--
"A designer knows he has arrived at perfection not when there is no
longer anything to add, but when there is no longer anything to take away."
- Antoine de Saint-Exupery