Henry Spencer wrote:


You might like it there, but other considerations can intervene, like the
extra structural weight incurred by putting most of the propellant mass up
high. The LOX was on the bottom in the S-II, the S-IV/S-IVB, and the
Ariane 1/2/3/4 third stage, and still is in the Centaur, the Delta IV
upper stage, and the GSLV third stage. It might have ended up on the
bottom in the ET, too, had it not been for the asymmetric vehicle
configuration -- keeping the ET's changing center of mass within the
limited gimbal range of the SSMEs absolutely dictated putting the LOX tank
as far away from the SSMEs as humanly possible.


I thought the gimbaling would probably be the main problem... the thing
is already fairly unstable without getting it completely unstable by
sticking the LH2 on top and having it constantly trying to go out of
control.
Was there any particular reason the LOX ended up on top in the Atlas?
Gimbaling limits again?
I note that both Jupiter and Thor had it on the bottom.

Pat