JF Mezei wrote on Sat, 26 May 2018
18:41:53 -0400:

On 2018-05-25 20:46, Fred J. McCall wrote:

I don't consider it a risk any more than doing it the other way.


From a performance point of view, isn't SpaceX concerned about having
the kerosene fuel as cold as possible? (aka: loaded only at last minute)


Well, not "as cold as possible", since that would mean it was frozen
solid, but I take your meaning and I already said just that an article
or two ago. Again, Block 5 has higher performance than Block 4, so
the performance difference from propellant density may be manageable.


Doesn't LOX remain cold naturally once loaded and the only concern to
have it constantly refilled as some of it boils out?


No. That would violate physics. There wouldn't be anything 'boiling
off' if it just remained cold.


Seems to me that loading the He2 under pressure and LOX that surrounds
it is the higher risk part and could be done before they board, and then
load the kerosene at last minute so it is as cold as possible.


Except LOX and helium don't violate the laws of physics, so they start
warming up the instant they hit the tanks.


Note: comemrcial aircraft have various restrictions on fueling aircraft
when there are passengers on-board vs boarding/deplaning vs empty. (and
these vary depending on fuel being used).


Note: Well, not really.


--
"Some people get lost in thought because it's such unfamiliar
territory."
--G. Behn