[AR] Re: helium tank submerged in LOX \ Re: Re: SpaceX failure update
- From: Henry Spencer <hspencer@xxxxxxxxxxxxx>
- To: arocket@xxxxxxxxxxxxx
- Date: Mon, 7 Nov 2016 14:05:05 -0500 (EST)
eOn Mon, 7 Nov 2016, Henry Vanderbilt wrote:
The problem with that is, you can't keep subcooled LOX at stable
temperature once loaded by letting some boil off. So running with
subcooled LOX means a fairly rapid propellant-loading cycle - AIUI on
the order of a half-hour from load start to engines lit...
There's at least one alternative: active refrigeration. Either put a
heat exchanger in the tank and circulate (say) LN2 (from ground support
equipment) through it, or have tank connections at both top and bottom and
circulate the LOX itself through a ground heat exchanger until just before
launch. It adds complications and a bit of hardware mass, but it is
feasible.
(This sort of thing got looked at in some detail in the Bad Old Days, when
people were seriously considering sizable rockets with liquid fluorine or
FLOX as the oxidizer. Such concepts tend to come with a non-negotiable
requirement that fluorine boiloff shall be zero, which means keeping the
oxidizer subcooled at all times.)
Henry
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