Evan, you made my day - I'm officially mildly less incorrect than Bill
Claybaugh!
Bill, I'd still love to hear anything you can say about AJ-26 Antares
subcooled LOX loading and launch timing.
Hmm. I see there was no common bulkhead between the Antares 100 LOX and
kero tanks, which I'd expect helped. -196C LOX versus F9's -207C may
also have helped. Looking at a launch countdown vid, the LOX tank
section is clearly distinguishable from the fog coming off it, so I'd
guess there's no (or not much?) insulation on the LOX tank.
There is a steady vapor plume from the tower alongside the first stage
LOX tank. If the LOX is subcooled, that shouldn't be boiloff. Some
sort of cooling arrangement? I should go back and take a closer look at
what's visible of the tower plumbing...
Henry
On 11/7/2016 7:23 PM, Evan Daniel wrote:
I'm used to hearing "supercooling" refer to a liquid that is below its
freezing point, but still a liquid:
https://en.wikipedia.org/wiki/Supercooling
This is clearly not what SpaceX is doing.
I don't know of a conflicting meaning for "subcooled".
I'd recommend using "subcooled" here.
Evan Daniel
On Mon, Nov 7, 2016 at 9:04 PM, Henry Vanderbilt
<hvanderbilt@xxxxxxxxxxxxxx> wrote:
Da. Both are ways of indicating it's cooled significantly below its
sea-level pressure boiling point of -183C.
I make no guarantee that my use of "subcooled" there is
rocket-terminology-weenie correct, mind. FWIW I've seen both used recently.
On 11/7/2016 6:53 PM, Randall Clague wrote:
Nomenclature question: are subcooled LOX and supercooled LOX the same
thing?
On Monday, November 7, 2016, Henry Vanderbilt
<hvanderbilt@xxxxxxxxxxxxxx <mailto:hvanderbilt@xxxxxxxxxxxxxx>> wrote:
NK-33/AJ-26 powered Antares, of course. (Not to mention the N-1.)
Which used subcooled LOX, because the NK-33 requires it.
Can you say anything about the arrangements (if any) for keeping LOX
at the proper temp in that version of Antares? I haven't been able
to find much on a casual search, beyond the assertion that Antares
LOX was at -196C, SpaceX F9's at -207C, and mention of a LOX
subcooler at the Wallops pad that they've restored anyway (despite
the RD-181 Antares not using subcooled LOX) because it was cheaper
than vac-jacketing the pipes from the LOX farm to prevent warmish
LOX on hot days.
Henry
On 11/7/2016 12:05 PM, William Claybaugh wrote:
Others have used supercool Lox and have not had to load in an
all fired
hurry....
Bill
On Monday, November 7, 2016, David Spain <david.l.spain@xxxxxxxxx
<mailto:david.l.spain@xxxxxxxxx>> wrote:
The crux of my question regards the use of supercooled LOX
putting a
time constraint on the launch window.
I was hoping to learn how the interaction of the helium
pressurization system and the supercold LOX might put a time
constraint on how long the F9 can stay fueled on the pad? Is
that
the main reason SpaceX has always planned on crewing the
vehicle first?
