https://twitter.com/elonmusk/status/677663227271118848QuoteElon Musk @elonmusk 1m1 minute ago@PaigeANjax -340 F in this case. Deep cryo increases density and amplifies rocket performance. First time anyone has gone this low for O2.
Elon Musk @elonmusk 1m1 minute ago@PaigeANjax -340 F in this case. Deep cryo increases density and amplifies rocket performance. First time anyone has gone this low for O2.
Luke @lukealization: Are you chilling RP-1 also?Elon Musk @elonmusk: yes, from 70F to 20 F
On an operational rocket, he means. NASA built a test plant and even a mock stage IIRC, so the basic idea was vetted. Always a surprising distance between theory and practice, of course.EDIT: and the Russians apparently used supercooled LOX on an upper stage... just not *as* cooled, apparently.
Quote from: ngilmore on 12/18/2015 12:38 amhttps://twitter.com/elonmusk/status/677663227271118848QuoteElon Musk @elonmusk 1m1 minute ago@PaigeANjax -340 F in this case. Deep cryo increases density and amplifies rocket performance. First time anyone has gone this low for O2.And further down that twitter thread:QuoteLuke @lukealization: Are you chilling RP-1 also?Elon Musk @elonmusk: yes, from 70F to 20 FThat's the first time I've seen a specific temperature mentioned for the RP-1 chill.~Kirk
Luke @lukealization 2h2 hours ago@elonmusk Are you chilling RP-1 also?
Elon Musk @elonmusk 2h2 hours ago@lukealization yes, from 70F to 20 F
Quote from: cscott on 12/18/2015 12:49 amOn an operational rocket, he means. NASA built a test plant and even a mock stage IIRC, so the basic idea was vetted. Always a surprising distance between theory and practice, of course.EDIT: and the Russians apparently used supercooled LOX on an upper stage... just not *as* cooled, apparently.I believe Antares also used sub-cooled LOX, needed by the engines. And since those engines were from the N-1, that probably used sub-cooled LOX as well. The sub-cooling was needed for turbopump lubrication, if nothing else.
Haven't been following it too closely, but that's the first I've heard mention of RP-1 chilling. Have they done this at all on previous Falcon 9 flights? If not it's a considerable change, which the LOX subcooling already was. Has anyone done RP-1 chilling for orbital launches before?
@elonmusk Did you guys get #Falcon9 O2 down to -340F on the test stand at #McGregor? Is this just an integration issue at LC40? Elon Musk @elonmusk 6h6 hours ago@craigcocca It worked in Texas
More importantly, given the temperatures listed above, could someone make an educated guess about the amount of fuel and oxidizer carried?
George Sowers @george_sowers 4h4 hours ago.@elonmusk Thats why we don't bother. Lots of complexity for little gain.
George Sowers @george_sowers 4h4 hours ago.@rocketrepreneur @elonmusk Tough to know the conditions of LOX at liftoff.
So it worked in Texas, weather data :TX relative humidity : 70% pressure : 1026hpatemp : 4°CDew point : 0°Cwind : ~15Km/hFL relative humidity : 90% pressure : 1012hpatemp : 23 C°Dew point : 21°cwind : 20-40Km/h
Would the lower RP1 temp affect S2 endurance at all? I thought that SX had a possible problem with long coasting periods because of RP1 freezing issues.
Pressurization is going to be interesting. -340 F is 66.5 K and at that temperature the vapor pressure of a liquid oxygen appears to be about 0.03 bar. So they're going to need to introduce some additional gas to pressurize the tank.
Quote from: ngilmore on 12/18/2015 12:39 amhttps://twitter.com/elonmusk/status/677663227271118848QuoteElon Musk @elonmusk 1m1 minute ago@PaigeANjax -340 F in this case. Deep cryo increases density and amplifies rocket performance. First time anyone has gone this low for O2.Here's an interesting response to Elon's tweets:https://twitter.com/george_sowers/status/677724984165330944QuoteGeorge Sowers @george_sowers 4h4 hours ago.@elonmusk Thats why we don't bother. Lots of complexity for little gain. https://twitter.com/george_sowers/status/677730399242457089QuoteGeorge Sowers @george_sowers 4h4 hours ago.@rocketrepreneur @elonmusk Tough to know the conditions of LOX at liftoff.
Quote from: rpapo on 12/18/2015 10:24 amTexas: Add dust.Florida: Add salt.don't forget the effects of Solar radiation ie sunshine
Texas: Add dust.Florida: Add salt.