No change as far as I know. The temp today will be 83 and on Saturday 65. Warmer then originally predicted. I did read that SpaceX because of design changes - more powerful motors and a return to land - would have to "get" FAA approval for both conditions. This might effect the return to land option if the FAA denies approval. I would think that by now if there was such a glitch it would have been announced so I remain optimistic. Come to think of it I did not here about the engine test on the 16th. Did it happen?
No change as far as I know. The temp today will be 83 and on Saturday 65. Warmer then originally predicted. I did read that SpaceX because of design changes - more powerful motors and a return to land - would have to "get" FAA approval for both conditions. This might effect the return to land option if the FAA denies approval. I would think that by now if there was such a glitch it would have been announced so I remain optimistic. Come to think of it I did not here about the engine test on the 16th. Did it happen?
[EDIT] Just did some poking around and there is nothing on the engine test on the 16th. I think that if this has not been done then it does not bode well for a launch on the 19th. Also found that the return to earth could be barge or land. No one is saying at the present. Oh well stay tuned.
[EDIT] Test firing is now scheduled for this afternoon 12/17.
AFAIK the Falcon is upright on the pad awaiting .....
I've looked up the supercooling of the liquid oxygen. It becomes solid at just over 50 K. Now I don't know SpaceX's usual propellant temperatures but I found some LOX data sheets which indicate, for instance, that cooling from 80 K to 55 K increases the density by about 10%. The barrel is also longer - more tank volume - plus there are other unspecified engine tweaks. This gives a peak thrust at an impressive 25% of an Apollo era Saturn V ! :-)
It seems a Florida newspaper may have actually been told "barge or land return" by SpaceX but only printed "land return".
Cheers, Mike.
( edit ) Silly Me Correction : the Florida newspaper was quoting AmericaSpace who said that NASA had a press conference where their spokesperson said that SpaceX told them that it would return the first stage to the Cape, possibly refurbishing & refueling with a test payload, and then launch shortly after that to show everyone that reusable is IN ..... :-)
SpaceX has reaffirmed their prior statement of Dec 10 :
Quote:
.... could not provide any new information or updates, nor could they confirm or deny NASA’s comments. Instead, SpaceX advised that more information would be made available in coming days.
So that would be Whisky-Tango-Foxtrot then ? ;-)
( edit ) Anyway to cheer you all up I found the following when browsing : electrons are here to stay. That's a relief. So will all the electronic devices still work after Christmas ? :-))
I have made this letter longer than usual because I lack the time to make it shorter ...
... and my other CPU is a Ryzen 5950X :-) Blaise Pascal
oh heck. Kick the tire, light the fire and brief on way to target.
I had a Methodist pastor twenty years ago who was an A-4 pilot (US Navy light attack--nuclear capable) in a previous life.
The version of that famous phrase he favored was:
"Kick the tires, light the fires, brief on guard".
Where "guard" in this case is a reference to a standardized communication frequency--not specific to a mission. So the same meaning as your version, just phrased a bit differently.
He could not break secrecy enough to say the name of the city which contained his target should SIOP every have gotten executed in those days, but did mention that he had a bit of a start when passing through our city airport to see that city listed as one of our sister cities.
Back to SpaceX.
This article at ScienceAlert discusses some of the recent SpaceX stuff, and in a somewhat roundabout way addresses a ticklish aspect of the landing the booster bit.
They spin it into a purely positive thing, asserting that the higher total vigor of the newest variant means that most missions have enough fuel to land the booster.
The less pie-in-the-sky way to put it is that landing the booster means reserving appreciable launch mass, mostly for fuel and bit for the extra pieces of hardware, for the landing function. Somewhat less if you land at sea in an energetically favorable location, a bit more if you insist not only on landing on land, but back at the launch site. Mass reserved for this is not available for boosting payload to orbit, or higher orbit for same payload.
While I'm wildly enthusiastic about SpaceX in general and their booster reuse intentions in particular, I think this cost has been mostly not mentioned in general press commentary, and that the (possibly larger) cost of inspection and refurbishment has been glossed over almost entirely.
Worries aside, I hope they land this one, in one piece.
oh heck. Kick the tire, light the fire and brief on way to target.
I had a Methodist pastor twenty years ago who was an A-4 pilot (US Navy light attack--nuclear capable) in a previous life.
The version of that famous phrase he favored was:
"Kick the tires, light the fires, brief on guard".
Where "guard" in this case is a reference to a standardized communication frequency--not specific to a mission. So the same meaning as your version, just phrased a bit differently.
He could not break secrecy enough to say the name of the city which contained his target should SIOP every have gotten executed in those days, but did mention that he had a bit of a start when passing through our city airport to see that city listed as one of our sister cities.
Back to SpaceX.
This article at ScienceAlert discusses some of the recent SpaceX stuff, and in a somewhat roundabout way addresses a ticklish aspect of the landing the booster bit.
They spin it into a purely positive thing, asserting that the higher total vigor of the newest variant means that most missions have enough fuel to land the booster.
The less pie-in-the-sky way to put it is that landing the booster means reserving appreciable launch mass, mostly for fuel and bit for the extra pieces of hardware, for the landing function. Somewhat less if you land at sea in an energetically favorable location, a bit more if you insist not only on landing on land, but back at the launch site. Mass reserved for this is not available for boosting payload to orbit, or higher orbit for same payload.
While I'm wildly enthusiastic about SpaceX in general and their booster reuse intentions in particular, I think this cost has been mostly not mentioned in general press commentary, and that the (possibly larger) cost of inspection and refurbishment has been glossed over almost entirely.
Worries aside, I hope they land this one, in one piece.
Your observations are valid. Until they land one and inspect it I don't believe they know how reusable the 1st stage will actually be. And then the question: how many times can that 1st stage be recycled before metal fatigue renders it unusable. Logically it seems like money can be saved if you can get X cycles out of it. But that remains to be seen. But damn, it is exciting!!!!!
side note: I am off to check my 15 year old pickup into the mechanics hospital to have its A/C compressor replaced. You can live without somethings but not "that" in Florida.
( edit ) Anyway to cheer you all up I found the following when browsing : electrons are here to stay. That's a relief. So will all the electronic devices still work after Christmas ? :-))
ONLY five-quintillion times the current age of the universe??? I demand a refund from the creator! The spec was "forever."
David
Miserable old git
Patiently waiting for the asteroid with my name on it.
Elon Musk's twitter account has a post dated 15 hours ago stating
Quote:
Falcon 9 is vertical on the launch pad at Cape Canaveral. Working towards static fire. Deep cryo liquid oxygen presenting some challenges
I take this to mean they did not meet the December 16 goal for static fire, which might suggest doubt about launch tomorrow.
The ExtremeText article which pointed me to this mentions that in this case "deep cryo" means -340F, an appreciable depression from -298F commonly used in this application.
While it does mot mention what the "challenges" are, an obvious one would be increased condensation and water ice formation, as the colder oxygen makes any outside surface which contacts ambient air grab more water from that wretched Florida high humidity. I suspect his Texas test site was drier.
Elon Musk's twitter account has a post dated 15 hours ago stating
Quote:
Falcon 9 is vertical on the launch pad at Cape Canaveral. Working towards static fire. Deep cryo liquid oxygen presenting some challenges
I take this to mean they did not meet the December 16 goal for static fire, which might suggest doubt about launch tomorrow.
The ExtremeText article which pointed me to this mentions that in this case "deep cryo" means -340F, an appreciable depression from -298F commonly used in this application.
While it does mot mention what the "challenges" are, an obvious one would be increased condensation and water ice formation, as the colder oxygen makes any outside surface which contacts ambient air grab more water from that wretched Florida high humidity. I suspect his Texas test site was drier.
This does not bode well for a launch tomorrow. To make matters worse there is a low ceiling today and light rain. This weather is not unexpected since it is proceeding a significant cool down for the area. Local news feeds seem quiet with respect to SpaceX. But that does not surprise me. They are more interested in the "Mouse House" and other "attractions".
that is : one can get another 10.3 % more actual oxygen molecules a given tank volume by doing this extra cooling. Now I forget which, but some of the racing car tribes were doing this - chilling the fuel - to get more into their tanks too ie. fewer fuel stops in the pits etc.
'some challenges' : well, metal freezes onto metal for a start eg. your spanner won't come off the bolt head ..... so you hit it with a hammer to loosen it and the spanner shatters etc. But you'd get that at 'usual' cryo anyway, so this extra 20 something Kelvin has exceeded expectations evidently.
My reference is this exceptional resource. For our purposes the 'triple point' is the melting/freezing temperature ( around 55K depending on pressure ) and 300K is about a nice 27 Celsius.
Cheers, Mike.
( edit ) This doesn't give you 10.3 % extra payload though. It depends upon what you are doing with the kerosene too, and whether they are sticking to the pure stochastic ratio given that at least some of the cryo purpose is to cool the rocket bell and stop it melting ( the newer Merlin's burn hotter also ). In any event some of that 10.3 % has to be there to propel that extra 10.3 % in that lovely exponential character of lifting against gravity.
[ .... piston engine pilots out there will be familiar with 'riching up' the fuel mixture to cool the engine. That winds up as unburnt fuel going out the back pipe, but if you are slowly chugging uphill without much airflow across the header ..... ]
( edit ) I don't fly anymore ( became risk averse after a certain bushfire ) but I lovingly remember Lycoming engines. With proper maintenance and operation ( ie. is the pilot stupid ? ) their failure rate in flight is awfully close to zero to many orders. They are seriously a work of brilliant engineering to purpose. What a great American product ( and yes, I am allowed to say that ). The fuel :
- is passed through channels in the block adjacent to the sump thus directly cooling the oil, and then
- by Joule-Thomson throttling during vaporisation in the carby would cool some more, and
- finally in the chamber would, if in excess, mop up more heat but not produce any by being burnt.
I could go on. Two sparkies per chamber, two magnetos per engine, two fuel pumps ( mechanical and electric ), 180 degree opposing pistons ( the best configuration BTW ), nitride enameled piston sleeving, direct drive to the prop. Simple. Rugged. You can only break them with a sledgehammer, or failing that, collision with a planet .... ;-0
I have made this letter longer than usual because I lack the time to make it shorter ...
... and my other CPU is a Ryzen 5950X :-) Blaise Pascal
RE: Is it still set for the
)
No change as far as I know. The temp today will be 83 and on Saturday 65. Warmer then originally predicted. I did read that SpaceX because of design changes - more powerful motors and a return to land - would have to "get" FAA approval for both conditions. This might effect the return to land option if the FAA denies approval. I would think that by now if there was such a glitch it would have been announced so I remain optimistic. Come to think of it I did not here about the engine test on the 16th. Did it happen?
RE: Is it still set for the
)
No change as far as I know. The temp today will be 83 and on Saturday 65. Warmer then originally predicted. I did read that SpaceX because of design changes - more powerful motors and a return to land - would have to "get" FAA approval for both conditions. This might effect the return to land option if the FAA denies approval. I would think that by now if there was such a glitch it would have been announced so I remain optimistic. Come to think of it I did not here about the engine test on the 16th. Did it happen?
[EDIT] Just did some poking around and there is nothing on the engine test on the 16th. I think that if this has not been done then it does not bode well for a launch on the 19th. Also found that the return to earth could be barge or land. No one is saying at the present. Oh well stay tuned.
[EDIT] Test firing is now scheduled for this afternoon 12/17.
AFAIK the Falcon is upright
)
AFAIK the Falcon is upright on the pad awaiting .....
I've looked up the supercooling of the liquid oxygen. It becomes solid at just over 50 K. Now I don't know SpaceX's usual propellant temperatures but I found some LOX data sheets which indicate, for instance, that cooling from 80 K to 55 K increases the density by about 10%. The barrel is also longer - more tank volume - plus there are other unspecified engine tweaks. This gives a peak thrust at an impressive 25% of an Apollo era Saturn V ! :-)
It seems a Florida newspaper may have actually been told "barge or land return" by SpaceX but only printed "land return".
Cheers, Mike.
( edit ) Silly Me Correction : the Florida newspaper was quoting AmericaSpace who said that NASA had a press conference where their spokesperson said that SpaceX told them that it would return the first stage to the Cape, possibly refurbishing & refueling with a test payload, and then launch shortly after that to show everyone that reusable is IN ..... :-)
SpaceX has reaffirmed their prior statement of Dec 10 :
So that would be Whisky-Tango-Foxtrot then ? ;-)
( edit ) Anyway to cheer you all up I found the following when browsing : electrons are here to stay. That's a relief. So will all the electronic devices still work after Christmas ? :-))
I have made this letter longer than usual because I lack the time to make it shorter ...
... and my other CPU is a Ryzen 5950X :-) Blaise Pascal
oh heck. Kick the tire,
)
oh heck. Kick the tire, light the fire and brief on way to target.
RE: oh heck. Kick the
)
I had a Methodist pastor twenty years ago who was an A-4 pilot (US Navy light attack--nuclear capable) in a previous life.
The version of that famous phrase he favored was:
"Kick the tires, light the fires, brief on guard".
Where "guard" in this case is a reference to a standardized communication frequency--not specific to a mission. So the same meaning as your version, just phrased a bit differently.
He could not break secrecy enough to say the name of the city which contained his target should SIOP every have gotten executed in those days, but did mention that he had a bit of a start when passing through our city airport to see that city listed as one of our sister cities.
Back to SpaceX.
This article at ScienceAlert discusses some of the recent SpaceX stuff, and in a somewhat roundabout way addresses a ticklish aspect of the landing the booster bit.
They spin it into a purely positive thing, asserting that the higher total vigor of the newest variant means that most missions have enough fuel to land the booster.
The less pie-in-the-sky way to put it is that landing the booster means reserving appreciable launch mass, mostly for fuel and bit for the extra pieces of hardware, for the landing function. Somewhat less if you land at sea in an energetically favorable location, a bit more if you insist not only on landing on land, but back at the launch site. Mass reserved for this is not available for boosting payload to orbit, or higher orbit for same payload.
While I'm wildly enthusiastic about SpaceX in general and their booster reuse intentions in particular, I think this cost has been mostly not mentioned in general press commentary, and that the (possibly larger) cost of inspection and refurbishment has been glossed over almost entirely.
Worries aside, I hope they land this one, in one piece.
RE: RE: oh heck. Kick
)
Your observations are valid. Until they land one and inspect it I don't believe they know how reusable the 1st stage will actually be. And then the question: how many times can that 1st stage be recycled before metal fatigue renders it unusable. Logically it seems like money can be saved if you can get X cycles out of it. But that remains to be seen. But damn, it is exciting!!!!!
side note: I am off to check my 15 year old pickup into the mechanics hospital to have its A/C compressor replaced. You can live without somethings but not "that" in Florida.
RE: ( edit ) Anyway to
)
ONLY five-quintillion times the current age of the universe??? I demand a refund from the creator! The spec was "forever."
David
Miserable old git
Patiently waiting for the asteroid with my name on it.
Elon Musk's twitter account
)
Elon Musk's twitter account has a post dated 15 hours ago stating
I take this to mean they did not meet the December 16 goal for static fire, which might suggest doubt about launch tomorrow.
The ExtremeText article which pointed me to this mentions that in this case "deep cryo" means -340F, an appreciable depression from -298F commonly used in this application.
While it does mot mention what the "challenges" are, an obvious one would be increased condensation and water ice formation, as the colder oxygen makes any outside surface which contacts ambient air grab more water from that wretched Florida high humidity. I suspect his Texas test site was drier.
RE: Elon Musk's twitter
)
This does not bode well for a launch tomorrow. To make matters worse there is a low ceiling today and light rain. This weather is not unexpected since it is proceeding a significant cool down for the area. Local news feeds seem quiet with respect to SpaceX. But that does not surprise me. They are more interested in the "Mouse House" and other "attractions".
RE: ... that in this case
)
OK.
-340 F = 84.27 K
-298 F = 107.6 K
O2 density @ 107.6 K = 33.1 [ units of no importance ]
O2 density @ 84.27 K = 36.9 [ ditto ]
fractional density increase = (36.9 - 33.1)/36.9 = 3.8/36.9 ~ 10.3 %
that is : one can get another 10.3 % more actual oxygen molecules a given tank volume by doing this extra cooling. Now I forget which, but some of the racing car tribes were doing this - chilling the fuel - to get more into their tanks too ie. fewer fuel stops in the pits etc.
'some challenges' : well, metal freezes onto metal for a start eg. your spanner won't come off the bolt head ..... so you hit it with a hammer to loosen it and the spanner shatters etc. But you'd get that at 'usual' cryo anyway, so this extra 20 something Kelvin has exceeded expectations evidently.
My reference is this exceptional resource. For our purposes the 'triple point' is the melting/freezing temperature ( around 55K depending on pressure ) and 300K is about a nice 27 Celsius.
Cheers, Mike.
( edit ) This doesn't give you 10.3 % extra payload though. It depends upon what you are doing with the kerosene too, and whether they are sticking to the pure stochastic ratio given that at least some of the cryo purpose is to cool the rocket bell and stop it melting ( the newer Merlin's burn hotter also ). In any event some of that 10.3 % has to be there to propel that extra 10.3 % in that lovely exponential character of lifting against gravity.
[ .... piston engine pilots out there will be familiar with 'riching up' the fuel mixture to cool the engine. That winds up as unburnt fuel going out the back pipe, but if you are slowly chugging uphill without much airflow across the header ..... ]
( edit ) I don't fly anymore ( became risk averse after a certain bushfire ) but I lovingly remember Lycoming engines. With proper maintenance and operation ( ie. is the pilot stupid ? ) their failure rate in flight is awfully close to zero to many orders. They are seriously a work of brilliant engineering to purpose. What a great American product ( and yes, I am allowed to say that ). The fuel :
- is passed through channels in the block adjacent to the sump thus directly cooling the oil, and then
- by Joule-Thomson throttling during vaporisation in the carby would cool some more, and
- finally in the chamber would, if in excess, mop up more heat but not produce any by being burnt.
I could go on. Two sparkies per chamber, two magnetos per engine, two fuel pumps ( mechanical and electric ), 180 degree opposing pistons ( the best configuration BTW ), nitride enameled piston sleeving, direct drive to the prop. Simple. Rugged. You can only break them with a sledgehammer, or failing that, collision with a planet .... ;-0
I have made this letter longer than usual because I lack the time to make it shorter ...
... and my other CPU is a Ryzen 5950X :-) Blaise Pascal