SpaceFlightNow also has a detailed story on the COPV issue.
informative read. on the subject of testing. Elon Musk's comment "its nuts" was equally interesting in that it was about the complexity of testing required.
Sounds like it's been rather an odyssey into the micro world of materials science. So yes it's seems that say, the snapping of a fibre ( molecular chain ) releases some of it's bonding energy ( earlier input when creating the chain ) quite focally and now adjacent oxygen molecules ( that should not have permeated ) may ride over their activation hump to combine with eg. nearby carbon. There's a nett excess free energy produced ( exothermic ) and in the blink of an eye every neighbourhood molecule is in on the party, etc etc. Even though the region began as quite cold, a tiny match was lit. Not with a supersonic shock wave as per high explosive detonation, as initially we thought, but very fast subsonic conflagration. Scratch one Israeli satellite.
But this comes from rapid filling with superchilled liquid oxygen, in turn a method to increase immediate take off thrust - and not a trivial benefit for some missions. Upon examining equation of state curves I see that holding any gaseous O2 under those conditions within a closed vessel is essentially impossible with known materials. You have to vent ie. lose oxidant as the tanks heat up within the rocket. Hence to get any benefit from superchilling you have to load late & fire up quickly when that's done. So there's the tension re. occupant ingress timing for manned flight. It's sensible but still sucks to require a design freeze in place for over 6 launches before certification.
{ Yet another 'production hell' to bother Elon. What a guy he is to aim for so much, bludgeon his way through nasty difficulties, thus snubbing the useless naysayers. Spectating is easy. I know that from my own work, but I only keep to the one field of knowledge ! So now you know that I want to come back next time as an Elon. It was once said of Alan Turing that he was born into the wrong age, by about two centuries too soon .... ;-) }
The strut failure is by comparison much easier : design, make, test & install in-house. So that you know that specifications are honored.
I think that Elon had said he was looking to move away from COPVs down the track. It seems no one else much likes them either.
Cheers, Mike.
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
It was said at the time that a fairing half was much closer to Mr. Steven on the latest try than the rather long miss previously. Now someone from SpaceX said it was about 50 meters.
Here are two pics:
Fairing half descending by parachute--possibly close by a camera on the boat (though a drone might have closed the distance).
A fairing half showing how very, very light weight it is compared to volume by "walking on water".
I tend to be disappointed when they throw away a booster. No fairing recovery attempt either. Listening to the fooshing and hissing on the pad, with crickets in the background, makes the experience quite real. I'd guess the throw-away was as much to do with an old block design as due to a geostationary target. Let's hope their flight success continues.
Cheers, Mike.
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
Yes, the Block 4 (older version) was meant "only" for 2 uses. This was the second launch of one particular booster. They may have tried some experimental landing on water.
As for the fairing the ship that tries to catch it (Mr. Stevens) is currently stationed in California....so no fairing recoveries in Florida yet.
Regarding fairing catching and Mr. Steven: Elon tweeted in response to a question suggesting enlarging Mr. Steven's arms "Yup, we are extending the net area by a factor of 4".
I'd take that as tacit admission that the attempts and calculations so far are not converging toward a success rate as high as they'd like.
I have a bit of trouble imagining how this will all work out making money for them. Owning or leasing and operating a boat of Mr. Steven class capability is not cheap, and they would seem to need two of them on each coast. No one has yet suggested that there is any idea of catching both fairing halves with one boat.
The thing is that the fairing is quite expensive and takes quite a lot of time to build one....so it could be a bottleneck for quick reusability of rockets.
Quote:robl
)
Sounds like it's been rather an odyssey into the micro world of materials science. So yes it's seems that say, the snapping of a fibre ( molecular chain ) releases some of it's bonding energy ( earlier input when creating the chain ) quite focally and now adjacent oxygen molecules ( that should not have permeated ) may ride over their activation hump to combine with eg. nearby carbon. There's a nett excess free energy produced ( exothermic ) and in the blink of an eye every neighbourhood molecule is in on the party, etc etc. Even though the region began as quite cold, a tiny match was lit. Not with a supersonic shock wave as per high explosive detonation, as initially we thought, but very fast subsonic conflagration. Scratch one Israeli satellite.
But this comes from rapid filling with superchilled liquid oxygen, in turn a method to increase immediate take off thrust - and not a trivial benefit for some missions. Upon examining equation of state curves I see that holding any gaseous O2 under those conditions within a closed vessel is essentially impossible with known materials. You have to vent ie. lose oxidant as the tanks heat up within the rocket. Hence to get any benefit from superchilling you have to load late & fire up quickly when that's done. So there's the tension re. occupant ingress timing for manned flight. It's sensible but still sucks to require a design freeze in place for over 6 launches before certification.
{ Yet another 'production hell' to bother Elon. What a guy he is to aim for so much, bludgeon his way through nasty difficulties, thus snubbing the useless naysayers. Spectating is easy. I know that from my own work, but I only keep to the one field of knowledge ! So now you know that I want to come back next time as an Elon. It was once said of Alan Turing that he was born into the wrong age, by about two centuries too soon .... ;-) }
The strut failure is by comparison much easier : design, make, test & install in-house. So that you know that specifications are honored.
I think that Elon had said he was looking to move away from COPVs down the track. It seems no one else much likes them either.
Cheers, Mike.
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
It was said at the time that
)
It was said at the time that a fairing half was much closer to Mr. Steven on the latest try than the rather long miss previously. Now someone from SpaceX said it was about 50 meters.
Here are two pics:
Fairing half descending by parachute--possibly close by a camera on the boat (though a drone might have closed the distance).
A fairing half showing how very, very light weight it is compared to volume by "walking on water".
All getting routine, huh ?
)
All getting routine, huh ? :-)
I tend to be disappointed when they throw away a booster. No fairing recovery attempt either. Listening to the fooshing and hissing on the pad, with crickets in the background, makes the experience quite real. I'd guess the throw-away was as much to do with an old block design as due to a geostationary target. Let's hope their flight success continues.
Cheers, Mike.
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
Yes, the Block 4 (older
)
Yes, the Block 4 (older version) was meant "only" for 2 uses. This was the second launch of one particular booster. They may have tried some experimental landing on water.
As for the fairing the ship that tries to catch it (Mr. Stevens) is currently stationed in California....so no fairing recoveries in Florida yet.
Regarding fairing catching
)
Regarding fairing catching and Mr. Steven: Elon tweeted in response to a question suggesting enlarging Mr. Steven's arms "Yup, we are extending the net area by a factor of 4".
I'd take that as tacit admission that the attempts and calculations so far are not converging toward a success rate as high as they'd like.
I have a bit of trouble imagining how this will all work out making money for them. Owning or leasing and operating a boat of Mr. Steven class capability is not cheap, and they would seem to need two of them on each coast. No one has yet suggested that there is any idea of catching both fairing halves with one boat.
The thing is that the fairing
)
The thing is that the fairing is quite expensive and takes quite a lot of time to build one....so it could be a bottleneck for quick reusability of rockets.
SpaceX propossing "serious"
)
SpaceX propossing "serious" expansion at Kennedy Space center: http://www.businessinsider.com/spacex-new-florida-campus-launch-control-tower-2018-6
bizarre
)
bizarre https://www.bbc.co.uk/news/technology-44642137
Richard
not everything is for sale
)
not everything is for sale
Sometimes it works.
)
Sometimes it works. Sometimes it doesn't.
https://apnews.com/d2385c3d78ff4e08a0971a78f3683c99/Rocket-developed-by-Japan-startup-in-flames-after-liftoff