Beware, the audio is a bit loud. The actual moment of touching seem surprisingly gentle. One can see a bit of hop or skid after initial touchdown, but it is not very much. But if they can't reduce that it may pose a maximum crosswind limit at the current barge size.
Beware, the audio is a bit loud. The actual moment of touching seem surprisingly gentle. One can see a bit of hop or skid after initial touchdown, but it is not very much. But if they can't reduce that it may pose a maximum crosswind limit at the current barge size.
Interesting videos. That rocket literally drops into camera frame and then gracefully levitates to the barge surface. It really is difficult to fathom how fast that rocket is closing on the barge only to have its flight interrupted resulting in a graceful landing.
ie. three Merlin's operating, but then a few metres down and 1.5 seconds later :
..... only the one central Merlin, perhaps with a bit of gimbal, and residual flame from the other two just shut down. As Elon would say : this is 21st century rocketry.
As the remainder of the video demonstrates, an engine shut-down is not instant even though the effective thrust change is rather quicker.
Cheers, Mike.
( edit ) A thought : could one of the outer ring Merlin's simulate the effect of the middle one using suitable gimballing ? I think yes but not exactly of course - it would induce some tilt of the barrel.
( edit ) Plus the direct and reflected radiant heat sets those legs a smokin' ...
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
Back to the dock handling from the first successful barge landing :
... I thought : what are these SpaceX techs ( not the transport company ) doing with their heads up each of the rocket bells in turn, at dockside rather than later ?
Try this : the pintles ! They're taking the very specially designed ( and very propriety ) throttle components out. This will be high value intellectual property and probably only physically accessed/managed by a small subset of the company. The finesse of thrust control through a very wide power range ultimately comes down to that component & setup. Sure, other mobs do pintles, since the early sixties. But only SpaceX has a SpaceX pintle and without that there is no deep throttle .... no smooth & deep throttle then no hover slams.
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
Someone posted a pretty nice video apparently shot from a drone with a decent image-stabilized camera with good views of the drone ship (aka barge) and the Falcon 9 before they took the legs off.
The burn marks help clarify how accurate the touchdown point was.
The NSF thread was quite clear that the Port has restrictions on drone activity, so either the maker got an exception, or just got away with it.
The burn marks help clarify how accurate the touchdown point was.
The asymmetry/prominence of the scorch pattern to the lower right quadrant of the frame suggests some gimbal ?
Quote:
.... radiant heat sets those legs a smokin' ....
As for the lingering flames from the bells, I think it is safer to just let remaining fuel/oxidant dribble out the throttle assembly ie. no pressure build. If that part of the structure can withstand nine full throttle Merlin's trying to melt it then a wee candle will be fine. Note to Elon : a new BBQ franchise may evolve from this, Genuine Falcon Fritters* !!! :-)
Cheers, Mike.
* If they are served rare then the landing is classified as a miss.
( edit ) The point about radiant heat is that most of the total EM luminosity is invisible to humans ......
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
The burn marks help clarify how accurate the touchdown point was.
The asymmetry/prominence of the scorch pattern to the lower right quadrant of the frame suggests some gimbal ?
Quote:
.... radiant heat sets those legs a smokin' ....
As for the lingering flames from the bells, I think it is safer to just let remaining fuel/oxidant dribble out the throttle assembly ie. no pressure build. If that part of the structure can withstand nine full throttle Merlin's trying to melt it then a wee candle will be fine. Note to Elon : a new BBQ franchise may evolve from this, Genuine Falcon Fritters* !!! :-)
Cheers, Mike.
* If they are served rare then the landing is classified as a miss.
( edit ) The point about radiant heat is that most of the total EM luminosity is invisible to humans ......
That decking they land on must be pretty thick and made of some very heat resistant material besides pure carbon steel.
I don't know about you guys but I never get sick of looking at the Falcon-9, this time returning from dockside. While the booster is on the truck, I think the truck could fit inside the booster.
.... I reckon this indicates that these two vanes at least were not equally employed. The burn to the forward end of the lower one in the picture shows substantially more radiant heat onto the barrel. My guess is that at some time the vane would have been glowing red or orange. Energy is Everything.
.... some of the whitish appearance on the vane is the original paint, most I think is metal oxide which is about the right color if titanium ( think toothpaste ). It's amazing to think that these hypersonic vanes slow and steer the Falcon on the way down while well alight. This is a seriously low tech solution, available at any time in this Age of Rocketry ! :-)
{ Hmmmmm ..... I think I have become a SpaceX fanboy. :-) }
Cheers, Mike.
( edit ) Pure titanium ( and most alloys ) have an auto-ignition temperature of ~ 1490 K with nitrogen and is rare in that regard, in the presence of oxygen only it is much higher. If it starts it won't stop, not even water will help. You can only wait until it runs out of either the metal or N2. Does anyone remember the Stark and/or Sheffield hit by Exocets ? That was aluminium at ~ 4100 K but with oxygen. This is an interesting bound on the peak heating issue. Mind you the problem has been 'solved' for the case of jet turbine blades, but may still occur with very high performance engines if special care is not taken eg. the Pegasus powerplant for the Harrier :
Quote:
THE maximum takeâ€off thrust available from the Pegasus engine is limited, particularly at the higher ambient temperatures, by the turbine blade temperature. As this temperature cannot reliably be measured, the operating limits are determined by jet pipe temperature. To enable the engine speed and hence thrust to be increased for takeâ€off, water is sprayed into the combustion chamber to keep the blade temperature down to an acceptable level. The water flow rate for the required turbine temperature reduction has been established and qualified in the engine Type Approval Test. The quantity of water carried is sufficient for and appropriate to the particular operational role of the aircraft.
... if the blades light up they almost instantaneously spray the interior components with furiously burning hot blobs ie. certainly thrust failure and typically explosion. So for Harrier pilots : thou shalt not overheat thine Pegasus ....
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
? LOX, because if it is true color then it's not kero
Correction. It's naturally clear. The only color it has is from any additive for that purpose. DownUnda that is blue, red in the USA ?
Anyhow I think the green pipe to the right of picture :
.... is the LOX feed going through the RP-1 tank. The LOX is above the kero in the Falcon-9 tanks. So we're looking at the RP-1 tank here ? But I've yet to find a sufficiently detailed schematic for the Falcon-9 and I doubt I will anytime soon.
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
... that really shows the gimbal aspect into the 50+ knot wind ie. the thrust is near vertical while the barrel is offset by the windage. So it won't land on all four legs simultaneously, hence the hop translation to leftwards when the barrel swings to vertical, and then the remaining legs contact the barge to stop that lateral movement.
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
SpaceX has released landing
)
SpaceX has released landing video taken by three separate cameras for JCSAT-14--all apparently on the barge, so all rather obscured at times.
Beware, the audio is a bit loud. The actual moment of touching seem surprisingly gentle. One can see a bit of hop or skid after initial touchdown, but it is not very much. But if they can't reduce that it may pose a maximum crosswind limit at the current barge size.
RE: SpaceX has released
)
Interesting videos. That rocket literally drops into camera frame and then gracefully levitates to the barge surface. It really is difficult to fathom how fast that rocket is closing on the barge only to have its flight interrupted resulting in a graceful landing.
Great video. Close inspection
)
Great video. Close inspection shows :
ie. three Merlin's operating, but then a few metres down and 1.5 seconds later :
..... only the one central Merlin, perhaps with a bit of gimbal, and residual flame from the other two just shut down. As Elon would say : this is 21st century rocketry.
As the remainder of the video demonstrates, an engine shut-down is not instant even though the effective thrust change is rather quicker.
Cheers, Mike.
( edit ) A thought : could one of the outer ring Merlin's simulate the effect of the middle one using suitable gimballing ? I think yes but not exactly of course - it would induce some tilt of the barrel.
( edit ) Plus the direct and reflected radiant heat sets those legs a smokin' ...
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
Back to the dock handling
)
Back to the dock handling from the first successful barge landing :
... I thought : what are these SpaceX techs ( not the transport company ) doing with their heads up each of the rocket bells in turn, at dockside rather than later ?
Try this : the pintles ! They're taking the very specially designed ( and very propriety ) throttle components out. This will be high value intellectual property and probably only physically accessed/managed by a small subset of the company. The finesse of thrust control through a very wide power range ultimately comes down to that component & setup. Sure, other mobs do pintles, since the early sixties. But only SpaceX has a SpaceX pintle and without that there is no deep throttle .... no smooth & deep throttle then no hover slams.
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
Someone posted a pretty nice
)
Someone posted a pretty nice video apparently shot from a drone with a decent image-stabilized camera with good views of the drone ship (aka barge) and the Falcon 9 before they took the legs off.
The burn marks help clarify how accurate the touchdown point was.
The NSF thread was quite clear that the Port has restrictions on drone activity, so either the maker got an exception, or just got away with it.
RE: The burn marks help
)
The asymmetry/prominence of the scorch pattern to the lower right quadrant of the frame suggests some gimbal ?
As for the lingering flames from the bells, I think it is safer to just let remaining fuel/oxidant dribble out the throttle assembly ie. no pressure build. If that part of the structure can withstand nine full throttle Merlin's trying to melt it then a wee candle will be fine. Note to Elon : a new BBQ franchise may evolve from this, Genuine Falcon Fritters* !!! :-)
Cheers, Mike.
* If they are served rare then the landing is classified as a miss.
( edit ) The point about radiant heat is that most of the total EM luminosity is invisible to humans ......
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: RE: The burn marks
)
That decking they land on must be pretty thick and made of some very heat resistant material besides pure carbon steel.
I don't know about you guys
)
I don't know about you guys but I never get sick of looking at the Falcon-9, this time returning from dockside. While the booster is on the truck, I think the truck could fit inside the booster.
.... I reckon this indicates that these two vanes at least were not equally employed. The burn to the forward end of the lower one in the picture shows substantially more radiant heat onto the barrel. My guess is that at some time the vane would have been glowing red or orange. Energy is Everything.
.... some of the whitish appearance on the vane is the original paint, most I think is metal oxide which is about the right color if titanium ( think toothpaste ). It's amazing to think that these hypersonic vanes slow and steer the Falcon on the way down while well alight. This is a seriously low tech solution, available at any time in this Age of Rocketry ! :-)
{ Hmmmmm ..... I think I have become a SpaceX fanboy. :-) }
Cheers, Mike.
( edit ) Pure titanium ( and most alloys ) have an auto-ignition temperature of ~ 1490 K with nitrogen and is rare in that regard, in the presence of oxygen only it is much higher. If it starts it won't stop, not even water will help. You can only wait until it runs out of either the metal or N2. Does anyone remember the Stark and/or Sheffield hit by Exocets ? That was aluminium at ~ 4100 K but with oxygen. This is an interesting bound on the peak heating issue. Mind you the problem has been 'solved' for the case of jet turbine blades, but may still occur with very high performance engines if special care is not taken eg. the Pegasus powerplant for the Harrier :
... if the blades light up they almost instantaneously spray the interior components with furiously burning hot blobs ie. certainly thrust failure and typically explosion. So for Harrier pilots : thou shalt not overheat thine Pegasus ....
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: ? LOX, because if it is
)
Correction. It's naturally clear. The only color it has is from any additive for that purpose. DownUnda that is blue, red in the USA ?
Anyhow I think the green pipe to the right of picture :
.... is the LOX feed going through the RP-1 tank. The LOX is above the kero in the Falcon-9 tanks. So we're looking at the RP-1 tank here ? But I've yet to find a sufficiently detailed schematic for the Falcon-9 and I doubt I will anytime soon.
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
I found this one for the CR-8
)
I found this one for the CR-8 landing :
... that really shows the gimbal aspect into the 50+ knot wind ie. the thrust is near vertical while the barrel is offset by the windage. So it won't land on all four legs simultaneously, hence the hop translation to leftwards when the barrel swings to vertical, and then the remaining legs contact the barge to stop that lateral movement.
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