stays on the camera with a left-side point of view. The details available differ appreciably from the other point of view. The critical stuff is at about time 2:30 on this one. There are a couple of frames with plain precursor anomaly before the first frame that appears to be the explosion itself.
I'm labelling frames with the number Rowvid shows at lower left
151.53 last normal frame
151.57 extra mist on upper stage
151.65 mist has grown
151.69 first frame showing burst -- already has a distinctly spherical shape
the next few frames show growth of the primary sphere before things get more chaotic.
From this update there is some, err, 'good' news IMHO :
Quote:
... Dragon remained healthy for some period of time following separation.
Now if there was a breach, say even a small gap, b/w the Dragon trunk section and the upper part of the second stage one will get hypersonic air entering at very high pressure and striking the LOX tank within. That will heat it quick slick .... it only needs to be quite a small gap initially with the maxQ phase precisely when this mechanism would disclose. And there could well be no indication on telemetry other than tank over-pressure.
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
On the left is the 151.57 frame that Peter refers to :
... which plus or minus a handful of milliseconds corresponds to the right side view at the 200.51 frame on the the other video. As Peter indicates the 151.57 frame is identical to the next one at 151.61 ....
The section of the rocket that I've have nominated with the adjacent yellow bar is the trunk section of the Dragon and the upper part of the second stage ie. the segment that blew first. Now the trunk is unsealed ie. not part of the pressured Dragon hull and so volume-wise is contiguous with the upper portion of the second stage tank. The LOX tank sits forward of the kero tank in both stages.
Other thoughts : all this happened a very short time before the 1st stage was to shut down anyway. So that means the second stage was yet to light, but the Merlins have a preload phase for fuel and oxidizer to flow distally through the various pipes to the engine, and the LOX turbo especially, prior to ignition in the combustion chamber. Relevance ??
Now here is a montage of images over a ~ 1.25 second span ( in steps of six frames beginning 154.96 top left ) which I believe shows the Dragon sans trunk exiting the scene :
... if so, I reckon any crew may have had a high chance of surviving to that point at least ie. even without the benefit of the escape system. A silver lining here ? Optimism ? :-)
Cheers, Mike.
( edit ) Actually robl you've triggered a memory. I think I remember one of the earlier launches where a late count abort was called due an issue with second stage tank venting. Possibly January the 6th. That launch missed the window on that day and later succeeded.
( edit ) Also robl you have triggered another thought : a colder day is a denser air day. Maybe the actual MaxQ was an all time high c/w other CRS launches. MaxQ is the maximum aerodynamic pressure : essentially a function of the momentum of the air in front of the craft. For a given fixed cross section this increases with increasing speed, and decreases with decreasing air density. The further into the flight you go then the faster you go, but as you are going up then the air gets less dense with time. At takeoff you are hardly moving however the air is very dense at the ground. Very high up you are going some amazing speed but through very thin air. In between there is a moment when the product of air density times speed has risen to a maximum and then subsides.
But there is also Mach 1 to worry about. It's not MaxQ, which is slightly later. But just aft of the Dragon is the low pressure area behind the bow of the shock wave ( 'sound barrier' ) where a mist briefly forms :
and there is a maximum differential of pressure across the trunk section ie. from the nose to the second stage. Push carefully down on an upright aluminium drink can and it buckles inwards. My timings show MaxQ 10.5 seconds after Mach 1, with rupture beginning 3.2 seconds later. Crush. Crump.
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
HOUSTON — NASA has named its first commercial crew "cadre" — four astronauts who will train to fly on board the first test flights of Boeing's CST-100 and SpaceX's Dragon spacecraft.
The agency Thursday (July 9) announced that astronauts Bob Behnken, Eric Boe, Doug Hurley and Sunita ("Suni") Williams will train to fly on the commercial capsules' maiden missions to the International Space Station. The test flights are slated to launch in 2017, though they could face delays of a year or more depending on congressional funding levels.
"These distinguished veteran astronauts are blazing a new trail," stated NASA's Administrator Charles Bolden, "a trail that will one day land them in the history books."
HOUSTON — NASA has named its first commercial crew "cadre" — four astronauts who will train to fly on board the first test flights of Boeing's CST-100 and SpaceX's Dragon spacecraft.
The agency Thursday (July 9) announced that astronauts Bob Behnken, Eric Boe, Doug Hurley and Sunita ("Suni") Williams will train to fly on the commercial capsules' maiden missions to the International Space Station. The test flights are slated to launch in 2017, though they could face delays of a year or more depending on congressional funding levels.
"These distinguished veteran astronauts are blazing a new trail," stated NASA's Administrator Charles Bolden, "a trail that will one day land them in the history books."
What is "ludicrous mode"? It's a feature announced Friday by Tesla CEO Elon Musk that takes the new Model S P90D from 0-60 miles per hour in 2.8 seconds with the press of a button.
I remember the days of the GTO w/ hurst shifters, baby moons, etc. Thought it was fast and it was. And maybe, just maybe, its speed to $ ratio was a bargain.
[Edit] I wonder?, do the tires have suction cups to keep them from slipping?
I wonder?, do the tires have suction cups to keep them from slipping?
Nope, but two really big advantages in addition to higher horsepower to weight ratio that help it beat the GTO:
1. all-wheel drive so the front tires are digging in to help with the program, not just going along for the ride.
2. instant-on power. An electric motor can deliver peak torque over a very wide rpm range. Cars like the Prius tame this to make the car more similar to conventional, but if unleashed an electric has a very different acceleration curve, front-end loaded compared to internal combustion.
I'd be extremely delighted to own a Telsa Model S P90D. The centre of gravity is quite low with the batteries in the base of the chassis and of course it is near perfectly mid-balanced ( fore to aft ). It has received a safety rating ( ANCAP ) higher than anything previously tested.
What I wouldn't be delighted with is having to pay for it. DownUnda the P85D brand new and going crazy with all the mods ( including Lucridous Speed Upgrade ) is $226K AUD all up. Notably Tesla guarantee a resale trade-in value of 50% after three years ( well kept, undamaged etc ). I find that quite interesting as many high end performance and/or luxury cars lose 30% just by driving it off the lot on day 1.
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
As it happens a good college friend of mine, who was a serial Corvette owner for decades, bought a Tesla model S not so very long ago, then when the double motor model came out upgraded to the model S P85D.
His comment in a note to me "0-60 in 3.1 seconds and much more stable doing so than the 0-60 in 4.2 seconds of my previous, rear wheel drive P85. Love the car."
The youtube video mentioned
)
The youtube video mentioned uses video from a camera looking at the right side at the moment of the event. But the NASA video available at Youtube:
https://www.youtube.com/watch?v=efjf37ZPYz4
stays on the camera with a left-side point of view. The details available differ appreciably from the other point of view. The critical stuff is at about time 2:30 on this one. There are a couple of frames with plain precursor anomaly before the first frame that appears to be the explosion itself.
I'm labelling frames with the number Rowvid shows at lower left
151.53 last normal frame
151.57 extra mist on upper stage
151.65 mist has grown
151.69 first frame showing burst -- already has a distinctly spherical shape
the next few frames show growth of the primary sphere before things get more chaotic.
Thanks to Mike for posting the Rowvid trick.
Comments I posted here used the URL:
http://rowvid.com/?v=efjf37ZPYz4
It appears that in this representation some sequential frames are actually identical in content.
From this update there is
)
From this update there is some, err, 'good' news IMHO :
Now if there was a breach, say even a small gap, b/w the Dragon trunk section and the upper part of the second stage one will get hypersonic air entering at very high pressure and striking the LOX tank within. That will heat it quick slick .... it only needs to be quite a small gap initially with the maxQ phase precisely when this mechanism would disclose. And there could well be no indication on telemetry other than tank over-pressure.
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
On the left is the 151.57
)
On the left is the 151.57 frame that Peter refers to :
... which plus or minus a handful of milliseconds corresponds to the right side view at the 200.51 frame on the the other video. As Peter indicates the 151.57 frame is identical to the next one at 151.61 ....
The section of the rocket that I've have nominated with the adjacent yellow bar is the trunk section of the Dragon and the upper part of the second stage ie. the segment that blew first. Now the trunk is unsealed ie. not part of the pressured Dragon hull and so volume-wise is contiguous with the upper portion of the second stage tank. The LOX tank sits forward of the kero tank in both stages.
Other thoughts : all this happened a very short time before the 1st stage was to shut down anyway. So that means the second stage was yet to light, but the Merlins have a preload phase for fuel and oxidizer to flow distally through the various pipes to the engine, and the LOX turbo especially, prior to ignition in the combustion chamber. Relevance ??
Now here is a montage of images over a ~ 1.25 second span ( in steps of six frames beginning 154.96 top left ) which I believe shows the Dragon sans trunk exiting the scene :
... if so, I reckon any crew may have had a high chance of surviving to that point at least ie. even without the benefit of the escape system. A silver lining here ? Optimism ? :-)
Cheers, Mike.
( edit ) Actually robl you've triggered a memory. I think I remember one of the earlier launches where a late count abort was called due an issue with second stage tank venting. Possibly January the 6th. That launch missed the window on that day and later succeeded.
( edit ) Also robl you have triggered another thought : a colder day is a denser air day. Maybe the actual MaxQ was an all time high c/w other CRS launches. MaxQ is the maximum aerodynamic pressure : essentially a function of the momentum of the air in front of the craft. For a given fixed cross section this increases with increasing speed, and decreases with decreasing air density. The further into the flight you go then the faster you go, but as you are going up then the air gets less dense with time. At takeoff you are hardly moving however the air is very dense at the ground. Very high up you are going some amazing speed but through very thin air. In between there is a moment when the product of air density times speed has risen to a maximum and then subsides.
But there is also Mach 1 to worry about. It's not MaxQ, which is slightly later. But just aft of the Dragon is the low pressure area behind the bow of the shock wave ( 'sound barrier' ) where a mist briefly forms :
and there is a maximum differential of pressure across the trunk section ie. from the nose to the second stage. Push carefully down on an upright aluminium drink can and it buckles inwards. My timings show MaxQ 10.5 seconds after Mach 1, with rupture beginning 3.2 seconds later. Crush. Crump.
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
NASA Assigns 4 Astronauts to
)
NASA Assigns 4 Astronauts to Commercial Boeing, SpaceX Test Flights
The link is broken.
)
The link is broken.
Corrected link/URLNASA
)
Corrected link/URL
NASA Assigns 4 Astronauts to Commercial Boeing, SpaceX Test Flights
On the subject of the Tesla
)
On the subject of the Tesla Model S:
What is "ludicrous mode"? It's a feature announced Friday by Tesla CEO Elon Musk that takes the new Model S P90D from 0-60 miles per hour in 2.8 seconds with the press of a button.
I remember the days of the GTO w/ hurst shifters, baby moons, etc. Thought it was fast and it was. And maybe, just maybe, its speed to $ ratio was a bargain.
[Edit] I wonder?, do the tires have suction cups to keep them from slipping?
RE: I wonder?, do the tires
)
Nope, but two really big advantages in addition to higher horsepower to weight ratio that help it beat the GTO:
1. all-wheel drive so the front tires are digging in to help with the program, not just going along for the ride.
2. instant-on power. An electric motor can deliver peak torque over a very wide rpm range. Cars like the Prius tame this to make the car more similar to conventional, but if unleashed an electric has a very different acceleration curve, front-end loaded compared to internal combustion.
I'd be extremely delighted to
)
I'd be extremely delighted to own a Telsa Model S P90D. The centre of gravity is quite low with the batteries in the base of the chassis and of course it is near perfectly mid-balanced ( fore to aft ). It has received a safety rating ( ANCAP ) higher than anything previously tested.
What I wouldn't be delighted with is having to pay for it. DownUnda the P85D brand new and going crazy with all the mods ( including Lucridous Speed Upgrade ) is $226K AUD all up. Notably Tesla guarantee a resale trade-in value of 50% after three years ( well kept, undamaged etc ). I find that quite interesting as many high end performance and/or luxury cars lose 30% just by driving it off the lot on day 1.
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
As it happens a good college
)
As it happens a good college friend of mine, who was a serial Corvette owner for decades, bought a Tesla model S not so very long ago, then when the double motor model came out upgraded to the model S P85D.
His comment in a note to me "0-60 in 3.1 seconds and much more stable doing so than the 0-60 in 4.2 seconds of my previous, rear wheel drive P85. Love the car."
I've not asked him about Ludicrous mode.