Accident at Cape

On 9/1/2016 11:53 PM, William Mook wrote:
https://www.youtube.com/watch?v=_BgJEXQkjNQ

At 1:11 the detonation of the Flight Termination System (FTS) is clearly seen in the upper stage engine housing and propellant tank.

That's one possibility yes. There is evidence of ejecta seen flying
largely vertically away from the booster as the "disassembly" starts
someone on ARocket thought might be related to FTS covers. The is a
downward jet I've seen moving downward alongside the exterior of the
booster in the earliest single frame grab I've seen from the video on
YouTube, but the frame rate is too slow for any kind of detailed analysis.

The explosion seems to begin with the second stage and proceeds from top
to bottom of the stack. Amazingly the stack retains enough structural
integrity that the payload + fairing topples over only AFTER the massive
main explosion. When it hits the ground there is another secondary
explosion, presumed propellants from either a PAM or the payload itself,
I've not studied the AMOS launch configuration.

Musk has indicated this was more of a progressive fire than explosion
and had this been a Dragon mission the LAS would have likely been
successful. In a tweet. His own words. See cite:

http://www.latimes.com/business/la-f...htmlstory.html


Have not heard anything official from SpaceX on the root cause however.
As for the theory of the FTS as a root cause I would not say this is
certain nor definitive.

Dave

On 9/2/2016 3:42 AM, David Spain wrote:
The explosion seems to begin with the second stage and proceeds from top
to bottom of the stack. Amazingly the stack retains enough structural
integrity that the payload + fairing topples over only AFTER the massive
main explosion. When it hits the ground there is another secondary
explosion, presumed propellants from either a PAM or the payload itself,
I've not studied the AMOS launch configuration.

Actually I'm going to revise this statement. After further review, it
appears to me that the payload is actually being supported by the hold
down rings at the top of the strong back. A delicate balancing act that
no doubt was disturbed by vibrations from the ensuing explosion (or
rapidly progressing fire) which cause it to topple over nose down off
the hold down rings.

Dave

On 9/2/2016 3:52 AM, David Spain wrote:
On 9/2/2016 3:42 AM, David Spain wrote:
The explosion seems to begin with the second stage and proceeds from top
to bottom of the stack. Amazingly the stack retains enough structural
integrity that the payload + fairing topples over only AFTER the massive
main explosion. When it hits the ground there is another secondary
explosion, presumed propellants from either a PAM or the payload itself,
I've not studied the AMOS launch configuration.

Actually I'm going to revise this statement. After further review, it
appears to me that the payload is actually being supported by the hold
down rings at the top of the strong back. A delicate balancing act that
no doubt was disturbed by vibrations from the ensuing explosion (or
rapidly progressing fire) which cause it to topple over nose down off
the hold down rings.

Dave


And the weight of the payload. The entire top of the strong back is bent
at the end, when the rocket structure failed it appears as if the weight
of the payload was transferred to the upper portion of the strong back
which appears not to have been up to the task.

Dave

In article om,
says...

If Range Safety is triggered, wouldn't explosives throughout the rocket
fire at the same time ?

Most likely, yes.

We saw progression of fire from the top moving down. So while one pyro
may have exploded, it wouldn't appear to have been triggered by range
safety.

Agreed.

Considering there was a lot of venting near where the fire started, I'd
think it could very well be a problem with the sub-cooled LOX filling
and/or venting. Possibly a static discharge or malfunctioning piece of
equipment igniting whatever is combustible in an oxygen rich
environment.

Jeff
--
All opinions posted by me on Usenet News are mine, and mine alone.
These posts do not reflect the opinions of my family, friends,
employer, or any organization that I am a member of.

On Friday, September 2, 2016 at 7:42:37 PM UTC+12, David Spain wrote:
On 9/1/2016 11:53 PM, William Mook wrote:
https://www.youtube.com/watch?v=_BgJEXQkjNQ

At 1:11 the detonation of the Flight Termination System (FTS) is clearly seen in the upper stage engine housing and propellant tank.

That's one possibility yes. There is evidence of ejecta seen flying
largely vertically away from the booster as the "disassembly" starts
someone on ARocket thought might be related to FTS covers. The is a
downward jet I've seen moving downward alongside the exterior of the
booster in the earliest single frame grab I've seen from the video on
YouTube, but the frame rate is too slow for any kind of detailed analysis..

The explosion seems to begin with the second stage and proceeds from top
to bottom of the stack. Amazingly the stack retains enough structural
integrity that the payload + fairing topples over only AFTER the massive
main explosion. When it hits the ground there is another secondary
explosion, presumed propellants from either a PAM or the payload itself,
I've not studied the AMOS launch configuration.

Musk has indicated this was more of a progressive fire than explosion
and had this been a Dragon mission the LAS would have likely been
successful. In a tweet. His own words. See cite:

http://www.latimes.com/business/la-f...htmlstory.html


Have not heard anything official from SpaceX on the root cause however.
As for the theory of the FTS as a root cause I would not say this is
certain nor definitive.

Dave

If it proves to be the FTS then we must examine appropriateness of FTS on highly reusable rockets. We don't preplace explosives on aircraft in case they go off course, despite 9/11. I doubt anyone would fly in such aircraft as those that had FTS on board. Further, the death toll from accidents with the FTS would swamp the death toll from all other accidents and events combined.

I'm also struck by the survival of the payload. This proves that if an abort system of the type I've described elsewhere were on the rocket that used the landing technology to recover the payload intact - at a cost of about 8% the mass of the payload being recovered - that payload would have escaped certain destruction.

With a rocket costing $62 million and the satellite $195 million - liquid fuelled abort system that used its rockets to land at the launch center might be the sort of technological insurance that is part and parcel of a radically reduced launch cost.

This foretells what the highly reusable rocket of the future will look like..

1) no FTS on board, having been proven in flight,
2) an abort system on board to recover payload in a catastrophic event.

On Friday, September 2, 2016 at 10:43:37 AM UTC-4, Jeff Findley wrote:
In article om,
jfmezei says...

If Range Safety is triggered, wouldn't explosives throughout the rocket
fire at the same time ?

Most likely, yes.

We saw progression of fire from the top moving down. So while one pyro
may have exploded, it wouldn't appear to have been triggered by range
safety.

Agreed.

Considering there was a lot of venting near where the fire started, I'd
think it could very well be a problem with the sub-cooled LOX filling
and/or venting. Possibly a static discharge or malfunctioning piece of
equipment igniting whatever is combustible in an oxygen rich
environment.

Jeff
--

I agree as well. Best photo of episode I've seen to date:

http://uploads.tapatalk-cdn.com/2016...cc824bf39d.jpg

This photo is credited to Ross Sackett in the Facebook SpaceX group. His caption:

"I used a trick we sometimes use to fix the position of a star in an astrophoto. While the fireball is burned into the image making it hard to locate the center, the lens flares (probably diffraction spikes) are centered on the brightest part. Make of this what you will."

That's the X overlaid on this photo. Hat tip to NasaSpaceFlight.com for republishing this photo and caption.

Dave

On Saturday, September 3, 2016 at 2:18:41 AM UTC+12, JF Mezei wrote:
If Range Safety is triggered, wouldn't explosives throughout the rocket
fire at the same time ?

We saw progression of fire from the top moving down. So while one pyro
may have exploded, it wouldn't appear to have been triggered by range
safety.

A full end to end system test resulting in ALL explosives going off would look different than the video. However, if only one charge were mis-wired somehow, and and that was the linear charge in the second stage lox tank, the video is consistent with exactly that happening. Since an FTS system test was being conducted at that moment, the video and the timing of the explosion are both suggestive and point to a failure in the FTS charge on the second stage as the cause.

If the FTS is confirmed as the cause, there are lots of issues that flow out of it;

(1) is FTS appropriate on a reusable rocket?
(2) what are the risk of FTS misfiring vs risks it supposedly abates in a 21st century rocket?
(3) was the accident in any way instigated by competitors who cannot compete?
(this does not shift responsibility away from SpaceX or their contractors - they should have
detected any exceptional condition that led to the FTS failure if indeed that was the case
i.e. any miswiring, or mis-signalling should have been detected before the test and corrected)

These questions deserve to be asked should FTS failure be confirmed through further study.

On Saturday, September 3, 2016 at 3:07:49 AM UTC+12, William Mook wrote:
On Saturday, September 3, 2016 at 2:18:41 AM UTC+12, JF Mezei wrote:
If Range Safety is triggered, wouldn't explosives throughout the rocket
fire at the same time ?

We saw progression of fire from the top moving down. So while one pyro
may have exploded, it wouldn't appear to have been triggered by range
safety.

A full end to end system test resulting in ALL explosives going off would look different than the video. However, if only one charge were mis-wired somehow, and and that was the linear charge in the second stage lox tank, the video is consistent with exactly that happening. Since an FTS system test was being conducted at that moment, the video and the timing of the explosion are both suggestive and point to a failure in the FTS charge on the second stage as the cause.

If the FTS is confirmed as the cause, there are lots of issues that flow out of it;

(1) is FTS appropriate on a reusable rocket?
(2) what are the risk of FTS misfiring vs risks it supposedly abates in a 21st century rocket?
(3) was the accident in any way instigated by competitors who cannot compete?
(this does not shift responsibility away from SpaceX or their contractors - they should have
detected any exceptional condition that led to the FTS failure if indeed that was the case
i.e. any miswiring, or mis-signalling should have been detected before the test and corrected)

These questions deserve to be asked should FTS failure be confirmed through further study.

#3 above can be looked at this way; A bank gets robbed and a million dollars is stolen. The bank manager and guard gets fired. Why? Because despite the guilt of the robber, there are procedures put into place that reduce the losses or avoid the robbery altogether. So, the event is a failure of the system that should have been in place to reduce or eliminate the event. Same here. Thousands of people touch any launch vehicle prior to launch, so there are plenty of opportunities to cause a mishap if they are motivated to do so. Generally speaking this doesn't happen. Security is very very tight. However, someone who knows the process, some competitor in the industry, may place the right person at the right place and time, to cause a minor change in the FTS so that during this test it misfired. There's no evidence at this point this happened, but it could happen in theory. Even so, notwithstanding who the bad actor was, SpaceX and their contractors, should have had in place procedures that detected, avoided and mitigated this event. Just like a bank has a vault, a guard, alarms and limited number of dollars at each teller station.

On Saturday, September 3, 2016 at 2:54:34 AM UTC+12, William Mook wrote:
On Friday, September 2, 2016 at 7:42:37 PM UTC+12, David Spain wrote:
On 9/1/2016 11:53 PM, William Mook wrote:
https://www.youtube.com/watch?v=_BgJEXQkjNQ

At 1:11 the detonation of the Flight Termination System (FTS) is clearly seen in the upper stage engine housing and propellant tank.

That's one possibility yes. There is evidence of ejecta seen flying
largely vertically away from the booster as the "disassembly" starts
someone on ARocket thought might be related to FTS covers. The is a
downward jet I've seen moving downward alongside the exterior of the
booster in the earliest single frame grab I've seen from the video on
YouTube, but the frame rate is too slow for any kind of detailed analysis.

The explosion seems to begin with the second stage and proceeds from top
to bottom of the stack. Amazingly the stack retains enough structural
integrity that the payload + fairing topples over only AFTER the massive
main explosion. When it hits the ground there is another secondary
explosion, presumed propellants from either a PAM or the payload itself,
I've not studied the AMOS launch configuration.

Musk has indicated this was more of a progressive fire than explosion
and had this been a Dragon mission the LAS would have likely been
successful. In a tweet. His own words. See cite:

http://www.latimes.com/business/la-f...htmlstory.html


Have not heard anything official from SpaceX on the root cause however.
As for the theory of the FTS as a root cause I would not say this is
certain nor definitive.

Dave

If it proves to be the FTS then we must examine appropriateness of FTS on highly reusable rockets. We don't preplace explosives on aircraft in case they go off course, despite 9/11. I doubt anyone would fly in such aircraft as those that had FTS on board. Further, the death toll from accidents with the FTS would swamp the death toll from all other accidents and events combined.

I'm also struck by the survival of the payload. This proves that if an abort system of the type I've described elsewhere were on the rocket that used the landing technology to recover the payload intact - at a cost of about 8% the mass of the payload being recovered - that payload would have escaped certain destruction.

With a rocket costing $62 million and the satellite $195 million - liquid fuelled abort system that used its rockets to land at the launch center might be the sort of technological insurance that is part and parcel of a radically reduced launch cost.

This foretells what the highly reusable rocket of the future will look like.

1) no FTS on board, having been proven in flight,
2) an abort system on board to recover payload in a catastrophic event..

LAWS or ADAM at the launch centre and the recovery centre could be an acceptable alternative to pyrotechnics on board the rocket that prove to be a safer alternative.

https://www.youtube.com/watch?v=D0DbgNju2wE

https://www.youtube.com/watch?v=dL9_Tldmrhs

William Mook wrote:


If it proves to be the FTS ...


Stuck on stupid. So far there is no reason to believe this other than
some lint you pulled from your ass.


... then we must examine appropriateness of FTS on highly reusable rockets. We don't preplace explosives on aircraft in case they go off course, despite 9/11.


Aircraft are under positive control by pilots. Rockets are NEVER
under positive control by pilots, even when people are the cargo.


I doubt anyone would fly in such aircraft as those that had FTS on board. Further, the death toll from accidents with the FTS would swamp the death toll from all other accidents and events combined.


Ridiculous assertion. How many FTS failures can you document?


I'm also struck by the survival of the payload. This proves that if an abort system of the type I've described elsewhere were on the rocket that used the landing technology to recover the payload intact - at a cost of about 8% the mass of the payload being recovered - that payload would have escaped certain destruction.


In that case there wouldn't be a payload because you would have added
enough weight to preclude the rocket from lifting it.


With a rocket costing $62 million and the satellite $195 million - liquid fuelled abort system that used its rockets to land at the launch center might be the sort of technological insurance that is part and parcel of a radically reduced launch cost.


Well, it will certainly lead to radically reduced payload. This is
already being accepted to get 'reusable boosters' but you can only
throw away so much performance and the payback here isn't nearly large
enough to warrant it.


This foretells what the highly reusable rocket of the future will look like.

1) no FTS on board, having been proven in flight,
2) an abort system on board to recover payload in a catastrophic event.


Then you won't be launching anywhere near people.


--
"Some people get lost in thought because it's such unfamiliar
territory."
--G. Behn