Accident at Cape

On 9/1/2016 11:06 AM, JF Mezei wrote:
As you have probably heard, a Falcon 9 had an "anomaly" with large sound
and lots of smoke. SpaceX confirmed loss of rocket and payload that was
about to do a firing test.

SpaceX seems perplexed, so apparently there will be no quick answers to
this accident. If the cause involved something as simple as the false
operation of a destructive charge, surely we would know by now. The
Falcon 9 fuel and oxidizer (and the handling thereof) are certainly
nothing new to the space industry. Yes, oxygen can be dangerous stuff,
but folks have been loading LOX into rockets for decades now, and I can
recall no similar launch pad accidents.

Can anyone else cite a similar incident?

This may seem farfetched but... Can we confidently exclude some sort of
foul play?

JF Mezei wrote:


Also, consider some defect INSIDE the rocket away from avionics panel.
But when explosion occured, avionics panel was first to blow, hence from
camera's point of view, explosion appears to originate there. (imagine
an electrical fire brewing some distance from panel and eventually get
hot enough to cause the thing to go "boom".


The problem with your thesis is that the explosion was right around
the fueling station, not up by the avionics tray.


At the end of the day, without any indication of what telemetry showed,
the images are worthless. We just know it happened somewhere near top of
second stage.


I suspect that telemetry all looks normal. If it didn't, they'd be
narrowing in on the cause. So what you really need is a fault tree
that shows all the stuff that might cause something like this that
would NOT affect telemetry.


Does the payload use hydrazine ? If it had leaked slowly, would it not
eventually drop to the top of stage 2? Would hydrazine self ignite once
in contact with pure O2 ?


If it was something like that from the payload I would have expected
the payload to explode once the LOX tank in the second stage ruptured.
That doesn't appear to have happened (the payload explosion doesn't
happen until the payload bay hits the ground).


--
"Insisting on perfect safety is for people who don't have the balls to
live in the real world."
-- Mary Shafer, NASA Dryden

In article , says...

On 9/1/2016 11:06 AM, JF Mezei wrote:
As you have probably heard, a Falcon 9 had an "anomaly" with large sound
and lots of smoke. SpaceX confirmed loss of rocket and payload that was
about to do a firing test.

SpaceX seems perplexed, so apparently there will be no quick answers to
this accident. If the cause involved something as simple as the false
operation of a destructive charge, surely we would know by now. The
Falcon 9 fuel and oxidizer (and the handling thereof) are certainly
nothing new to the space industry. Yes, oxygen can be dangerous stuff,
but folks have been loading LOX into rockets for decades now, and I can
recall no similar launch pad accidents.

SpaceX is using sub-cooled LOX. Sub-cooled LOX is a new thing and in
some ways is pushing the edge of the envelope.

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.

JF Mezei wrote:

On 2016-09-10 18:08, Fred J. McCall wrote:

If it was something like that from the payload I would have expected
the payload to explode once the LOX tank in the second stage ruptured.
That doesn't appear to have happened (the payload explosion doesn't
happen until the payload bay hits the ground).

Fair enough.

So if explosion was first seen near LOX storage and filling transfer
pipe, what fuel would have burned ?


Well, that is sort of the $64 question.


Say O2 leaked inside the rocket once tank got full (pipe fitting gets
cold enough that fitting gets loose, starts to spray liquid O2 on
something. If that something contains plastic, or wiring insulation,
rubber, woudln't it self ignite ? That fire could then cause some
electrical malfunction and go kaboom.


It takes relatively high temperatures to get 'auto-ignition'.


But that would likely send some telemetry alarm before going kaboom, right ?


If wiring was involved I would expect some sort of telemetry noise, at
the very least. Large leaks should show some pressure fluctuations
and spontaneous ignition requires fairly large volumes of atomized
propellants.


I guess SpaceX needs to precisely corelate the timing of any video with
timing of any telemetry they got. Did event happen 2ms before visible
explosion, or 1ms after ? (aka: precurson to visible explosion, or a
side effect of explosion).


If there are no telemetry anomalies, this won't help.

I still think they're going to have to lock a bunch of smart guys in a
room and come up with a fault tree of all the possible things that
would explain what happened that wouldn't show telemetry signs. Then
they're going to have to go through video to try to thin that tree.

This is going to take a while, but they've got a few months before
they can return to flight anyway...


--
"Insisting on perfect safety is for people who don't have the balls to
live in the real world."
-- Mary Shafer, NASA Dryden

In article . com,
says...

On 2016-09-10 18:08, Fred J. McCall wrote:

If it was something like that from the payload I would have expected
the payload to explode once the LOX tank in the second stage ruptured.
That doesn't appear to have happened (the payload explosion doesn't
happen until the payload bay hits the ground).

Fair enough.

So if explosion was first seen near LOX storage and filling transfer
pipe, what fuel would have burned ?

One theory is that LOX was leaking from the strong-back. On some
forums, the design of the S bend in the LOX feed line is considered
suspect because it was "unconstrained" or something like that. Take
that with a grain of salt, since this is the Internet.

Pretty much any sort of organic compound soaked in LOX will burn. I'd
expect SpaceX (and the other parties investigating) to go over
everything near the point of ignition to determine what materials were
involved so as to identify anything combustible when soaked in LOX.


Say O2 leaked inside the rocket once tank got full (pipe fitting gets
cold enough that fitting gets loose, starts to spray liquid O2 on
something. If that something contains plastic, or wiring insulation,
rubber, woudln't it self ignite ? That fire could then cause some
electrical malfunction and go kaboom.

MrMackey from South Park says: LOX leaks are *bad*, mmmmkayyyy...

But that would likely send some telemetry alarm before going kaboom, right ?

Like what? If natural gas leaks in a house, no alarm sounds unless the
home contains a CO/natural gas alarm. No sensor, no alarm.

I guess SpaceX needs to precisely corelate the timing of any video with
timing of any telemetry they got. Did event happen 2ms before visible
explosion, or 1ms after ? (aka: precurson to visible explosion, or a
side effect of explosion).

Clearly. Any accident investigation will build a detailed timeline of
events. Any identified event will be placed on the timeline.

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.

JF Mezei wrote:


Are there any drawings that show the structures and systems located at
the top of Stage2, as well as those that would be found on a payload
that is mated to the top of stage2 ?


I'm sure there must be some. Whether you can find them or not is a
different matter. For payload see the Falcon 9 User's Guide.


From a stress point of view, would this test exercise be the first time
the stage2 is fully fueled in vertical position?


Probably, since there's no reason to do so otherwise.


Could it be as simple as a defect in the LOX rank which ruptured due to
extreme cold and/or pressure? (I take it there are scenarios which
would kill sensors or telemetry transmitters before they can report loss
of pressure in LOX tank?


You've got a chicken and egg problem here. Killing a sensor would
presumably show up on telemetry,


--
"Insisting on perfect safety is for people who don't have the balls to
live in the real world."
-- Mary Shafer, NASA Dryden

JF Mezei wrote:

On 2016-09-11 19:51, Fred J. McCall wrote:

You've got a chicken and egg problem here. Killing a sensor would
presumably show up on telemetry,


This is why schematics become important. What was located near the site
of explosion?


You mean drawings, right? 'Schematics' are just electrical. It's a
privately developed vehicle. They have them and you do not.


If LOX tank ruptured next to avionics board that gathers all sensor data
for transmission (or even antenna), it could have litterally frozen
telemetry before it could send anything.


In which case someone would have noticed.


Since we don't know whether SpaceX recorded any telemetry, then we
really don't know what could have happened.


But we do know, if you were paying attention. “We are currently in
the early process of reviewing approximately 3,000 channels of
telemetry and video data covering a time period of just 35-55
milliseconds,” SpaceX spokesman Phil Larson said in a statement.

You are also confused. WE don't need to know what happened. They do.


(for instance, if no anolany is send out prior to explosion, biut at
time of explosion, there is telemetry emitted to show proble (LOX tank
pressure, probably loss of contact with payload module etc) this would
show that lack of problem report prior to explosion was not due to
telemetry tramsmission failure.

But total lack of telemetry could mean that there was nothing to report
prior to explosion and at explosion, telemetry was knocked out first.


Uh, you seem to be under the impression that TM only reports
anomalies. It doesn't. It constantly reports thousands of items on
the state of the vehicle. If it suddenly stopped prior to the
explosion, I'm pretty sure someone would have noticed.


Question: obviously, SpaceX will analyse its logs, photos, videos. But
for such an accident at the Cape, is there also a formal government
investigation ? I believe it is the FAA that does them ? or would it be
air force because it was on air force property or NASA because Nasa is
in charge for space flight ?


No. SpaceX owns the investigation. The vehicle wasn't in flight so
the Feds have no jurisdiction.


--
"Insisting on perfect safety is for people who don't have the balls to
live in the real world."
-- Mary Shafer, NASA Dryden

In article ,
says...
Question: obviously, SpaceX will analyse its logs, photos, videos. But
for such an accident at the Cape, is there also a formal government
investigation ? I believe it is the FAA that does them ? or would it be
air force because it was on air force property or NASA because Nasa is
in charge for space flight ?


No. SpaceX owns the investigation. The vehicle wasn't in flight so
the Feds have no jurisdiction.


While that may be technically true, considering USAF and NASA are both
customers of SpaceX, it does not hurt to keep them both "in the loop" so
to speak.

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.

"Jeff Findley" wrote in message
...

In article ,
says...
Question: obviously, SpaceX will analyse its logs, photos, videos. But
for such an accident at the Cape, is there also a formal government
investigation ? I believe it is the FAA that does them ? or would it be
air force because it was on air force property or NASA because Nasa is
in charge for space flight ?


No. SpaceX owns the investigation. The vehicle wasn't in flight so
the Feds have no jurisdiction.


While that may be technically true, considering USAF and NASA are both
customers of SpaceX, it does not hurt to keep them both "in the loop" so
to speak.

Jeff

Also, since I believe technically USAF still OWNS the pad, I'd be surprised
if they don't have some sort of jurisdiction.


--
Greg D. Moore http://greenmountainsoftware.wordpress.com/
CEO QuiCR: Quick, Crowdsourced Responses. http://www.quicr.net

Jeff Findley wrote:

In article ,
says...
Question: obviously, SpaceX will analyse its logs, photos, videos. But
for such an accident at the Cape, is there also a formal government
investigation ? I believe it is the FAA that does them ? or would it be
air force because it was on air force property or NASA because Nasa is
in charge for space flight ?


No. SpaceX owns the investigation. The vehicle wasn't in flight so
the Feds have no jurisdiction.


While that may be technically true, considering USAF and NASA are both
customers of SpaceX, it does not hurt to keep them both "in the loop" so
to speak.


I answered the question that he asked. Under FAA rules the launch
provider owns the investigation if there is no loss of life, injury,
or outside property damage. This is the way it's done and it's why
NASA managed Space Shuttle investigations (which had other people
brought in due to loss of life). ATK managed the investigation when
their rocket exploded.

As to the board (of approximately 20 people) involved in the
investigation, there is ONE NASA seat, ONE USAF seat, and virtually
all the voting seats are SpaceX people. So they're 'in the loop' but
have no say.


--
"Adrenaline is like exercise, but without the excessive gym fees."
-- Professor Walsh, "Buffy the Vampire Slayer"