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SpaceX Dragon 2 capsule destroyed in abort motor ground test



 
 
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  #1  
Old April 22nd 19, 12:05 PM posted to sci.space.policy
Jeff Findley[_6_]
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Posts: 2,307
Default SpaceX Dragon 2 capsule destroyed in abort motor ground test


Accident Claims SpaceX Dragon Abort Test Capsule
Apr 21, 2019 Irene Klotz - Aerospace Daily & Defense Report
https://aviationweek.com/space/accid...on-abort-test-
capsule

This is bad. My guess is at least a year delay for SpaceX commercial
crew. Here is hoping that Boeing gets its act together because we need
something to replace Soyuz for US crew.

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.
  #2  
Old April 22nd 19, 09:06 PM posted to sci.space.policy
Fred J. McCall[_3_]
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Posts: 10,018
Default SpaceX Dragon 2 capsule destroyed in abort motor ground test

Jeff Findley wrote on Mon, 22 Apr 2019
07:05:42 -0400:


Accident Claims SpaceX Dragon Abort Test Capsule
Apr 21, 2019 Irene Klotz - Aerospace Daily & Defense Report
https://aviationweek.com/space/accid...t-test-capsule

This is bad. My guess is at least a year delay for SpaceX commercial
crew. Here is hoping that Boeing gets its act together because we need
something to replace Soyuz for US crew.


I don't know if we know enough to be talking about how much delay this
would inject. The headline makes it sound like the capsule is a dead
loss but I don't think we even know that for sure.


--
"Insisting on perfect safety is for people who don't have the balls to
live in the real world."
-- Mary Shafer, NASA Dryden
  #3  
Old April 23rd 19, 05:55 PM posted to sci.space.policy
Rocket Man[_2_]
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Posts: 8
Default SpaceX Dragon 2 capsule destroyed in abort motor ground test


"Fred J. McCall" wrote in message
...
Jeff Findley wrote on Mon, 22 Apr 2019
07:05:42 -0400:


Accident Claims SpaceX Dragon Abort Test Capsule
Apr 21, 2019 Irene Klotz - Aerospace Daily & Defense Report
https://aviationweek.com/space/accid...t-test-capsule

This is bad. My guess is at least a year delay for SpaceX commercial
crew. Here is hoping that Boeing gets its act together because we need
something to replace Soyuz for US crew.


I don't know if we know enough to be talking about how much delay this
would inject. The headline makes it sound like the capsule is a dead
loss but I don't think we even know that for sure.


It looked to me that the capsule had dissappeared after the explosion. Not
good. Not good at all.

I agree with OP that this could take a year to fix, not to mention the loss
of goodwill. I can imagine the knifes are being drawn in Congress. I'm sure
this is exactly the thing Boeing / LockMart / ULA have been waiting for.

OTOH it would've been infinitely worse if it had happened during a manned
test flight.


  #4  
Old April 29th 19, 02:01 PM posted to sci.space.policy
David Spain
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Posts: 2,901
Default SpaceX Dragon 2 capsule destroyed in abort motor ground test

On 4/22/2019 7:05 AM, Jeff Findley wrote:

This is bad. My guess is at least a year delay for SpaceX commercial
crew. Here is hoping that Boeing gets its act together because we need
something to replace Soyuz for US crew.

Jeff


FWIW the conventional wisdom seems to be focusing on the COPV tanks used
to fuel the SuperDracos. But this is pure speculation (SWAGs if you
will). I have seen ONE still frame taken from a normal speed camera that
appears to show an explosion taking place "around" the capsule where the
hatch window still appears in the frame. In another video you can see at
least two explosions, the first as mentioned where the capsule is
largely still intact and a 2nd to the left (from the viewer viewpoint)
of the first which appears to blow the capsule off the test stand. Which
would tend to indicate multiple possibly cascading explosions.

AFAIK know from what has been published in other forums the capsule is
believed to be a total loss.

Yes this is bad, but the test engineer in me is very happy that this
happened during *testing*. Although a RUD is never a welcome event it is
a learning opportunity with the net result of an improved design. This
is what happened after the Apollo 1 fire. The following block
improvements to the Command Module made the follow-ons very different
from the original article including the wiring and hatch design from
what I have read. It was poor judgement and bad test design that I feel
were the real reason behind the fatalities that should not have happened.

You could say we were "lucky" that this happened while no crew were
on-board, but I *hate* that term. What is proper to say is that an
anomaly was caught in testing, just as it should be. What keeps me up at
night are the anomaly's that I didn't test for. That is why you do
design review after design review and test and test again, and then
alter and add to the testing regimen and test again to prove out design
margins.

Luck as defined simply means you missed a test and found a failure mode
at an opportune time.

David

  #5  
Old April 30th 19, 03:28 AM posted to sci.space.policy
Fred J. McCall[_3_]
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Posts: 10,018
Default SpaceX Dragon 2 capsule destroyed in abort motor ground test

David Spain wrote on Mon, 29 Apr 2019 09:01:20
-0400:


FWIW the conventional wisdom seems to be focusing on the COPV tanks used
to fuel the SuperDracos.


Possible, but this seems odd to me. Neither of the fuels is even
mildly cryogenic, so what failure mode would there be? This isn't
like the Falcon 9 explosion where cryogenic chilling was involved. If
it was something like that I would expect it would have to be a 'one
off' manufacturing defect of some kind, which would lead to a pretty
rapid return to flight.


--
"Insisting on perfect safety is for people who don't have the balls to
live in the real world."
-- Mary Shafer, NASA Dryden
  #6  
Old April 30th 19, 03:49 AM posted to sci.space.policy
David Spain
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Posts: 2,901
Default SpaceX Dragon 2 capsule destroyed in abort motor ground test

On 4/29/2019 10:28 PM, Fred J. McCall wrote:
David Spain wrote on Mon, 29 Apr 2019 09:01:20
-0400:


FWIW the conventional wisdom seems to be focusing on the COPV tanks used
to fuel the SuperDracos.


Possible, but this seems odd to me. Neither of the fuels is even
mildly cryogenic, so what failure mode would there be? This isn't
like the Falcon 9 explosion where cryogenic chilling was involved. If
it was something like that I would expect it would have to be a 'one
off' manufacturing defect of some kind, which would lead to a pretty
rapid return to flight.



Let's hope so. Could be a weld issue? Could be a lot of things I
suppose. If these things are made in batches it might be informative to
pull COPV's from the same build run and check them, maybe run some
stress tests on them. It's all SWAG at this point and I'm sure as hell
no expert. Could be something else entirely. Conventional wisdom is
often wrong.

Dave

  #8  
Old April 30th 19, 07:08 PM posted to sci.space.policy
Jeff Findley[_6_]
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Posts: 2,307
Default SpaceX Dragon 2 capsule destroyed in abort motor ground test

In article , says...

On 4/22/2019 7:05 AM, Jeff Findley wrote:

This is bad. My guess is at least a year delay for SpaceX commercial
crew. Here is hoping that Boeing gets its act together because we need
something to replace Soyuz for US crew.

Jeff


FWIW the conventional wisdom seems to be focusing on the COPV tanks used
to fuel the SuperDracos. But this is pure speculation (SWAGs if you
will). I have seen ONE still frame taken from a normal speed camera that
appears to show an explosion taking place "around" the capsule where the
hatch window still appears in the frame. In another video you can see at
least two explosions, the first as mentioned where the capsule is
largely still intact and a 2nd to the left (from the viewer viewpoint)
of the first which appears to blow the capsule off the test stand. Which
would tend to indicate multiple possibly cascading explosions.

AFAIK know from what has been published in other forums the capsule is
believed to be a total loss.

Yes this is bad, but the test engineer in me is very happy that this
happened during *testing*. Although a RUD is never a welcome event it is
a learning opportunity with the net result of an improved design. This
is what happened after the Apollo 1 fire. The following block
improvements to the Command Module made the follow-ons very different
from the original article including the wiring and hatch design from
what I have read. It was poor judgement and bad test design that I feel
were the real reason behind the fatalities that should not have happened.

You could say we were "lucky" that this happened while no crew were
on-board, but I *hate* that term. What is proper to say is that an
anomaly was caught in testing, just as it should be. What keeps me up at
night are the anomaly's that I didn't test for. That is why you do
design review after design review and test and test again, and then
alter and add to the testing regimen and test again to prove out design
margins.

Luck as defined simply means you missed a test and found a failure mode
at an opportune time.


I agree with all of this.

Also, from what I understand, there is a list of safety related issues
that NASA wanted SpaceX to take care of before flying crew on DM-2. The
other "silver lining" is that this gives SpaceX more time to take care
of those issues as well.

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.
  #9  
Old May 1st 19, 01:54 AM posted to sci.space.policy
Fred J. McCall[_3_]
external usenet poster
 
Posts: 10,018
Default SpaceX Dragon 2 capsule destroyed in abort motor ground test

Jeff Findley wrote on Tue, 30 Apr 2019
14:08:51 -0400:


Also, from what I understand, there is a list of safety related issues
that NASA wanted SpaceX to take care of before flying crew on DM-2. The
other "silver lining" is that this gives SpaceX more time to take care
of those issues as well.


Would you happen to know what those are or be able to point me to a
description of them?


--
"Insisting on perfect safety is for people who don't have the balls to
live in the real world."
-- Mary Shafer, NASA Dryden
  #10  
Old May 1st 19, 12:02 PM posted to sci.space.policy
Jeff Findley[_6_]
external usenet poster
 
Posts: 2,307
Default SpaceX Dragon 2 capsule destroyed in abort motor ground test

In article ,
says...

Jeff Findley wrote on Tue, 30 Apr 2019
14:08:51 -0400:


Also, from what I understand, there is a list of safety related issues
that NASA wanted SpaceX to take care of before flying crew on DM-2. The
other "silver lining" is that this gives SpaceX more time to take care
of those issues as well.


Would you happen to know what those are or be able to point me to a
description of them?


Neither SpaceX nor NASA has released this list. So I have no idea what
is on it. This is part of the double edged sword of a "commercial"
program like this. NASA is paying for results and milestones and has
insight into the designs. But the designs remain the property of the
company, not NASA. So information like this is tightly controlled.

I'm guessing that Starliner has a list of open issues as well, but again
neither Boeing nor NASA is talking about the issues (well, beyond their
anomaly with their hypergolic propellants after a ground test). We have
no idea how severe the damage was after that test because no one leaked
any pictures or video.

Also, NASA has reiterated their policy for images and video. Leaks like
that SpaceX Dragon 2 video, by a NASA employee, can have dire
consequences up to and including termination. The email sent out to KSC
employees has been widely reported on space news websites over the last
day or so.

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.
 




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