Strut snap stops SpaceX strutting

http://www.engadget.com/2015/07/20/s...=rss_truncated

During a call today about the Flacon 9 rocket mishap in June, Musk
announced that a strut holding a high pressure helium bottle
failed during the second stage of the launch.

...

Going forward, SpaceX will stress test individual struts. The
strut that failed was about two feet long and one inch thick at
its thickest point. The struts are supposed to handle 10,000
pounds of force, the strut that failed broke after only 2,000
pounds of force.

Has there been a failure that simple/basic/fundamental (better term?)
since the aluminum nut of Falcon 1? Reading between the lines, it
would seem that not all struts were being tested. An added test here,
an added test there I suppose.

rick jones
--
the road to hell is paved with business decisions...
these opinions are mine, all mine; HP might not want them anyway...
feel free to post, OR email to rick.jones2 in hp.com but NOT BOTH...

In article ,
says...

http://www.engadget.com/2015/07/20/s...=rss_truncated

During a call today about the Flacon 9 rocket mishap in June, Musk
announced that a strut holding a high pressure helium bottle
failed during the second stage of the launch.

...

Going forward, SpaceX will stress test individual struts. The
strut that failed was about two feet long and one inch thick at
its thickest point. The struts are supposed to handle 10,000
pounds of force, the strut that failed broke after only 2,000
pounds of force.

Has there been a failure that simple/basic/fundamental (better term?)
since the aluminum nut of Falcon 1? Reading between the lines, it
would seem that not all struts were being tested. An added test here,
an added test there I suppose.

From a design point of view, there was a sufficient factor of safety.
Unfortunately, the part didn't meet the specification. SpaceX was
relying on the supplier to do any testing. From this point on, SpaceX
will do its own testing. This is clearly prudent since we've now proven
that the failure of a strut can cause loss of vehicle. But, that is
hindsight.

How much testing is enough? How much is too much? How much paperwork
do you need before you decide it is "safe" to fly? How large of a cost
increase will customers tolerate in the name of safety?

Jeff
--
"the perennial claim that hypersonic airbreathing propulsion would
magically make space launch cheaper is nonsense -- LOX is much cheaper
than advanced airbreathing engines, and so are the tanks to put it in
and the extra thrust to carry it." - Henry Spencer

--
"the perennial claim that hypersonic airbreathing propulsion would
magically make space launch cheaper is nonsense -- LOX is much cheaper
than advanced airbreathing engines, and so are the tanks to put it in
and the extra thrust to carry it." - Henry Spencer

nasas approach, nothing will fly till the weight of the paperwork equals the weight of the vehicle

In article ,
Jeff Findley wrote:

From a design point of view, there was a sufficient factor of safety.
Unfortunately, the part didn't meet the specification. SpaceX was
relying on the supplier to do any testing. From this point on, SpaceX
will do its own testing. This is clearly prudent since we've now proven
that the failure of a strut can cause loss of vehicle. But, that is
hindsight.

Do they force the supplier to lower the price a bit, as clearly they
weren't doing everything that price covered?

--
Chris Mack "If we show any weakness, the monsters will get cocky!"
'Invid Fan' - 'Yokai Monsters Along With Ghosts'

In article ,
says...

In article ,
Jeff Findley wrote:

From a design point of view, there was a sufficient factor of safety.
Unfortunately, the part didn't meet the specification. SpaceX was
relying on the supplier to do any testing. From this point on, SpaceX
will do its own testing. This is clearly prudent since we've now proven
that the failure of a strut can cause loss of vehicle. But, that is
hindsight.

Do they force the supplier to lower the price a bit, as clearly they
weren't doing everything that price covered?

News reports say they will "most likely" switch suppliers and make the
struts out of another material. Inconel is reportedly the material of
choice he

https://en.wikipedia.org/wiki/Inconel

From above:

Inconel 718 is commonly used for cryogenic storage tanks...

Inconel is more expensive, but reportedly less likely to suffer from
embrittlement caused by submersion in cryogenic LOX than the previously
used steel material.

Note, I'm not a material scientist, so I'm just reporting what I've read
recently.

Jeff
--
"the perennial claim that hypersonic airbreathing propulsion would
magically make space launch cheaper is nonsense -- LOX is much cheaper
than advanced airbreathing engines, and so are the tanks to put it in
and the extra thrust to carry it." - Henry Spencer