SpaceX releases investigation update on CRS-7 launch failure: "Needs *less* struts!"

[Tataffe]

On June 28, a Falcon 9 powered ISS supply mission failed in the slowest rocket launch disassembly I have ever seen. Yesterday, SpaceX released an investigation update.

 

On June 28, 2015, following a nominal liftoff, Falcon 9 experienced an overpressure event in the upper stage liquid oxygen tank approximately 139 seconds into flight, resulting in loss of mission. This summary represents an initial assessment, but further investigation may reveal more over time.

Prior to the mishap, the first stage of the vehicle, including all nine Merlin 1D engines, operated nominally; the first stage actually continued to power through the overpressure event on the second stage for several seconds following the mishap.  In addition, the Dragon spacecraft not only survived the second stage event, but also continued to communicate until the vehicle dropped below the horizon and out of range.

 

The last sentence is an important part. With manned Dragon capsules in the pipeline, this event shows that the passengers aboard a Dragon capsule can possibly survive such an event. On the other hand, the astronauts aboard the failed Challenger space shuttle launch were probably alive as well when the orbiter's cockpit section hit the ocean after the explosion ...

 

Preliminary analysis suggests the overpressure event in the upper stage liquid oxygen tank was initiated by a flawed piece of support hardware (a “strut”) inside the second stage.  Several hundred struts fly on every Falcon 9 vehicle, with a cumulative flight history of several thousand.

 

As a former KSP player, I find this hilarious. However, they continue to note that the flawed piece failed at a load of 2000 lbs (8.9 kN) while being designed to hold up to 10 000 lbs (44 kN). Which is also important because it shows that the failure was caused by a quality (control) problem rather than a design problem. With the following consequence:

 

Despite the fact that these struts have been used on all previous Falcon 9 flights and are certified to withstand well beyond the expected loads during flight, SpaceX will no longer use these particular struts for flight applications.  In addition, SpaceX will implement additional hardware quality audits throughout the vehicle to further ensure all parts received perform as expected per their certification documentation.

 

Source: http://www.spacex.com/news/2015/07/20/crs-7-investigation-update

[BoredErica]

Every launch must be nerve-racking for Musk.

[Sakkura]

They're going to use this for manned operations later, so at least it's nice that this failure happened before it was a manned flight. So they can address the problem before lives are at stake.

[Trik'Stari]

Looks like someone forgot to X-ray these struts and look for micro-fractures or metal fatigue.

[Alurit]

there's no such thing as too many struts, only misplaced struts

[Curufinwe_wins]

Looks like someone forgot to X-ray these struts and look for micro-fractures or metal fatigue.

Xrays don't actually do a good job with metallic objects however neutron bombardment works insanely well. Lockheed Martin and Boeing both use it basically constantly for QC.

[Trik'Stari]

Xrays don't actually do a good job with metallic objects however neutron bombardment works insanely well. Lockheed Martin and Boeing both use it basically constantly for QC.

 

They use X-rays to inspect for micro-fractures. There are also a number of other ways to inspect metal for fatigue and micro-fractures. Although X-ray is the most expensive. (that I am aware of. Haven't heard of neutron bombardment)

[Curufinwe_wins]

https://www.youtube.com/watch?v=Tb5VmXsamfQ

They use X-rays to inspect for micro-fractures. There are also a number of other ways to inspect metal for fatigue and micro-fractures. Although X-ray is the most expensive. (that I am aware of. Haven't heard of neutron bombardment)

http://neutrons.ornl.gov/imaging/videos

The issue with xrays is all they really can detect in metals is omission defects. They can't detect issues with composition or say a section within the surface with too high of carbon content.

With neutron imaging, you actually see varying compositions in addition to fractures which is insanely important in high strength alloys.

[Trik'Stari]

http://neutrons.ornl.gov/imaging/videos

The issue with xrays is all they really can detect in metals is omission defects. They can't detect issues with composition or say a section within the surface with too high of carbon content.

With neutron imaging, you actually see varying compositions in addition to fractures which is insanely important in high strength alloys.

Dayum.

[Curufinwe_wins]

Dayum.

It's beautiful. Which is why so many aerospace partners ate it up instantly even though the technology is very new.

[Ohlyver]

https://www.youtube.com/watch?v=Tb5VmXsamfQ

They use X-rays to inspect for micro-fractures. There are also a number of other ways to inspect metal for fatigue and micro-fractures. Although X-ray is the most expensive. (that I am aware of. Haven't heard of neutron bombardment)

Neutron = gamma rays = hard to stop = expensive facilities

[Curufinwe_wins]

Neutron = gamma rays = hard to stop = expensive facilities

Ignorance=assumptions=wrong.

[Sakkura]

Neutron = gamma rays = hard to stop = expensive facilities

 

Gamma rays consist of photons, not neutrons.

[Ohlyver]

Ignorance=assumptions=wrong.

Go look it up, neutron rays are in fact what we call gamma rays!

[Curufinwe_wins]

Go look it up, neutron rays are in fact what we call gamma rays!

You are an idiot. Gamma emissions are actually speficially photonic emissions from nuclear sources. X-Rays are photonic emissions from electrical sources. Hell xrays can be massively more energetic than gamma emissions because the strongest gammas producable are on the 10s of MeV scale.

Neutrons are baryons... Gammas are bosons. They literally could not be more different.

[Ohlyver]

You are an idiot. Gamma emissions are actually speficially photonic emissions from nuclear sources. X-Rays are photonic emissions from electrical sources. Hell xrays can be massively more energetic than gamma emissions because the strongest gammas producable are on the 10s of MeV scale.

Neutrons are baryons... Gammas are bosons. They literally could not be more different.

You are really kind with people

[AHaskin14]

I'm glad to know that the they have successfully launched identical vessels numerous times and that the only possible reason for failure was a quality control. Ive had to deal with quality control a lot and it can be a pain in the ass. hopefully they get things squared away and get launching again.

[patrickjp93]

 

 

They use X-rays to inspect for micro-fractures. There are also a number of other ways to inspect metal for fatigue and micro-fractures. Although X-ray is the most expensive. (that I am aware of. Haven't heard of neutron bombardment)

You do know that works primarily because arc-welds are made with sand (to prevent hyper-oxidation, look it up), so you get a glass-metal crystal, and not just pure metal, right?

[patrickjp93]

You are an idiot. Gamma emissions are actually speficially photonic emissions from nuclear sources. X-Rays are photonic emissions from electrical sources. Hell xrays can be massively more energetic than gamma emissions because the strongest gammas producable are on the 10s of MeV scale.

Neutrons are baryons... Gammas are bosons. They literally could not be more different.

 

 

You are really kind with people

Cur is right, and you clearly need to review your definitions. At least he and I are both educated in quantum physics. https://en.wikipedia.org/wiki/Baryon https://en.wikipedia.org/wiki/Gamma_ray

 

Please go skulk into the shadows and emerge only when you've learned to not open your mouth unless it is a question or you actually know what you're talking about.

[Curufinwe_wins]

You are really kind with people

I apologize for the aggressiveness, but indeed they could not be more fundamentally different.

[Trik'Stari]

You do know that works primarily because arc-welds are made with sand (to prevent hyper-oxidation, look it up), so you get a glass-metal crystal, and not just pure metal, right?

Most arc welding is done with an inert gas. Only robotic welding is done with sand, even then that's only specific situations. Most arc welding either uses a flux wire which creates a surface flux that has to be removed, or inert gas that comes out of the nozzle around the welding electrode.. I would know, I used to be a welder. Which is how I knew about the X-ray thing.

 

Not counting stick welding which uses flux. But both MIG and TIG use a shield gas.

[Ohlyver]

I apologize for the aggressiveness, but indeed they could not be more fundamentally different.

Thank you , I should've simply said nothing in the first place, its more than obvious that my memory failed me and also that my physics classes where probably more of an introduction than a deep down education.

IMO spaceX will bounce back and stronger, while their concurrent will use this fail as a shit-talk weapon..

[dalekphalm]

While it's really terrible that we lost that rocket, SpaceX's record is still pretty fucking good. Also, if people were aboard the Dragon Capsule, they would very likely have survived.

 

@Tataffe the Challenger cockpit was never designed for emergency escape procedures, unless they were just at the right altitude at a low enough velocity to literally jump out the hatch for Parachute/HALO drop escape. The dragon capsule has parachutes, and is designed to fall to the ground/ocean, with people inside it, as per normal operation.

 

In this case, had there been people aboard, they likely would have simply initiated emergency landing procedures, engaged the parachutes, and ride that fucker down

 

 

Go look it up, neutron rays are in fact what we call gamma rays!

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

 

Gamma radiation, also known as gamma rays, and denoted by the Greek letter γ, refers to electromagnetic radiation of an extremely high frequency and therefore consists of high-energy photons.

Just gonna put this here...

[dalekphalm]

Thank you , I should've simply said nothing in the first place, its more than obvious that my memory failed me and also that my physics classes where probably more of an introduction than a deep down education.

IMO spaceX will bounce back and stronger, while their concurrent will use this fail as a shit-talk weapon..

SpaceX will be fine. They'll learn from this mistake and make their equipment even better. Their safety reputation is still miles better than most of the other space/rocket companies.

 

No worries about your lapse in memory. It happens. But in the future, don't act like you're 100% right without proof

[patrickjp93]

Most arc welding is done with an inert gas. Only robotic welding is done with sand, even then that's only specific situations. Most arc welding either uses a flux wire which creates a surface flux that has to be removed, or inert gas that comes out of the nozzle around the welding electrode.. I would know, I used to be a welder. Which is how I knew about the X-ray thing.

 

Not counting stick welding which uses flux. But both MIG and TIG use a shield gas.

Most welds done for steel cross-beams, like on a bridge, have the material buried under sand or another substrate in addition to the shield gas. I will admit the last time I saw anything about it was two years ago on the discovery channel, but I'm disinclined to believe it's a lie given they shoved live bridge welding.

 

And X-Rays cannot be reliably used for most metals welded for such industrial use. The navy uses neutron beams to test their propellers for instance. X-Rays aren't practical except for some grades of structural steel not meant to be used in a dynamic (motion) setting.