The Falcon 9 explosion: Why SpaceX says it's found the flaw

[WhiteTara]

http://www.csmonitor.com/Technology/2016/1029/The-Falcon-9-explosion-Why-SpaceX-says-it-s-found-the-flaw

Technology
First Look
The Falcon 9 explosion: Why SpaceX says it's found the flaw
csmonitor icon
Latest News
Save for later
Subscribe

Although a joint investigation continues, SpaceX has been able to duplicate the Falcon 9 flaw. And SpaceX plans to return to flight by the end of the year.
By Rowena Lindsay, Staff October 29, 2016

Following a joint investigation with the Federal Aviation Association (FAA), NASA, and the US Air Force, the private space company SpaceX has finally zeroed in on the likely system flaw that caused one of its Falcon 9 rockets to explode on the launch pad in Cape Canaveral, Fla., two months ago.

The explosion occurred while the fuel tanks were being prepped, leading SpaceX CEO Elon Musk and President Gwynne Shotwell to believe that the problem was with fueling process rather than a vehicle design or engineering flaw. On Friday, the company announced it had been able to replicate the failure of a helium tank, which is believed to be the cause of the explosion.

Although the investigation is still ongoing, it has not disrupted plans for SpaceX to return to flight by the end of the year.
Recommended: How well do you know Elon Musk? Take our quiz!

“SpaceX’s efforts are now focused on two areas – finding the exact root cause, and developing improved helium loading conditions that allow SpaceX to reliably load Falcon 9,” SpaceX said in a statement Friday. “With the advanced state of the investigation, we also plan to resume stage testing in Texas in the coming days, while continuing to focus on completion of the investigation.”

[backscatter712]

1. Looks like they were loading the LOX and helium too fast.

Both the liquid oxygen and the helium were super-chilled, well below the liquid oxygen's boiling temperature, closer to its freezing temperature, and the helium was chilled to similar temperatures (though still gaseous). Purpose being colder fuel and oxygen is denser, so you can put more on the rocket, and launch heavier payloads into higher orbits.

They loaded the LOX and helium too fast, and the temperature changes caused the carbon fiber overwrap around the compressed helium tank to delaminate from the aluminum tank liner. Result: tank ruptures, and instant RUD (Rapid Unscheduled Disassembly)...