SpaceX | CRS-7 Investigation Update

Via email

 
  

CRS-7 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.

 
SpaceX has led the investigation efforts with oversight from the FAA and participation from NASA and the U.S. Air Force. Review of the flight data proved challenging both because of the volume of data —over 3,000 telemetry channels as well as video and physical debris—and because the key events happened very quickly. 

 
From the first indication of an issue to loss of all telemetry was just 0.893 seconds. Over the last few weeks, engineering teams have spent thousands of hours going through the painstaking process of matching up data across rocket systems down to the millisecond to understand that final 0.893 seconds prior to loss of telemetry.

 
At this time, the investigation remains ongoing, as SpaceX and the investigation team continue analyzing significant amounts of data and conducting additional testing that must be completed in order to fully validate these conclusions. However, given the currently available data, we believe we have identified a potential cause.

 
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. The strut that we believe failed was designed and material certified to handle 10,000 lbs of force, but failed at 2,000 lbs, a five-fold difference. Detailed close-out photos of stage construction show no visible flaws or damage of any kind.

 
In the case of the CRS-7 mission, it appears that one of these supporting pieces inside the second stage failed approximately 138 seconds into flight. The pressurization system itself was performing nominally, but with the failure of this strut, the helium system integrity was breached. This caused a high pressure event inside the second stage within less than one second and the stage was no longer able to maintain its structural integrity. 

 
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.
As noted above, these conclusions are preliminary. Our investigation is ongoing until we exonerate all other aspects of the vehicle, but at this time, we expect to return to flight this fall and fly all the customers we intended to fly in 2015 by end of year.  

 
While the CRS-7 loss is regrettable, this review process invariably will, in the end, yield a safer and more reliable launch vehicle for all of our customers, including NASA, the United States Air Force, and commercial purchasers of launch services. Critically, the vehicle will be even safer as we begin to carry U.S. astronauts to the International Space Station in 2017.

 
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How We’ll Live on Mars

In the same way we can draw a line from Wernher von Braun straight to Apollo 11, when a spaceship carrying astronauts lands on Mars in 2027, we may well be able to draw a line straight to Elon Musk—because that Mars lander will most likely have the SpaceX logo on it.

Musk is arguably the most visionary entrepreneur of our time. Seven years after he quit a PhD program in applied physics at Stanford University, he sold his share of PayPal and Zip2, companies he cofounded, giving him a reported net worth of $324 million. He rolled his money into Space Exploration Technologies Corporation (SpaceX), a company he founded in 2002, then went on to cofound Tesla Motors, which is poised to revolutionize the automobile world. He is a devout environmentalist and proponent of solar energy—his Teslas can literally be driven on sunlight. In 2013, Musk proposed a unique high-speed transportation system in a vacuum tube called Hyperloop, which he put into the public domain. A Hyperloop tube running between Los Angeles and San Francisco could reduce travel time to thirty minutes.

Musk formed SpaceX just when it seemed as if NASA was slipping into irrelevance. Like von Braun, he is a transplant, in this case from South Africa and Canada. Musk, like von Braun, is a perfectionist who is convinced of his vision and determined to achieve it. And as with von Braun, no one seems to understand how serious Musk is when he says we must get to Mars. Against all advice and all odds, he has managed to do the impossible: find enough capital to finance Space Exploration Technologies and to keep it afloat and moving forward even when its first three rockets blew up. Along the way, he has raised a truly revolutionary question: Who needs NASA to get to Mars?

 
Excerpt From: Petranek, Stephen. “How We’ll Live on Mars.” TED Conferences LLC. iBooks. 

This material may be protected by copyright.

 
Check out this book on the iBooks Store: https://itun.es/us/5DUPZ.l

Also available from Amazon and all of the usual sources.

  

 
I am currently reading … and listening … to this book (via Audible.com).

iTextEditors

What do you use your iPad (or iPhone) for? 

Ever had a need to edit text files or code?

Brett Terpsta maintains a list of iOS text editors and features that is nothing short of phenomenal. Titled iTextEditors, this webpage lists each text editing app in a dynamically filterable matrix of features.

 

Touching (or clicking on) the app name opens a pop-up window with additional information not captured by the feature matrix. Touching the More info … link takes you to a review of the app.

  
  
I am currently using his page to decide which text editor(s) might be worth adding to my stable of apps. :-)

http://brettterpstra.com/ios-text-editors/