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posted by Fnord666 on Sunday January 14 2018, @06:53PM   Printer-friendly
from the space-is-risky dept.

Safety panel raises concerns about Falcon 9 pressure vessel for commercial crew missions

An independent safety panel recommended NASA not certify SpaceX's commercial crew system until the agency better understands the behavior of pressure vessels linked to a Falcon 9 failure in 2016. That recommendation was one of the stronger items in the annual report of the Aerospace Safety Advisory Panel (ASAP) released by NASA Jan. 11, which found that NASA was generally managing risk well on its various programs.

The report devoted a section to the composite overwrapped pressure vessels (COPVs) used to store helium in the second stage propellant tanks of the Falcon 9. The investigation into the September 2016 pad explosion that destroyed a Falcon 9 while being prepared for a static-fire test concluded that liquid oxygen in the tank got trapped between the COPV overwrap and liner and then ignited through friction or other mechanisms.

SpaceX has since changed its loading processes to avoid exposing the COPVs to similar conditions, but also agreed with NASA to redesign the COPV to reduce the risk for crewed launches. NASA has since started a "rigorous test program" to understand how the redesigned COPV behaves when exposed to liquid oxygen, the report stated. ASAP argued that completing those tests is essential before NASA can allow its astronauts to launch on the Falcon 9. "In our opinion, adequate understanding of the COPV behavior in cryogenic oxygen is an absolutely essential precursor to potential certification for human space flight," the report stated, a sentence italicized for emphasis in the report.

[...] The report raised issues in general about the commercial crew program, including concerns that neither Boeing nor SpaceX, the two companies developing vehicles to transport NASA astronauts to and from the International Space Station, will meet a requirement of no greater than a 1-in-270 "loss of crew" (LOC) risk of an accident that causes death or serious injury to a crewmember. That includes, the report stated, a risk of no more than 1 in 500 for launch and reentry.

Both programs are likely to be delayed:

Boeing, SpaceX have razor-thin margins to fly crew missions in 2018

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  • (Score: 5, Informative) by maxwell demon on Sunday January 14 2018, @08:52PM (4 children)

    by maxwell demon (1608) on Sunday January 14 2018, @08:52PM (#622268) Journal

    With 2 fatal failures in 135 missions, the Space Shuttle didn't even come close to those figures.

    The Tao of math: The numbers you can count are not the real numbers.
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  • (Score: 2) by frojack on Monday January 15 2018, @01:26AM (1 child)

    by frojack (1554) Subscriber Badge on Monday January 15 2018, @01:26AM (#622357) Journal

    You counting deaths or vehicle here?

    No, you are mistaken. I've always had this sig.
    • (Score: 2) by maxwell demon on Monday January 15 2018, @07:11AM

      by maxwell demon (1608) on Monday January 15 2018, @07:11AM (#622483) Journal

      Vehicles. With deaths, it would be an even worse statistics because IIRC both times there were 7 astronauts on board, while there were plenty shuttle missions with less than 7 astronauts.

      The Tao of math: The numbers you can count are not the real numbers.
  • (Score: 2) by JoeMerchant on Monday January 15 2018, @04:44AM (1 child)

    by JoeMerchant (3937) on Monday January 15 2018, @04:44AM (#622428)

    I moved to Houston in 2003, the tasteless joke of the day was: What does NASA stand for? Need Another Seven Astronauts.

    14 deaths in 135 missions is not a great track record. I'd much rather see a heterogeneous program flying multiple designs and continually refining for improvement, instead of fixing up 20 year old space-pickup-trucks to be used again and again. I drive 20+ year old cars, lots of "interesting" things happen when you try to use a big, complex machine that long, especially when you push the performance envelope with hot turbo pumps & similar things. Interesting in a bad way, if your life depends on it.

    Україна не входить до складу Росії.
    • (Score: 2) by takyon on Monday January 15 2018, @07:04AM

      by takyon (881) <reversethis-{gro ... s} {ta} {noykat}> on Monday January 15 2018, @07:04AM (#622481) Journal

      We need an alien enemy. Then we can throw military assets in space without worrying about a Cold War on Earth, and it will be totally OK if 1.4-3.3% of the astronauts die, or even ten times that.

      #JWST #SETI #Search4EnemiesToIncinerate

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