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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: 1) by khallow on Monday January 15 2018, @07:53AM (2 children)

    by khallow (3766) Subscriber Badge on Monday January 15 2018, @07:53AM (#622488) Journal

    You're wrong that attempting to design for high standards of reliability is senseless. It's quite expensive to train new astronauts and build replacement vehicles, not to mention politically difficult to fund a program that makes us look foolish and incompetent.

    It can be worse than senseless. For example, such design can actually introduce risks that are higher than the ones that the effort is trying to reduce. It can also create moral hazards and other systemic or behavior problems that increase risk.

    Even the Space Shuttle managed to successfully take off and land in 132 of 134 tries. You don't get to that level of reliability without designing for it.

    And having a few dozen manned launches already under one's belt.

  • (Score: 0) by Anonymous Coward on Monday January 15 2018, @08:40AM (1 child)

    by Anonymous Coward on Monday January 15 2018, @08:40AM (#622490)

    t can also create moral hazards

    Say what?
    And you didn't even mentioned ethical hazards.

    • (Score: 1) by khallow on Monday January 15 2018, @07:02PM

      by khallow (3766) Subscriber Badge on Monday January 15 2018, @07:02PM (#622665) Journal
      It's an economics term and while it has some relevance to morality and ethics, it's just a label. Moral hazard [] means merely that when someone is protected from the consequences of risk, they tend to engage in riskier behavior. For example, people who drive rental cars tend to be more careless with them than if they were their own cars. The consequences of minor scratches and dings are far less significant when one doesn't have to look at it for years or pay for repairs. In turn, this creates elevated risks for the party that intentionally rents out these vehicles. The moral hazard isn't for the driver, but for the rental business (and perhaps the outside world) that is subject to these increased risks.