Mathematics, Media Criticism, Political Commentary, Space, Technology and Society

NASA And Safety

6 Comments

A long piece at Aerospace America by Debra Werner and Anatoly Zak. I haven’t had time to read the whole thing yet, but this is absurd:

“The actual loss of crew value will vary depending on the mission,” William C. Hill, NASA deputy associate administrator for exploration systems development, says by email. “This makes the loss-of-crew number one example where it is difficult to compare shuttle with Orion/SLS.” To evaluate safety, NASA analyzes risk for specific elements of a mission and aggregates those numbers. Launch and ascent gets a rating. In-space activity gets another. Atmospheric entry, descent and landing gets a third. For launch and ascent, NASA will require Lockheed Martin to show that Orion poses no more than a 1-in-1,400 risk of loss of crew. Boeing must show that SLS poses no more than a 1-in-550 risk. For Orion’s entry, descent and landing, the risk must be no more than 1 fatal accident in 650 missions.

Neither company will be capable of “showing” that for vehicles used so rarely. One in fourteen hundred for a vehicle that is not planned (and can’t be afforded) to fly more than a couple dozen times effectively means that NASA is demanding zero risk of LOC.

Someone should write a book about this sort of thing.

Oh, wait.

6 thoughts on “NASA And Safety”

  1. Orion and SLS are coming in nowhere near these LOC figures. Per the ASAP’s 2014 report, p. 13, the LOC for Orion entry is 1-in-300, not the 1-in-650 that Hill quotes for this article. As the ASAP notes, the total LOC for a circumlunar mission is only 1-in-75, which is slightly worse than STS to LEO. Why the hell are we spending billions and billions of dollars developing a human space transportation system that offers no improvement in flight safety over a system developed 35 years ago?

      1. Someone should call NASA out on the specifics. It’s one thing to say that SLS/MPCV will never be safe because they won’t fly enough. It’s another to show that SLS/MPCV’s flight safety figures are no better or worse than STS.

  2. Someone should write a book about this sort of thing.

    Oh, wait.

    Does this sell books, Rand? I bought your book. I’ve read it twice. I even have an Amazon review drafted. I suspect many of your blog readers have done the same. I see you tweet this snark on a regular basis. Who are you trying to reach?

  3. Last night I watched The Challenger Disaster on Youtube, starring William Hurt as Richard Feynman. Hurt is in nearly every scene, as the movie centers around Feynman’s involvement in the Rogers Commission.

    1 in 650? 1 in 300? 1 in 75? Bullshit. This is the same set of calculations that led NASA to believe LOC for shuttle had odds of 1 in 100000. In reality, the actual odds were 2 in 135.

    The truth is, they don’t know. They can’t. They don’t have the data, and won’t until they launch many, many times.

  4. Did anyone notice the caption the picture of the Dragon pad abort? With Super Draco engines blazing, barely 100 ft off the pad, the caption reads, “A SpaceX Crew Dragon prepares to land during a pad-abort test in May.” I guess they mean in the sense that any airplane on take-off is preparing to land. Lol.

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