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Comment by physcab | Hacker News Reader

This is a pretty important observation. I will applaud SpaceX for their efforts as well, but there is a massive difference between transporting cargo into space and human beings.

SpaceX claims their transport is cheaper but they have not claimed it is safer. If they are really aiming for the human transportation business I wonder if the true cost of their rocket ships will be much more on par with existing vehicles. I'm sure they have taken advantage of some optimizations and efficiencies in new technologies and materials. But I also believe one of the reasons the other rockets are so much more expensive is not because they are relying on old technology, but having to satisfy much more stringent government regulations regarding safety, testing, and quality control. The ATLAS V has had 100% Mission Success and that does not come cheaply.

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From TFA: "This is a decisive milestone in human spaceflight and sets an exciting course for the next phase of American space exploration," said SpaceX CEO and Chief Designer Elon Musk. "SpaceX, along with our partners at NASA, will continue to push the boundaries of space technology to develop the safest, most advanced crew vehicle ever flown."

So yes, he is claiming it is the safest, and I think he has good reason to, as your sibling comments explain.

Safety isn't as much determined by your aspirations, as it is by your record. 37% failure is an acceptable milestone considering all the SpaceX has achieved in its short lifetime, but I doubt would satisfy NASA's safety regulations for human spaceflight.

Not counting their initial failures, SpaceX has had a 100% success rate. And each rocket was so significantly different from the previous rocket[1], that it's more fair to say they had 3 rocket models with 100% failure, rather than one model with 60% failure rate. And the Falcon 9 has a 100% success rate. And they were awarded this contract, so obviously NASA believes they can achieve the desired reliability and safety for the rocket that will be used under the contract (not F1).

I'm not affiliated with SpaceX, nor trying to be a fanboi, but I believe you are distorting things.

[1] Which did earn them a lot of criticism from the industry, actually

>Not counting their initial failures, SpaceX has had a 100% success rate.

And other than the ones that exploded, NASA never lost a shuttle.

That's not what I'm saying at all. Every shuttle was designed the same. Every F1 that failed had a different design, and the company's policies and practices changed drastically over that time as well. You can't compare it to an established program with intermittent failures.

The shuttles that failed were not initial failures. Not by a long shot.

Suspect you may be confusing the state of 'being safe', with the measurement of 'being safe'. Empirical methods are not the only way to quantify something.

Either world view relies on

"Just trust me, I know" or "The numbers never lie"

Would be potentially problematic.

This debate has been going on for centuries.

http://en.wikipedia.org/wiki/A_priori_and_a_posteriori

'to develop the safest' is the future tense. It seems nitpicky but I believe Elon is trying to communicate that safety of the crew will be a priority.

If you read some of the Congressional debate on the commercial crew program you will see that some people question whether or not a commercial enterprise will put the safety of the crew ahead of their own profits, and even the survival of their own company. Their argument is that only a government agency with a mandate for safety can be assured of making that choice even when that results in escalating costs.

It was pointed out in counter arguments that the Challenger blew up in part because NASA launched it over the objections of the commercial provider of the solid rocket boosters.

My personal bias is that while we lost a lot of people doing barnstorming stunts in Aviation, their willingness to put their life on the line allowed things to happen faster than they might otherwise. I am not sure if I could objectively reason to that bias though. I did get a chance to talk to the folks at Scale Composites just after they did their X-prize winning flight and they felt that they were over regulated in the name of crew safety. Nobody objected to regulations to protect the safety of the people down range or nearby, it was constraints on the crew that chafed. A tech remarked that he would not be surprised if they were asked to put an ADA compliant bathroom in Spaceship One at the next review.

I'm not sure what SpaceX's "failures" were. Did the spacecraft crash and explode? Was this the Falcon 9 or the Falcon 1?

Historical safety is indicative of actual safety but not definitive, and not all you should be interested in. The shuttle was almost certainly less safe than its statistics indicate. If every launch delay of more than one day were considered a failure the shuttle's success rate would be very poor indeed.

Another question is how safety statistics are calculated. E.g. The overall safety of cars, measured by deaths per passenger mile, say, reflects many things, not just the engineering of cars themselves (in like manner, NASA's cautious use of the shuttle did much to ameliorate its excessively fraught design). On the other hand, crash safety ratings are prospective -- a five star crash rating won't save you colliding with a semi trailer, driving off a cliff, or into a lake, or having an accident at 120mph, or having your fuel tank explode.

There was an interesting discussion of actual car safety per model in the New Yorker a few years back, with the Toyota Avalon on top, and the VW Jetta second. Who drives a car and how it is driven turn out to be more important than crumple zones.

The 3 failures (http://en.wikipedia.org/wiki/List_of_Falcon_1_launches):

1. Exploded 25 seconds after launch, rocket parts are still washing ashore

2. Successful transition to second stage, but didn't deploy its payload properly. 1st stage has not been recovered

3. 1st stage engine was 'more efficient than expected' and continued to burn after separation of 2nd, bumping into it. I got to see a video of this at a conference, very sad. But impressive that the 1st stage was able to generate thrust (pressure in its fuel tank was rediculously low). Mostly I was relieved because my satellite was almost on that launch, and now still has a chance of going up.

I wouldn't consider a launch delay/abort a failure in any sense, especially not due to design or related to safety. Every rocket is designed to work within certain parameters, and when those aren't satisfied, the launch is aborted. This can be due to weather (completely out of human control) or malfunction (not the designer's fault). In the case of a design error, operators usually don't know what faults to look for, and then there is a failure.

You bring up an important distinction, though. There is a difference between the safety of a design, and the safety record of its implementations. In the quote in question, Musk promises it will be the "safest rocket ever designed" which doesn't mean that he's promising the safest record, or that it will have the same 100% success rate as other rockets, but that it will be designed to be safe for the astronauts. Already it has a safer design than the shuttle, since it is using liquid rather than solid fuel. That means a launch can be aborted mid-flight, and the crew brought down safely somehow. The shuttle required a man on the ground to be ready to hit a 'kill' switch.

Edit: turns out that the top comment here wasn't actually quoting anything when he put "safest rocket ever designed" in quotes. Musk said "safest, most advanced crew vehicle ever flown," which I suppose could be interpreted as a promise about its as-flown safety record. I still don't see the harm in him saying that, since he's also said that he accepts a non-zero risk of casualties. It's not like the families of dead astronauts are going to sue him over this quote.

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