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Showing content with the highest reputation on 11/03/2014 in all areas
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Very interesting thread. It caused me to wonder how commercial space travel vehicles are licensed, permitted and/or approved. I am fairly confident, admittedly without knowing all the details involved, that commercial air travel has a rather developed process to approve new aircraft designs, which undoubtedly involves new technologies at times. I would hope (expect) at least the same rigor would be applied for commercial space vehicles. I would further hope (expect) that this would extend to test vehicles and test lauches/flights. I googled this question I had and found that there is a part of the FAA tasked with various responsibilities related to commercial space travel, as it relates to US responsibilities, and it is the Office of Commercial Space Transportation. I thought it was very enlightening and for those interested in the details, here are two links for your perusal: https://www.faa.gov/about/office_org/headquarters_offices/ast/ http://en.wikipedia.org/wiki/Office_of_Commercial_Space_Transportation It would seem reasonable to state that commercial space vehicles are pushing the envelop of various aspects related to what is well established in the rest of commercial air travel. As is often the case, there may be some catching up in establishing or adjusting monitoring and controls as things move into new areas such as this. The important thing, it seems to me, is that a thorough review is done to see not only the cause of the accident but also how effective is the monitoring, control and approval process that is currently in place. We may learn that the rigor does in fact exist (and the accident happened regardless of well understood and managed/mitigated risk) or we may learn there are clear deficiencies. Time will tell.2 points
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I am temporarily out of 1/6 of a Drachma coins. Would you be willing to accept 100 million Lira? Of course, now that we know what you are, we are only discussing the price. :) Best regards, RA11 point
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Said the father of 8 whose wife was using the "rhythm" method. Best regards, RA11 point
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Perish the thought! But reading about risk and actually eliminating it are different things, no? All too true. I think in the case of rockets, though, the goal is to design them so that the explosion happens at the propulsion end, and not elsewhere in the works. No doubt your confidence will be amply rewarded. Though they may have to up their their game a bit and show that not only didn't they completely disregard the danger but that they regarded it highly enough. The bits that AdamSmith quoted from his linked article caught my eye also. I'm sure the company will have plenty of opportunity to defend its design choices, but I doubt they'll get by with just telling folks to trust them. The other thing that caught my eye in that blurb I quoted earlier on 'Blowback' was the danger of nitrous oxide in the presence of 'unstable combustion'. I know rockets have been around for a long time but I still don't think of them as cocoons of stable combustion. May be just an error on my part. Still, there will be lots of new info as the weeks go by and we can continue to reconnoiter as it rolls in. In the meantime, let's just hope Justin Bieber doesn't come asking for his money back.1 point
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This from the same article, if proven true, will also have been extraordinarily irresponsible of Virgin: Tomasso Sgobba, executive director of IAASS and the former head of safety at the European Space Agency, said that Virgin Galactic had refused to share information with industry experts outside the company and declined to have its rocket design peer-reviewed. A couple of business acquaintances who early in their careers worked at Rocketdyne on the F-1 engines used in the Saturn V described being responsibly paranoid at every turn, in effect, and it thus being a matter of course to seek input and review from as many external discipline experts as they could find, across the course of concept engineering, detailed design, simulation and testing.1 point
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From the Telegraph article linked above: It also emerged on Saturday that three senior Virgin Galactic executives -- the vice-president in charge of propulsion, the vice-president in charge of safety, and the chief aerodynamics engineer -- had all quit the company in recent months... ...In another email -- this time to the US Chemical Safety Board and sent on July 17 2013 -- Mr Daly wrote: "Sir Richard Branson, his two children, Justin Bieber [the singer] and one other will be the first passengers to fly into space during this coming December 2013, and everyone realises there is a problem, even the engineers ... have said so off the record." Of course there is too little yet known to form a judgment. But to say the above is not, at the least, eyebrow-raising is Pollyanna-ish. That management can push not only design performance goals but also unrealistic schedules, over engineers' objections, to fatal effect, was shown by the Challenger disaster, as indeed you reminded, not to mention the Apollo 1 fire and other examples. Anything that credibly suggests this may have been the case here is, even at this early stage, not irresponsible reporting, I think.1 point
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RIP Mayor Menino
AdamSmith reacted to TampaYankee for a topic
I worked in the Boston area when Tom Menino became mayor. Not being a neighborhood resident myself, he seemed to me no more than a backwater neighborhood pol. He had ascended to President of the City Council through rotation as much as any real campaign, a position he held almost as an accident of fate when then Mayor Ray Flynn was tapped to become the Ambassador to the Vatican. I thought his tenure to fill out Flynn's term would be quiet and then he would fade from the scene after passing the reigns to a more dynamic and Irish personality. Boy was I wrong!! He rolled up his sleeves and got into the trenches with the neighborhood people -- all the neighborhoods. A common man dedicated to the common welfare every day of the week. He was loved by all the common people and imagine -- five terms in office without the taint of corruption. He deserves all of the accolades that that have been bestowed upon him.1 point -
Are you accusing "Branson's" engineers of not reading Wikipedia? Any oxidizer is by definition a substance that contains oxygen. A rapid oxidation is commonly called an explosion. Any vessel that contains a fuel + oxygen is a potential bomb aka something that explodes. I feel fairly certain that the engineers did not choose this particular hybrid rocket simply because of its power potential and completely disregarded any inherent danger thereof. However, they did have design performance goals to meet. Best regards, RA11 point
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Found this in a safety discussion at Wikipedia: Blow back - For oxidizers that decompose exothermically such as nitrous oxide or hydrogen peroxide, flame or hot gasses from the combustion chamber can propagate back through the injector, igniting the oxidizer and leading to a tank explosion. Blow-back requires gases to flow back through the injector due to insufficient pressure drop which can occur during periods of unstable combustion. Blow back is inherent to specific oxidizers and is not possible with oxidizers such as oxygen or nitrogen tetroxide unless fuel is present in the oxidizer tank. As Virgin Galactic is using nitrous oxide, this might be behind the 'warnings' sounded by some of the experts. If Branson can prove that his engineers were aware of the danger, had been diligent in designing around it, and that safer alternative oxidizers were not workable, he should be able to eventually get something in space. It's sad that someone died and even more so if engineering errors were made.1 point
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No One Should Bring Their Kids to These Playgrounds http://likes.com/comedy/no-one-should-bring-their-kids-to-these-playgrounds?v=m2674TrriEeY7BctOZjcY3D51xKIsH4FQ&page=41 point
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1 point