Overpressure from the Blue Origin blast shattered windows at a hangar about a mile away from the pad.
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Safety officials finally have a good idea of what a big rocket explosion can do
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Hey now, Bezos left his first (similarly aged) wife for an older woman (who seems to be trying to use the dark arts to look younger with...mixed results). Credit where it's due, I guess?
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Does NASA/KSC have pressure sensors and seismometers set around their estate 'opportunistically', so as not to waste a RUD event?
Sounds like it's a bit more scientific than looking at the debris field and burn marks, would be interesting to know what they do.
I wonder if some landscaped berms like they have in some fields around Schipol could soften the pressure wave from a blast rather than steady-state sound.
Sounds like it's a bit more scientific than looking at the debris field and burn marks, would be interesting to know what they do.
I wonder if some landscaped berms like they have in some fields around Schipol could soften the pressure wave from a blast rather than steady-state sound.
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I wonder how much the hydrogen portion of the explosion was able to help drive the methane combustion. Hydrogen flammability (and combustion) limits are famously wide. Often, one doesn't worry about hydrogen in open air because it's so light it floats upwards faster than a flame can propagate. However, in this case, the hydrogen was liquid (more dense) and there was already a source of ignition waiting to set it off. But with burning hydrogen helping drive pressure into the methane, the latter fuel would have ignited more rapidly than on its own.
Armchair analysis suggests it was about a 1 kilotonne-equivalent of TNT which ... would be right at the 1:4 limit SpaceX and Blue are advocating. Maybe it's worthwhile to replace all the windows in the nearby buildings with hurricane-rated panes. Yes, they can still shatter, but the transparent film keeps them intact rather than throwing glass shards.
Armchair analysis suggests it was about a 1 kilotonne-equivalent of TNT which ... would be right at the 1:4 limit SpaceX and Blue are advocating. Maybe it's worthwhile to replace all the windows in the nearby buildings with hurricane-rated panes. Yes, they can still shatter, but the transparent film keeps them intact rather than throwing glass shards.
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There are certainly sound-pressure-level monitoring devices at the periphery of the property to ensure launches remain within their FAA-allowed noise footprint. I would assume there are others closer. The thing is, they have the temperature and humidity readings for the evening. They only need the arrival times to determine the blast power.
Finally, the near-explosion details won't be resolved by any of this, but nobody really cares about this. The peak pressure very near to a blast wave from a 1 kilotonne backpack nuke would be far higher than the highest pressures see in this event - even though the explosive power might be the same. Here, the energy release was distributed over a larger volume. It's the far-field effects that are equivalent. In the near field, only the rocket operator themselves that have anything at risk.
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Plus windows in a mile.
So current BDA is pretty good. If you reduce it 4x you gonna have debris outside not to mention the windows...
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Reducing the blast power 4x doesn't reduce the diameter of the BDA by a factor of 4. Debris only went half as far as the BDA. My naïve guess is diameter drops as the square root of equivalency* - so half a mile for this last event. In other words, exactly where debris was found.
Unreinforced windows are silly easy to break and certainly will break at a level far below that which will damage humans. The solution there is to use high-strength and/or laminated windows within a large footprint. Nobody cares if you break a window or two during a failure like this. It's a rounding error. The issue is one doesn't want glass shards flying.
* because Starship is 4x the yield of New Glenn but only 2x the exclusion zone diameter.
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Any chance that someone could do a quick markup on the photo that Stephen provided to put a distance/radius measurement on it?
the photo is otherwise information limited: what is the radius of the exclusion zone for a given pad?
I'm curious how many other pads get shut down when (for example) there's a fully fueled starship on 39A...
the photo is otherwise information limited: what is the radius of the exclusion zone for a given pad?
I'm curious how many other pads get shut down when (for example) there's a fully fueled starship on 39A...
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I'm a little surprised that Florida allows non-hurricane windows at all. I mean, I'm not super surprised, I assume those building regulations would have been removed by the goofballs that run that state at some point in the last 20 years, but I'm a little surprised.
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SLC-40 and -41 are almost exactly a mile apart (and since the article was written in feet, a mile is 5,280 feet).
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New construction requires hurricane-rated windows or shutters you can put up when a storm is coming.
Storm rated windows are freakin' expensive so this building probably has shutters. But they wouldn't have been closed - nor would they necessarily have prevented window breakage from a sound wave. They're designed to stop flying debris.
Edit: And as I mentioned, storm-rated windows still break when something hits them. And are freaking expensive. I'd rather just put my corrugated aluminum shields up when a storm is coming. I don't care if they get dented. I hammer it back.
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Thanks. So "mark one eyeball". a starship on 39A is more than a mile from -41 or -40, and -36 is actually well away from -37
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Google maps is your friend. You can get the linear distance between two points by right-clicking on the map at the first spot.
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I hope that aapis guy at least got a timeout for that comment, jeez
Edit: at the time I wrote this I thought it had been removed but guess I missed it
Edit: at the time I wrote this I thought it had been removed but guess I missed it
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Jesus dude I hate the Epstein class and their projects as much as anyone but that's a little too... simplistic... a take.
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Just to double check that I followed this.
If that is the suggestion, then reducing the exclusion zone by 25% seems like a pipe dream. But I feel like I am missing something.
- 2/3rds of a mile radius is the current New Glenn exclusion zone, assuming 100% TNT equivalent explosion.
- "About a mile" from the pad some windows were being shattered.
- 1/2 mile from the pad is the furthest debris was thrown.
If that is the suggestion, then reducing the exclusion zone by 25% seems like a pipe dream. But I feel like I am missing something.
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You're missing that blast-equivalent energy is not the same as exclusion zone diameter.
And we'll have to see the mass of the debris that was thrown. Flat sheets of aluminum might eventually find their way a long distance from the event because they sail It might just mean that during energetic events, a hardhat might be required. And that's probably already required. And in the event of an explosion, everyone simply gets under cover. This is pretty normal industrial safety considerations.
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Have to figure when a Starship goes it'll be a fair bit stronger. There's the inverse-square distance effect, but maybe 1.5 mile shatter radius?
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To elaborate about how important speed is in an explosion, generally speaking, the major difference between a high explosive and a low explosive is that a low explosive burns and doesn't propagate faster than sound. It "deflagrates" through the material, traveling from molecule to molecule in a combustive manner, burning as it goes.
A high explosive generally doesn't burn and does propagate faster than sound. The shock wave from a high explosive is far more powerful and damaging. So the SPEED of the detonation (hence high and low velocity) is what causes the damage.
So the New Glenn explosion was a low velocity explosion, but a humongous one. Had it been a high velocity explosion, like dropping a 1 KT atomic bomb, there'd probably be nothing left to repair and people a few miles away would have felt effects, if not been killed by it.
Thankfully no one was hurt in this one.
Gotta admit, though, outside of atomic tests, that was the biggest boom I've seen in a long time. And a lot of rocket men, having seen the "what if...?" of a fully fueled megarocket exploding on the pad, are probably drooling over that data to make better rocket pads and design the surrounding region to be more resistant to another such accident.
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Very possible that many of the buildings were build prior to modern storm standards. Existing structures are normally grandfathered from complying with new regulations unless a remodel happens. Also, as a Federal Government site, probably excluded from State regulations.
NASA and the Military may want to rethink building standards. Distances from pads and blast resistance that were fine for Atlas, Falcon 9 and Shuttle probably aren't enough for the current crop of mega-rockets.
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This is a good time to recommend John D Clark's Ignition! A Formal History of Liquid Rocket Propellants. It's totally worth buying a print copy, but a PDF version is available here.
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Yes, it was mostly deflagration, but if it was all subsonic combustion, there would be no blast wave at all. That's what the 1:1 or 1:4 equivalence argument is all about. The 1:4 number suggests that only 25% of the energy released was coupled to a detonation wave.
And in the far-field, a 1 kT blast doesn't matter if it's from a MOAB, a pile of TNT, or an inefficient methalox rocket RUD. Far away from the source, the blast wave of a 1 kT explosion is the same.
Yes, people might have dropped dead had a 1 kT fission bomb gone off, but not because of the blast but because of the radiation.
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About to ask a potentially dumb question, but would earth berms sufficiently far away from the rockets mitigate/disrupt the blast wave enough to shrink exclusion zones? It wouldn't handle the potential for debris, but could it ease the pressure wave by deflecting part of it off?
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Well, it's pretty easy to keep everyone safe when the protocols are nobody is allowed near the big bomb. Those who are "close" are in bunkers and the only time that was almost a problem was a solids failure you can find on YouTube when bits of solid propellant rained down on top of one such bunker.
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One has to assume the explosion can happen at any point of launch. So I'll just raise my rocket above your proposed berm and then blow up.
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Honestly, keeping people at a safe distance may be simple and obvious, but at this point in my life I'm grateful when people are doing at least the most simple and obvious things to ensure safety.
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Right, basically this gets into momentum vs force (1st derivation, change in momentum over time) vs impulse (2nd derivation, force over time). Another maybe more intuitive example is the operation of firearms. If one takes a moment to think about it, obviously both the shooter and the target being shot must experience near identical (the target gets less but it's not significant within effective range) changes in momentum since momentum is conserved, yet of course the effect on the target is rather different, that's the whole point after all. Guns fundamentally work by ensuring the operator experiences the force spread out over time and area relative to the target, aiming to keep it within an elastic regime whereas the target experiences inelastic effects. You can easily exceed the force of a bullet just by pressing down firmly on your arm with a finger for a bit. It's the compression of time and area that makes all the difference.
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Fair enough, but one has to remember just how many rockets blew up during the Space Race - and since. Energetic RUD's at the pad are just common enough for everyone to realize those ancient safety rules are there for a reason.
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You mean that they don't use safety glass everywhere at the Cape? It's pretty much an industrial facility...
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I assume the blast fall off calculation is proportional to r^3 although I guess it might be more like r^2 near the earth? In any case reducing the energy by a factor of 4 would presumably reduce the keep out radius only 35% or so. But it sounds like the current value isn't that far off.
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If the windows broke from a sound wave, I'd have to guess not. Or maybe they did, but didn't shatter. In which case, it's hardly worth mentioning.
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I don't know the answer, but I'd guess it has to do with blast energy per blast wave area - so it would fall off with r^2.
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