"We put fuel in a rocket, blow it up in a remote location, and measure how big the boom is."
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NASA is blowing stuff up to study the explosive potential of methalox rockets
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The issue with the condensed-phase detonation is somewhat poorly described. The volume of mixing one can achieve between liquids methane and oxygen is very small so the overall energy release due to that modality is correspondingly small.
However, achieving such a reaction allows one to achieve a very rapid onset of detonation (reducing the DDT time and distance). That allows more of the rest of the system to release energy as a detonation rather than a deflagration. Unless you're in a confined space, nobody really cares about the latter.
However, achieving such a reaction allows one to achieve a very rapid onset of detonation (reducing the DDT time and distance). That allows more of the rest of the system to release energy as a detonation rather than a deflagration. Unless you're in a confined space, nobody really cares about the latter.
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Did SpaceX provide access to the data? Or did they allow NASA to copy it, use it in their models, and share it with other interested parties? If it's not the latter, NASA doesn't have the data. Part of their mission is providing datasets to others so that one doesn't have to repeat their own experiments.
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Why do you inherently trust what SpaceX says? I'd rather NASA or other outside agency conduct their own tests to be sure.
It's not really different from when SpaceX starting landing F9s at the pad. I worked in the industrial area at CCSFS for a decade; the first handful of pad landings required full evacuation of that entire area, but after they proved success then it stopped being so broad. I see no reason to expect a different outcome here.
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In the picture, I notice that they have a shrapnel barrier set up in-line with the ranged blast discs. While this makes sense from a "let's not shred the discs instead of measuring percussive force" perspective, won't that barrier also affect the wash from the explosion? I would have expected all the range discs to be distributed such that each has a clear path from the explosion site.
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shall we cue up the opportunity for "largest peacetime explosion" ?
(I have a family member who lives in halifax who periodically walks past one of the anchors from the halifax harbour explosion that was deposited miles away from the harbour)
(I have a family member who lives in halifax who periodically walks past one of the anchors from the halifax harbour explosion that was deposited miles away from the harbour)
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I'd guess that the shape of the pole will offer no significant reduction in the blast effect once around the pole. Dynamically, air is very much like water. So a shock wave in the air will react like water. A blast wave is a wave, and will rejoin itself if interrupted, even though it's traveling at Mach speed.
Some side view shock wave videos show it pretty well. That pole will be invisible to the sensors, but should deflect any debris that can damage them.
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Bill Swallow
Ars Centurion
Testing like this is a damn good idea. We don't want our launch facilities turning into footage from a Gerry Anderson 'Supermarionation' production, exciting as those are.
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Bill Swallow
Ars Centurion
I agree that NASA needs to do their own carefully controlled and rigorously instrumented testing, but I was under the impression that, while SpaceX has a lot of data, by far most of it came from decidedly uncontrolled events, unplanned, and mostly useless for a quantitative analysis like this needs to be.
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I’m surprised they’re not doing this at White Sands Test Facility (the NASA facility, not the missile range on the other side of the Organ Mountains). They did a bunch of drop tests of large LH2/LOX there - there’s pictures various places.
OTOH, Eglin is where they test Fuel Air Bombs, and perhaps the MOAB, and it’s currently active. WSTF probably hasn’t done drop/explosion tests for 40-50 years.
OTOH, Eglin is where they test Fuel Air Bombs, and perhaps the MOAB, and it’s currently active. WSTF probably hasn’t done drop/explosion tests for 40-50 years.
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Well, NASA could do all that work themselves, or they could just give Boeing a few billion and tell them to make a their own methane rocket that definitely, positively, 100% doesn't explode and then see what happens. I say its time to give Boeing a job where they can meet expectations, though they'd probably still blow the budget.
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Signs that it's been a long week: My brain saw "White House Test Facility" at first glance.
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No one grades their own homework, even if they're the best student in the class. Or to be less paternalistic, for the same reason papers get peer-review. SpaceX might be providing excellent data, but when that data is uncorroborated by sources with different incentive structures, it probably shouldn't be taken as gospel. FWIW, I'm sure SpaceX cares a lot about this and has already spent a lot of resources on getting actionable data because they don't want to destroy their own facilities and people. Glad to see NASA spending money to answer this thoroughly.
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As I understand it, they WERE doing some methalox tests when I was at White Sands last year (for something completely unrelated). Or was it the year before? Anyway, the explosion that rattled the conference room we were in startled the dickens out of me but the folks who work there just carried on like it was any other random Tuesday.
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Methane is better suited for reusable engines because they leave less behind sooty residue...
I think we are all are glad that methane leaves a less sooty behind (especially after a plate of beans for dinner).
I think we are all are glad that methane leaves a less sooty behind (especially after a plate of beans for dinner).
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Nit:
Range Safety has been a USAF, now USSF, responsibility for decades. I don't think that's changed, someone more recently there can pipe in.
I bring this up because, if the above still holds, USSF is telling NASA how it's gonna work. Indeed, for operations at the Cape (separate place from KSC), USSF will set the requirements.
Range Safety has been a USAF, now USSF, responsibility for decades. I don't think that's changed, someone more recently there can pipe in.
I bring this up because, if the above still holds, USSF is telling NASA how it's gonna work. Indeed, for operations at the Cape (separate place from KSC), USSF will set the requirements.
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Possibly an ammonium nitrate explosion in a ship many decades ago? One of the more terrific industrial accidents.shall we cue up the opportunity for "largest peacetime explosion" ?
(I have a family member who lives in halifax who periodically walks past one of the anchors from the halifax harbour explosion that was deposited miles away from the harbour)
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Extrapolating from an explosion of 20,000 lbs of propellant is not gonna be accurate enough. They need to blow up 7.5 million lbs of propellant (capacity of starship booster), and provide lots of good video angles. For science, totally for science
(/jk)
(/jk)
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Nonsense. If NASA (or, more likely, Los Alamos) had run these tests before, nobody would be repeating them. Everyone (government and industry) would simply take NASA's data at face value.
And I'm sure NASA trusts the data from SpaceX.
But that doesn't mean the data from SpaceX is a viable dataset upon which to build models for NASA or other USG entities. SpaceX built their tests to be representative of risks SpaceX is expecting. That doesn't make it a useful, all-purpose test suite. It doesn't mean the NASA scientists building the models have access to the measurements that would be most helpful in building their models. And, as I observed above, there's nothing that says that NASA can pass along these data to other third parties.
I have no direct knowledge of either sets of test, but I've participated with similar efforts in the past. I can almost guarantee that there's very little doubt in anyone's mind that SpaceX's data is suspect in any way. Faking data eventually comes back to bite you in the ass - physics is physics after all. At some point, models build on poor data fail and future researchers will uncover the fraud. And you really don't want to be an industry source of intentionally fraudulent data whose purpose is to weaken government regulation. Well, unless you have the political coverage of Boeing and even they took quite a grilling and had quite a bit of turnover at the top when their fraud was uncovered.
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RP-2 has entered the chat
Oh what, all kerosene looks the same to you? Just because RP-1 is cool with sulfur and aromatics you're going to bad mouth all kerosene fuels?
Joking aside, methane can be better for regenerative cooling depending on your peak temperatures so long as you're ok with cryo and lower volumetric energy density. Plus RP-2 is relatively expensive.
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Statistical
Ars Legatus Legionis
KSC (Kennedy Space Center) is a bit weird. It isn't technically part of CCSFS (Cape Canaveral Space Force Station) although it does rely on CCSFS for some aspects like range radars and flight termination. From a regulatory standpoint KSC often has regs and procedures which differ from CCSFS.
Some of SpaceX launch pads are on the KSC side of the imaginary line and some on the CCSFS side. This means the regs and procedures SpaceX has to follow and points of contact vary depend on which pad it is launching from.
Honestly KSC and CCSFS just need to be merged. Keeping it separate in the 1960s at the height of the cold war made sense but the clear line between military and civil spaceflight doesn't exist anymore. If the Kennedy part is what people want to keep then rename the merged facility the Kennedy Space Force Station. After that NASA is just a tenant of KSFS same any any private company. Unified access and procedures for all pads and occupants. No doubt NASA will scream bloody murder but they will adapt.
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Agreed. To reword an oft quoted axiom: Verify before you trust. It's a rewording I find more practically useful. You're not really trusting anything if you need to verify the work anyway.
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