twitter.comPosted May 8, 2019, 9:05 PM UTC
Sounds like they have to do this before properly accessing the site. I’m guessing the “venting” is blowing up unexploded hypergolic fuel tanks from inside Crew Dragon.
That would damage parts that would be needed for the investigation though.
Unless they used bomb teams to cover them, gathered the other parts, and are now going to burst them. Alternatively they could be covering them and then bursting them to minimize the impact on the other debris. You see it done in Europe pretty often to neutralize unexploded ordinance.
You want to spread toxic, carcinogenic, Austic and incredibly flammable liquids around? Blowing them up is just the way to do that!
They aren't pleasant, but they do decompose in fairly short order exposed to moisture. Florida just so happens to have an ample supply of natural moisture in the atmosphere.
Look, the Cape has used thousands of tons of the stuff over the years, and plenty of accidents on the launch pads. They have a handle on the situation...
I think you are grossly underestimating the amount of fuel and size of the dispersion area around the pad. By the time the wind took it anywhere harmful, it will have decomposed enough not to really do anything.
Plus, it’s not like this is a first. NASA has a whole document just outlining these type of failures:
https://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/20100038321.pdf
That would damage parts that would be needed for the investigation though.
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How do you know they have not already used a robot to either collect what they need, or move the still-pressurized tanks to a location where blowing them up wouldn't affect the parts they still need?
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There's likely a way to puncture them without blowing them up
more likely puncturing the plumbing rather tha the pressure vessel itself.
What I find interesting is that these tanks need some sort of valve to allow fuel to enter and exit. These valves survived the explosion!
That doesn't follow. Both fuel and oxidizer are liquid at ambient temperature and pressure. A tank could have a hole in it and still contain some propellant.
That's not really correct. N2O4 (only thing on board that could make an orange cloud) has a boiling point of 71F (21.7C). (It can also evaporate naturally if its close to boiling point, the same as water.) More so it reacts with water in the air to form nitric oxide and nitric acid. If there was a hole in the tank it would have long ago vented. It also has quite a high vapor pressure so it will rapidly evaporate.
N2O4 (only thing on board that could make an orange cloud) has a boiling point of 71F (21.7C). (It can also evaporate naturally if its close to boiling point, the same as water.)
Good point, but there seems to be an erroneous assumption here that surviving tanks with any contents are necessarily sealed and under high pressure.
More so it reacts with water in the air to form nitric oxide and nitric acid. If there was a hole in the tank it would have long ago vented. It also has quite a high vapor pressure so it will rapidly evaporate.
I think you could end up with a puddle of RFNA.
Good point, but there seems to be an erroneous assumption here that surviving tanks with any contents are necessarily sealed and under high pressure.
I would say that's a valid assumption. You can't have a vat of N2O4 sitting out and open to the air without it all disappearing. Especially sitting in the hot sun.
I think you could end up with a puddle of RFNA.
RFNA is fuming, because it's getting carried away. The puddle won't last too long, but it may last a while. Certainly possible they are containers full of RFNA now if they are vented.
The tanks wouldn't still be pressurized if they had a hole in them.
The problem with approaching them is that they're pressurized, not that they contain residual propellant. That of course implies no holes, and closed valves.
An unpressurized tank could easily contain MMH. Do you want to walk up to an intact-looking tank and open the drain valve by hand even if you are fairly sure that it is unpressurized?
[Edit] In any case I'm sure that there is an established procedure for this. They've been using this stuff in rockets since WWII.
That is the reason that I think that these tanks are still attached to the Crew Dragon pressure hull. The tanks and valves would have been shielded on the far side of the Dragon from the explosions that blew the Dragon off its test stand.
Understand; however, still surprised that the RUD didn't affect these valves.
Makes you wonder just how extensive was the RUD. Sure, the footage we saw didn't look good, but it mostly was just the flash and smoke.
Has there been any flyovers with photos of the pad? I would assume a small aircraft and a nice beefly lense could get something of the state of the LZ?
Based on the fact that their being pretty calm, I would like to imagine that the crew compartment is actually ok. The armor held up, and there being extra careful because they want to verify the damage caused by the RUD vs. damage caused by safing the site. This is just supposition and hope.
Why on earth does a space unit have a shark as their insignia? As a reminder of what is waiting for the astronauts when they de-orbit in the wrong place?
It’s not usually like that, this is their normal emblem.
I hope they send in a robot and pokes a drill into the pressurized tanks that survived this long.
Acronyms, initialisms, abbreviations, contractions, and other phrases which expand to something larger, that I've seen in this thread:
|Fewer Letters|More Letters| |-------|---------|---| |LC-13|Launch Complex 13, Canaveral (SpaceX Landing Zone 1)| |LZ|Landing Zone| |LZ-1|Landing Zone 1, Cape Canaveral (see LC-13)| |MMH|Mono-Methyl Hydrazine, (CH3)HN-NH2; part of NTO/MMH hypergolic mix| |NTO|diNitrogen TetrOxide, N2O4; part of NTO/MMH hypergolic mix| |RFNA|Red Fuming Nitric Acid, hypergolic oxidiser| |RUD|Rapid Unplanned Disassembly| | |Rapid Unscheduled Disassembly| | |Rapid Unintended Disassembly| |ULA|United Launch Alliance (Lockheed/Boeing joint venture)|
|Jargon|Definition| |-------|---------|---| |hypergolic|A set of two substances that ignite when in contact|
^(Decronym is a community product of r/SpaceX, implemented )^by ^request
^(7 acronyms in this thread; )^(the most compressed thread commented on today)^( has 72 acronyms.)
^([Thread #5153 for this sub, first seen 9th May 2019, 23:12])
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They said this would happen in the 8th. It's the 11th now. Did it happen? Or is there a new date for it?
I assume that they did it and there just wasn't any cloud. They did say "may".
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I really wonder how they are going to vent the tanks.
Exploding them might be the most straight forward option but I just don't think that they would risk another explosion because it might make it even harder to inspect the pieces of dragon to figure out what went wrong.
On the other hand the internal systems to vent these tanks if most likely fubar.
Drilling a hole into the tanks using a robot? No idea...
Get a remote controllable "Rover" like a scissor crane and attach a powerdrill to it. I think we could whip something like that up in a couple of hours.
One of the metal tubing lines would be the easiest...
You could vent it quite safely with a rifle. I recall this was proposed for an Atlas stuck pressurized on the pad back in the day.
I think it was Mercury-Redstone 1 after its 4 inch flight. Fortunately calmer heads prevailed and they didn't shoot it.
Mercury-Redstone 1
Indeed. Which makes more sense. Depressurizing an Atlas would have been a bad idea.
only safe if you don’t want to preserve the evidence.
That would relieve any pressure but unless you could shoot a hole exactly in the bottom of the tank it would not drain the contents. It would make the tanks safer to approach, though.
If I had guess very high pressure water cutting or projected water disruptors
Need a hole in the tank large enough to let propellant out, but not large enough to cause a full structural failure of the tank. Sounds tricky
How would these tanks normally be emptied (apart from actually being used)? I would have thought they would be a way to detain - maybe this has been damaged?
By way of the same outlet in the bottom that leads to the engines. However:
That outlet is probably not at the bottom the way the tanks are sitting now
The electrical mechanism that would open the drain won't be working
No one is willing to get close enough to open it manually.
Couldn’t a robot be the answer to both #1 and 3?
Maybe I’m overestimating what current robots can do, but Boston Dynamics videos have left me under the impression that they have enough degrees of freedom to twist a valve open and to lift/rotate the tank (and if the tank weighs too much... this sounds simple enough you could just use a crane... I’d assume the crane can have the cockpit reinforced enough for a person to be safe if the tank explodes.)
Perhaps they did use one of the remotely controlled devices[1] that the press erroneously calls "robots".
[1] Not the Boston Dynamics machines. Those really are robots.
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