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NASA Supports SpaceX Plan To Fuel Rockets With Astronauts On Board (engadget.com)
For years, NASA has been debating whether to allow SpaceX to fuel its spacecraft with super-cold propellant after astronauts have boarded. While the company typically fuels its rockets shortly before launch in order to prevent the coolant from warming up too much, the practice has been deemed "a potential safety risk" by NASA safety advisers due to the high risk of an explosion. Now, according to Engadget, NASA has "decided that it will move forward with the SpaceX plan to fuel rockets after astronauts have already boarded." From the report:
"To make this decision, our teams conducted an extensive review of the SpaceX ground operations, launch vehicle design, escape systems and operational history," Kathy Lueders, manager of NASA's Commercial Crew Program, said in a statement. "Safety for our personnel was the driver for this analysis, and the team's assessment was that this plan presents the least risk." SpaceX will have to prove its system is safe, however. The company will have to demonstrate the fueling procedure five times prior to its first crewed flight and afterwards, NASA will assess any remaining risk before certifying SpaceX's system. In September 2016, a Falcon 9 rocket exploded on the launchpad while it was being loaded with propellant. No injuries were reported, but it didn't look good to NASA which was already reviewing the fueling procedure.
Sorry but to be fair, some "private" industry engineers had warned of what might happen prior to the launch but NASA pressured them to give the go ahead anyway, even excluding those "private" industry engineers from the talks regarding the go/no-go decision..
https://en.wikipedia.org/wiki/...
Everything I write is lies, read between the lines.
Reading comprehension problem maybe?
Re-read what I wrote and re-read the linked page entirely and make sure that you understand everything.
Thank you,
Everything I write is lies, read between the lines.
according to Engadget, NASA has "decided that it will move forward with the SpaceX plan to fuel rockets after astronauts have already boarded.
And maybe NASA will learn a thing or two about how to conduct a space-launch operation, as well.
politicians are like babies' nappies: they should both be changed regularly and for the same reasons
Is it safer to do a whole lot of manipulation (as required with the boarding procedure, climbing the launch tower, sealing the hatch etc) around a rocket that is already filled with potentially explosive material, and might blow up at any point consuming in a ball of fire anything within the area that can't get away fast enough?
Or would it be safer to enter the capsule while the rocket is just an inert tube, buckle up, and wait till the rocket is filled up, sitting comfortably in a hermetic capsule equipped with a launch escape system - capable of getting away from the explosion fast enough to be safe?
Paradoxically, before the launch, the crew compartment is the safest of all places near the rocket.
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Off you go then.
Feynman had some choice things to say about NASA's grasp of "potential safety risks". I hear they haven't materially improved since.
They're going to fuel the rockets with the on-board astronauts? Soylent green is rocket fuel, too!
"National Security is the chief cause of national insecurity." - Celine's First Law
LES would have gotten away from AMOS-6 type scenario, that's pretty well determined. Sitting on the ground is when it's easiest for LES to get away from the exploding rocket, if LES can't get away from a fueling explosion one would have to ask, what's the point of LES to begin with? Because it sure as hell wouldn't get away from the rocket under acceleration.
Here's a video of Soyuz using its LES. It definitely saved the crew.
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Since Apollo, all manned vehicles use atmosphere-like mix at 1bar. Apollo used pure oxygen at about 0.3 bar, which was sufficient for breathing but made everything extremely flammable. (although EVA suits are still pressurized to 0.3 bar with pure oxygen - thankfully the chance for a fire inside a spacesuit is rather low.)
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I'm not entirely sure whether astronauts are actually less costly than regular fuel. Maybe they're using those who wouldn't have flown anyway?
CLI paste? paste.pr0.tips!
First, it's Russian Roulette, due to the lack of safety culture. (Note: I've worked at NASA.) This means that accidents might not happen the first time, or the twenty first. Each spin that ends up OK will convince others that it's safe, when it's really just lucky. Five successes is like rolling dice five times and not getting a one. It's going to happen. I would want something a little more technical, such as detailed analysis of failure modes, extensive sensory data showing precisely what is happening physically and electrically, and an ultrasound scan of metal items before and after the series of runs to determine how they're handling the stress.
Second, potentially, it could be made safe, but only by raising costs. SpaceX is cheap because it cuts corners. Some of those corners weren't needed. Some were. We aren't going to get told enough information to determine which is which, and failure rates with such small numbers are statistically meaningless.
Third, I don't see the added value. The refrigeration doesn't have to be internal (so you don't need the extra weight on board and can avoid ice buildup).
Fourth, we know from the launch of the car that the guidance systems and engine control are flaky. They failed to put the car on the intended orbit by a few million miles. Buggy software in a rocket is never good, but said buggy software controls the refuelling systems and we've seen where that goes. All over the landscape. Now, SpaceX and NASA want to do this with people on board.
One or two accidents could put back space research 20+ years. Such an accident at NASA nearly resulted in Hubble plunging to Earth as an uncontrolled missile, due to a delayed repair mission. We can't afford to be trapped on this badly degraded mudball any longer than necessary. We need successes, even if that ups the cost by a dollar or two. I care more about success for these missions than I care about SpaceX shareholders. The shareholders will live. The astronauts might very well not.
It's a small world and it smells funny; I'd buy another if it wasn't for the money; Take back what I paid (SoM)
As they were testing valves and other gas handling, the Apollo 1 spacecraft was being tested with a pure atmosphere environment at 0.3 bar above the ambient, or 1.3 bar absolute. There were many things they were doing wrong with Apollo 1.
Prediction for end of Universe #42: Fencepost error in Quantum_bogosort.cpp
Fixed link: https://www.youtube.com/watch?v=UyFF4cpMVag
Good question. In my opinion the logic suggests that first placing the astronauts in the capsule and then fueling would be safer because in the event of an accident the astronauts would already be inside a system capable of moving away from the explosion (the capsule). While if you fueled the rocket first and then put the astronauts, in the event of an explosion the astronauts (and the ground crew assisting them) would still be in the tower and would be caught in the blast without being able to escape.
Religion: The greatest weapon of mass destruction of all time
You're joking of course, but industrial saboteurs are a pretty real thing.
Religion: The greatest weapon of mass destruction of all time
SpaceX also plans to fuel its ship in parking orbit in the future, topping off many times, with presumably crew and payload aboard. What does NASA think about that? The fuel will not be supercold I think, but explosions in orbit could anyway cause a debris cascade making space travel unsafe for years. https://en.wikipedia.org/wiki/...
This sounds a bit inhumane. At the very least, they could use puppies or kittens.
> After fueling, the rocket is once again inert.
After fueling, the rocket is supposed to be again inert. Leaks, short circuits, construction bending under strain, oxygen corroding stuff, static charge accumulating, ice buildup, these things can cause problems even on an "inert" rocket.
Of course LES is not meant as replacement for safe procedures, but having the secondary safety feature accessible and ready to use throughout all operations is preferable to just relying on nothing going wrong during boarding. I'd call it a very valid part of safety procedures.
And they really, really don't need to squeeze these extra few kilograms of oxidizer at the last second for manned launches. What are they gonna load up into the saved space? Several extra cans of food? An extra astronaut? Extra fuel to reboost ISS into an even higher orbit? Launches to ISS are as routine as they get. They follow a fixed schedule, if there's need for extra payload, it can be squeezed into a cargo mission, there's very little benefit from increasing the payload capacity of a manned launch above nominal, and liquid oxygen is cheap enough it would be outright stupid to try to save off on the hour or so of boil-off.
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So "fueling mishap causing rapid unplanned disassembly of the launch vehicle" doesn't qualify as "something goes wrong" ?
Slashdot still doesnâ(TM)t support Unicode after it was added to the HTML standard in 1997.
Actually the volume of propellants is significantly reduced when they are cooled, on the order of 10% or better. Where this adds weight for propellant, it lessens the vehicle's weight because it can be built smaller and lighter. It may not sound like much, but adding 10% more fuel can mean quite a bit of payload increase to orbit.
The question is if this increase in fuel capacity is worth the added risk? I don't know, that's what the rocket scientists are discussing.
"File to fit, pound to insert, paint to match" - Aircraft Maintenance 101
Why wouldn't it be? Critical failure of rocket on launchpad, endangering the astronaut lives. This is the primary job of the LES.
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> it lessens the vehicle's weight because it can be built smaller and lighter. ...which would be an issue in pretty much any other case, except SpaceX launchers are reusable, so the extra cost is insignificant.
As for payload to orbit, once again, we're talking manned launches. The launcher in current form, fueled before boarding, is perfectly capable of fulfilling the payload requirements for that type of missions. There's simply no need for that extra payload capacity. It would be worthwhile for cargo launches, but with these the entire boarding issue doesn't exist.
The volume of propellant is reduced when supercooled, yes, but even if the capsule is boarded after fueling the rocket up, the propellant doesn't heat up to boiling point, or anywhere close. You're losing maybe 2% of volume, not the entire 10%.
Due to tyranny of rocket equation, increasing fuel capacity by 10% does not increase payload capacity by 10%.
As for added risk: once again, while the risk of an emergency situation occurring with astronauts in danger radius is increased, the risk of astronaut death in case such occurs is actually reduced, as at no point are they in position where they wouldn't be able to escape. Since the moment fueling starts, nobody has to approach the rocket anymore, and the astronauts can activate LES at any time. This is not the case if they need to board a fully fueled rocket.
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It's safer. Is it entirely safe? And in case something *does* go wrong, while the astronauts are on the launchpad, preparing for boarding, or on the lift, are they safer than inside the capsule?
The difference is "higher chance of accident with a low chance of death" vs "low chance of absolutely deadly accident."
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Maybe they're going to use high-test astronauts?
#naabhaprzrag, #sverubfr-000, #agi-fcbafberq, negvpyr[pynff*=' negvpyr-ary-'] { qvfcynl: abar !vzcbegnag; }
And yet, NASA require the zip line because it is still not safe with a fully loaded system.
I prefer the "u" in honour as it seems to be missing these days.
Most of which companies hire them.
I prefer the "u" in honour as it seems to be missing these days.
That's not the story that was given.
"When asked, on Twitter, if the capsule would have survived had the escape system activated, Musk replied: “yes [sic]. This seems instant from a human perspective, but it really a fast fire, not an explosion. Dragon would have been fine.”"
Source: http://www.spaceflightinsider.com/organizations/space-exploration-technologies/nasa-may-be-warming-to-the-idea-of-spacexs-load-and-go-fueling-procedure/
I've got to disagree. Weight is a major issue and if you can get 5% more payload at the same vehicle hardware weight, you will be money ahead in the commercial realm and have extra performance margins all around. Extra performance margin usually means a safer more fault tolerant system which is a huge advantage for manned flights. It also means you can add weight to the vehicle to make it safer, carry more stores or even an extra seat or two. Having weight margin can be a very good thing.
Now, I'm not arguing that it's necessarily a good idea to fuel the rocket after the people are on board, I'm only saying there are benefits to Space-X's approach to go with the added risks. It's up to the rocket scientists to figure out if the risks can be managed in a way that makes it worth it. Personally, I don't know if they are or not and I figure our two opinions do not matter.
BTW, the 10% number is something I pulled out of thin air for illustrative purposes. I have no idea if the number is 1% or 30% or more only that it's not insignificant or Space-X wouldn't bother with it. If you get a chance, I'd love to know what the actual numbers are, I just don't have time to look them up myself.
"File to fit, pound to insert, paint to match" - Aircraft Maintenance 101
Most of Dragon cargo launches don't reach full payload capacity, being limited by volume more than mass. With manned launch there will be much more empty space added. That means they absolutely don't need the extra delta-V.
The primary benefit to SpaceX fueling immediately before launch is that they do it before every cargo launch nowadays, and they have at least two launches per month. They have all the systems and engines calibrated for supercooled propellants, and everything is running smoothly. The last thing they want is change the process when they are launching humans to orbit.
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Can you link to that "previous falcon fueling" accident you refer to?
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You're not having a meltdown because all your lies are catching up to you are you Windy? Have another try with English this time, tell us what you mean.
https://www.youtube.com/watch?...
LES would have worked, though.
That one is the infamous Amos-6. I believe GP referred to some prior unspecified event. Amos was not an instant explosion; it was a rapid fire, and indeed LES would save the day.
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Sorry but to be fair, some "private" industry engineers had warned of what might happen prior to the launch but NASA pressured them to give the go ahead anyway, even excluding those "private" industry engineers from the talks regarding the go/no-go decision..
https://en.wikipedia.org/wiki/...
Exactly, not to mention that Shuttles (as marvelous as they were):
- had no escape system whatsoever, whilst all the capsules do - such a system would have saved Challenger crew
- had exposed all its heat shield during launch, whilst all the capsules do not, so the event as with Columbia, when an isolation foam hit its heat shield on the wing is not possible with capsules like the ones being developed (Orion, CST-100 and Dragon2)
Sorry but to be fair, some "private" industry engineers had warned of what might happen prior to the launch but NASA pressured them to give the go ahead anyway, even excluding those "private" industry engineers from the talks regarding the go/no-go decision..
https://en.wikipedia.org/wiki/...
Forgotten to mention that such a procedure is only slightly less safe for the crew, whilst being much, much safer for the ground support team.
If you are incapable of reading and comprehending English than go back to mandarin.
I prefer the "u" in honour as it seems to be missing these days.
Right...because decades of history of rocket design and operational history mean nothing because SpaceX.
By Apollo my forefathers loaded this rocket using donkey powered carts, and that is the way it shall be done until the end of time!
"There is more worth loving than we have strength to love." - Brian Jay Stanley
The image it invoked in my head of astronauts either being used as rocket fuel, or some kind of poop based fuel, or something.
I know the actual explanation was more realistic, but the former was more fun.
This signature has Super Cow Powers
I don't know that they have, but a couple considerations that occur to me:
- How do you get the foam off during launch? It has to be skin tight, at least at the ends, or it'll just act as a big chimney creating a draft that accelerates the warming. And if any of it gets snagged on the rocket, it'll introduce aerodynamic instabilities
- As the rocket takes off, that whole tower of foam will be melted, incinerated and/or blown apart by the rocket plume, which could create serious hazards and cleanup efforts (the fumes from burning foam are generally quite toxic, unlike those from kerosene or methane (aka rocket fuel) )
- Building a 23-storey hollow foam tower is a serious engineering challenge in its own right, and it's likely to get quite expensive to build a new one for every launch.
- It wouldn't have helped keep ice from forming on the tanks - the tanks are *inside* the rocket, and the ice is formed from liquid/vapor that is likewise inside the rocket - nothing outside the rocket will help with that.
Finally, to mangle an old saying about fishing nets - foam insulation is a bunch of holes glued together with plastic - it's not exactly super heavy stuff to begin with, and can even be made lighter than air while maintaining impressive strength (as in the case of many aerogels). It's primary job is to thoroughly prevent air circulation, and it need only be strong enough to support its own mass against the stresses of launch.
--- Most topics have many sides worth arguing, allow me to take one opposite you.
hey porky, are you such a liar that you refuse to attach your name to the crap that you spew all over the web?
I prefer the "u" in honour as it seems to be missing these days.
Porky, again, you continue to hide your trolling. Why? Just post as your alternative ID of Crimson Tsunami. It is bad enough that you are simply a lying troll, but at least have the courage to back it up.
I prefer the "u" in honour as it seems to be missing these days.
Doh, I can't read. Well, the only other one was CRS-7 and that took even longer, so I really don't know what the AC was on about, then.
... there have been a number of incidents where police dealt with an unstable person brandishing a gun by having a police sniper shoot the gun out of their hands. In those incidents, you typically hear that there were minor injuries from gun fragments. Meaning that the bullet broke the gun.
Any links to such an actual incident?
In sounds plausible, but I have never run across such an incident that I recall. But I question very much that they report that there are "minor injuries from gun fragments". I would believe minor injuries from bullet fragments however.
Starships were meant to fly, Hands up and touch the sky - Nicky Minaj
Not necessarily a troll. Poor AC may just be in denial.
My thinking is that if the passengers and crew can get to safety, go for it. But lets ask Gus Grissom and Dick Scobee what they think about it?
I read a NASA report on this fire last year, so I know the detailed sequence of events, and the conditions of the accident.
In space the Apollo command module was supposed to be at 0.2 bar pure oxygen, since the one-component gas at low pressure made the capsule engineering easier. Since the system set up to only handle oxygen, on the ground it was filled with pure oxygen at 1.0 bar. The exercise the crew was going through was supposed to be as close to launch configuration as possible. NASA had not spent much effort analyzing the module furnishings for flammability, and there was widespread use of Velcro, which was the primary fuel for the fire.
The capsule door opened inward, and the pressure was equalized with the outside so that there was no pressure on the door.
When the fire started the heat rapidly increased the pressure in the module so that it was not possible to open the hatch. There were pressure relief valves, but they were too small to handle the rising pressure. The timeline was extremely short.
Stage one (0 to 24 seconds) - start of the fire and initial spread:
0 seconds: voltage surge that is believed to correspond with the short that ignited the fire
10 seconds: the first voice indication of the crew of a fire.
24 seconds: the pressure blew open the hatch (which did not open outward, it was a gross integrity failure). The pressure had risen to almost 2 bars at that point.
Stage two (24 to 30 seconds) - "This stage was characterized by the period of greatest conflagration due to the forced convection that resulted from the outrush of gases through the rupture in the pressure vessel... Evidence of the intensity of the fire includes burst and burned aluminum tubes in the oxygen and coolant systems at floor level.": 28 seconds: last voice signal from the crew.
Stage three (30 to 36 seconds) - "characterized by rapid production of high concentrations of carbon monoxide... unlike the earlier stages where the flame was relatively smokeless, heavy smoke now formed": The fire burned out due to lack of oxygen at this point. During this stage, less than half a minute from when the fire was first noticed the crew would have inhaled a lethal dose of carbon monoxide.
See this summary.
Second class citizen of the New Gilded Age
I think when reusable launch vehicles are taking folks up on the first leg of the flight, reusable might be a good thing. But I believe that when Anti-Gravity generators are invented, folks will become frustrated at not being able to scrap engine driven vehicles fast enough.
/sarcasm Ouch, burn! (pun intended)
Consider also the possible added risk of diverging procedures. If the vast majority of launches use the last minute loading of super-cooled fuel, changing that procedure for the occasional manned launches introduces less-tested situations to the launch process. It's not impossible that a component could fail from being fueled an hour early and at warmer temps that doesn't fail in the super-cooled scenarios.
This space intentionally left blank
Amos-6 went from nothing to an explosion, with shrapnel, directly under the payload.
There isn't much in the way of shrapnel to worry about. The majority of the force of the explosion is going sideways, and taking most of the rocket fragments with it. The bit of "shrapnel" being directed upwards is likely just large chunks of the end-cap of the stage, and they're being pushed at relatively low speeds compared to shrapnel propelled by an actual explosive.
But you'd need to react in 3 secs or you'll be pointing in the wrong direction for it to have any hope.
Any decent automated escape system would be able to react in a fraction of a second. Even if you were silly enough to leave it up to a human, a well trained pilot would react in a second or so.
Also escape systems don't care much about what direction you're pointed in; even ejection seats in fighter jets have automatic systems to detect orientation and steer the seat in the desired direction. As long as you're not inverted and very low to the ground, you'll be OK. There's a great video online of a Canadian F-18 pilot ejecting from an aircraft which was on the ground but had begun to tip over; he ejects sideways but the seat quickly turns and rockets upwards. (Amusingly enough, the force of the ejection also pushes the F-18 sideways and stops it from tipping. The "dashcam" video shows the plane rolling to a perfect stop as the pilot thunders down onto the ground in front of it.)
This is just space shuttle thinking applied once again. You ok a thing because you want to do a thing. That's all. Wait for the disasters.
E Proelio Veritas.
Listen Windy, not everyone pointing out your lies and laughing at your incompetence is me. Plenty of people don't like liars and think you are an idiot.
Plenty of people don't like what I say too, but that is usually because they are entitled assholes who don't like having to admit their country is so polluting. Or they somehow believe your other lie that I'm a Chinese troll. Repeat the lie often enough and some people will believe it. Maybe thats your whole plan lie often about everything and hope people are too lazy to check.
What were you trying to say though? Can you explain it in English?
PS: Everyone knows who the liar is, when have you showed even a single lie of mine?
PPS:Not attaching your name to something doesn't make you a liar. Is that more Windy logic?
Listen Windy, not everyone pointing out your lies and laughing at your incompetence is me. Plenty of people don't like liars and think you are an idiot. Plenty of people don't like what I say too, but that is usually because they are entitled assholes who don't like having to admit their country is so polluting. Or they somehow believe your other lie that I'm a Chinese troll. Repeat the lie often enough and some people will believe it. Maybe thats your whole plan lie often about everything and hope people are too lazy to check.
What were you trying to say though? Can you explain it in English?
PS: Everyone knows who the liar is, when have you showed even a single lie of mine?
PPS:Not attaching your name to something doesn't make you a liar. Is that more Windy logic?
On the flip side...
Take a rocket that is loaded with so much payload and fuel it has TWR of exactly 1 on launchpad. It must burn some fuel to actually start climbing. Now keep adding more fuel instead. It won't take off until all that extra fuel is burnt and its TWR climbs above 1. And it will still burn lots and lots of fuel before it gets up to any reasonable speed.
Adding 10% fuel, and 10% thrust, plus 10% infrastructural overhead, will give you 10% more payload. Adding just fuel, not changing thrust nor infrastructure, from a certain point on, has rapidly diminishing returns. And all launches operate well on the "diminishing returns" side of the curve, following the adage 'fuel is cheap, engines are expensive'.
For your truck analogy, adding 10% of payload to climb a hill requires extra fuel. But that extra fuel needs to be carried uphill as it's spent as well, adding to total mass - and requiring even more fuel. And add to that that the truck's wheels are constantly slipping.
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I wonder what sort of shrapnel can penetrate the heatshield...
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I don't talk your ghetto slang, and I differentiate between combustion, deflagration and detonation.
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Most of which companies hire them.
What? Did you mean, "Most companies hire them" or something else?
Range safety is *very* important. (Obscure?)
Any links to such an actual incident?
https://www.youtube.com/watch?... I remember videos of a couple of other such incidents but I can only find that one at the moment.
He's making a list, and checking it twice. Gunna find out who's naughty who's nice...
He's making a list, and checking it twice. Gunna find out who's naughty who's nice....
1. Not during. Before.
2. Not most dangerous; less dangerous than launch for certain. And the rocket sitting fueled on the launchpad is not quite safe either.
3. The aluminium shell can evacuate the area in time. Astronaut climbing to it from that concrete room can't.
4. If you modify things deviating from the regular procedure for this specific type of rocket, the most dangerous part (launch) becomes much more dangerous.
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Agree, not to mention quantum wave teleporters (aka improbability drive) ;-)
Challenger proved that cost savings are important, it is time the "private" industry learn the lesson too.
Isn't that the one where the private sector engineers recommended against a launch, but the government agency went ahead?
https://en.wikipedia.org/wiki/Rogers_Commission_Report#Flawed_launch_decision
There's no time like the present. Well, the past used to be.
I concede, the irony is that we do have a leader that fits the bill with a team of loyal jackasses.