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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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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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Fixed link: https://www.youtube.com/watch?v=UyFF4cpMVag
> 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).
SpaceX uses densified propellant. Meaning, it's loaded at a temperature significantly below boiling point, which means simply replentishing what boils off doesn't work, as at that point it's already too warm to be useful.
That's why SpaceX needs to abort if the rocket spends too long sitting on the pad. The only solution if the propellant warms up too much is to drain all the fuel, and refuel the rocket again.
That's unless you're suggesting they should make some sort of giant cooler that wraps around the entire rocket.
> Fourth, we know from the launch of the car that the guidance systems and engine control are flaky.
If I recall correctly, given that this was a test, they simply pushed the rocket as far as it would go, and weren't aiming for an exact orbit.
So we need to do it gold plated or not at all? You really did work for the US government, I can tell.
Shutting down free speech with violence isn't fighting fascism. It IS fascism!
This sounds a bit inhumane. At the very least, they could use puppies or kittens.
Second, potentially, it could be made safe, but only by raising costs
Money is not the issue. Late fuel loading increases rocket performance.
The refrigeration doesn't have to be internal
What are you talking about ? There's no refrigeration.
Fourth, we know from the launch of the car that the guidance systems and engine control are flaky.
How is the guidance system software relevant for the fuel loading procedure ? The explosion happened because the designers didn't completely anticipate all the physical interactions between the oxygen and the carbon wrapped pressure vessel. Once you do understand these systems, the software is the easy part.
And don't forget that if you are pre-fueling before crew ingress, you've got all kinds of ground crew crawling around on the tower and such, that's far more people next to a big hazardous device. If you fuel when the astronauts are in the capsule belted in and buttoned up, and everyone else has a chance to GTFO before the fuel pumps turn on, the maximum risk to life would be the flight crew and they have far better chances due to the launch escape system.
Obviously no one wants anyone to die, but in the proposed scenario the only people around would be the astronauts, one with their hand on an abort handle capable of getting them out of there with extreme rapidity with a twist of the wrist. That seems like a better scenario to me.
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
Risks need to be managed or avoided in rocket science.
Gene Kranz has some insights into this, having lived though Apollo as flight director of multiple missions. https://www.reddit.com/r/Space... Rocket science is a dangerous business, people WILL die. At issue is an analysis of the risks, mitigation strategies for the identified risks and the acceptance of the remaining risks that cannot be controlled.
Where I share your concern with Space-X's process, the question is really for the rocket scientists to argue over and not a PR campaign. Is this an acceptable risk? Can it be effectively managed in the processes and procedures used to fuel the rocket and are the remaining risks acceptable? Maybe, maybe not.
I'm just an engineer, so I'll let the rocket scientists hash this one out.
"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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The 2016 explosion didn't rip the fairing apart. There's the entire service module (trunk) as a buffer between the launcher and the capsule. The engines are on the sloped sides, not beneath the capsule. And in the end, after analyzing the incident, Musk announced "Dragon would have been fine"
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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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out of there with extreme rapidity with a twist of the wrist
And it doesn't even take that much. There is an automatic process which can trigger the LES upon loss of connectivity through a wire that runs the length of the rocket. The moment that wire is broken, the LES can fire, and this can react faster than any human could.
Actually, no hand on the button, so to speak. Instead, super fast sensors that trigger in an instance, combined a redundant set of 8 dracos ( and only 4 required ). I would guess that they are likely to have a false abort, and yet, no injuries.
I prefer the "u" in honour as it seems to be missing these days.
https://www.youtube.com/watch?...
LES would have worked, though.
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.
Nothing to do with guidance or engine control. They just let the second stage engine burn to fuel exhaustion and it burned longer than expected. Except for the aborted ride-along satellite with the one ISS servicing mission because of the single engine failure in the first stage, all their launches have been precisely where the client wanted them. Including the spy sats.
Trying to become famous by taking photos. Visit my homepage please.
Judging from Google search results, the Momo-2 seems most notable for exploding at launch.