Merged: SpaceX’s Starship Rocket Explodes After Launch/Starship hop

[Ziggurat]

Originally Posted by jeremyp

I'm not completely convinced about their analysis of the new water deluge system.

I think their analysis is simply wrong. They make several assumptions that I don't think are at all justified. For one, they assumed that the amount of water pumping through the plates has to match the deluge system used by Artemis. Even assuming that SpaceX wants to use that much water (and it looks like they don't), it doesn't all have to flow through the plates. Second, they're interpreting a statement by Musk about the water pressure pushing against the rocket exhaust pressure as meaning a lot more than I think it actually means. They seem to think that Musk is claiming that the water spray from the plates will act like a water rocket to counter the booster rockets. But I don't think that's at all what Musk is saying. I think all he's saying is that the internal water pressure has to exceed the gas pressure on top of the plates so that water comes out the plates. That water doesn't have to form a counteracting rocket of its own. It's fine if that water layer stays on the surface of the plates. Hell, it may even work if there's NO liquid water on the surface, if you're just getting water vapor coming out the holes, as long as you're pushing enough water into the sandwich to keep it cool enough.

As for thermal expansion, he seems to be going off third party speculative renders to conclude that there's nothing in the design to account for thermal expansion. I wouldn't consider that reliable.

He's also stuck on the whole cement thing, and how fondag isn't the strongest cement out there. Which, yeah, looks like it's true: it doesn't have the strongest compressive strength. But it's got really good thermal resistance, which was the expected limiting factor. And I don't think he understands how the concrete failed. It didn't fail because the concrete just crumbled under the immense pressure because the compressive strength wasn't high enough. What appears to have happened is that the foundation under the slab got compressed, allowing the concrete to crack under a bending load, and once it cracked, that allowed high pressure to get in under the slab and start pushing stuff up from underneath. One of the big things SpaceX is doing with the reconstruction which isn't getting a lot of press is reinforcing the foundation. They're putting in much stronger pillars under the base than they previously had. If the foundation doesn't sag, then you won't get that same failure mode.

[Gulliver Foyle]

Originally Posted by jeremyp

I'm not completely convinced about their analysis of the new water deluge system. SpaceX has got some clever people, so surely the idea can't be debunked with some simple back o the envelope maths, can it?!

There are some other interesting points that come out of the video, that came directly out of Musk's mouth, so they must be true...

- It seems that SpaceX lost directional control of the vehicle after only 79 seconds. That doesn't sound good to me. Why didn't they initiate self destruct at that point?

- The guidance system effectively had a single point of failure. That doesn't sound good to me.

- The next booster will have different better engines an electrical control system instead of a hydraulic one, no single point of failure in the guidance system and better heat shielding. Why didn't they wait until that one was ready before humiliating themselves on the world stage. If they'd waited a few more weeks, they could have launched a much better rocket from a much better launchpad.

- They will 100% complete a successful launch into orbit within the next twelve months. That puts them well on track to having ships on Mars in 2022 and regularly launching Starlink with Starship in 2022 so they don't go bankrupt.

- The next year of Starship development will cost $2 billion. It will take them " a few years" to get full reusability. Seems like it's getting pretty expensive.

My guess is ten years from now, should the company still survive, SpaceX will be within twelve months of a first successful orbit. It's about standard for Musk's promises.

[smartcooky]

Originally Posted by Ziggurat

I think their analysis is simply wrong. They make several assumptions that I don't think are at all justified. For one, they assumed that the amount of water pumping through the plates has to match the deluge system used by Artemis. Even assuming that SpaceX wants to use that much water (and it looks like they don't), it doesn't all have to flow through the plates. Second, they're interpreting a statement by Musk about the water pressure pushing against the rocket exhaust pressure as meaning a lot more than I think it actually means. They seem to think that Musk is claiming that the water spray from the plates will act like a water rocket to counter the booster rockets. But I don't think that's at all what Musk is saying. I think all he's saying is that the internal water pressure has to exceed the gas pressure on top of the plates so that water comes out the plates. That water doesn't have to form a counteracting rocket of its own. It's fine if that water layer stays on the surface of the plates. Hell, it may even work if there's NO liquid water on the surface, if you're just getting water vapor coming out the holes, as long as you're pushing enough water into the sandwich to keep it cool enough.

As for thermal expansion, he seems to be going off third party speculative renders to conclude that there's nothing in the design to account for thermal expansion. I wouldn't consider that reliable.

He's also stuck on the whole cement thing, and how fondag isn't the strongest cement out there. Which, yeah, looks like it's true: it doesn't have the strongest compressive strength. But it's got really good thermal resistance, which was the expected limiting factor. And I don't think he understands how the concrete failed. It didn't fail because the concrete just crumbled under the immense pressure because the compressive strength wasn't high enough. What appears to have happened is that the foundation under the slab got compressed, allowing the concrete to crack under a bending load, and once it cracked, that allowed high pressure to get in under the slab and start pushing stuff up from underneath. One of the big things SpaceX is doing with the reconstruction which isn't getting a lot of press is reinforcing the foundation. They're putting in much stronger pillars under the base than they previously had. If the foundation doesn't sag, then you won't get that same failure mode.

Good post that nails a few facts to the wall.

I generally don't agree with you much on political issues Zig, but you are one of the few people posting in this thread who clearly understands the engineering and technology being discussed.

Its also clear that, like Thunderf00t, the Common Sense Skeptic analyses are heavily coloured with his own strong, personal bias against Musk and SpaceX.

[Myriad]

Originally Posted by Ziggurat

I think their analysis is simply wrong. They make several assumptions that I don't think are at all justified. For one, they assumed that the amount of water pumping through the plates has to match the deluge system used by Artemis. Even assuming that SpaceX wants to use that much water (and it looks like they don't), it doesn't all have to flow through the plates. Second, they're interpreting a statement by Musk about the water pressure pushing against the rocket exhaust pressure as meaning a lot more than I think it actually means. They seem to think that Musk is claiming that the water spray from the plates will act like a water rocket to counter the booster rockets. But I don't think that's at all what Musk is saying. I think all he's saying is that the internal water pressure has to exceed the gas pressure on top of the plates so that water comes out the plates. That water doesn't have to form a counteracting rocket of its own. It's fine if that water layer stays on the surface of the plates. Hell, it may even work if there's NO liquid water on the surface, if you're just getting water vapor coming out the holes, as long as you're pushing enough water into the sandwich to keep it cool enough.

As for thermal expansion, he seems to be going off third party speculative renders to conclude that there's nothing in the design to account for thermal expansion. I wouldn't consider that reliable.

I agree that thermal expansion can be disregarded until the main design parameters are defined, because there are various ways to mitigate it that can only be designed and implemented in a specific context. And also because the upper plate of the metal can't go too high or else it will fail for other reasons, so there is a ceiling on the amount of expansion that needs to be allowed for.

An internal cooling system has to transfer away heat that's already been absorbed by the plates. It can't blanket the pad surface because the rocket exhaust streams will blast it away from the flat surface. Nor can steam expanding outward deflect the focused streams of rocket exhaust from the engines. Steam can't transfer heat from metal as fast as liquid water can, so if the metal heats to the point where it's surrounded by steam instead of water, the temperature will run away.

Someone in NASA must know how much of the deluge water is boiled away by heat and/or sonic energy during their launches. A SpaceX cooling system must result in a comparable amount of steam relative to the heat output, so it requires at least that much water plus margins for inefficiencies and safety. It's a pretty big cloud, so even if the system works perfectly do they really want a comparable volume of steam blasting outward (and upward) from the pad right underneath the vehicle? Is there any daylight between "the heat transfer is too slow so the cooling pad melts down" and "the heat transfer is too fast so the cooling pad produces a continuous high-velocity steam explosion"?

[smartcooky]

They also completely fail to account for the difference in distance between engine and the plate in the test they criticise and the real world, and then labelled it a "Fail" before they show their analysis (talk about analysis to reach a preferred conclusion!).

Taking the known size of the sea-level Raptor engine bell, it's not hard to estimate that the test plate is about 6.5 metres from the engine bell. Meanwhile, the water-cooled plate will be positioned at the bottom of the OLM about 18.5 metres from where the Starship Raptor engine bells will be at launch... almost three times further away.

The velocity of rocket exhaust gases decreases as the exhaust plume expands into the surrounding atmosphere. This happens as a result of the conservation of mass and the increase in the cross-sectional area of the expanding plume. The mass flow rate of the exhaust gases remains constant throughout the expansion process. As the cross-sectional area increases, the same amount of mass is spread over a larger area, resulting in a decrease in the velocity of the gases and a decrease in the force impact of those gases on any object it might strike. This is analogous to standing behind a jet engine - the further away you are, the less impact the jet exhaust will have on you.

How much the impact force decreases depends on the design of the rocket engine, the expansion ratio of the nozzle, and the ambient conditions. It is typically determined through computational fluid dynamics (CFD) simulations or experimental testing specific to the rocket engine in question.

The YouTuber in question did not take any of this into account in his so-called analysis. Once I saw that first segment, I didn't bother watching any further because if he doesn't understand the bare basics, I have no confidence he will understand anything once they get more complicated, and get more complicated they will!

[Roger Ramjets]

Originally Posted by Checkmite

Sadly it really hangs Musk's hardcore supporters out to dry, after they've expended pages and possibly hundreds of collective man-hours hammering out impassioned explanations...

'Sadly'? I'm sure the hardcore Musk detractors are not at all sad. In fact they're loving it.

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...for why the choices surrounding the launch were practically and scientifically sound and crucial for collecting undefined but very super important "data".

Are you saying the data they collected wasn't valuable?

The idea that they were just getting junk off the pad and nothing else is silly. At a minimum they were gaining valuable experience, and if 'clearing the launch pad' was the only essential mission goal that gave them more freedom to experiment. Not launching would give them nothing.

Let me tell you a little story. 5 years before Covid I was approached by some scientists who wanted fly a fixed wing drone over apple orchards to drop sterile insects. Originally the idea was that I would train them to fly the drone. However it soon became apparent that it would need an experienced model aircraft pilot like myself to deploy in the locations available. At this point I knew that the fixed wind drone would not be suitable for commercial operation, and we would eventually have to use multirotor drones that could be flown with minimal training. However we continued to use the fixed wing drone while investigating alternatives.

The last scheduled flight of 2019 was in a challenging location. The normal flying strip wasn't available so I had to take off on a narrow strip between two rows of trees with only a few meters clearance. Chances of getting the aircraft down again without damage were slim, but that didn't matter so long as it could take off and do the mission. I skillfully (or luckily) managed to get it off OK, switched to autonomous control and let it do its thing. Sadly however the flight was cut short at the far end of the orchard about half a mile away. Due to the wind direction it got blown off course into the top of a tree, and that it was it for the season. The next year Covid hit and we couldn't fly, so the (now repaired) drone was mothballed.

That did not mean the fixed wing drone was a failure. We gathered very useful data and well as gaining valuable experience. The scientists used the data collected to publish a paper on the effectiveness of the technique with different drone types. Other people had been using fixed wing drones and even full size aircraft, but we were able to show that multirotor drones were far more effective, and despite being more expensive were cheaper to deploy and safer to operate. Data from the 'obsolete' fixed wing drone was essential for making that comparison.

Some day I hope to take the fixed wing drone out for one more spin just to see if the repairs were successful. If it breaks up in the air and crashes it will be a good training exercise for handling such events. We will of course not advertise this flight, as there are people out there who might take it the wrong way and cause very bad publicity for us.

[Ziggurat]

Originally Posted by Myriad

An internal cooling system has to transfer away heat that's already been absorbed by the plates. It can't blanket the pad surface because the rocket exhaust streams will blast it away from the flat surface.

If liquid water is exiting the plates, it doesn't need to wet the surface, it will still help cool it.

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Nor can steam expanding outward deflect the focused streams of rocket exhaust from the engines.

It doesn't need to.

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Steam can't transfer heat from metal as fast as liquid water can,

Sure. Which is why you want to be able to flow water fast enough to cool it enough that you aren't getting a liedenfrost effect inside the sandwich. But that doesn't require liquid water on both sides of the top plate.

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Someone in NASA must know how much of the deluge water is boiled away by heat and/or sonic energy during their launches.

Much of it isn't, which is why they need the catch basins for runoff.

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A SpaceX cooling system must result in a comparable amount of steam relative to the heat output, so it requires at least that much water plus margins for inefficiencies and safety. It's a pretty big cloud, so even if the system works perfectly do they really want a comparable volume of steam blasting outward (and upward) from the pad right underneath the vehicle?

The rocket exhaust pretty much guarantees steam won't be going up under the rocket. Steam out the sides is harmless to the rocket.

[jeremyp]

Originally Posted by smartcooky

Good post that nails a few facts to the wall.

I generally don't agree with you much on political issues Zig, but you are one of the few people posting in this thread who clearly understands the engineering and technology being discussed.

Its also clear that, like Thunderf00t, the Common Sense Skeptic analyses are heavily coloured with his own strong, personal bias against Musk and SpaceX.

There are very good reasons to have a personal bias against Elon Musk.

Anyway, leaving that aside, are you not concerned at some of the things he said in the call? For example, by his own admission the rocket was out of control by around 80 seconds but they didn’t even try to make it self destruct for over a minute after that.

Are you not concerned about the time scales Musk talked about for getting this thing operational or the annual costs involved?

[smartcooky]

Originally Posted by jeremyp

There are very good reasons to have a personal bias against Elon Musk.

Yes, I agree, there are.

I personally can't stand him, and despite what you and others here have said, I'm not a fanboy. I think hes a jumped up prick with a very strong and disturbing tendency towards the more objectionable aspects of the political right. But, unlike Thunderf00t, Common Sense Skeptic, and some of the ISF members posting in this thread, I can set aside my own dislike for him as a person, and not let it effect my respect for what SpaceX have achieved, and what they are trying to do. This is why those two YouTubers, and several members here have lost my respect.

Now, I don't give a fat rats arse about Musk's personality and character flaws. AFAIC, anyone in future who wants to conduct an Elon Musk hate fest can just bugger-off and make their own thread for that discussion - I'm only interested in the technical and engineering aspects, so I won't be joining them.

Originally Posted by jeremyp

Anyway, leaving that aside, are you not concerned at some of the things he said in the call? For example, by his own admission the rocket was out of control by around 80 seconds but they didn’t even try to make it self destruct for over a minute after that.

As I said, I didn't watch past the first segment about the water test (and have no intention of doing so - I have better things to do with my time).

Yes, I am somewhat concerned by those things, just as I was concerned when several of the first few attempts to land F9 boosters resulted in crashes. And while its probably not good practice to allow a rocket to continue out of control, there was also no danger to anyone on the ground or at sea - the stack was still well inside the downrange exclusion zone and importantly, it was still gaining altitude!. It was only when the rocket began to fall back to earth that they triggered the FTS... and I might be wrong about this, but I understand this is fairly common practice in rocketry circles. Someone like Jay Utah or STS60 would be better placed to comment on that.

My biggest concerns are these

First concern - they did not correctly predict the level of destruction to the OLM. It is worth noting that NO observers predicted that would happen not even Common Sense Skeptic, but they sure as hell jumped on the bandwagon PDQ when it did happen. However, the SpaceX engineers had direct access to all the data they would have needed to calculate that the concrete was not going to withstand the launch. That they were unable to do so is very concerning. I guess no-one is perfect - and engineers do make mistakes sometimes, don't they....

Second concern - the FTS did not cause the stack to lose its structural integrity within a few seconds. Either the tanks are so strong that they withstood the ruptures and and didn't depressurize quickly enough (causing them to maintain their structural integrity far beyond the expected point of failure) or the charges themselves were insufficiently powerful to do the job.

On the positive side, SpaceX appear well on their way to fixing these issues, so I will reserve my concerns and wait until Starship Test Launch V2

Originally Posted by jeremyp

Are you not concerned about the time scales Musk talked about for getting this thing operational or the annual costs involved?

Meh.

When you have been following SpaceX for as long as I have (over 20 years now) you'll get used to "Elon Time"

As for costs...

How much has the Artemis 1 rocket cost so far?... US$23bn
How much will each launch cost?.. US$4.3bn
How much of the rocket will they get back for reuse... 0.00%

[jeremyp]

Originally Posted by smartcooky

Yes, I agree, there are.

Now, I don't give a fat rats arse about Musk's personality and character flaws. AFAIC, anyone in future who wants to conduct an Elon Musk hate fest can just bugger-off and make their own thread for that discussion - I'm only interested in the technical and engineering aspects, so I won't be joining them.

The problem is that Musk's personality and character flaws directly impact the companies he runs. Whose decision was it to launch Starship before they had the water system in place? Was it his? Because it has definitely cost them.

Quote:

As I said, I didn't watch past the first segment about the water test (and have no intention of doing so - I have better things to do with my time).

You didn't have to watch the CSS video. You could have watched the original Twitter live video. The things I listed were all things that Musk himself said and so potentially true.

Quote:

Yes, I am somewhat concerned by those things, just as I was concerned when several of the first few attempts to land F9 boosters resulted in crashes.

And those crashes nearly bankrupted SpaceX. The fact that they got past them doesn't mean it will be the same this time.

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And while its probably not good practice to allow a rocket to continue out of control, there was also no danger to anyone on the ground or at sea - the stack was still well inside the downrange exclusion zone and importantly, it was still gaining altitude!

Well they were quite lucky. The rocket continued to go in more or less the right direction. Suppose it had veered off course? The rocket was only 80 seconds from the launch pad when they lost directional control. It took 90 seconds for the FTS to destroy the rocket when they finally did activate it. The places the rocket could have got to in 90 seconds clearly include the launch site and probably South Padre Island which is only six miles away.

Quote:

First concern - they did not correctly predict the level of destruction to the OLM. It is worth noting that NO observers predicted that would happen not even Common Sense Skeptic, but they sure as hell jumped on the bandwagon PDQ when it did happen. However, the SpaceX engineers had direct access to all the data they would have needed to calculate that the concrete was not going to withstand the launch. That they were unable to do so is very concerning. I guess no-one is perfect - and engineers do make mistakes sometimes, don't they....

Actually, I saw a few videos last year from some of the SpaceX fanboys discussing the problem. They raised concerns about the lack of flame deflectors but ultimately dismissed them on the grounds that the SpaceX engineers must know what they were doing. At the time I didn't question the logic because SpaceX engineers, as a rule, do know how to build and launch rockets. I still find it hard to believe that the same company that runs Falcon 9, Falcon Heavy and Dragon are responsible for the fiasco that was this launch.

Quote:

Second concern - the FTS did not cause the stack to lose its structural integrity within a few seconds. Either the tanks are so strong that they withstood the ruptures and and didn't depressurize quickly enough (causing them to maintain their structural integrity far beyond the expected point of failure) or the charges themselves were insufficiently powerful to do the job.

I think the problem was that the charges didn't make big enough holes. A shaped charge running the length of the tank should do the trick. I understand that's what NASA usually does.

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On the positive side, SpaceX appear well on their way to fixing these issues, so I will reserve my concerns and wait until Starship Test Launch V2

Well Elon Musk regards the FTS as being on the critical path so I suspect they are not "well on the way" with that aspect.

On the other hand he did list a number of other issues with the booster such as the hydraulic actuators, the quality of the engines and the jerry built heat shield which are all fixed on booster 9. Given that this rocket seems to have been a complete junker, I wonder why they didn't just scrap it and go with booster 9 in a few weeks and with a launchpad that could survive a launch.

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Meh.

When you have been following SpaceX for as long as I have (over 20 years now) you'll get used to "Elon Time"

But it's now become a risk for NASA's programme to go back to the Moon.

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As for costs...

How much has the Artemis 1 rocket cost so far?... US$23bn
How much will each launch cost?.. US$4.3bn
How much of the rocket will they get back for reuse... 0.00%

But if it's costing SpaceX $2 billion a year to develop Starship, it won't be long before it overtakes SLS in overall cost. And how long can SpaceX sustain such costs?

[Myriad]

Originally Posted by Ziggurat

If liquid water is exiting the plates, it doesn't need to wet the surface, it will still help cool it.

It doesn't need to.

Sure. Which is why you want to be able to flow water fast enough to cool it enough that you aren't getting a liedenfrost effect inside the sandwich. But that doesn't require liquid water on both sides of the top plate.

Much of it isn't, which is why they need the catch basins for runoff.

I don't disagree with any of that.

The temperature of the water when it reaches the catch basins would also be useful data.

Given that it's neither necessary nor possible to have liquid water covering the top surface of the plate during the launch, it appears the holes in the top plate are only needed to increase the cooling area (the contact area between the plate and the water). Otherwise you could have for instance a lateral flow that vents out the sides. Larger holes have more cooling area, but the linear water flow rate through the holes has to stay ahead of the flash-steam front. The resulting fountaining of the water out the holes (when the rocket engines aren't blasting at the plate) is just a side effect of creating the necessary internal conditions.

As for steam getting under the rocket, though, sure it won't be blasting directly up the engine bells. But the steam cloud is going to envelop the entire vehicle during those seconds just before and just after liftoff. Rockets have to withstand harsh conditions, of course, but given that they don't launch in the rain, I have to wonder if those particular steam cloud conditions (turbulence, condensation) will make rocket engineers at least a little nervous.

Maybe they could add a wide skirt (designed to either retract or be ejected off shortly after liftoff) around the booster to catch that steam explosion updraft for a bit of extra boost!

[Ziggurat]

Originally Posted by jeremyp

But if it's costing SpaceX $2 billion a year to develop Starship, it won't be long before it overtakes SLS in overall cost. And how long can SpaceX sustain such costs?

I have no idea how much money SpaceX has available. But supposing Starship costs surpass Artemis, it will still be a much better deal. Artemis has no other uses besides the moon mission. It's far too expensive on a per launch basis to be useful for anything else. But Starship and Heavy Lift, if they work, will be able to do a lot more than the moon mission.

[smartcooky]

Originally Posted by jeremyp

The problem is that Musk's personality and character flaws directly impact the companies he runs. Whose decision was it to launch Starship before they had the water system in place? Was it his? Because it has definitely cost them.

Still irrelevant AFAIC.

Originally Posted by jeremyp

You didn't have to watch the CSS video. You could have watched the original Twitter live video. The things I listed were all things that Musk himself said and so potentially true.

I don't do Twitter; never have and never will, and even less likely to now that Musk has turned it into a platform for right-wing extremists to post unfettered.

Originally Posted by jeremyp

And those crashes nearly bankrupted SpaceX. The fact that they got past them doesn't mean it will be the same this time.

Completely wrong. It was their failures with Falcon 1 that nearly bankrupted them.

The crashes of Falcon 9 booster landing attempts had little financial effect on anything. The cost involved in trying was having a ADS on station and a small lowering of payload size. There is no effective financial difference between trying to develop a system to land boosters, or not even bothering to try. I either case, they were not getting them back anyway.

Originally Posted by jeremyp

Well they were quite lucky. The rocket continued to go in more or less the right direction. Suppose it had veered off course? The rocket was only 80 seconds from the launch pad when they lost directional control. It took 90 seconds for the FTS to destroy the rocket when they finally did activate it. The places the rocket could have got to in 90 seconds clearly include the launch site and probably South Padre Island which is only six miles away.

The weren't lucky, they took precautions. The downrange exclusion zone was huge - a rough cone over 250 miles downrange, and about 20 miles wide at the point where the trouble started (and widening as it got further downrange. It would likely have taken longer than the burn time of the booster's available fuel load to go outside of that zone.

Originally Posted by jeremyp

Actually, I saw a few videos last year from some of the SpaceX fanboys discussing the problem. They raised concerns about the lack of flame deflectors but ultimately dismissed them on the grounds that the SpaceX engineers must know what they were doing. At the time I didn't question the logic because SpaceX engineers, as a rule, do know how to build and launch rockets. I still find it hard to believe that the same company that runs Falcon 9, Falcon Heavy and Dragon are responsible for the fiasco that was this launch.

Of course, you will be able to provide links to these videos you saw?

Originally Posted by jeremyp

I think the problem was that the charges didn't make big enough holes. A shaped charge running the length of the tank should do the trick. I understand that's what NASA usually does.

Agreed

Originally Posted by jeremyp

Well Elon Musk regards the FTS as being on the critical path so I suspect they are not "well on the way" with that aspect.

They have already conducted some tests of a revised FTS.

Originally Posted by jeremyp

On the other hand he did list a number of other issues with the booster such as the hydraulic actuators, the quality of the engines and the jerry built heat shield which are all fixed on booster 9. Given that this rocket seems to have been a complete junker, I wonder why they didn't just scrap it and go with booster 9 in a few weeks and with a launchpad that could survive a launch.

If you are implying it had something to do with stupid 4/20 meme, I am surprised. That is a dumb conspiracy theory, I would not have expected you to believe in conspiracy theories.

The rest of your post answered by Ziggurat.

[Checkmite]

Originally Posted by jeremyp

At this point, it looks like they really were going for the 4/20 meme. If somebody told me that the original plan to launch on the 17th was fake and the technical problem manufactured to give them an excuse to delay until the 20th I would consider it plausible.

You know - I haven't said it all this time, but I'd be lying if I said I didn't consider that a possibility bordering on likely since the beginning.

[Checkmite]

Originally Posted by Myriad

An internal cooling system has to transfer away heat that's already been absorbed by the plates. It can't blanket the pad surface because the rocket exhaust streams will blast it away from the flat surface. Nor can steam expanding outward deflect the focused streams of rocket exhaust from the engines. Steam can't transfer heat from metal as fast as liquid water can, so if the metal heats to the point where it's surrounded by steam instead of water, the temperature will run away.

That's a very key detail. Water has to survive and exit the plates in liquid form in order to carry away the heat, otherwise there's no cooling going on. Anyone who owns a car knows or should know what happens when the coolant inside the vehicle's cooling system begins to boil into steam.

[theprestige]

Originally Posted by jeremyp

And those crashes nearly bankrupted SpaceX.

https://en.wikipedia.org/wiki/List_o...%E2%80%932019)

Almost every single early launch of Falcon 9 that failed, failed after successfully conveying the customer's payload into orbit.

And a lot of the earlier ones didn't even try to recover the first stage; instead being incremental tests of the system, or else otherwise not intended to recover. It's hard to see how successful deliveries for paying customers customers, and planned loss of test articles during R&D, would lead to (near) bankruptcy.

"Our rockets always blow up."

[Doubt]

Originally Posted by Checkmite

That's a very key detail. Water has to survive and exit the plates in liquid form in order to carry away the heat, otherwise there's no cooling going on. Anyone who owns a car knows or should know what happens when the coolant inside the vehicle's cooling system begins to boil into steam.

That is not true. Steam is a substance used to move energy. To get the steam, the water has to absorb heat. The moving steam carries heat with it. If it did not, boilers would use much less energy and radiators would not work.

Hell, the state transformation from water to steam consumes energy without changing the temperature until the transformation is complete and then gains even more energy as the steam temperature keeps rising.

I have no idea if the new Space X system will work. Even if it does work, I wonder if the steel will just end up oxidized from the flames if the temperature ends up being enough to crack some of the water into hydrogen and oxygen.

[Roger Ramjets]

Originally Posted by jeremyp

The problem is that Musk's personality and character flaws directly impact the companies he runs. Whose decision was it to launch Starship before they had the water system in place? Was it his?

I give up. Was it?

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But it's now become a risk for NASA's programme to go back to the Moon.

Hopefully they will decide it's too risky. We went to the Moon in 1969. There are zero good reasons for going back now.

[The Great Zaganza]

as payment for hosting his campaign launch, DeSantis signed a law permitting Musk to kill his astronauts.

https://www.rollingstone.com/politic...ty-1234742632/

[Gulliver Foyle]

Originally Posted by The Great Zaganza

as payment for hosting his campaign launch, DeSantis signed a law permitting Musk to kill his astronauts.

https://www.rollingstone.com/politic...ty-1234742632/

Fine then, have meatball Rob be the first SpaceX astronaut

[jeremyp]

Originally Posted by smartcooky

Still irrelevant AFAIC.

I don't do Twitter; never have and never will,

Don't worry, what Musk said in the Twitter Live was widely reported elsewhere.

Quote:

and even less likely to now that Musk has turned it into a platform for right-wing extremists to post unfettered.

There were no right wing extremists involved in the Twitter Live (accepted that some people think Musk himself is a right wing extremist). And, even if you had accidentally read one of their posts, it would be unlikely to infect you.

I'm surprised that somebody like yourself who has been following the development of Starship with such keen interest completely ignored Elon Musk's own assessment on what happened just because you don't like the platform he used.

Quote:

Completely wrong. It was their failures with Falcon 1 that nearly bankrupted them.

My mistake, but the point stands. Having lots of failures can bankrupt a rocket company.

Quote:

The weren't lucky, they took precautions. The downrange exclusion zone was huge - a rough cone over 250 miles downrange, and about 20 miles wide at the point where the trouble started

The trouble started at t=0 - in fact, before then. Three engines were shut down before lift off. They were lucky that the configuration of the failed engines made the rocket move away from the tower, not towards it.

They lost directional control at t=79. At that point the rocket was still accelerating. That means it could pretty much get back to where it started in 90 seconds - or the near by town of South Padre Island. To be fair, the engineers did not know that it was going to take 90 seconds for the FTS to be effective, so I guess we can cut them some slack.

Twenty miles, by the way, is not a lot when you have a vehicle travelling at 1000 mph. The margins are pretty tight.

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Of course, you will be able to provide links to these videos you saw?

You haven't bothered to properly view any of the links you already been provided with.

Quote:

They have already conducted some tests of a revised FTS.

Elon Musk said (in the presentation you refuse to listen to) that the re qualification of the FTS is what will take the longest time. They don't have to just design and build a new one, they need to get approval from the FAA. I think, in light of what happened with the original one, they are going to take their time to make sure the new is done right.

Quote:

If you are implying it had something to do with stupid 4/20 meme, I am surprised. That is a dumb conspiracy theory, I would not have expected you to believe in conspiracy theories.

I'm just looking at the evidence. They have another booster with superior engines, guidance systems and heat shields almost ready to go. They had a launchpad system that, if it worked, would be revolutionary, almost ready to go. Why the hell didn't they wait? We'd probably be talking about a successful launch here at the end of May instead of the fiasco that was.

[jeremyp]

Originally Posted by Checkmite

That's a very key detail. Water has to survive and exit the plates in liquid form in order to carry away the heat, otherwise there's no cooling going on. Anyone who owns a car knows or should know what happens when the coolant inside the vehicle's cooling system begins to boil into steam.

This is not correct. The transition from liquid to gas carries far more heat away than just making the water hotter. This is because of the latent heat of vaporisation. It takes a lot of energy to turn water into steam.

It would be far more effective in a car to let the water boil off but that would mean you'd need vast amounts of the stuff.

[jeremyp]

Originally Posted by The Great Zaganza

as payment for hosting his campaign launch, DeSantis signed a law permitting Musk to kill his astronauts.

https://www.rollingstone.com/politic...ty-1234742632/

I never thought of that being an issue. Astronauts are strapped to the top of a massive bomb and then launched into space - hopefully. Common sense suggests that there must already be a way to stop law suits in case of death.

Did the relatives of the Challenger astronauts sue?

[Ziggurat]

Originally Posted by jeremyp

I never thought of that being an issue. Astronauts are strapped to the top of a massive bomb and then launched into space - hopefully. Common sense suggests that there must already be a way to stop law suits in case of death.

Did the relatives of the Challenger astronauts sue?

Its much harder to sue the federal government. And we've never really had private companies sending astronauts into space before.

[theprestige]

Originally Posted by Ziggurat

Its much harder to sue the federal government. And we've never really had private companies sending astronauts into space before.

Makes you think maybe it would be difficult to encourage innovation and entrepreneurship in space launch, if the investors and executives aren't at least as well protected as NASA and its contractors, in these extremely high-risk endeavors.

[Checkmite]

Originally Posted by jeremyp

This is not correct. The transition from liquid to gas carries far more heat away than just making the water hotter. This is because of the latent heat of vaporisation. It takes a lot of energy to turn water into steam.

But when the steam is trapped inside and against the item being cooled the heat isn't "carried away", so there is no cooling going on.

If water is flashing into steam after exiting the cooling system, yes that's fine. But if the water is flashing into steam inside the the system, the system is broken. The surfaces that are in contact with the steam rather than flowing liquid water will not be able to transfer their heat effectively. It's the whole reason why ICEs can't use a closed loop of plain water for cooling.

[smartcooky]

Originally Posted by Checkmite

But when the steam is trapped inside and against the item being cooled the heat isn't "carried away", so there is no cooling going on.

What is going to "trap" the steam? I would expect from what designs I have seen so far, that the steam would be blasted outwards between the supports of the OLM ring. water keeps deluging from the holes in the plate, and it turns to steam, providing the cooling.


The white clouds left and right of the rocket are mostly steam
with a small quantity of rocket exhaust

Originally Posted by Checkmite

If water is flashing into steam after exiting the cooling system, yes that's fine. But if the water is flashing into steam inside the the system, the system is broken.

Well the system is not designed to operate that way. If the water inside the cooling plate were to turn into steam, then yes, that would be trouble.

[ohms]

There was a recent test of the water cooled steel plating. Hard to tell too much from testing of 1 plate but nothing seemed to be trapped anywhere

YouTube Video This video is not hosted by the ISF. The ISF can not be held responsible for the suitability or legality of this material. By clicking the link below you agree to view content from an external website.

I AGREE

[smartcooky]

Here is a very good animated render and commentary giving a brief explanation of how the water-cooled steel plate system is supposed to work. Its from Alpha Tech's YouTube channel, with the computer rendering by Ryan Hansen. Credit to both of them for this excellent presentation.

Note: right-click on the link and choose to play it in a new tab. It will play a short (1m 41s) video in Dropbox

https://www.dropbox.com/s/1zi550dn80...luge.mp4?raw=1

[Darat]

How do we know that is accurate?

[smartcooky]

Originally Posted by Darat

How do we know that is accurate?

We don't.

How would we know if its not? I'm simply offering it for people to view. Form your own opinion.

[Darat]

Originally Posted by smartcooky

We don't.

How would we know if its not? I'm simply offering it for people to view. Form your own opinion.

I thought you saying "..giving a brief explanation of how the water-cooled steel plate system is supposed to work...." and that is was a "excellent presentation" meant details had been released.

[smartcooky]

Originally Posted by Darat

I thought you saying "..giving a brief explanation of how the water-cooled steel plate system is supposed to work...." and that is was a "excellent presentation" meant details had been released.

OK, that was a bit confusing. I was referring to the quality of the renderings.

I have asked some of the rocket scientists over at ApolloHoax to have a look and give their opinions.

[Solitaire]

Originally Posted by jeremyp

I never thought of that being an issue. Astronauts are strapped to the top
of a massive bomb and then launched into space - hopefully. Common sense
suggests that there must already be a way to stop law suits in case of death.

Did the relatives of the Challenger astronauts sue?

Yes. And they won in court.

Quote:

Challenger Settlements Disclosed

The government and rocket manufacturer Morton Thiokol paid $7,735,000
in cash and annuities, dividing the cost 40-60, to settle all claims with the
families of four of the crew members who died.

Originally Posted by Roger Ramjets

Hopefully they will decide it's too risky. We went to the Moon in 1969.
There are zero good reasons for going back now.

It's right there on the Artemis web page.

Discovery, economic opportunity, inspiration, what more would you want?

Oh, maybe beating China to the Moon. But that's just sprinkles on the top.

One thing I want to make clear. It's not like the 2010 movie, Red Ball by Boondocks.

In America we change billionaires like you change hats.

Quote:

Jeff Bezos Rocket Company Wins NASA Moon Contract

On their second try, Jeff Bezos and his rocket company have won a contract
to take NASA astronauts to the moon. NASA announced on Friday that it had
awarded a contract to Mr. Bezos’ company, Blue Origin, to provide a lunar
lander for a moon mission that is scheduled to launch in 2029. NASA agreed
to pay $3.4 billion for the 50-foot-tall spacecraft, which is named Blue Moon
and can transport four astronauts to the moon’s surface.

[smartcooky]

Originally Posted by jeremyp

But if it's costing SpaceX $2 billion a year to develop Starship, it won't be long before it overtakes SLS in overall cost. And how long can SpaceX sustain such costs?

In 2012, SpaceX announced the intention to develop a launch system with substantially greater capabilities than Falcon 9. SpaceX created a succession of designs under various names (MCT, ITS & BFR leading up to a 2019 decision to go with a stainless-steel body design. The project then became know as Starship, so the development truly began in 2019 using their iterative design methodology (design - test - break stuff - learn from it, rinse and repeat).

What has that cost so far? $3 billion over 3½ years... less than $1 billion per year so far. SpaceX have just announced that investment has reached $5 billion, with $2 billion of that for development over the next year.

Meanwhile, the costs for the Artemis launch system continue to accumulate, Each successful launch will cost about $4.1 billion, that is more than twice total cost of Starship development over the next 12 months. SpaceX's Starship costs are not going to overtake Artemis any time soon... or at all.

https://spacenews.com/spacex-investm...hes-5-billion/

[Roger Ramjets]

Originally Posted by Solitaire

Discovery, economic opportunity, inspiration, what more would you want?

Oh, maybe beating China to the Moon. But that's just sprinkles on the top.

So like I said, zero good reasons...

[Gulliver Foyle]

Originally Posted by ohms

There was a recent test of the water cooled steel plating. Hard to tell too much from testing of 1 plate but nothing seemed to be trapped anywhere

YouTube Video This video is not hosted by the ISF. The ISF can not be held responsible for the suitability or legality of this material. By clicking the link below you agree to view content from an external website.

I AGREE

And if you look at the end of the video after the engine is shut off, the the water being released is following a significantly different trajectory than at start-up, suggesting significant damage to the system.

Given what we know of the modus operandi of Musk led operations, the system is very likely to be nowhere near ready to work in a launch environment and everything Musk says is stringing others along.

[Ziggurat]

Originally Posted by Gulliver Foyle

And if you look at the end of the video after the engine is shut off, the the water being released is following a significantly different trajectory than at start-up, suggesting significant damage to the system.

That's one possibility. Another is that they started turning off the pump when they turned off the jet, because they don't need water flowing once the jet is off.

[smartcooky]

Originally Posted by Gulliver Foyle

Given what we know of the modus operandi of Musk led operations, the system is very likely to be nowhere near ready to work in a launch environment and everything Musk says is stringing others along.

Well, that was certainly the case for Falcon 9, wasn't it.

.... oh, wait!

[Checkmite]

Originally Posted by Ziggurat

That's one possibility. Another is that they started turning off the pump when they turned off the jet, because they don't need water flowing once the jet is off.

Then how are you supposed to be able to tell whether there WAS damage to the system? Leaving the water flowing at the same rate provides the easiest visualization of whether something has changed.