SuperHeavy+Starship have the thermal energy of the Hiroshima bomb.

RobertDyck · 2023-04-24 08:19:06

If you watch the video, 2 engines of the outer ring failed to light. At least at 16 seconds after liftoff, and before it cleared the tower they were not burning. 3 more engines in the outer ring failed during flight. 2 more engines of the outer ring failed, but did relight. The last 2 did not fail at the same time. I didn't see a second inner engine fail, but I just watched SpaceX coverage of their own launch.

SpaceNut · 2023-04-24 20:33:10

Here is what a plume near the ground appeared like for just the starship.

I also saw the stream of cooled venting coming down the side that entered into the engine path.

Starship-Engine-Flame-Launch-20-April-2023-1024x762.jpg

spacex_large_0953_145.webp?w=550&ssl=1

tahanson43206 · 2023-04-25 06:30:51

The analysis in this YouTube report includes Elon accepting responsibility for the lack of a flame diverter.

https://www.youtube.com/watch?v=h2gEQIlWULQ

(th)

GW Johnson · 2023-04-25 09:26:10

The three photos that Spacenut posted in post #52 just above, are very informative.

In the first one at liftoff, look at the color and character of the "smoke" cloud. That's not smoke, it is dust, and not very fine-grained, either, or it would have billowed up a lot higher. Combine that with the reports of concrete blocks coming down multiple city blocks away, and sand coming down 6 or more miles away, and you understand that what you are looking at is really the excavation debris being flung out b the rocket blast as the launch stand is being destroyed. For lack of a flame deflector.

The other two photos show two separate things quite clearly:

(1) Yes, there was vented methane streaming down the side of the vehicle. It caught fire and base-burned around the engines, which plays merry hell with the wiring and plumbing on those engines! It's also entrained onto the engine plumes as subsonic flaming sheath around the supersonic plumes. You can tell by the bright yellow color and the wavy nature that this is a subsonic fuel-rich flame.

(2) There are supersonic plumes encased in subsonic flame sheaths that point straight aft (from the undamaged engines), and there are some supersonic plumes sheathed in subsonic flame jetting out to the side, well off-axis. Those are coming from badly-damaged engines that are not shut down. I can see at least 3 of these. They represent forces that act to spin the vehicle end-over-end.

Informed speculations:

(1) Odds favor that some of the concrete block debris chunks hit and badly-damaged multiple engines at ignition and during liftoff, as the rocket blast excavated that huge hole. Loss of engines reduced vehicle thrust, and (more importantly) those damaged engines shedding lateral streams added very large side forces at the rear, which eventually overcame the thrust vectoring control of vehicle attitude. Which is why it eventually spun end-over-end.

(2) It's not yet bent at the staging joint in these views (Spacenut's posted photos), but I saw the to stages bent out of alignment by around 5-10 degrees in the video footage of the sinning vehicle. Once the vehicle gets broadside-enough to the supersonic slipstream (about Mach 2 at about 100,000 feet), the dynamic pressure is around 65 pounds per square foot. That pressure acting on multiple thousands of square feet of broadside area is way more than enough to bend very thin stainless steel structures, and the weakest point is where the two stages are clamped together. Which is right where it bent out-of-line.

My own conclusions:

(1) SpaceX already knows a lot more about what happened than they are saying in public. Musk's admitting they should have had a flame diverter is a hint of that. This test flight would have gone a LOT BETTER had they had one, and they know it.

(2) SpaceX is in trouble again with the FAA, because the debris that was flung far, far exceeded the estimated debris risk distances in the environmental impacts documents, upon which their launch license depended. That would not have happened if they had had a flame diverter, and they (and now the FAA) know that, too.

(3) FAA will likely not grant another launch license, until they are shown just how bad "top-level management" decisions can be avoided. I'm talking about Musk, not Shotwell. She knows better. He does not. And the FAA knows that, too.

(4) That should give them plenty of time to install and properly test a flame diverter. Any few-seconds static test of the Superheavy can serve to test the flame diverter. And show the suppression of debris-flinging. They don't need a launch license to do that. But until they do, they should not fly again. And I think the FAA now understands that, too.

GW

Last edited by GW Johnson (2023-04-25 09:35:56)

RobertDyck · 2023-04-25 11:11:13

GW Johnson: the pictures posted by SpaceNut in post #52 are from suborbital launches. They aren't from the recent orbital test.

tahanson43206 · 2023-04-25 11:26:35

For SpaceNut ... please consider adding more text to Post #52

It seems clear that readers (members or not) will (can) become confused, because you have included one picture that is not of the Heavy launch.

(th)

RobertDyck · 2023-04-25 11:43:25

Oh, the pictures of the flame plumes are orbital launches. But were they deliberately venting methane, or was it leakage from damage from chunks of concrete from the launch pad?

SpaceNut · 2023-04-25 19:47:04

First off the launch of a starship is just 6 engines and the dust cloud is huge so what do you think we would get for a full 30 plus engines for the booster should have told you what would happen.

The STARSHIP Was UNDERPOWERED From the Start: Analysis Shows Why SpaceX Launch Failed to Reach Orbit! by Dr Scott Walker plus many more videos on the page.

Some images for the ground damage also show that the fuel tanks were hit quite a bit as well.

minvan footage

Not sure how far away the camera is but wow Elon Musk's giant SpaceX Starship rocket leaves craters and causes serious damage at Texas base

SpaceX Is in Big Trouble With the FAA After Starship Explosion

what is this from????
AA1ak5Q5.img?w=300&h=158&m=6

SpaceNut · 2023-04-25 21:04:40

https://youtu.be/w8q24QLXixo
Video show camera looking up a grid fin bend plus a hugh crunk can be seen lofted in the first 10 seconds of flight

GW Johnson · 2023-04-26 11:32:06

The photos that Spacenut posted are very most definitely Starship/Superheavy in flight. The forward and aft aerosurfaces on Starship are visible, as are the grid fins on the forward portion of the Superheavy booster. Most telling is the number of active engines glowing on the aft end. It is way more than the 3 that ALL the Starship-only tests used, or even the 6 total that Starship is eventually supposed to have.

Looking at the Scott Manley video, it seems he and I came to very similar conclusions about what happened. The ascent footage he showed had much clearer views of explosions happening just inside the aft fairing where the engine thrust chambers and hydraulics are located. You can even see debris shed in flight from those explosions.

There's a lot of earthwork and concrete repair that has to be made, and they have to install not just a steel flame diverter, but one with a big-time water deluge cooling system. That was required for Saturn 5, and this thing has more than twice that thrust. They also have a lot of repairs to make where ground support equipment (and very likely their launch tower) sustained damage from flung chunks of concrete and flung twisted pieces of steel. You can even see some of that being flung in the video footage of liftoff that Scott Manley showed.

The more one looks at video and photos, the more one can see. You can bet that the engineers at Spacex are looking closely and repeatedly at this stuff, plus the telemetry that they have. This thing most definitely lost too many engines, and the most probable cause is the decision to fly it without doing a flame diverter. The force exerted on the concrete when they lit, was equal to the thrust of all the engines that lit. That's around 16 million pounds, on an area roughly 30 feet in diameter. If a cold flow, the concrete might have withstood it, but the thermal effects of 5500 F rocket exhaust are simply overwhelming. They always have been, and they always will be. Even the little tactical rocket motors excavate holes in seconds, if you point that exhaust at the dirt.

GW

RobertDyck · 2023-04-26 18:25:53

I remember in the 1960s the explanation that shock waves from the engines would reflect off concrete causing damage to engines. LC#34 had a steel flame diverter. LC#39 had a massive concrete structure with flame trench and water deluge system. Saturn 1 caused so much vibrations it broke windows of houses. Saturn V definitely needed a water deluge system for both cooling the flame diverter, but more importantly dampening vibration so buildings miles away don't get damaged.

RobertDyck · 2023-04-26 18:41:15

I'm counting on Starship to lift parts and tooling to construct the Large Ship.

RGClark · 2023-04-30 18:02:29

Three quite alarming facts were revealed in Elon’s twitter Spaces discussion:

Elon Musk - Spaceship update after explosion - Spaces Twitter.
https://www.youtube.com/watch?v=pe4B2eIeXfs

First, the Raptors likely were not damaged by the concrete thrown up. If so, then 8 Raptors failed on their own during the flight. Second, thrust vector control, TVC, failed at some point during the flight. Third, the FTS took far too long to destroy the vehicle at 40 seconds.

These three facts together could have led to catastrophic results to the public. If that many Raptors had failed and without TVC closer to the ground, the FTS would not have been able to destroy it before it was over densely populated area if headed in that direction.

The multiple failures of Raptors during tests, and not just shutting down or being shut down, but actually leaking fuel and catching fire, led to my arguing SpaceX should be required by the FAA to construct a separate all-up test stand for full thrust, full flight duration testing. Had this been done then both the launch pad damage and the likely Raptor failures would have been picked up.

I also argued there should be an independent review aside from the FAA by space safety experts on the safety of the launch. If so, the inadequacy of the FTS likely also would have been picked up. I say it’s likely it would have been seen beforehand because assuming the FTS did activate there seems to be only one reason why it did not destroy the vehicle immediately: the strength of the explosives used were not sufficient to penetrate beyond the tank wall strength. This SHOULD have been seen beforehand.

Tank wall thickness depends on the width of the tanks and the material used. Because of its size, the closest analog to the SuperHeavy stage was the Saturn V’s S-1C first stage. It’s max wall thickness was in the range of ~6.5 mm while for the SuperHeavy it’s in the range of ~8mm, about 25% thicker. BUT it’s also important to remember the specialty high strength stainless steel used on the SuperHeavy is much stronger than the standard aerospace grade aluminum used on the S-1C.

Given the greater thickness and greater material strength, these two facts together give a tank wall tensile strength for the SuperHeavy about 3 times higher than that of the S-1C. The amount of explosives used should have been adjusted accordingly.

I discussed the inadequacy of the safety review in the first post of this thread:

SuperHeavy+Starship have the thermal energy of the Hiroshima bomb. UPDATED, 3/8/2023.
https://exoscientist.blogspot.com/2023/ … nergy.html

Key Points.
1.)While the explosive force of the SuperHeavy/Starship (SH/ST) is not likely to reach that of its full thermal content of 13.3 kilotons of TNT, comparable to the Hiroshima bomb, it is still likely to be in the range of 3 to 5 kilotons of TNT.

2.)The Halifax and Texas City disasters of comparable explosive force suggests damage can extend kilometers away.

3.)The hazard or exclusion zones of only 2 miles, 3 km, for SH/ST is likely inadequate based on the Halifax and Texas City disasters.

4.)SpaceX ignored FAA warnings not to launch SN8 due to weather conditions exacerbating the effects of a possible blast wave from an explosion.

5.)The Starship SN11 explosion in midair may have been a BLEVE, which introduces an additional detonation mode for cryogenic fuels.

6.)At least one Raptor leaked methane and caught fire on multiple test flights of the Starship.

7.)Since the SuperHeavy static test lasted little more than 5 seconds, a strong possibility exists that multiple engines will fail during a full burn of an actual flight.

Recommendations.
1.)It should be revealed to the public the SH/ST has the thermal energy content of the Hiroshima bomb.

2.)Experts on launch vehicle explosions and fuel-air detonations should present a report to the public explaining what the likely explosive force would be if the vehicle exploded.

3.)SpaceX should not be granted a launch license for the SH/ST until SpaceX constructs a separate engine test stand sufficient to test all 33 Superheavy engines at the same time at full power and at full flight duration, and for such tests to complete successfully for multiple tests.

Make no mistake, this is on the FAA as well as on SpaceX.

Bob Clark

SpaceNut · 2023-04-30 18:39:51

I began to wonder about the vapor stream from the top of the bfr stage and wonder if this played into some of what we saw as well.

SpaceX scrubs Starship launch attempt over pressurization issue

If a valve stuck then would others also do the same

kbd512 · 2023-04-30 20:25:46

RGClark,

I also argued there should be an independent review aside from the FAA by space safety experts on the safety of the launch. If so, the inadequacy of the FTS likely also would have been picked up. I say it’s likely it would have been seen beforehand because assuming the FTS did activate there seems to be only one reason why it did not destroy the vehicle immediately: the strength of the explosives used were not sufficient to penetrate beyond the tank wall strength. This SHOULD have been seen beforehand.

A simplified form of your arguments seems to be that our flight safety regulatory agency is incompetent to regulate flight safety when it comes to this specific rocket (Starship), and that we need more governance provided by "independent space safety exports", to resolve a problem that months and months of regulatory effort failed to solve, in your opinion. Your evidence for that is your interpretation of Elon Musk's Twitter tweets and your assumptions about what you think is implied in those tweets, or at least what should have happened. If you think I have mischaracterized your line of argumentation or salient facts, then I stand ready to be corrected.

My questions to you are as follows:

Who will provide this independent review, who or what are they independent of, and why are they being employed to regulate this specific vehicle, as opposed to all the other space flight vehicles that the FAA has provided regulatory oversight for?

Is this desire for independent regulation based upon how powerful the Starship vehicle is in comparison to all others, existing safety record from prior Starship test flights, flight safety issues not being resolved to your satisfaction, some combination of all those issues, or something else?

Basically, what distinguishes these independent regulators from the FAA and can you articulate the reasons why SpaceX's Starship launch vehicle requires the formation of an additional regulatory body to oversee its approval for flight operations?

How would we evaluate whether or not these independent flight safety regulators are more or less competent to regulate Starship than our existing regulators?

We need clearly defined performance metrics to evaluate the job this body will be responsible for, since the implication is that the existing regulators are incompetent to regulate this specific space launch vehicle.

Will this independent review be applied to any other vehicles besides Starship? If not, then why not?

What are you ultimately after with respect to this course of action and why is that worthwhile?

These are not rhetorical questions. They require honest and complete answers to entertain such a proposal.

tahanson43206 · 2023-04-30 20:58:43

For kbd512 ...

Just FYI ... a request by RGClark for the SpaceX launch to be discussed was forwarded to Dr. Stanley for the May meeting.

Dr. Stanley replied with an indication he will try to add that to his presentation.

Thanks for engaging with RGClark on this important subject.

(th)

Void · 2023-04-30 22:18:14

I guess I will interfere a bit.

I understand that the new Superheavy will not have Hydraulics, which is said to have failed in this flight. I think that they are going to electrical methods.

We don't know officially why engines failed. So, at least wait for that before encumbering the process.

It does look like the situation was perhaps on the edge of disaster, but that is the nature of this sort of thing. What about that train wreck in Ohio, was it? What was the relative damage?

As per the engines, they were good enough to get the machine well away from a dangerous surface explosion, so they did good.

If there needs to be improvements to the engines in a singular deployment and in a clustered deployment, I have every reason to believe that SpaceX wants those engines to be good enough. I am sure they would like to make some money using a big launcher, not keep crashing.

As for testing the 33 engines all at once, I guess they could test the steel plate apparatus and the water deluge in increments.

For that, it would be silly to stack the Starship on top filled up. And as for the Superheavy, you would not fully fill it. So, in the testing you should be able to reduce the magnitude of an explosion to a fraction of the launch risk explosion potential.

Start with a few seconds, evaluate the damage, and if it seems sensible, then do a longer one. If it can work that way then you might consider a full launch. Building a separate test jig would not be realistic testing anyway.

And, (Using the Starship only, SS), further testing of Raptors could be done with just a SST-Sub-Orbit, or even a attempt at an almost orbit, that might terminate near Hawaii. This could test the heat shielding and the Raptors and the other subsystems, without the use of the Superheavy, while further evaluation of the Superheavy could be done.

SpaceX drew a short straw this time, but not the shortest. It did not blow up on the pad. It is typical of their philosophy to go with minimum parts first and see what happens, and then add in parts if they are demonstrated to be needed. "The best part is no part".

Another good that could have come out of this is they are going to have to think hard on how to handling landings and launches on the Moon and Mars.

I am satisfied, that their course was not that reckless. It was already understood that the stack could have exploded on the pad. I am sure glad that we got lucky. I include myself in the "We" as I am an enthusiast.

Done.

Last edited by Void (2023-05-01 09:19:35)

kbd512 · 2023-05-01 00:09:46

Void,

I'm satisfied that the engines work, despite opinions to the contrary, but the plumbing and/or control systems seem to be problematic. We don't yet know what failed or why it failed. We're all speculating without knowledge. The only way we're going to know is a complete flight accident investigation. I still think the FAA is competent to investigate flight accidents. If they're not, then I don't know who is. The booster and the majority of the engines made it all the way to MECO, despite the engine failures. That has to count for something. Even so, I don't want to see any in-flight explosions or deaths on the ground.

I'm more interested in why someone thinks we need to have special regulations for this particular vehicle, that have not applied to STS or SLS. We had two fatal in-flight accidents during the STS program which killed the entire crew. The FAA and NASA still authorized subsequent space flights, so that must mean there is a threshold which qualifies or re-qualifies a vehicle for a space flight authorization. Testing alone is not a guarantee of success. It's a check in a block that provides a false sense of security that does not exist. STS conducted full duration burns followed by routine flights (not test flights) which still produced catastrophic in-flight failures.

Whatever independent oversight action looks like, it cannot be punitive in nature, nor directed solely at SpaceX's Starship. If Starship has to meet some special launch authorization criteria on account of its size / power, then so should SLS or any other very large launch vehicle, assuming the power level is primarily what RGClark is objecting to.

What we should not do is discourage space launch service providers from even trying to build and test. That is precisely what gave us horrendously expensive STS hardware, which failed anyway, because no amount of block-checking will ever equate to "safety". That course of action directly prevented us from going back to the moon or conducting any other actual space exploration flights since the Apollo program, which also had its share of deaths and close-calls.

This Starship launch was a test flight. There was no presumption that all aspects of the test flight would proceed according to plan. Normally, or at least in rocketry, when things go wrong they go very wrong. Lockheed-Martin / Boeing / Northrop-Grumman / Orbital ATK / Virgin Galactic have all had catastrophic launch failures that didn't result in the formation of new regulatory agencies or groups. If we're going to apply special rules to SpaceX, then they should get special dispensation for their efforts. ULA has received billions of dollars in government funding to maintain test and launch capabilities. SpaceX should either get the same level of funding for testing, or we stop acting as if every aspect of their test efforts needs to meet a special standard beyond what their direct competitors are subjected to.

I'm okay with holding SpaceX to a higher standard, which seems to be the thrust of RGClark's recommendations, if that also means they get special privileges for the special requirements we subject their rockets to. In the very short time SpaceX has existed, they've done vastly more to advance the state-of-the-art in rocketry and lower the costs of routine space flight than all of their competitors have done over the same period of time. If ULA or Boeing cries foul, then we can use their own behavior as "Exhibit A", with respect to favoritism shown to defense contractors who both exceed their budgets by considerable margins, yet still receive special treatment.

Everything I have seen thus far makes me think that SpaceX is a good-faith actor actively pursuing the same space flight objectives that NASA was created to pursue. If RGClark thinks more regulation or special regulation is required to temper SpaceX's "Go flight!" enthusiasm with greater prudence, then so be it, but special rules came with special privileges for all of our other aerospace defense contractors. If the veneer of fairness is to be maintained, then SpaceX should also get special status as a favored services provider.

Void · 2023-05-01 09:21:22

I think I am in your camp on this. Another damage to human and American interests would be to be so risk adverse that we can't achieve the progress that such new technology could offer.

I have a concern that there are those who only want to leach off of the energy of developmental motion. To exploit dreams for low purposes. Such entities would consider motion and not success the item of value. This is of course the pork people.

Some pork is inevitable and even helps a move towards success, but a perpetual motion machine that simply makes entities gather wealth, but does not move towards a goal, is a concern.

I think things are OK, but you have to have concern that people with low purposes will highjack the effort and even hold it for a ransom.

Done.

Last edited by Void (2023-05-01 09:25:54)

kbd512 · 2023-05-01 12:08:58

Void,

I am concerned about people holding the Starship program hostage, which is why they need to clearly define their criteria for authorizing subsequent Starship launches. If they're asserting that Starship is half-baked, then they cannot do so using half-baked arguments.

RGClark's concerns are real and valid. My response was not intended to trivialize his concerns. I think he might be selling SpaceX and the FAA short in some ways, but he's fundamentally correct when it comes to consequences. We should not ignore that, nor should SpaceX.

If a Starship explodes on the pad or anywhere near the pad, it will do so with a staggering amount of force, potentially equal to a small nuclear bomb, with blast effects extending well beyond the launch complex. That risk is very real. No amount of testing will ever make it "go away".

We want to reassure the public that enthusiasm for launch doesn't wipe out Starbase or their nearby homes. That would set us back faster and farther than nearly any other outcome. If SpaceX needs a "safety stand-down" to get their priorities straight, as we would call it in the military, then perhaps that best serves everyone.

My question about the other vehicles related to why we did not make similar demands of STS or SLS. STS was crewed from the very first all-up / all engines running test flight. At no point in time during engine testing did we light off both solid rocket motors and all three RS-25s on the same test stand, all at the same time. We're now making that exact demand of Starship. It may not be unreasonable, but we're not subjecting the world's second most powerful rocket to the same launch authorization criteria, despite the fact that SLS is also more powerful than a Saturn V. We're stating that Starship Super Heavy is in a class of its own, which is a true statement.

If we engage in the practice of picking winners and losers, then we incur an additional duty-of-care to SpaceX as well as to the general public. The US government accepted and funded ULA after that same argument was made by ULA. If we demand that SpaceX conforms to a special and exacting set of standards that none of their competitors are forced to conform to, then we extend to SpaceX the same privileges that we extend to ULA, such as providing test stands at tax payer expense, purchasing test hardware, keeping their staff employed building rockets for us, etc. If the government dictates offshore launch to SpaceX, then they provide the floating launch platform. Since Uncle Sam owns the pad, he gets to decide when we're ready to launch. So long as SpaceX is willing to play ball, which they seem perfectly willing to do, the game continues.

If someone does have ulterior motives for forcing SpaceX to conform to their standards for acceptable launch criteria, then they should know that they're incurring the additional expenses on their tax bill and not preventing SpaceX from achieving their space flight objectives. If writing a blank cheque to SpaceX was not what they had in mind, then perhaps they should've give more thought to the implications of their proposals.

Void · 2023-05-01 14:09:50

Quote:

RGClark's concerns are real and valid. My response was not intended to trivialize his concerns.

I did not intend to be abusive to another member.

My concern it the news media, they do not make maximum money except by promoting a manic/depressive representation of reality.

I did not intend at all to be rude to RGClark, or you. I point out that a Hiroshima Bomb would explode without announcement and would have fallout emitting radiation.

So, for evaluation, how dangerous is the worst case relative to a Hurricane or strong Tornado?

I agree that any time that a lot of explosive materials have been made more risky by deployment, even then concern should be employed.

When there is an attempt to launch a rocket, there is significant danger.

Once the rocket has traveled a relatively small period of time in this case, the danger is reduced.

In the case of Hiroshima, the explosion was central to a populated area wasn't it? And the timing was not announced to the local people.

So, those outside got burned, (Very sadly), and of course physically damaged otherwise. And then there was fallout.

So, knowing the timing of the event, the people could have taken measures to not experience such damage. And that is what I think Boca Chica is like. I would be surprised it SpaceX had not made an effort to reduce the damage to the locals, should a worst case occur.

Perhaps SpaceX should consider building some public places with very good protection where people could go if they are concerned, as well.

Have things like gyms, restaurants, theatres, learning facilities incorporated into them. Granted it would be an inconvenience for the locals, but this then as made better than Hiroshima. This would help protect the people, but of course damage to other buildings would occur and how that is compensated for, would be sort of legal, I expect.

You see the raw title of the topic is completely honest, but you know how the news media are. Better to temper such a negative projection of danger and bring the needle closer to reality.

Done.

Last edited by Void (2023-05-01 14:30:09)

RobertDyck · 2023-05-01 14:34:41

Bob Clark, you are exaggerating and trying to incite trouble. There is no way it would release as much energy as the Heroshima bomb. Catastrophic failure cannot produce ideal fuel/oxidizer mix. There's a reason they're stored in separate tanks. I have already posted that the second test launch of N1 in 1969 is the most realistic example of worst case catastrophic failure. N1 first stage engines failed, it tilted 45° and fell back on the launch pad. It split open upon hitting the concrete of the launch pad and exploded. Debris was thrown up to a maximum of 10 km (6 miles). If you want to raise alarm then point out the observation area in on South Padre Island is 5 miles from the launch pad.

RobertDyck · 2023-05-01 14:45:10

Yes, the range safety self-destruct was triggered but failed. It did detonate but didn't destroy the rocket. When the rocket fell into thick air as it tumbled end-over-end it split open and exploded. Elon said they will have to use more det-cord.

One fan claimed that he saw Starship separate and try to start it's engines after RUD. But Elon responded that this was not reported to him. Self-destruct destroys the whole rocket, not just SuperHeavy. But Elon also said that's a good idea, they will look into it.

::Edit:: Elon said they had planned a steel thrust diverter with regenerative cooling with water. That means a steam cloud, not sand cloud. It will be installed before the next launch.

YouTube: https://youtu.be/L2Xzx9Ej578

Last edited by RobertDyck (2023-05-01 16:15:10)

Calliban · 2023-05-01 14:49:15

A rocket explosion is very different to an A-bomb blast. The bulk of the energy is released slowly compared to an equivelent mass of explosive. The actual blast effects will be mostly related to pressure vessel burst and subsequent BLEVE, as fuel and oxidiser mix and combust too slowly to contribute much to the pressure wave. An A-bomb converts all of its stored energy into superheated plasma in a millisecond. The expansion of the A-bomb fireball exceeds the speed of sound in air, allowing a high amplitude pressure wave to develop. In comparison, a BLEVE fireball develops only after the pressure wave is generated, as mixing doesn't occur until the pressure vessel has burst and flammable gas has expanded and mixed with surrounding air.

So a simple comparison of the energy contained in the rocket fuel to the energy release by an A-bomb is misleading. That isn't to downplay the dangers of rocket failure. Falling fragments are obviously always dangerous. Thermal radiation from the fireball could be intense enough to start fires several miles away. But I suspect water vapour in the air will attenuate much of thermal radiation. But comparing the energy release to an A-bomb is misleading.

GW Johnson · 2023-05-01 15:41:20

As near as I can tell, based on the paucity of confirmable info published, multiple engines on the Superheavy booster failed during its ascent, some at liftoff. The booster was incapable of reaching the design staging point. An informed speculation (!!!) says concrete chunks flung from the destroyed launch pad damaged a lot of engines, and who knows what else, at liftoff.

The vehicle did climb for a while until control was lost, and then it tumbled. During the ascent, there are some very clear pictures showing base-burning of the vented methane with air, forming subsonic flame sheaths about the supersonic plumes from the engines still working. No vented LOX went into that in any significant quantities, or there would have been a massive explosion that would have destroyed the vehicle immediately. However, there may have been some LOX-induced small explosions during the ascent. The photography clearly shows flashes and shed debris, suggesting multiple small explosions.

Until the vehicle tumbled, it appeared that Starship was in proper alignment with Superheavy. After the tumbling began, the videos clearly show a bent vehicle: misaligned Starship vs Superheavy, by something like 5-10 degrees. That is more than enough to jam the staging mechanism, which is a set of pneumatically-powered clamps that release, to let the stages part.

There's not much reliable information about the flight termination system, except that the vehicle blew up some 40 seconds after the signal to self-destruct was sent. Some sources say that destruction is delayed to allow Starship to get clear of Superheavy, before Superheavy self-destructs. I do not know whether that is true or not. But the 40 second delay suggests (suggests!!!!) that the FTS never went off, that instead the vehicle exploded because the tumbling airloads were just too much, over time, as it descended into thicker air where the forces are higher. I could be wrong, but that is the first thing apparent.

That in turn suggests (suggests!!!) that there is an FTS on Superheavy, but not on the Starship upper stage. Which makes sense once Starship is crewed. Maybe not so much in uncrewed flight tests.

The explosion of an atom bomb really is quite different from the explosion of propellant and oxidizer kept in separate tanks, yet the total theoretical quantity of releasable energy really is comparable to a small atom bomb, no matter how you figure it. All I know "for sure" is that when you bust tanks open, and start a fuel-air fire, and then dump LOX into that fire, the resulting explosion is very powerful indeed. We have seen that since the V-2 developments in WW2. We saw it again in 1986 when space shuttle Challenger broke up on ascent. It's NOT a detonation, but it is a very, very powerful deflagration.

Musk admits he is the one who ordered this launch without a cooled flame deflector. This is entirely on him. I checked his credentials: he has only Bachelor-level degrees in economics and physics. He is very most definitely NOT an engineer, despite being officially listed as SpaceX's "chief engineer" in addition to being its CEO. What that really suggests is that he is in violation of the Texas engineering practice act for calling himself "chief engineer" when he he is NO engineer, and that he is certainly unqualified to have made the decision to launch this thing without a proper flame deflector.

An economics degree at only the Bachelor level does not qualify him to be a competent corporate manager either. The mess he has made at Twitter certainly confirms that assessment.

I see in the news that FAA is being sued for issuing the launch license on an environmental impact statement that is not a full EPA environmental impact statement. No surprise about that. Doing this launch without a flame deflector and creating all the problems it has inarguably created, has made not only Musk look incompetent, but has also seriously tarred the reputation of the FAA as a safety regulator. Perhaps that is not justified, but perhaps it is. Money talks way too loudly in the halls of government, as we all already know.

At any rate, I predict that FAA is going to be be really, really hard on SpaceX before they allow another launch. And rightly so. If I were the FAA, I would question anything ever said again by Musk, and any decisions he might make regarding SpaceX operations. Unless it came from Shotwell and her engineers without being over-ridden by Musk, I would not believe it, either.

Publicity is not competence.

GW

PS -- I have already posted a forensics article about this test on "exrocketman". And I just posted today (5-1-23) an article about entry heat shield materials.

Last edited by GW Johnson (2023-05-01 16:10:10)

New Mars Forums

Announcement

#51 2023-04-24 08:19:06

Re: SuperHeavy+Starship have the thermal energy of the Hiroshima bomb.

#52 2023-04-24 20:33:10

Re: SuperHeavy+Starship have the thermal energy of the Hiroshima bomb.

#53 2023-04-25 06:30:51

Re: SuperHeavy+Starship have the thermal energy of the Hiroshima bomb.

#54 2023-04-25 09:26:10

Re: SuperHeavy+Starship have the thermal energy of the Hiroshima bomb.

#55 2023-04-25 11:11:13

Re: SuperHeavy+Starship have the thermal energy of the Hiroshima bomb.

#56 2023-04-25 11:26:35

Re: SuperHeavy+Starship have the thermal energy of the Hiroshima bomb.

#57 2023-04-25 11:43:25

Re: SuperHeavy+Starship have the thermal energy of the Hiroshima bomb.

#58 2023-04-25 19:47:04

Re: SuperHeavy+Starship have the thermal energy of the Hiroshima bomb.

#59 2023-04-25 21:04:40

Re: SuperHeavy+Starship have the thermal energy of the Hiroshima bomb.

#60 2023-04-26 11:32:06

Re: SuperHeavy+Starship have the thermal energy of the Hiroshima bomb.

#61 2023-04-26 18:25:53

Re: SuperHeavy+Starship have the thermal energy of the Hiroshima bomb.

#62 2023-04-26 18:41:15

Re: SuperHeavy+Starship have the thermal energy of the Hiroshima bomb.

#63 2023-04-30 18:02:29

Re: SuperHeavy+Starship have the thermal energy of the Hiroshima bomb.

#64 2023-04-30 18:39:51

Re: SuperHeavy+Starship have the thermal energy of the Hiroshima bomb.

#65 2023-04-30 20:25:46

Re: SuperHeavy+Starship have the thermal energy of the Hiroshima bomb.

#66 2023-04-30 20:58:43

Re: SuperHeavy+Starship have the thermal energy of the Hiroshima bomb.

#67 2023-04-30 22:18:14

Re: SuperHeavy+Starship have the thermal energy of the Hiroshima bomb.

#68 2023-05-01 00:09:46

Re: SuperHeavy+Starship have the thermal energy of the Hiroshima bomb.

#69 2023-05-01 09:21:22

Re: SuperHeavy+Starship have the thermal energy of the Hiroshima bomb.

#70 2023-05-01 12:08:58

Re: SuperHeavy+Starship have the thermal energy of the Hiroshima bomb.

#71 2023-05-01 14:09:50

Re: SuperHeavy+Starship have the thermal energy of the Hiroshima bomb.

#72 2023-05-01 14:34:41

Re: SuperHeavy+Starship have the thermal energy of the Hiroshima bomb.

#73 2023-05-01 14:45:10

Re: SuperHeavy+Starship have the thermal energy of the Hiroshima bomb.

#74 2023-05-01 14:49:15

Re: SuperHeavy+Starship have the thermal energy of the Hiroshima bomb.

#75 2023-05-01 15:41:20

Re: SuperHeavy+Starship have the thermal energy of the Hiroshima bomb.

Board footer