Was Starship’s Stage Zero a Bad Pad? 

Can we expect a "I built a small-scale Starship in my garage" clip? 😂

Another big reason why 39 was so monstrous was that NASA was tired of building custom pads for each rocket. KSC is littered with single use pads.

Just a point of clarification: The flame deflectors of launch pad 39A and 39B, during the Saturn and Shuttle eras, were steel frames covered in concrete. At least during a Saturn launch, approximately one foot of the concrete was ablated off of it. Also, the one shown in your graphic at about the 6:18 point is for the Ariane pad in French Guiana. It is a one sided deflector. The Saturn deflector split the exhaust to two sides. Also, the flame trenches were initially lined with ceramic fire bricks to protect the underlying concrete. I don't know if that has been replaced by refractory concrete or some combination.

This brings me back to a retort of the "Mechanical Engineers build weapons, Civil Engineers build targets" joke from my uni physics days: Civil Engineers build cities, Mechanical Engineers build headaches for Civil Engineers.

I was part of the team that re-furbed the test stand at Edwards after Challenger failed. The mechanical systems to provide the water for cooling are impressive. The diverter there was hollow, with tens of thousands of holes in the "hot side" to shield the diverter surface from the flame with a "fog" discharge of water through the surface. The criteria was 5 million gallons of water, delivered in something like 3~5 minutes. The pump houses (there were two) had about 20,000 HP of pumps. The water into the diverter was carried in two 48" pipes. One of our guys took videos of the "dry run" (no flame) test of the water system. The audio can be heard "shut it down, shut it down!!!" once someone realized that without the flame, the water flew downhill into the sloped desert...right toward the tiny berg of Boron, CA. The "fishtail" bottom end of the diverter caused the water to jump right over the drainage canal that was supposed to carry off excess water. It was a fun project. Almost forgot to mention: we didn't determine the criteria for water flow, etc., but we were instructed that no material available (late 80's) could withstand the rocket blast, so the water protected the gantry, diverter, etc. When I saw the damage to the impact area of the flame, I wondered if the real problem was a mechanical one: not enough water? Pump fail?

I would love to see a garage model of a flame diverter with a deluge system, I know you can do it Grady!

I know it's new, but it would be interesting to hear your perspective on the I95 collapse and repair before the final report is finalized, and apparently repaired. Maybe a topic for a short?

My dad worked on the designs of the launch pads and launchers for the Atlas missile. The issue of making reusable launch pads led to concrete turn buckets with refractor brick lining. Water flooding was developed latter by NASA at Cape Canaveral. The cost of a fleet of Atlas missiles pads that would be used once against the USSR led to the coffin launcher. This launcher had the missile horizontal until fueled, then erected to vertical for launch. The launcher was surrounded by a wall mostly to keep things out while waiting for years for a launch order that never came. If launched, the Atlas would destroy the launcher and surrounding wall. When the US went to silos for ICBMs there were extensive systems to direct the blast out the bottom of the silo and to vents outside the silo tube. This was intended to prevent the missile from destroying itself before leaving the silo. Over at the Soviet Cosmodrome the solution was brutally simple: dig a deep hole in the ground, canterleaver a platform over the hole, put rocket on platform. When the rocket took off the blast went into the hole and the effect on dirt in the bottom wasn't an issue. Of course you cannot (as you pointed) out, economicly dig a giant hole at Cape Canaveral (Kennedy) or Boca Chica. I cannot imagine that SpaceX didn't know that they had built an expendable launch pad. The question is do they want to pay for a reusable pad? It might be cheaper to build an expendable pad for each launch, just like the Atlas coffin launcher.

The problem with boca chica site is its built on the rio grande flood plain. The sand is essentially delivered down the rio grande during historic floods that occurred before the two upsteam dams were built, falcon lake and lake amistad. Within the sand laid down since the last ice age when sea levels were lower is a spongey like material with organic material and bacteria trapped in an anoxic environment. While the surface may look firm, putting pressure on the surface can cause the sand to become more maleable. Now imagine, you have a set of rocket engines with their thrust vector pointing down at a sheet like structure laying over something that is hard agregate on top and spongey below. The ISP of the engine is in the 350 range which we multiply a 9.8 m/s for and exhaust velocity of Mach10. This does not reach the launch pad, but the rocket engines resonate and their wave functions create pulse waves that travel at hypersonic speed to the sheet of concrete. This is much like a sonicator used to clean off surface debris but a million times more powerful. The sheet itself begins to vibrate and the substrate below begins to undergo liquifaction. The pad is now free to vibrate, and because concrete is fairly weak under stretching it just breaks up. Because of the nature of the sand below this causes the substrate to give and the action of the Ve on the concrete itself scours it away. I am been to boca chica, i had the fortunate exoerience of sinking a car in that sand, Its not like other soils with tightening layers as you go down, its just goopy sand, often pitch black layers of bacteria laden sand. When they chose the site I pondered how they were going to stabilize the soil, just to build the equipment. They had problems with the soil in the begining because it was so wet and soft. They demonstrate some magical technique they use to dry things out. But look at boca chica, on any given day it looks dry and sand, until you get below the surface. The region has suffered from storm after storm, flood after flood. After hurricane allen, the main road up S. padre island was chopped into a dozen pieces, 8x8x8 blocks of granite were torn out nowhere to be found. There were tropical fish from the offshore island living in the large ponds that Allen created were the road used to be. This is the nature of boca chica, its not stable, over thousands of years it gets torn up and completely rebuilt, what looks like dry land today is just an illusion.

The water deluge system was as much, if not more, for protection the pad from the incredible sound pressure rather than thermal protection. Saturn V nearly maxed out the possible sound pressure possible in 1atm of air

It's worth pointing out that one of the speculated reasons that there were so many engine failures that ultimately doomed the launch was because of debris from the launchpad striking the engines. So even without considering government regulations or neighbors, there is a strong reason for the company to build a more durable launchpad to protect the rocket itself.

Calling a rocket launch "thunderous" may be an understatement, but it is definitely a thunderstatement!

"Exciting to watch" reminds of cars which are "exciting to drive" in that you don't know if you'll arrive at your destination.

NASA also used asbestos in the flame trench at 39a, I believe in the joints between the concrete slabs. I remember mesothelioma lawsuit ads talking about the flame trench specifically as a potential source of exposure.

"Rapid development cycles" means "don't ask for permission".

Thanks for the historical perspective. Seems like NASA was all over the launch pad issue from the start. I wish you had said more about the SpaceX water deluge plan. I couldn't tell how you felt about the odds of success.

Great to see content related to space travel and rocketry. So much of the channel (we've followed since the early days) relates to civil engineering for municipalities - its good to see some other areas of interest, like this, covered. Keep it up!

5:41 I feel like a good little engineer- that was the first thing I wondered when you mentioned they used the dredged material as fill.

I usually find in video ads to be obnoxious and they get skipped immediately. But I found your Nebula ad well done and worth watching.

I went down to the launch pad a month ago and gathered up a bunch of concrete chunks from the launch. Super cool stuff and place to visit.

HI Grady! I've been waiting for this video to come out for a while now. I knew there was no way you weren't going to cover this lol. This was a fantastic review, although I was a bit surprised you didn't go deeper into the actual failure mechanics I considered reaching out to you as I was working on my deep dive investigation to see if you may want to partner on this topic, but I figured you may be a bit too busy.

You have not mentioned the most interesting part. - They said the problem is because the *soil* below the concrete slab compressed, and thus the concrete _snapped_ and flames got through it. It would have been much less violent, if the concrete ablated as it was supposed to. - I was hoping for analysis of that.

Every time Grady said "launchpad", my brain finished with "McQuack".

One of my biggest concerns with the Starship pad is how close the fuel farm is. We saw several tanks damaged by the last launch which could easily have resulted in an explosion and even more damage. So far I haven't see SpaceX address this issue.

As it was explained to me on a tour (I also flew over the pads often). The flame trench originally didn't have a water deluge and it shot fire brick far away. In May 2008 (STS 124) 3,500 19 pound fire bricks from the wall were shot out at up to 680 mph, 1,800 feet away.

The wildlife around Boca Chica are not quite so chipper I think.

At 8:45 "I think that the results came as a surprise to no one..." Elon stated that they did not expect the pad to be destroyed and would not have launched if they did. Showing NASA built flame trenches, implying that this is a solved problem is misleading. The flame trench at 39a frequently needed repairs and was reconfigured many times. Spacex static fired Starship at about the same thrust of a Saturn 5 and the pad only had minor damage. As far as this not being mentioned in the environmental PEA, that's not surprising since it wasn't anticipated. At 10:54 "..not to mention the public safety aspects of the showering debris." The debris particles that fell on Port Isabel have been tested at UCF. They found that it did not contain elements of the concrete and Fondag, just sand. At 11:-00 "The FAA has effectively grounded Starship..." The FAA has not grounded Starship. The launch license was for one launch. The mishap investigation is standard procedure. I was expecting so kind of analysis of how the pad failed.

SpaceX: psh, yeah we knew that would happen. EPA: Did you? SpaceX: Um....

Would love a follow up to this now that the water cooled plate has performed excellent during the latest launch.

there is an important mistake at 0:50 the flight termination system was triggered but didn't succeed in terminating the flight. you can see clearly from the footage, the explosion started from the engines which means it wasn't caused by the FTS. you can also see in the footage that before the main explosion the FTS was triggered and caused a small explosion but didn't succeed in causing the whole rocket to explode.

I’ve been hoping you would make this video since we first saw the aftermath of the launch!

There is an old NASA documentary that is all about the development of the eventual Saturn 5 launch pad. I watched it about 5 years ago, there was good information on flame diverting and water suppression systems and the mistakes along the way. I am surprised SpaceX didn't come close to following the lessons learned.

*SO* many Kerbal Space Program flashbacks...

I have watched many videos about this launch yet I still learned several things from your video that no one else mentioned. Thank you for providing well researched content

Now after 2nd launch, without this damage, i really wish a follow-up video explaining how the stage 0 is intact with newly designed water system

Certainly some info on the mode of failure would be nice.

You look at the NASA launch site and see awesome engineering. You look at SpaceX and it looks like some guys launching rockets from their backyard.

I wonder how many of those engines that failed to ignite or failed early did so due to damage done to them by the launch pad blowing apart.

Digging in the sand near sea-side was an evocative image!

Fondag is a really interesting product. My family owns a ready mix concrete company that services an aluminum smelting plant. Every so often the floors in the furnaces are replaced and they will use Bulk Fondag for the concrete. The laborers and finishers that are working it will sometimes have to vibrate around their feet when they want to move to a new work position.

What I think... is that the creators of Nebula are so focused on their negative experiences with the algorithm, that they don't realize that for _viewers,_ the algorithm can be extremely helpful and positive as well! Sure, there are some downsides to it, especially when it caters too much to advertisers and serves as silent censorship... but it also connects us to new creators and new videos, learns what we enjoy watching and lets us discover more in similar spaces, and makes it easy to fall down fun (and lucrative) rabbit-holes. Most of all, whenever I'm on Nebula (I have had a subscription since basically the moment it launched, because I was already watching most of the co-founders' channels), I _really_ miss the _engagement_ RU-vid offers, with comments to interact with both the creator and other members of the community. I love the _idea_ of Nebula, but it has a long way to go to be the "best possible viewing experience". I'm sure it competes very favorably with basic, free RU-vid, with $2.50 a month to get rid of ads... but I have a family RU-vid Premium account that works out to only about $3.60 a month for each member of my household, which _also_ gets rid of all ads, both pre-roll and interruptive, and those annoying pop-up ads, _and_ gives me the community engagement and the help of the algorithm to boot. As a newish member of the Nebula team, maybe you can help nudge them in the direction of at least seeking some form of parity with RU-vid's polish as a platform. I'd love to be able to just watch my favorite creators on Nebula, but it's just too clunky to be enjoyable, and I don't feel like the creators understand that, or acknowledge it, let alone plan to improve it. To be clear, the _content_ isn't the problem. It's the interface. I'll stay subscribed, because I _do_ want to support you guys, but for now, at least, I'm almost always going to actually watch your videos on RU-vid, even if I have to wait, even if I have to listen to sponsorship ad reads, and even if I miss out on "bonus content". That's just how I feel.

What did they think was gonna happen?

Funny how space-x seemingly went from reusable first stages to disposable launch-pads. I’m not sure if their commitment to re-discovering stuff NASA and apparently their own engineers knew beforehand is aligned with the idea of rapid development cycles. I respect your commitment to value-neutral, informative coverage. But to me it seems like the company was pursuing very thin savings in costs to engineer their own solution, discovered said solution to be insufficient under half the projected strain, but chose to not correct the clear issue before the launch. It seems like a very reckless decision made solely to meet a deadline, with full understanding that something “unexpected” will definitely happen. It’s hard to see their insurance company or the FAA using such novel definition for the word “unexpected”. I also can think only one person walking to the NASA launch site, pointing at a hugely complex set of equipment and saying “I bet those are entirely unnecessary, let’s build a lean, clean-sheet design”, and not being politely told to shut up, and entirely dismissed by the leading engineers working on the project. And that guy does not hold an engineering license, despite often implying or acting as if they did. This is not a website, you can’t just disable the “unnecessary microservices” and expect no consequences aside from self-inflicted financial losses. Someone could have died.

that shot of cape canevaral at 4:24 looks so nice! the sky, the rainbow and the giant rocket! absolute perfect :D

So, the advantage of commercial spaceflight is that they ask for forgiveness instead of permission? Not sure what to think of that.

The fact that Starship cartwheeled in the atmosphere, still under power, multiple times without breaking apart is as insane ad what it did to Stage 0.

Another thing to consider is the Pad39 diverter was designed with bigger rockets in mind…

Move fast and break things is fine when there are no externalities, but when you're launching rockets on this scale, there are a _lot_ of externalities

are you planning to take a look at the ocean gate titan sinking once more information comes out?

I hadn't been following Starship much the past few months due to work and life and such. When I watched the launch my first thought was "Uh, where's the flame diverter? Water deluge??" Yeah, no one is surprised that happened. I am still skeptical about a large steel plate firing water directly up at the bottom of the 33 Raptor engines. It should be exciting to watch either way but I'm not sold on it working. ;)

Good summary, but would have been worth mentioning that the engines blasted the pad longer than expected due to engine outage. And also the sand underneath collapsed under the pressure impact, causing the concrete to fracture Would have also been worth discussing their solutions for reinforcing the substructure (not just the installation of the water deluge) so that the concrete can't fracture under pressure again

Concrete can handle pressure, special concretes handle high thermal loads, but concrete is a poor choice against sound energy. Reflecting world record sound energy back at your rocket with a flat plate should have "ACME" printed on it somewhere. The rocket plume helps and both the water mass and steam will help more, but it seems foolish to not deflect a large portion of that energy away from the rocket. It would seem unlikely that they will launch without damaging engines and equipment until they do. As noted even with the SLS launch system, flat surfaces reflect sound and that reflected sound will destroy things it is focused on. This system too has some work required to prevent sound damage.

Per various news articles, an actual flame trench was under construction at the launch site. Elon Musk chose not to wait for its completion and forced the launch to happen earlier. Local news in the area also found a 10ft piece of concrete about a mile away from the launch site, not just a few hundred meters. It's a good thing that scrutiny is being placed on SpaceX now, especially about how this launch was even allowed to happen by the FAA, but much of it could be avoided if SpaceX wasn't headed by someone who views environmental destruction and endangering lives of normal people as necessary sacrifice.

was waiting for your video on this from just moments after I watched the launch! I'd love more videos covering things like this, related to Space!

Why does the whole SpaceX thing make me think of Salvage 1? Anyway, thank you Grady! Your channel is one of my favorite. You keep me hopeful there are more good engineers.

Dam I thought you might’ve talked more about the science behind how it was probably the foundation that really failed and that the concrete they used probably would have survived a lot better if the slab didn’t crack.

Was hoping for a deeper dive on the failure mode. SpaceX thinks the sand compressed and cracked the concrete. Do you agree with that? Is there a potential way to do this without water? Just seems there's a lot more to be said on this topic.

Grady I know you won’t say it but I will. You are just as good if not even better than those old discovery and science channel shows and you’re definitely a billion times better than the shows they air now.

That t-shirt is so back to 70 s, I was born then and as a very young boy I remember those stripes and colors.

I'd be interested in a follow-up analysis of this after IFT3👍

The thing with the damage is that people have been calling out SpaceX about this since they first started building. Even the EM drones would comment on it, though they would finish with "but I'm sure they know what they're doing

You didn't cover the reasons SpaceX didn't build a flame diverter.

thanks for this, I thought the design of the pad and all the collateral damage caused by the debris being scattered was the more interesting part of the event

12:01 "They’re betting it will pay off to develop fast instead of ." - (my underline) - In the middle of a wet lands preserve and not far from residential structures.

I've been waiting for this from you...

10:13 It is worth mentioning that the assessment DOES include the case of the entire rocket detonating on the pad, which is going to be significantly more severe in terms of debris and blast damage, and for which the exclusion ranges, etc are already budgeted accordingly. It may be the case that both or either parties felt this was sufficiently broad to cover for lower energy events, which this event undoubtedly was.

It's just hysterical that Musk first made a decision 'All of that fancy stuff is too expensive, just pour some concrete' and then says it 'may be a mistake' after he realised what he told them to do.

Question: What will SpaceX learn from this? Answer: Nothing.

Elon: "We aspire not to have a flame deflector." Physics: "Yeah you don't know how this works."

Yes yes sacrifice safety for speed… classic big business talking point.

You completely missed the part about steam pressure below the pad, blowing up the pad! SpaceX, nor anyone, can get enough of a deluge system in place to mitigate the heat pumped into proximal ground water to prevent a repeat explosion. But the next time will feature metal shrapnel instead of "just" concrete. If the FAA allows a repeat, it's going to be ugly. Nobody should trust SpaceX's analysis on this, especially after, as you point out, SpaceX environmental risk assessment said nothing about the risk of a massive pad explosion, then Musk saying they knew it was a possibility. The move fast and break stuff approach does not work for space operations that move quickly through public spaces.

So, after listening to almost fifteen minutes, the question, in the thumbnail, is never answered. 😮‍💨

My favorite comment: "The launchpad left starbase faster than the rocket did.". My favorite comment: "The launchpad left starbase faster than the rocket did.".

The crawlerway wasn't built using the stones from the site itself though, they used river rock from the Tennessee River since it has almost no flint in it so when the rocks are crushed by loads they don't pose any additional fire risk to loads with chemical fuel onboard like SRBs.

Water logged concrete + lot of heat is 💥 of concrete, only the top layer as i understand is the special concrete the lower layers is normal concrete mixuee

The concrete under the pad had been expected to ablate as it had during the static fires and in flame trenches, not disintegrate like it did. SpaceX had also been conducting tests at their MacGregor facility by firing raptors at concrete blocks, presumably to measure ablation and fragmentation. While plenty of people have be treating the outcome as obvious, their theory as to why it disintegrated didn't match the actual reasons - which has been given by SpaceX as to do with the ground underneath the concrete. The FAA should certainly issue updated requirements to ensure it doesn't happen again, but as with other issues like the FTS not working as expected, SpaceX is already working on it, such as adding a heap of new deep foundations under the pad.

In rocketry what happened is what is called "pad rich exhaust".

love your videos and thank you for mixing the music in this one !

"Choose a location with a large unpopulated area to the east, like an ocean" Sharks and whales: "Am I a joke to you?"

Thank you Grady for another awesome video!

There's a huge difference between "pushing limits" and outright engineering and environmental negligence.

I'm not sure that rocket engineering is something that should be subject to a rapid development cycle. Hopefully the regulators force more care into their preparations as this situation looked like it was entirely avoidable, they were just too cheap to build a well-tested existing design.

Spacex: Reusable rockets, expendable launch pads.

"Was Starship’s Stage Zero a Bad Pad?" Well, I wouldn't want to live there.

Grady you've got an amazing channel - congratulations. You're one of the few creators who has NOT put your hard-earned RU-vid plaques for subscriber achievement in the background of your video. Why? I think you SHOULD brag about your achievements - we all love you - and that bookshelf is just ASKING for some company! Put up your plaques Grady!

one small correction, when Elon said it went about as expected, he meant the rocket launch itself, not the launch pad. He stated on twitter that they did not anticipate the severity of the destruction of the launch pad.

Yes, clearly, unless the pads goal was to destroy things and burn money. You can say you did it to "learn" all you want, but no one wants to deal with this cleanup and rebuilding something you didn't have to destroy.

And this is the first I’m learning of the water deluge system. I love this channel!!!

I seen studies of the depth of jet impingement into pools of water (it’s apparently of interest in steel production) and if they extrapolate to the scale of a Starship launch, the rocket exhaust should penetrate a depth of about 2 meters. It looks like the penetration depth is a function of the exhaust velocity to a power between 1-2. All the artists conceptions of how the inverted shower head should work only show a thin film of water which I think would get blown away. Further, if the exhaust is able to convert the water under the plate to steam, it will provide significant resistance to sustaining the water flow and possible water-hammer effects. Each Raptor rocket engine puts out a power output equivalent to the thermal power of over two large nuclear reactors. And there are 33 engines powering the first stage.

I've been a sci fi fan for as long as I can remember, and I'm 70. None of those early writers gave any thought to the launch pads. Oh, E.E. Smith wrote about the spherical ships being so heavy they'd sink 1/3 deep into the ground, and the land was scorched. That was about it. Over the years I've been sort of compiling a list of what sci fi missed. Completely missed computers until they were already being developed, for example. None wrote about problems adjusting to zero gravity or reduced gravity, again, until that was already discovered. On the other hand, it's interesting to see what they "forecast", metaphorically. Heinlein's been pretty much on track in his "future history". We haven't settled other planets or discovered a faster than light ship, but we've sent robots almost everywhere and the JWSpaceTelescope is showing us the universe. (He wrote almost all his stories with the same background.) It's been compiled -- and guess what? Near the end there's a pandemic, and then: the first human civilization. Gives me hope.

Well, this was a bit disappointing. It seems like only a sentence or two in the whole video actually discuss the engineering of launch pad. It also feels like the video just cuts off without any real conclusion. Maybe this is a case of Betteridge's law. 10:08 / 10:30 - The PEA very extensively mentions the potential for debris through normal operations, anomalies, and even launch pad anomalies and sets the requirements for what must be done for each of them. I'm not sure how you could have missed that. The word debris is used 106 times in the PEA. 11:00 - Previously to the PEA there were multiple fires in the state park caused by static fires that were determined to actually be beneficial to the area. Because of this the mitigated FONSI didn't require any significant actions to prevent these from occurring. This one however was so small it did not spread. I'm not sure why it's noteworthy. I also think it should have been mentioned that this pad was only supposed to last one launch. It wasn't a CYA excuse by SpaceX, but the parts for the upgraded pad were already on site and being installed well before launch.

Actually the damage to the pad was surprising. The half thrust static fire left next to no damage on the concrete. The static fire earlier that did damage the concrete was even less powerful than half thrust, but it was done before the FONDAG concrete was used. The last static fire of the booster mentioned in the video used the upgraded concrete and caused minimal damage.

NASA: "We're doing proper engineering to ensure safety and reliability." SpaceX: "Do whatever, screw it. Musk has that emerald bucks to pay off any lawsuits and the dead can't complain."

I’d like to see a video on how NASA got the Saturn V and the Space Shuttle off the crawler and on to the pad. That part of the prelaunch process always gets overlooked.

Elon thought he knew better..... LMAO!!

SpaceX's overt disregard for environmental damage is quite likely to eventually paint them into a corner one day. Maybe it already has. From night lighting (impacts hatching sea turtles) to access for environmental inspectors, SpaceX has consistently disregarded environmental impact agreements negotiated with regulators.

If you've never been to a rocket launch, you totally should. You can literally feel the sound / pressure wave from launch from several miles away. It's amazing.

Your video reflects some of the early furor and speculations that went on around the web after the launch. A more complete image surfaced later and you failed to find it in your research. The primary reasons for the flame diverter and water deluge system was sound pressure on the vehicle itself which simply is not much of an issue for starship because of its height and construction. I, too, retweeted Elon’s quote about having no flame diverter. But now i know it was not really the issue. The underlying reason for the concrete failure was that the ground underneath it compacted or liquefied under the pressure, causing it to crack without adequate backing. At that point the engine exhaust started digging through.

I’ll defend NASA’s approach to research and design before doing full scale tests. The public has gained much more valuable information from this approach than just throwing everything at the wall and seeing what sticks. Most of these CFD and finite element programs were developed by NASA and were instrumental in so many other industries. The private sector benefitted from this too.

A friend’s company managed the underground portion of the pad and he said they had a lot of struggle with getting SpaceX to pay for a proper pad