If it was just heat they could use something flame resistant like ceramics.  But there is also the thrust of the exhaust.  Heat + high velocity exhaust = Erosion of most materials.  Water deluge system gives the hot exhaust something to erode.

I suspect the reason Elon decided to avoid a flame diverter + deluge system is more about time than cost.  Imagine how long the environment impact study will be for dumping tons of potentially contaminated water into the bay would be.  

Also they would have had to move in mountains of dirt, pack it down, wait for it to settle and compress the waterlogged dirt below, then coat everything in concrete before they could even build the launch mount.

I've worked on a job site in Iowa where the water table is only a few feet deep.  If you try to put a heavy structure on top the dirt will settle and cause your building to fail.  The method they used on site to deal with this is to pile dirt a few story's high and wait a year for the weight of the dirt mound to compress loose dirt and push the water out of from under building pad.

A small crew has arrived at the heavily damaged Starship pad following yesterday's launch. Watch live: https://t.co/McQ3KV5CV2 pic.twitter.com/nFH3eEikTi

Spaceflight Now  (@SpaceflightNow) April 21, 2023

More video's are popping up. Go full screen with this one, holy shit !
Pretty sure that's the HPU blowing up and the fluid igniting.

View from Mexico. I think it's the best angle so far! https://t.co/g32o4ljSbW

— TJ Cooney \uD83D\uDE80 (@TJ_Cooney) April 21, 2023

Should build tanks and barriers out of traffic cones.

I'm not convinced a flame diverter is necessary.

A Water deluge system is needed and the parts for it are already there, ready to be installed.  Once installed the sound from launch will be reduced and the impact on the concrete beneath the launchpad will also be reduced.

It may well make a flame diverter superfluous.

That moment where you realize you're looking at near-enough 1,000 feet of rocket and flame headed skyward.

Attached File

(link)

Awesome

Oh and people finding debris all over

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This is a view of highway 4 taken during our flyover.
probably one of the few reasons why it remains closed to the public. pic.twitter.com/QVYL79WiGb

RGV Aerial Photography  (@RGVaerialphotos) April 21, 2023

Live at 4 pm Central with a post-flight reaction and an update on the van. \uD83D\uDE05https://t.co/IVPo1CfjF1 pic.twitter.com/DR6t4nd5uE

Michael Baylor  (@nextspaceflight) April 21, 2023

Interesting hadn't seen the side profile of the interior of a tile before. Mass savings I guess.

Safe to say that Stage 0 is…toasty.

The same can be said for the rest of the structure and surrounding GSE.

Key notes are: OLM still venting & tank farm has taken significant damage pic.twitter.com/PMFqh3OFGA

— Max Evans (@_mgde_) April 21, 2023

Always wondered why they didn't bury the tank farm underground with the launch pad so close and decent enough chance of a launch pad explosion

Concrete slab leaning on the helium tanks as seen from our recent flyover.https://t.co/l5nZ12tVTO pic.twitter.com/GG1zagHg8p

RGV Aerial Photography  (@RGVaerialphotos) April 21, 2023

Water table

that makes sense

Scott Manley

SpaceX’s Starship Kicked Up a Dust Cloud, Leaving Texans With a Mess




As the most powerful rocket ever built blasted from its launchpad in Boca Chica, Texas, on Thursday, the liftoff rocked the earth and kicked up a billowing cloud of dust and debris, shaking homes and raining down brown grime for miles.

In Port Isabel, a city about six miles northwest where at least one window shattered, residents were alarmed.

“It was truly terrifying,” said Sharon Almaguer, who, at the time of the launch, was at home with her 80-year-old mother. During previous launches, Ms. Almaguer said she had experienced some shaking inside the brick house, but “this was on a completely different level.”

Meanwhile, SpaceX’s Starship exploded minutes after liftoff and before reaching orbit. Near the launch site, the residents of Port Isabel, known for its towering lighthouse and less than 10 miles from the border with Mexico, were left to deal with the mess.

Virtually everywhere in the city “ended up with a covering of a rather thick, granular, sand grain that just landed on everything,” Valerie Bates, a Port Isabel spokeswoman, said in an interview. Images posted to social media showed residents’ cars covered in brown debris.

A window shattered at a fitness gym, its owner, Luis Alanis, said. Mr. Alanis, who was at home at the time of the launch, said he felt “rumbling, kind of like a mini earthquake.” He estimated that the window would cost about $300 to fix.

Closer to the launch site, large pieces of debris were recorded flying through the air and smashing into an unoccupied car. Louis Balderas, the founder of LabPadre, which films SpaceX’s launches, said that while it was common to see some debris, smoke and dust, the impact of Thursday’s liftoff was unlike anything he had ever seen.

“There were bowling ball-sized pieces of concrete that came flying out of the launchpad area,” Mr. Balderas said. The blast, he added, had created a crater that he estimated was around 25 feet deep.

In a statement posted to Facebook, the city of Port Isabel said that the emergency management division of Cameron County had confirmed the dust “was sand and soil from near the SpaceX launch site that was lofted into the air by the force of liftoff.” A spokeswoman for the county’s emergency management division said that all questions regarding the dust from the explosion should be directed to SpaceX.

On Thursday, the Cameron County judge, Eddie Treviño Jr., ordered the closure of Boca Chica Beach and a section of State Highway 4 until 2 p.m. on Friday “for the purpose of protecting public health and safety during anomaly cleanup efforts.”

Ms. Bates, the Port Isabel spokeswoman, said that based on current information, there was no “immediate concern for people’s health.”

Eric Roesch, an expert in environmental compliance and risk assessment who has been tracking SpaceX’s rocket launches, said in an interview that he and others had long warned of the environmental risks to the surrounding region. But without a chemical analysis of the dust and debris, he added, it was difficult to say whether or not they were harmful to human health.

But, Mr. Roesch said, “the presence of that dust kind of indicates to me that the impact modeling was inadequate, because this was not really disclosed as a possible impact.” In June, an environmental assessment by the Federal Aviation Administration concluded that SpaceX’s plans for orbital launches would have “no significant impact” on the region along the Gulf Coast.

Mr. Roesch, who runs the environmental policy blog ESG Hound, said he believed the dust and debris came largely from a giant crater formed during the rocket’s liftoff. Normally, major launch sites are engineered with a trench or water system that helps to divert the rocket’s flame away from the ground and to dampen the impact, he said.

“They didn’t do that,” he said. “It appears they just went ahead and just launched this thing.”

Neither SpaceX nor the F.A.A. immediately responded to questions about the dust and debris on Thursday evening.

Continued

Stainless steel armor plate skirt ring at top worked pretty good.

Looks the same as pre launch.

The Launch of Starship From Isla Blanca Park

Elon Musk Reaction Rocket Explosion | AI

The tower itself is toast where the chopstick rollers ride, looks like a chunk missing. Not going to buff out.
The shielding for the draw-works is highly perforated, draw-works may be toast too.

Now I can't wait for the next launch.
Rocket addiction is worse than drinking.

lol aint making no multi year bet with someone who just joined last month.

Stevie Wonder could have seen that the tank farm would be damaged in a launch.
As for the town of Port Isabel...stop whining and grab a broom.

Here is an image we took in 2020 (left) of what the construction of the foundation looked like.
Right image is the aftermath. pic.twitter.com/V5ZULVXaJT

RGV Aerial Photography  (@RGVaerialphotos) April 21, 2023

poor Hoppy

Some of the skin is peeled away but it’s standing proud and tall pic.twitter.com/fqZPE1nJkc

Justin Swartz  (@jswartzphoto) April 21, 2023

This is not a render. This is not a simulation. This is @SpaceX’s first integrated test flight of #Starship with the Super Heavy booster, the world’s largest and most powerful rocket to ever fly. This #slomo is from our 8k tracker shot by @considercosmos. pic.twitter.com/srxmuStn2N

Everyday Astronaut  (@Erdayastronaut) April 21, 2023

They don't realize how lucky they are to receive dust and debris from the largest and most powerful rocket in the world.

oof

The damage in Boca Chica at the Starbase launch site looks pretty serious, but a former senior SpaceXer from there says he believes the pad can be repaired; and a (water-cooled?) flame diverter installed in 4 to 6 months. Just passing on what I was told.

Eric Berger  (@SciGuySpace) April 21, 2023

3 months ago, we started building a massive water-cooled, steel plate to go under the launch mount.

Wasn’t ready in time & we wrongly thought, based on static fire data, that Fondag would make it through 1 launch.

Looks like we can be ready to launch again in 1 to 2 months.

Elon Musk  (@elonmusk) April 21, 2023

meh nobody died or was injured as far as we know

Fuckin A.

Even in Elon time, that's pretty damn quick.

1-2 months!

With all that damage to be fixed, even 6-12 months is dreaming, then the enviro-weenie lawsuits and the court orders to cease launches until they are settled, we will be lucky to see a launch in 1-2 years.

Don't get me wrong I'd love to see a launch in 1 or 2 months but I'm realistic.
I watched the whole site get built day after day on NSF, I know how long it took just to build new tanks etc..
You are not just building new stuff, your tearing out the old first, that takes way longer.
Any scratch on any tank on that site and inspectors will probably make them replace it.
Not even talking about the OLM, tower, piping, electric, controls and wiring yet.
Realistically, that entire site and everything on it is toast.

Now Elon prove me wrong, I hope you can.

For any cameras at the pad that managed to survive, the chef's kiss is on the way! pic.twitter.com/GoJEkA5SgR

Michael Baylor  (@nextspaceflight) April 21, 2023

Oh jesus oh god

Jack Beyer  (@thejackbeyer) April 21, 2023

their van is gonna be ruined now.

now available in the NSF store

So after conversion from elon time, what is that? 1-2 years?

1-2 years is my estimation.

elon said 1 to 2 months so conversion of elon time actually make 4-6 months close

Update on the van live right now:https://t.co/IVPo1CfjF1

(this is the final frame) pic.twitter.com/UAugQ8ZKjR

Michael Baylor  (@nextspaceflight) April 21, 2023

SLS: Oops, we wrecked our elevators when we launched.

SpaceX: Hold my beer.

All that’s left of the concrete lateral support beam is the rebar! Hopefully, this didn’t gronk the launch mount.

Elon Musk  (@elonmusk) April 21, 2023

Mustang driver:  Watch this! (As he floors it, leaving a Cars & Coffee)

Elon:   Hold my beer....

SpaceX elevator didn’t even wait for the launch and checked itself out early.

It knew what was coming and took the easy way out.

They tried cheap/stupid once.  Just go all in with flame diverter and water deluge system....extra grande.