Starship is Go...

SpaceNut · 2025-07-14 18:54:37

Major change coming on the presurization tanks as they are going to a smaller more distributed system . Also the vacuum raptors are being more 3d printed with less parts, more cooling and higher output ISP. On this next flight.

GW Johnson · 2025-07-15 09:11:13

Composites are particularly vulnerable to impact damage. Anything small and hard thrown fairly fast will do that damage, and you won't see it just looking at it. Unless you have some sort of pre-damage imaging to compare, it is unlikely you would detect the damage. THAT is the risk you accept when you use these materials. There is no way around it.

As for "sabotage", the COPV tank is inside the nosecone of the upper stage. The rifle shooter would have to be inside the stage to hit the tank with a bullet. That would seem to be more nonsense than a real theory about what happened. Although a bullet from something more powerful than a rifle shooting 22 caliber long-rifle ammunition, would penetrate the nosecone and perhaps strike the COPV tank. That would be an unlikely long shot of a sabotage theory (if you'll excuse my choice of words).

But what if a rivet or bolt broke and threw a piece that happened to hit the COPV tank? A small piece of steel traveling more than about 100 mph would do internal damage to any carbon composite. There are composite materials that are impact and puncture damage-resistant, such as kevlar-vinyl ester, but these are nowhere near as stiff and strong as carbon-epoxy.

Here's another theory to consider: what if there was a weld defect at the joint between cylinder and tank head? The overwrap is likely not cloth, but carbon yarn wetted with epoxy resin, wound onto the cylinder section of the tank. The hoop stress in the cylinder section is twice the longitudinal stress in the cylinder section. Assuming the tank head is a hemisphere or a spherical segment, the stress in that metal membrane is equal to the longitudinal stress in the hoop section. That membrane can be thinner than the cylinder. Using too-thin a metal cylinder to save weight is what the composite overwrap counters. But if the weld has a defect, it locally raises the longitudinal stress at the joint, and that would cause the head to part from the cylinder.

Here's another: what if they didn't thicken the metal enough locally right at the weld joint cylinder-to-head? There's mismatched radial displacement at the joint, increasing stress there with bending stresses. The extra material is needed to "sop up" those bending stresses. Not enough extra thickness, and you have something straining plastically locally at the joint, leading to a very short fatigue life for the metal, and especially so in the heat-affected zone of the weld.

I can think up lots more. These are school-of-hard-knocks things coming from 2 decades doing aerospace defense work. Newbies wouldn't know much about it. This is the engineering art stuff.

GW

Last edited by GW Johnson (2025-07-15 09:24:30)

kbd512 · 2025-07-15 10:28:54

GW,

Aerospace has gone from natural composites to metals and now to synthetic composites. There's no acceptable substitute for their strength. Every modern airliner in existence uses truck loads of synthetic composites. All or almost all payload fairings and inter-stages are now made from composites as well, and for the same benefits. That's why they're so fuel efficient and light. They're not "bad" or "wrong", just different. There are some things you can do to metals that you cannot do to composites, such as throw debris at them. There are also many things that can be done with composites that are impossibilities with metals. Off the top of my head, all modern turbofans and turboprops use composite blades because they're less than half the weight of metal and many times stronger. When a fan blade does let go, a composite Kevlar ring around the fan section prevents the blade from penetrating into the cabin of the airliner. A 700bar storage tank would be ridiculously heavy if it was made from steel or Titanium thick enough to reliably contain the pressure. Thankfully, CFRP is much lighter and stronger- light enough to locate the Nitrogen storage tank onboard the vehicle to spin-up the pumps.

Yes, composites are more difficult to work with than metals in certain ways. Aluminum is also more difficult to work with than steel. That hasn't stopped us from using Aluminum, so it's not a valid reason to abandon the use of composites.

GW Johnson · 2025-07-15 14:15:30

Kbd512:

I didn't say there was anything wrong or bad about composites. I just pointed out the impact damage vulnerability using carbon fiber or cloth. That results from the low elongation capability of carbon fibers. It is inherent. The other materials do not have the strength and stiffness needed for that option, but at least one of them is very resistant to impact and puncture damage. That is the kevlar-vinyl ester material used in airliner interiors, especially the floor deck panels. They found out back in 1958 not to use aluminum alloy floor panels: ladies' spike heels poked holes through those panels, simply walking. The kevlar-vinyl ester panels have successfully resisted that ever since.

I did point out ways that a composite overwrapped steel tank might fail. The ways I pointed to are defects in the metal weld zone, not the composite, which gets added later in the manufacturing process. Could be a weld defect, could be a bad joint design with too little added thickness near the weld. Some steel with a lot of elongation would survive only a single handful of pressurizations, before cracking apart, without the extra thickness to "sop up" the bending stresses coming from the radial displacement mismatch at the cylinder-to-head joint. A more "brittle" steel would fail immediately.

My guess is that these newbies at SpaceX (none over 40-45 years old, most are under 25-30) are welding as-supplied stock sheet metal together without any added thickness at the joint. With a single handful of fatigue cycles available at the weld joint in a pressure vessel, at the cylinder-head joint, "unexpected" failure is inevitable! The overwrap cannot prevent that, even if you lap it over the joint a bit! They need to use the weld joint shapes in the ASME boiler code.

And this same design flaw applies to a lesser degree to all the welded ring joints in the Starship and Superheavy hulls. Those are all heat-affected zones that are also affected by weld physical chemistry. They have less tolerance of strain than the base metal, even if you get full weld strength by doing electron beam welding, which SpaceX is NOT doing! I've seen the videos, they are stick-welding those hulls.

Makes you wonder where some of the methane (and maybe oxygen) leaks have come from, does it not? Maybe where all the ice particles came from, inside the cargo bay during that last flight? Since there was a LOX header tank in the nose, adjacent to a nitrogen COPV. Any sort of tank flaw, or any sort of plumbing defect, could cause such leaks. And many others not well understood up to now.

Just food for thought.

By the way, I actually like composite materials. I've built a lot of them with my own two hands, many years ago. Every material has a "right" application, and a "right" way to be processed. And a "right" way for the application to be designed, for that matter. You do it "wrong" at your peril.

GW

Last edited by GW Johnson (2025-07-15 14:22:33)

GW Johnson · 2025-07-16 12:10:55

Found this in today's AIAA "Daily Launch" email newsletter:

Space
SpaceX will launch next Starship flight in 'about 3 weeks,' Elon Musk says
SpaceX plans to launch the 10th test flight of its Starship megarocket about three weeks from now, according to company founder and CEO Elon Musk.

GW

SpaceNut · 2025-07-23 15:16:31

Elon Musk Revealed SpaceX's Inside Raptor V3 Problem

SpaceX’s Starship Raptor 3 Engine Problem!

Elon Musk Revealed SpaceX's Inside Raptor V3 Problem

SpaceNut · 2025-07-24 16:17:02

Merlin vs Raptor engine comparison

RGClark · 2025-07-25 17:57:36

Is Elon Musk’s Starship Doomed? The future of SpaceX keeps blowing up, and no one knows if he can fix it.
By Jeff Wise, a science journalist and private pilot.
JULY 21, 2025
https://nymag.com/intelligencer/article … oomed.html

Bob Clark

GW Johnson · 2025-08-07 08:48:13

I've recently been hearing a new type of testing out of SpaceX's McGregor site. These are repeated start-stop tests. It starts, burns several seconds, then shuts down for several seconds, then restarts. This process repeats several times. I see no steam or plume clouds, so it's not on the tower stand or the two big surface deluge stands, it has to be on one of the horizontal open-air stands. The level of loudness and a hint of combustion roughness suggests these are Raptor tests. Odds favor these are Raptor 3 development tests, but that's just a guess on my part. The shutdowns have a sort of "bang" sound to them, not very loud. Every now and then I hear a loud one, though.

GW

SpaceNut · 2025-08-07 14:41:48

Saw a youtube video that indicate that they are for the block 2 of starship that is going to be 10M taller.

AI Overview
Evolution of the Raptor engine, by @cstanley : r/SpaceXLounge
SpaceX's Raptor 3 is an upgraded version of the Raptor rocket engine, boasting increased thrust, higher efficiency, and a simplified design compared to its predecessors. It eliminates the need for an external heat shield by utilizing a secondary cooling loop and is lighter and more powerful, enabling Starship to carry heavier payloads.
Here's a more detailed breakdown:
Key Improvements:
Increased Thrust:
Raptor 3 delivers significantly more thrust than previous versions. For example, it produces 280 tons of thrust at sea level, a 21% increase over Raptor 2.
Higher Efficiency:
The engine features a higher combustion chamber pressure and improved fuel efficiency, enhancing its overall performance.
Simplified Design:
Raptor 3 incorporates a more streamlined design with fewer components, including the elimination of the external heat shield and the integration of secondary piping and electronics into the engine structure.
Weight Reduction:
The simplified design and removal of the heat shield contribute to a significant weight reduction, with Raptor 3 being lighter than both Raptor 1 and 2.
Enhanced Durability:
The engine is designed for 1,000 flights with minimal maintenance and utilizes welded joints for increased strength and reduced potential for leaks.
More Payload Capacity:
The lighter weight and increased thrust of Raptor 3 allow Starship to carry a greater payload mass to orbit.
Key Features:
Full Flow Staged Combustion Cycle:
This advanced cycle maximizes efficiency and performance.
Liquid Oxygen and Methane Propellants:
These propellants enable cleaner burning and potential in-situ resource utilization on Mars.
Regenerative Cooling:
The engine uses a secondary cooling loop to manage extreme temperatures and pressures, eliminating the need for a heat shield.
Welded Joints:
Welded joints replace screws, bolts, and flanges in many areas, improving structural integrity and streamlining production.
Impact:
Enabling Deeper Space Exploration:
.
The improvements in Raptor 3 are crucial for SpaceX's ambitious goals of establishing a self-sustaining civilization on Mars.
Advancing Rocket Engine Technology:
.
The Raptor 3 engine represents a significant step forward in rocket engine design and manufacturing.
Increasing Launch Efficiency:
.
The engine's increased thrust, reduced weight, and higher efficiency translate to greater payload capacity and lower launch costs

RGClark · 2025-08-13 18:55:49

Robert Zubrin again gives his argument why Starship should have a smaller third stage to do the actual landing on Mars:

Crewed Mars missions will require a new ascent vehicle.
by Robert Zubrin
August 12, 2025
https://spacenews.com/crewed-mars-missi … nt-vehicle

Bob Clark

Void · 2025-08-18 14:43:03

An interesting story: https://www.bing.com/videos/riverview/r … 2807039880 Quote:

Elon Musk REVEALS: Ship 37’s Fuel Crisis Was PLANNED to Rule Space!
YouTube
SpaceX Report

Well!!!!!!!!!!!

Ending Pending

Last edited by Void (2025-08-18 14:43:53)

GW Johnson · Yesterday 13:29:05

An air separation plant has nothing to do with producing methane fuel! It has everything to do with producing liquid oxygen, which for the Raptor engines, outweighs the methane by a factor near 6. It also produces more liquid nitrogen than they could ever use, which they could sell.

The methane for the Raptor engines comes from natural gas, which is a mix out of the ground of methane, carbon dioxide, water vapor, ethane, propane, butane, and some others, sometimes including even hydrogen and nitrogen. Methane is separated from the rest in a cryogenic chilling plant, as the purest of several products from such plants, such as LNG.

Your household or camping propane or butane comes from these same natural gas cryo separation plants. The ethane usually goes to the chemical industry. Power plants can use unseparated natural gas right out of the ground , although the "higher quality" fuel that causes fewer maintenance problems has been de-watered by the mildest of the chilling in the separation plants.

There are a bunch of these facilities on the Texas coast near the Houston ship channel, amongst all the oil and chemical plants. They are not owned in any way by anyone but the fossil fuel industry. They are not very far by road, rail, or ship, from Brownsville, Texas. Less than 400 miles.

The BE 4 engines in the new ULA Vulcan rocket burn hydrogen as the fuel, not methane. The oxidizer is the same liquid oxygen that the Raptors, and almost all other modern engines, use. Hydrogen is also made in chemical plants, by reaction, from natural gas.

Lets just say that with technical flaws like that, I have my doubts about the strategies and motivations claimed in that video.

GW

Last edited by GW Johnson (Yesterday 13:35:53)

Void · Yesterday 14:53:09

You know that I have the greatest of respect for you Dr. Johnson. And I agree that if it is on Utube, on average, it is at least half under suspicion. I believe you that it might make sense to get these resources from the canal/vendors.

But the BE4 is Methane fuel. BE7, I think is Hydrogen.

I don't expect anyone to be perfect, especially not me.

I think we all appreciate your contributions here, sir.

Ending Pending.

tahanson43206 · Today 05:53:12

This post is about failures of SpaceX Starship tests in 2025...

https://www.yahoo.com/tech/science/arti … 33871.html

The article contains links that may lead to details in support of the summary in the article itself.

Starship's upcoming flight test was previously delayed June 18 when the Starship vehicle SpaceX assigned to the next flight, designated Ship 36, unexpectedly exploded while SpaceX was preparing it for launch. No one was hurt in the incident, which occurred as the Starship spacecraft was standing alone on the test stand being filled with cryogenic propellants for an engine test-firing prior to being mounted on top of the rocket booster.
The mishap, which SpaceX later referred to on its website as "a sudden energetic event," completely destroyed the spacecraft and ignited several fires that caused damage in the area surrounding the test stand.
The explosion was the latest fiery mishap SpaceX's Starship has encountered during – and, now, prior to – its flight tests in 2025.
Starship's most recent demonstration came May 27 when the spacecraft spun out of control roughly halfway through its flight and disintegrated in a fireball. Though Starship was unable to achieve its most important objectives, the distance the vehicle traveled far surpassed the previous 2025 flights in January and March, when Starship exploded within minutes.
Why does Starship keep exploding? SpaceX releases report
SpaceX had previously released findings into the first two Starship explosions in January and March. Now, the company has unveiled the results of investigations for the two most recent mishaps, as required by the Federal Aviation Administration, which licenses commercial rocket launches.
The May 27 mission got off to a positive start, with the successful first-ever launch of a rocket booster – known as Super Heavy – that had flown during a previous flight in January. Reusing a booster was an important milestone for SpaceX to demonstrate that the rocket can be flown multiple times.
But rather than making a controlled splashdown as planned, the booster came apart in the air and plummeted into the Gulf of Mexico, which the U.S. government has renamed as the Gulf of America.
SpaceX attributed the crash to a structural failure to the booster’s fuel transfer tube, which resulted in methane and liquid oxygen mixing and igniting.
The vehicle's upper stage – known simply as Starship, or Ship – managed to separate from the booster and fire its six Raptor engines to propel itself on a trajectory taking it into suborbital space as it soared around the world. But contact with Starship was lost approximately 46 minutes into the flight as it spun out of control and once again came apart over the Indian Ocean.
SpaceX traced the failure to the main fuel tank pressurization system diffuser, located on the forward dome of Starship's primary methane tank. Other issues with the nosecone prevented Starship from deploying eight test Starlink satellites.
As for the June explosion, SpaceX said it was caused by undetected damage to a high-pressure nitrogen storage tank inside Starship's payload bay section, called a composite overwrapped pressure vessel (COPV.)
In a statement, the FAA said it "oversaw and accepted" SpaceX's findings and gave it the greenlight to proceed with its next Starship launch.
"SpaceX identified corrective actions to prevent a reoccurrence of the event," the FAA said.
But when it comes to Starship's development, SpaceX has become known for its risk-tolerant philosophy. Musk has stressed that rapid and frequent testing that sometimes leads to explosive ends can still provide data that helps engineers improve the vehicle's design.
SpaceX is developing Starship to be a fully reusable transportation system, meaning both the rocket and vehicle can return to the ground for additional missions.
In the years ahead, Starship is set to serve a pivotal role in future U.S. spaceflight. Starship is the centerpiece of Musk's vision of sending the first humans to Mars, and is also critical in NASA's plans to return astronauts to the moon's surface.
But the next-generation spacecraft has yet to reach orbit on any of its nine uncrewed flight tests, which began in 2023.
SpaceX received key regulatory approval earlier in 2025 to conduct up to 25 Starship tests a year, after which Musk took to social media in late May to proclaim that the vehicle's next three launches would occur much faster than normal – at a cadence of one "every 3 to 4 weeks."
How big is Starship?
The Starship, standing nearly 400 feet tall when fully stacked, is regarded as the world’s largest and most powerful launch vehicle ever developed.
When fully integrated, the launch system is composed of both a 232-foot Super Heavy rocket and the 171-foot upper stage Starship itself, the spacecraft where crew and cargo would ride. That size makes Starship large enough to tower over SpaceX's famous 230-foot-tall Falcon 9 – one of the world's most active rockets.
Super Heavy alone is powered by 33 of SpaceX’s Raptor engines that give the initial burst of thrust at liftoff. The upper stage Starship section is powered by six Raptor engines that will ultimately travel in orbit.
Eric Lagatta is the Space Connect reporter for the USA TODAY Network. Reach him at elagatta@gannett.com
This article originally appeared on USA TODAY: SpaceX reveals why Starship exploded last 2 times ahead of flight 10

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