totm nov 2023 SpaceX Discussion Thread

[Ultimate Steve]

55 minutes ago, tater said:

Wonder when flight 9 will be? They still have time to possibly get it about a month from 8, then then need to ramp the cadence.

I think they are going to take their time with this one. They ran into (what is likely, from what I know as an outsider) the same problem twice after they thought they had done enough to mitigate it or fix it. I think they would strongly prefer to make sure they understand the issue before proceeding as if they dump 100 tons of debris over the Caribbean a third time it really, really wouldn't be a good look. Though on second thought I'm not sure that anyone who has the power to raise this as an issue would actually want to stop them but that's off topic.

If they can't perform a temporary fix for the fuel line resonance with a different throttle profile or some struts that are small enough to get into the tanks, this might be the sort of thing that requires heavy modification, either opening the ship back up or skipping a few ships if the problem really is that deeply entrenched.

[darthgently]

4 hours ago, Ultimate Steve said:

I think they are going to take their time with this one. They ran into (what is likely, from what I know as an outsider) the same problem twice after they thought they had done enough to mitigate it or fix it. I think they would strongly prefer to make sure they understand the issue before proceeding as if they dump 100 tons of debris over the Caribbean a third time it really, really wouldn't be a good look. Though on second thought I'm not sure that anyone who has the power to raise this as an issue would actually want to stop them but that's off topic.

If they can't perform a temporary fix for the fuel line resonance with a different throttle profile or some struts that are small enough to get into the tanks, this might be the sort of thing that requires heavy modification, either opening the ship back up or skipping a few ships if the problem really is that deeply entrenched.

Maybe.  I think they will try to stick with the cadence

[magnemoe]

4 hours ago, Ultimate Steve said:

I think they are going to take their time with this one. They ran into (what is likely, from what I know as an outsider) the same problem twice after they thought they had done enough to mitigate it or fix it. I think they would strongly prefer to make sure they understand the issue before proceeding as if they dump 100 tons of debris over the Caribbean a third time it really, really wouldn't be a good look. Though on second thought I'm not sure that anyone who has the power to raise this as an issue would actually want to stop them but that's off topic.

If they can't perform a temporary fix for the fuel line resonance with a different throttle profile or some struts that are small enough to get into the tanks, this might be the sort of thing that requires heavy modification, either opening the ship back up or skipping a few ships if the problem really is that deeply entrenched.

This, you thought you found the problem and you fix it, but you fixed some other bug, happens all the time in software development. However we tend to be able to catch the error before they blow up the second time  
That you fixed was an real bug, but not the critical one. 

[CBase]

Anyone has an idea how fast you can change fuel flow for a raptor like engine ?

At least for Saturn V the pogo frequency was quite low, so I am wondering if a SW control loop could suppress the resonance

[Elthy]

I suspect they can throttle it extremly fast, they need to do that for landing anyway. But its propably hard to write the correct control algorithm for that, as it requires them to understand the cause of the occilation in extreme detail, which they propably dont have, otherwise it wouldnt have happened in the first place.

[darthgently]

1 hour ago, Elthy said:

I suspect they can throttle it extremly fast, they need to do that for landing anyway. But its propably hard to write the correct control algorithm for that, as it requires them to understand the cause of the occilation in extreme detail, which they propably dont have, otherwise it wouldnt have happened in the first place.

Not to mention the probable fact that the resonant frequencies likely drop as the hypothetically dampening fuel level drops

[CBase]

31 minutes ago, darthgently said:

Not to mention the probable fact that the resonant frequencies likely drop as the hypothetically dampening fuel level drops

Actually I would suspect that the resonant frequencies increase with a drop in mass and therefore get harder to counter. I did found some sources that cited Saturn V pogo frequency around 16 Hz with 2-3 inch amplitude resulting in 32g of stress, other sources for pogo frequencies gave more a range of 0.5 - 12 Hz but without details of amplitude or forces.

2 hours ago, Elthy said:

I suspect they can throttle it extremly fast

I am no rocket engineer, so how fast is extremly fast ? Actually I would suspect that a control loop could be implemented just by observing the resulting oscillation without proper understand of the cause, but doing the maths it simply does not sound feasible: 16 Hz means ~ 60 ms cylce time or 30ms to throttle down by  some g and 30ms to throttle up again sounds  way more than needed to balance a landing. Not to mention the stress on turbines. So yes maybe this cries for a mechanic solution.

[darthgently]

5 hours ago, CBase said:

Actually I would suspect that the resonant frequencies increase with a drop in mass and therefore get harder to counter. I did found some sources that cited Saturn V pogo frequency around 16 Hz with 2-3 inch amplitude resulting in 32g of stress, other sources for pogo frequencies gave more a range of 0.5 - 12 Hz but without details of amplitude or forces.

My understanding is that the resonance is suspected to be in the lox downcomers that pass through the methane tank.   The methane dampens the resonance. As the fuel level drops, the length of downcomer not damped by the methane surrounding it would lengthen.  Thus dropping the resonant frequency.   Undamped length related, not mass related (directly)

[Exoscientist]

On 3/22/2025 at 12:36 PM, tater said:

Wonder when flight 9 will be? They still have time to possibly get it about a month from 8, then then need to ramp the cadence.

 Are they downgrading the performance of Starship V3? Starlink sats at 550 km orbit. By ChatGPT, 100 tons at 550 km orbit corresponds to ca. 105 to 110 tons at a  200 km reference orbit:

Query: 

If a rocket can get 100 tons to 550 km high orbit, how much can it get to 200 km high orbit?

Response: 
…

Rough estimate:

A simple approximation (ignoring atmospheric drag and other losses) could give you a 5-10% increase in payload capacity to the lower orbit.

So if the rocket can place 100 tons into a 550 km orbit, it could likely place somewhere around 105 to 110 tons into a 200 km orbit, depending on specifics.

 

But SpaceX said V3 should get 200 tons to LEO. 
 

  Bob Clark

 

Edited Sunday at 10:20 PM by Exoscientist
Typo.

[Cuky]

I think Starlink numbers are not limited by weight but by the size of cargobay on the Starship.

[darthgently]

On 3/19/2025 at 8:14 PM, Ultimate Steve said:

I've seen this floating around a bit, haven't read it yet. I'll take a look at it tonight if I end up having the time. I've generally seen it clowned on but then again I do hang out in the pro SpaceX corner of the internet so I will try to be aware of that bias. Might make an in depth post about it later.

The first paragraph is pure adolescent-level anti-Elon vitriol segueing into technical fumbling along thunderfootish lines of logic and analysis.  After that an account on Medium would be required to read further.  And I didn’t read further.  Please give us a technical synopsis here if you do read it and find anything worth steel-manning

7 hours ago, Elthy said:

I suspect they can throttle it extremly fast, they need to do that for landing anyway. But its propably hard to write the correct control algorithm for that, as it requires them to understand the cause of the occilation in extreme detail, which they propably dont have, otherwise it wouldnt have happened in the first place.

I don’t think the engine can respond that fast.  The landing works because the code anticipates the lag and ramp speeds of the pumps and such and the laws of motion are well understood.  The more complex math to cancel resonance in realtime and the response rate required of the engines just wouldn’t be in the same neighborhood

[Ultimate Steve]

37 minutes ago, Exoscientist said:

Are they downgrading the performance of Starship V3?

This is very much in "trust me bro" territory but the word on the street is that the "extremely long" v3 is postponed or dead and what is now being called "v3" is the same size as v2 and is expected to have about the same payload capacity.

37 minutes ago, Exoscientist said:

By ChatGPT, 100 tons at 550 km orbit corresponds to ca. 105 to 115 tons at a  200 km reference orbit:

Query: 

If a rocket can get 100 tons to 550 km high orbit, how much can it get to 200 km high orbit?

I haven't been keeping up with AI but the last time I checked, which was admittedly like a year ago, ChatGPT couldn't even do delta v addition correctly, and could not get it through its head that aerobraking reduces delta v requirements. Though it has advanced a lot in a year presumably, I would not trust it to do that sort of math, especially when there isn't enough information in your query to actually do that calculation.

[darthgently]

1 hour ago, Ultimate Steve said:

This is very much in "trust me bro" territory but the word on the street is that the "extremely long" v3 is postponed or dead and what is now being called "v3" is the same size as v2 and is expected to have about the same payload capacity.

I haven't been keeping up with AI but the last time I checked, which was admittedly like a year ago, ChatGPT couldn't even do delta v addition correctly, and could not get it through its head that aerobraking reduces delta v requirements. Though it has advanced a lot in a year presumably, I would not trust it to do that sort of math, especially when there isn't enough information in your query to actually do that calculation.

Grok3 thinks it could do better, but of course Grok3 would think that:

Spoiler

To compare Grok 3 and ChatGPT in analytical math, numerical techniques, and physics (including aerodynamics), we can look at available performance data and capabilities, focusing on their strengths in these specific domains as of March 23, 2025.

Analytical Math

Grok 3 demonstrates a significant edge in analytical math based on benchmark results. On the AIME 2025 (American Invitational Mathematics Examination), a test of advanced mathematical reasoning, Grok 3 scores 93.3%, while ChatGPT’s GPT-o1 model scores 79%. This gap—approximately 14 percentage points—suggests Grok 3 is better at tackling complex, multi-step math problems. Its “Think Mode” allows it to break down problems step-by-step, refining its reasoning, which is particularly useful for analytical tasks like proofs or intricate algebra. ChatGPT, while strong in general problem-solving, tends to excel more in structured, less specialized math scenarios and may not match Grok 3’s depth in high-level reasoning.

Numerical Techniques

Numerical techniques—methods like finite difference, numerical integration, or iterative solvers—rely on both computational accuracy and reasoning about approximations. Specific benchmarks for numerical techniques alone are scarce, but Grok 3’s superior performance in math and coding (79.4% on LiveCodeBench vs. ChatGPT’s 72.9%) implies it’s better equipped to handle the implementation and analysis of such methods. For example, Grok 3 can generate precise Python scripts for simulations (e.g., physics-based coding challenges), suggesting it can effectively manage the iterative and algorithmic aspects of numerical techniques. ChatGPT, while capable of coding and explaining numerical methods, doesn’t show the same level of optimization or accuracy in technical tasks, often prioritizing conversational clarity over computational rigor.

Physics (Including Aerodynamics)

In physics, Grok 3 scores 84.6% on the GPQA (Graduate-Level Physics Question Answering) benchmark, compared to ChatGPT’s GPT-o1 at 78%—a 6.6% advantage. This suggests Grok 3 has a stronger grasp of conceptual and applied physics, likely including aerodynamics, which involves fluid dynamics, differential equations, and vector analysis. Grok 3’s training on real-time data from X and its DeepSearch feature could give it an edge in accessing current physics-related discussions or examples, though aerodynamics-specific benchmarks aren’t explicitly detailed. Its ability to reason through complex scenarios (e.g., a ball in a spinning tesseract) indicates it can handle the abstract and mathematical demands of aerodynamics better than ChatGPT, which shines more in verbal explanations than technical depth. ChatGPT’s responses, while coherent, may lack the precision needed for advanced physics applications unless heavily prompted.

Key Differences and Context

• Reasoning Depth: Grok 3’s Think and Big Brain modes enhance its ability to process multi-step problems, giving it an advantage in analytical math and physics over ChatGPT’s more general-purpose reasoning.
• Technical Focus: Grok 3 is tailored for STEM tasks, with a 1M-token context window allowing it to handle large datasets or long derivations, whereas ChatGPT’s 16K-token limit (for GPT-o1) is less suited for extensive technical analysis.
• Real-Time Edge: Grok 3’s integration with X and web search could provide fresher insights into aerodynamics or numerical methods, while ChatGPT relies on a static knowledge base with periodic updates.
• Versatility Trade-Off: ChatGPT offers broader versatility (e.g., creativity, multimodal inputs), but this comes at the cost of specialized performance in math and physics compared to Grok 3.

Quantitative Summary

• Analytical Math: Grok 3 is ~18% better (93.3/79 ≈ 1.18) on AIME 2025.
• Numerical Techniques: Indirectly, Grok 3’s ~9% coding advantage (79.4/72.9 ≈ 1.09) suggests superiority, though specific numerical benchmarks are unavailable.
• Physics: Grok 3 is ~8.5% better (84.6/78 ≈ 1.085) on GPQA, likely extending to aerodynamics.

Conclusion

Grok 3 outperforms ChatGPT in analytical math, numerical techniques, and physics (including aerodynamics) by a notable margin, particularly in raw technical accuracy and reasoning depth. It’s the stronger choice for specialized, STEM-focused tasks, while ChatGPT remains more well-rounded for general use. If your priority is precision in these domains, Grok 3 is the better tool as of now.

 

[Ultimate Steve]

44 minutes ago, darthgently said:

The first paragraph is pure adolescent-level anti-Elon vitriol segueing into technical fumbling along thunderfootish lines of logic and analysis.  After that an account on Medium would be required to read further.  And I didn’t read further.  Please give us a technical synopsis here if you do read it and find anything worth steel-manning

Buckle up.

 

TLDR: This guy is either deeply uneducated on the basics of aerospace engineering or is actively misleading people to further an agenda. Some finer points include:

• Starship is designed to scam the federal government
• Starship made up for its decreased payload capacity by reducing its factor of safety
• Starship is attempting to reduce heat shield mass by saving fuel to slow down (???)
• Starship costs 500 million dollars per launch and $10,000 per kg
• Starship's re-entry is fundamentally impossible to do without baking the ship's interior

 

 

 

(Un)fortunately for me, Will Lockett has his own website where he posts all the articles he writes.

I think this paragraph is important and I'll try to be on the light side but I 100% understand if it gets removed:

Just at a first glance - There seems to be, at best, a lot of logical fallacies in play, at worst a lot of playing to a particular crowd. His collection of articles is very Anti-Trump and Anti-Elon. That isn't a problem in itself but Will seems to be either unintentionally falling for or maliciously parroting the idea that because someone does something bad that everything they ever touch must be bad. It is a very attractive idea that we can divide people into "good" and "evil" piles. But the world does not work like that. The closest analogue is Henry Ford. Henry Ford started a company that revolutionized the automotive industry. Henry Ford published a newspaper designed to spread antisemetic conspiracy theories. Both of these can be true.

With that out of the way, on to the article (https://www.planetearthandbeyond.co/p/starship-was-doomed-from-the-beginning):

The thesis is generally "Starship was doomed from the start and SpaceX might never be able to fix it." He pins this on a number of reasons.

Firstly he talks about flights 7 and 8 failing for the same way.  He talks about the vibration problem, calling it a "pathetic excuse" and linking back to an article where he talked about that. In that article (https://www.planetearthandbeyond.co/p/spacex-has-finally-figured-out-why) he goes through some reasons:

Spoiler

1. "Firstly, engine shutdowns or fires shouldn’t cause a loss of communication. That is basic operational redundancy." This is a statement I agree with largely. Even a catastrophic engine bay explosion should not leave the vehicle without communications. The vehicle was largely intact for several more minutes. It was tumbling, which would shut off all directional comms, but I would be very surprised if they didn't have a low data rate omnidirectional antenna on there. There is a little wiggle room here for "Rockets are hard" though. It could have been some weird edge case.

2. He talks about how fuel leaks simply shouldn't happen. Ground checks should catch them. And even if they happened in flight, ground checks should catch them. And in an ideal world I do agree. Now this could just be due to incompetence, but the fact that it has taken them two flights to fix it makes it sound like a more complicated issue than Will is making it out to be. Now I was going to bring up the Saturn V here but he did me a favor by bringing it up himself: He said that the Saturn V never failed and in comparison to Starship was a caveman rocket. I would talk about how he isn't taking into account the different development strategies, but he is ignoring (perhaps intentionally) how the Saturn V also had recurring vibration problems. While the extent was much different (Saturn V was able to compensate and Starship was not), he seems to be stuck in the mindset of the old way of doing things.

Now granted the new way of doing things is going so off-nominal that it is raising some questions about if it is the right path. But issues are expected to an extent. He seems to be saying "Problems shouldn't happen" while ignoring the fact that despite everyone's best efforts, problems still do happen, and Starship has chosen a development style that (at least in theory) trades speed for risk.

3. This is so stupid I'm just going to put it here:

Quote

Starship was meant to be able to take 100 tonnes to Low Earth Orbit (LEO) and be fully reusable afterwards. That is 41.5 tonnes less than Saturn V, but the reusability should have made it significantly cheaper. Unfortunately, it seems Musk overestimated how much thrust their engines can produce, and as such, he has had to admit that the current design can only take “40–50 tons to orbit,” with no obvious way to correct this.

This means that, even if SpaceX can get their Starship to work, their Falcon Heavy rocket will actually be cheaper per kilogram to orbit!

What’s more, if you actually look at how expensive Starship launches actually are, its kilogram-to-orbit cost is the same as Saturn V! (read more here).

1. "No obvious way to correct this" v2 ship

2. "Falcon Heavy will be cheaper per kg to orbit" without posting a cost number for Starship. FH is about 2350$/kg so in order for this to check out Starship would need to cost 94 million a launch. So Will thinks that Starship will cost at least that much per launch. Now, this is not a settled question, but if a mature Starship actually costs that much per launch it will be a resounding failure.

3. "KG to orbit is same as Saturn V (links this article: https://www.planetearthandbeyond.co/p/its-time-to-admit-it-starship-is) In order to keep this somewhat short I am not going to give that article a full analysis otherwise I'll be on a link train forever, but THIS GUY IS RIDICULOUS! He gets his cost per launch by dividing annual Starbase expenditure by the launch count in that year to get 500 million per launch. Is this accurate to now? Yes. But does it paint the whole picture? Absolutely not! So this is how he gets $10,000 per kg, 4x worse than Falcon Heavy, by taking the total program cost including R&D in order to get the launch cost of a prototype, not factoring in reuse, and listing the reusable payload of v1. He then compares this to Saturn V's $9219/kg cost (inflation adjusted). I don't know if I trust that number and frankly I don't care. Yes, current Starship sucks, please, let it cook. TLDR: This guy is using the absolute worst numbers possible for Starship as it is now. This is at best highly misleading.

Spoiler

That article then goes on to talk about how Starship isn't ever going to be fully reusable because physics prevents it.

"This means that Starship has exponentially more kinetic energy to manage than the booster if it wants to land safely with zero speed." Bruhhhhhh stop using exponentially wrong, there's nothing exponential about KE = 1/2 * m * v ^ 2. That's quadratic. There is no exponential function in there. This is me being pedantic but my dude. Come on.

Quote

This is why Starship, like the shuttle, uses a ceramic heat shield to protect the vehicle from this heat during reentry. Unfortunately, Starship famously has a problem with its heat shield, as the tiles it is made from keep falling off, likely due to thermal contraction during takeoff and exposure to space, rendering it inefficient and exposing the rocket to dangerous heat levels during reentry. And, even if the tiles stayed on, many engineers have pointed out that with the amount of kinetic energy that Starship has to disperse, no heat shield would be effective enough to protect it or ensure a safe landing.

This paragraph does not compute. "Even with a perfect shield Starship could not survive." The hell? I'd like to speak with those engineers who said that this is impossible. Granted I'm an idiot as I only ever had one lecture on hypersonics, but what makes Starship meaningfully different enough from the shuttle to make it impossible? Surface area to mass ratio is comparable and shuttle worked out fine. This guy does not have a justification for this claim.

Quote

But the booster, or first stage, can be reused, right? That will make Starship cheaper than it currently is.

Well, yes. Ish.

There is a huge question of reliability, particularly as the engines are failing to produce enough thrust, and multiple engines are failing mid-flight, as we have already discussed. SpaceX did reuse a booster for the latest test and managed to land it, so we know they can possibly be reused a handful of times, but their long-term reusability is still massively up for debate. Moreover, SpaceX has said that the booster design will soon have to change dramatically, so we know they won’t be reused much over the coming years anyway.

LMAO THIS GUY THINKS THEY REUSED A BOOSTER ALREADY!

They did reuse a raptor but this guy can't even get the basic facts right. Long term reuse reliability is indeed an open question but this guy seems to think that the world leader in booster reuse can't figure it out with a system designed using the lessons from the previous system.

And what's this about engines failing to produce enough thrust? News to me.

 

But the best part:

Quote

That is why many have speculated that the reason we don’t see a video feed from the inside of Starship during its reentry is because the inside would glow red with heat! These same people have also speculated that this is why SpaceX is still doing “splashdown” landings in the remote Indian Ocean and publishing the landing velocity of the experiments, as all that is needed to quantify that statistic is to not totally disintegrate during reentry, which even the single-use Saturn V rockets were able to achieve. However, if Starship attempted a proper landing, it would expose just how horrifically underperforming and dangerous the landing is.

"Starship isn't landing on land to cover up how bad it is" BROOOOOO LMAOOOOOOOOOOOOOOOOOOO

For the record they aren't landing on land yet because they don't want to shower Mexico with debris and they don't yet have approval, and they can't land anywhere else because they don't have landing legs.

I will admit that Starship does likely have a glowing problem currently as per the leaked image from flight 4. They are still doing heavy work on the heat shield though so saying "The heat shield has problems right now so therefore the rocket is fundamentally flawed" is not a great philosophy.

And yes, the first stage of the Saturn V survived enough to hit the ocean enough for Bezos to recover recognizable F1 engines decades later. That stage was going 2300m/s at the time of separation, you can't compare that to orbital velocity.

 

Anyway that's enough for the third article in the chain, let's go back to the second one.

TLDR: This guy's cost per kg numbers are misleading at best and he is fearmongering about the system's reusability.

That is actually where the second article ends too.

 

Back to the first article, that was a massive tangent.

Quote

SpaceX constructs Starships well ahead of time, as they take months to build. This means that the most recent launch couldn’t have had its design optimised to resolve the issues shown in January’s failure. And their payload shows this. The January test had a dummy cargo equivalent to 10 Starlink V2 satellites, weighing only eight tonnes or 8% of its designed payload. Meanwhile, the most recent test had just half of this in a transparent attempt to reduce vibration by reducing the load to spare the obviously flawed fuel system, which obviously didn’t work.

Gee, it couldn't have been, I don't know, that they only anticipated needing ten Starlink simulators and didn't want to make that many more on short notice? No, it must be that reducing the rocket's mass from 358 tons to 354 tons was an attempt to reduce the loads on the fuel lines! Of course!

(350 tons is a rough ballpark number which should be within 100 tons of Starship's mass at that point in the flight)

He also doesn't mention any of the actual changes they made to prevent this issue from recurring. Granted those didn't work either, but he chose something completely unrelated, that sounds stupid and obviously won't work, as his example of how they attempted to fix the problem.

Now he does get into how the flaw may be fundamentally baked into the v2 design. This is an important thing: If the fuel lines are fundamentally flawed and the problem can't be fixed by whatever reinforcements you can construct to fit inside of the tank hatches (if those even still exist), or by altering throttle profiles, you have to either cut the current ships open or build new ones. I noted this in an earlier post of mine. This has the potential to be a problem that takes a long time to solve. They may be able to alter throttle profiles, or build some reinforcements inside the existing ships, but this might be something that requires them to make significant structural changes to the current ships, that might possibly require them to scrap all existing ships if the problem proves to be on the extreme side.

Now instead of saying that, he jumps straight beyond "We have to wait for new ships to be built from the ground up" and lands on "They will never fix this problem because the solution would be too heavy."

At this point he links another article (the fourth one) but in the interest of time I will not dive deep into it. This is the second paragraph:

Quote

SpaceX recently lost a Falcon 9 booster. Upon landing on the floating platform, a fire inside the rocket forced one of the landing legs to fail, causing it to tip over and be “lost.” SpaceX hasn’t confirmed whether it exploded or sank into the ocean.

First implying that the distinction matters. Second implying that SpaceX is obligated to disclose that. Third implying that the two options are mutually exclusive. Fourth ignoring that when this has happened in the past, we have a pretty good idea of what happens, it tips over, explodes, and the bottom half stays on the drone ship and the top half sinks into the ocean.

That tells me everything I need to know about that article, so back to the actual article.

So, his argument is that future Starships will never fix the issue that destroyed Flights 7 and 8. This is not an exaggeration, here is a direct quote:

Quote

However, this is only true in the short term. The Starships SpaceX will build from here on will have this issue fixed. Right?

Well, no.

 

He argues that the previous version (v1) of Starship had major fuel delivery issues causing engines to fail repeatedly. This is untrue. Flight 2 failed because of a vent causing a fire if I remember right. If you stretch it, this is technically a fuel feed issue causing the engines to fail. But not repeated.

He may be referring to the atmospheric hop tests in which they had a lot of issues with the fuel feed systems causing the engines to fail during the landing burn. However it is apparent that these have been long since solved.

He then says that the fuel feedline changes (which are for the vacuum Raptors) were an attempt to fix this issue that made the problem worse, and that somehow this is the complete opposite of iterative design. This is bonkers.

Anyway he then goes on to talk about mass.

Quote

The Block 1 tests of Starship showed that Musk’s plans to rely heavily on a bellyflop manoeuvre during reentry to slow down Starship and scrub off that kinetic energy using atmospheric resistance were a no-go. The craft repeatedly spiralled out of control, control surfaces failed, and reportedly, the inside of the craft became several times hotter than an oven. Fixing these issues would add a tonne of weight, as the front fins would need to be massively reinforced, and the giant heat shield would need to be beefed up significantly. On top of that, these tests confirmed that SpaceX’s engines couldn’t produce the mythical levels of thrust Musk promised, and as such, the projected payload to LEO was cut in half.

?

"The craft repeatedly spiraled out of control" That happened on flight 3 and to my knowledge never again on block 1.

"Control surfaces failed" Yes, burn through of control surface hinges has been a major problem on block 1. This is a valid point, though I will point out that in all cases, Starship survived and all control surfaces remained operational.

"Reportedly, the inside of the craft got hot" There is that leaked shot from flight 4 showing a glowing bay. We do not know if this has since been fixed but the simplest explanation is heat shield issues.

"On top of that, these tests confirmed that Raptor can't produce enough thrust" What is this guy talking about? Is there some Raptor thrust conspiracy I'm not aware of?

Quote

These faults would render Starship utterly useless. Musk needed a solution. Here is my hypothesis of how he tried to solve this with Block 2.

Ok here's this guy's opinion.

Quote

Because the bellyflop manoeuvre is a no-go, Block 2 is designed to slow down more with its retro rockets (where the rockets are fired in the direction of travel to slow down). This should make landing more viable, as the craft should be more controllable. This would also enable the front fins to be shrunk and the heat shield to be thinned, saving weight. But this will also require more propellant, especially as the rockets have less thrust than planned. This is why Block 2 is larger and heavier than Block 1.

WHAT

WHATTTTTTTTT

God, please forgive me for wasting this Sunday arguing with someone who has no idea what he's talking about.

This guy is basically saying that instead of putting mass towards atmospheric protection, mass should go towards a massive de-orbit burn to reduce heating loads.

"This should make landing more viable" Bruh the landing burn was like not a problem

"The craft should be more controllable" What

"The lower heating loads can allow the TPS to be shrunk" sure if this were the case at all

"saving weight" Generously, let's say you can make your TPS 10 tons lighter this way. At best 10 tons of fuel is like 400m/s. That isn't doing jack squat up against re-entry. 

"Lower thrust means you need to bring more fuel" that's an isp thing not a thrust thing

"Block 2 is larger and heavier than block 1" I have not seen heavier justified. But I will get into this later.

Quote

To solve the fuel system issues with Block 1, fuel lines with larger internal diameters were needed to increase fuel flow, and larger external walls were needed to increase durability. But this would add an incredible amount of weight that they don’t have the liberty to use, as it would further reduce their already pathetic payload to space and make landing the damn thing even harder than it already is.

"Ah yes, we need more fuel flow to feed the same six engines that there was on block 1!"

(For the record, vacuum jacketing the feedlines is to reduce boiloff)

"Landing would be harder with the bigger fuel lines" I mean slightly? This is a very small amount of additional mass.

 

Okay so, skipping to the punchline: This guy believes that SpaceX's only solution is to save mass is by reducing the factor of safety.

Quote

Where have these weight savings come from? They aren’t changing any major materials. They aren’t changing any structural designs. They aren’t redesigning the entire engine or fuel tank setup. The only way is if major systems are built with a smaller safety factor, making crucial systems vulnerable and weak.

Now what I've heard in my circles is that the planned mass reductions are largely coming from better integration of systems they had previously tacked on as temporary fixes. Throughout block 1 they kept tacking on temporary fixes to problems, and added permanent solutions to future blocks. Some examples include the detachable hot stage ring, the massive "pasta strainer" 9m wide ice filter that is rumored to exist, and, if they end up doing it, struts inside the fuel tank to deal with fuel line resonances. And those are just some of the obvious ones we know about. In the future these will all be lighter, less "brute force" fixes.

That and general iteration. Raptor didn't get light by just sitting around. Switching to Raptor 3 should enable a massive amount of mass savings for a variety of reasons.

 

This guy then says "You can never achieve iterative design with a full scale prototype." Uhhhh.... They are? Also, Falcon 9? To a lesser extent, of course. But F9, especially the reuse program, has been a very iterative process.

 

He then proceeds to argue for a 1/10 scale test Starship to help "determine the best compromise from bellyflop and retro-rockets."

 

Firstly... What compromise? The landing burn is the same regardless. The mass of beefing up the heat shield to handle higher re-entry stresses will always (within sane bounds, LEO methalox re-entry) be lighter than the mass of the fuel required to slow down to what the heat shield can handle. There is no compromise.

Secondly, you cannot test re-entry dynamics with a 1/10 scale model. The distance between a shockwave and the surface of your spacecraft, a factor which heavily influences heating, depends on the curvature of the spacecraft body. Blunter objects push the shockwave back further, and that is why re-entry vehicles tend to be very blunt. You are not going to get a particularly meaningful result out of the box with a 1/10 scale re-entry test article. Maybe with some extensive computer analysis.

Quote

Not only that, but these tests would highlight any of the design’s shortcomings, such as the rocket engines not having enough thrust-to-weight ratio to enable a high enough payload.

I'm sorry, what?

1/10 scale versions, which wouldn't be large enough for even a single Raptor, being able to say "Oh Raptor isn't making enough thrust" despite the fact that even if that were true you could figure that out on the ground, and that TWR is the dominant driving factor for payload capacity?  Despite the fact that even Raptor 2 is like the second or third highest TWR rocket engine ever, behind only Merlin 1D and possibly the RD-276????????

Quote

If you have even a passing knowledge of engineering, you know this is what iterative design looks like. So, why hasn’t Musk done this?

Well, developing a Starship like this would expose that making a fully reusable rocket with even a barely usable payload to space is impossible. Musk knows this: Falcon 9 was initially meant to be fully reusable until he discovered that the useful payload would be zero. That was his iterative design telling him Starship was impossible over a decade ago, as just making the rocket larger won’t solve this! But he went on ahead anyway. Why?

1. Falcon 9 was not initially meant to be fully reusable. Falcon 9 was initially meant to be expendable to my knowledge, and then had a brief period where they thought they could do full reuse, and then went with partial reuse.

2. Just making the rocket larger is one of the things necessary to solve this. As I mentioned earlier, a higher radius of curvature will make surviving re-entry easier. The square cube law also helps a lot with larger things. Larger rockets in general get better mass ratios to orbit because of this, leaving a lot more "Oh this was harder than we expected, I will use 2 tons of mass to fix this" margin before the payload drops to unusable levels.

3. This told them that Falcon 9 full reuse wasn't practical. Not that Starship is impossible.

Quote

Well, through some transparent corruption and cronyism, he could secure multi-billion-dollar contracts from NASA to build this mythical rocket. But, by going for full-scale testing, he could not only hide the inherent flaws of Starship long enough for the cash to be handed over to him but also put NASA in a position of the sunk cost fallacy. NASA has given SpaceX so much money, and their plans rely so heavily on Starship that they can’t walk away; they might as well keep shoving money at the beast.

This is why Starship, in my opinion, is just one massive con.

That is the real reason why Starship was doomed to fail from the beginning. It’s not trying to revolutionise the space industry; if it were, its concept, design, and testing plan would be totally different. Instead, the entire project is optimised to fleece as much money from the US taxpayer as possible, and as such, that is all it will ever do.

If this was the plan, then it isn't working very well and SpaceX would be hemorrhaging money. HLS is like 2.9 billion and by the author's own numbers that only covers less than 1.5 years of Starship dev. To my knowledge this is most of the current government funding for Starship. If I was trying to fleece the federal government, I wouldn't build an entirely new launch site and conduct several suborbital tests with my own money, underbid on (and agree to self fund part of) a Moon lander contract for 2.9 billion dollars, build out much of the hardware for that moon lander (individual systems are deep into testing), launch eight full scale rockets, and do a lot more dev work. I would instead do what Bechtel is doing and charge NASA 2.7 billion dollars for a launch tower. https://oig.nasa.gov/wp-content/uploads/2024/08/ig-24-016.pdf

Do be aware that I am flirting with whataboutism in that last paragraph.

 

 

 

So, TLDR:

• Will Lockett is either misguidedly or dishonestly pushing an Elon Bad agenda.
  • "Elon Bad" is a justifiable thing to think.
  • "Elon Bad, therefore anything Elon does is Bad" is not a justifiable thing to think.
  • Will's articles at best seem like someone who doesn't understand aerospace falling for confirmation bias and finding evidence that on the surface appears to support his agenda.
  • Will's articles at worst seem like someone trying to push an "Elon Bad" agenda to a group of people who know nothing about aerospace, with just enough technical fluff that someone who doesn't know any better could believe every word of this despite it being utter nonsense.
• He asserts that Starship is a scheme to scam the federal government.
• He asserts that Starship v2 is a failure and will never be a success because Starship's mass growth problems necessitated dipping into a factor of safety.
• He asserts that Starship V2 is attempting to reduce re-entry loads and save mass by slowing down with rockets first. Which makes no mathematical sense if you've ever played KSP RO/RP-1.
• He makes several basic factual and reasoning errors.
• He claims Starship is expensive by dividing the estimated annual program cost by the amount of flights in that year. Yes, each individual starship flight is expensive right now. But he holds this up as the number that customers will be charged. This is almost as bad as saying that Artemis 1 cost 26.5 billion dollars because that's the total SLS expenditure up to that point divided by the number of flights.

 

I would not trust a word out of this guy's mouth.

[Exoscientist]

On 3/22/2025 at 1:37 PM, Ultimate Steve said:

I think they are going to take their time with this one. They ran into (what is likely, from what I know as an outsider) the same problem twice after they thought they had done enough to mitigate it or fix it. I think they would strongly prefer to make sure they understand the issue before proceeding as if they dump 100 tons of debris over the Caribbean a third time it really, really wouldn't be a good look. Though on second thought I'm not sure that anyone who has the power to raise this as an issue would actually want to stop them but that's off topic.

If they can't perform a temporary fix for the fuel line resonance with a different throttle profile or some struts that are small enough to get into the tanks, this might be the sort of thing that requires heavy modification, either opening the ship back up or skipping a few ships if the problem really is that deeply entrenched.

 

 Quote, “These days Elon can do essentially whatever the hell he wants.”

  Bob Clark

[Ultimate Steve]

Seeing this makes me think I could honestly become a space journalist if this is where the bar is at.

[Mr. Kerbin]

1 hour ago, darthgently said:

Big Brain

did I just read that and

does DOGE remind anyone of a certain dog?

[Exoscientist]

3 hours ago, Ultimate Steve said:

This is very much in "trust me bro" territory but the word on the street is that the "extremely long" v3 is postponed or dead and what is now being called "v3" is the same size as v2 and is expected to have about the same payload capacity.

I haven't been keeping up with AI but the last time I checked, which was admittedly like a year ago, ChatGPT couldn't even do delta v addition correctly, and could not get it through its head that aerobraking reduces delta v requirements. Though it has advanced a lot in a year presumably, I would not trust it to do that sort of math, especially when there isn't enough information in your query to actually do that calculation.

 If it is true its size and payload will be V2-like then ChatGPT was giving the right estimate of ca. 100 tons.

  Bob Clark

[darthgently]

2 hours ago, Ultimate Steve said:

"Elon Bad" is a justifiable thing to think.

When people  begin to realize that things like the “salute” FUD come from the same or similar fantastical mindset that produced this really bad article then one wonders what “justifiable” even means anymore.  People are afraid of offending those who make these absurd claims for some reason

Edited Monday at 12:00 AM by darthgently

[Minmus Taster]

Just now, darthgently said:

one wonders what “justifiable” even means anymore. 

Before this whole thing is deleted I would like to point out for all involved that questions like these make the entire conversation pointless regardless of where you fall. You've effectively conceded that not only is your opponents opinion rooted in delusion and not worthy of consideration, but that you aren't even sure what you're arguing for anymore or what you're opposing, you're winning a chess game by smashing the board.  And as far as justifiable goes, as long as were doing this again, I think raising an eyebrow at a major political figure's "pendant salute" shouldn't be considered  as "FUD" as I so often hear in this thread.

[Nuke]

13 hours ago, Elthy said:

I suspect they can throttle it extremly fast, they need to do that for landing anyway. But its propably hard to write the correct control algorithm for that, as it requires them to understand the cause of the occilation in extreme detail, which they propably dont have, otherwise it wouldnt have happened in the first place.

or just use a pid controller. nailing it down might take a couple flights though. this is why early flights had wonky steering characteristics from rcs and grid fins. one flight usually gives you enough telemetry to calibrate it to near perfect by next flight. using it for throttle control is certainly possible, but then again pumping the throttle may be its own can of worms and the engines may not like that.

1 hour ago, Mr. Kerbin said:

did I just read that and

does DOGE remind anyone of a certain dog?

elon loves his memes.

[Nuke]

38 minutes ago, Minmus Taster said:

Before this whole thing is deleted I would like to point out for all involved that questions like these make the entire conversation pointless regardless of where you fall. You've effectively conceded that not only is your opponents opinion rooted in delusion and not worthy of consideration, but that you aren't even sure what you're arguing for anymore or what you're opposing, you're winning a chess game by smashing the board.  And as far as justifiable goes, as long as were doing this again, I think raising an eyebrow at a major political figure's "pendant salute" shouldn't be considered  as "FUD" as I so often hear in this thread.

fans of 1984 will be familiar with the concept "hate week" (which is not too dissimilar from stuff that actually happened in germany in the prelude to ww2). people just naturally want to hate someone or something, to distract them from their own problems. the scapegoat is not a new concept. it is a thing to be discouraged if we are to remain civil. the demagogues who fan the flames are the real enemy. unfortunately those exist on all points of the political compass. if you really want to understand politics, dont listen to pundits, watch what they actually do on cspan.

Edited Monday at 12:48 AM by Nuke

[Ultimate Steve]

BONUS TIME!

I went through this article, the seven deadly sins of Starship as described by Will Lockett (https://www.planetearthandbeyond.co/p/starship-will-simply-never-work).

The amount of misinformation and bad math in here is so laughably absurd that I almost want to make a video out of it. However I've now wasted like 1/4 of my entire weekend free time on Will Lockett and I have little desire to continue.

Will's Starship Deadly Sin #1: Thrust

Spoiler

In short, Will says that Starship cannot take more than 40-50 tons to orbit because Raptor thrust is significantly lower than expected.

Now firstly: Is the thrust significantly lower than advertised? This got long, so:

Spoiler

The best evidence for this comes from this chart:

Where Flight 3's liftoff thrust is listed as 7130 ton-force. This gives a thrust of only 216 tons per Raptor 2 when the expected value is 230 ton-force.

Does recent telemetry support this estimate?

In order to double check this I grabbed the telemetry (https://github.com/SofieBrink/StarshipTelemetryExtractor/blob/main/Examples/IFT-6 Telemetry.csv) from flight 6, as that is a flight without engine outs and uses the slightly better defined v1 fuel load. The average acceleration from T+ 6 seconds to T+ 10 seconds (region chosen as it is mostly straight up and not a lot of fuel will have been burned, but it is far enough off of the pad for the numbers to have largely stabilized) is 4.79 m/s^2. Adding in g of 9.81 m/s^2 and subtracting the ~0.03 m/s^2 centripetal acceleration due to Earth's rotation at that latitude (26 degrees ish) (though it is not exactly straight up but it is probably close enough for this analysis), Starship is accelerating off of the launch pad at 14.57 m/s^2, a TWR of 1.485.

The problem is that we can't really estimate liftoff mass. SpaceX underfills their stages for these early flights according to the fuel meter, we don't know the accuracy of the fuel meter, we don't know the dry mass of the ships or booster, and we don't know anything else.

The mass at T+8 seconds for the given acceleration would have to be, very roughly:

5100 tons for a Raptor thrust of 230tf

5000 tons for a Raptor thrust of 225tf

4900tf for a Raptor thrust of 220tf

4775tf for a Raptor thrust of 215tf

(the liftoff mass would be around 150-180 tons higher depending on various factors, as the Raptors burn some fuel in those 8 seconds)

 

Depending on the exact propellant volumes, loads, temperatures, and structural dry masses, the number could vary across this range and more.

 

So there is room for his assertion to be correct given the uncertainty in Starship's mass.

Verdict: Possible.

The 40-50 ton figure is from the 2024 Starship update referring to flight 3/"the current design", Elon did not mention thrust whatsoever in that explanation.

Third, while TWR is an incredibly important metric for a reusable RTLS architecture, a 6.5% thrust shortfall (230 to 215 tf) causing a 50-60% payload drop does not pass the sniff test. Though  to steel-man this, SpaceX could be lying to our faces and the actual Raptor 2 thrust could be lower.

 

However, on that 6.5% number:

Spoiler

The (pe-p0)*Ae term is at a maximum in vacuum. If Raptor is perfectly expanded (I think it is actually underexpanded but I would have to double check) and has a nozzle diameter of 1.3 meters, the "pressure thrust" in a vacuum would be about 132 kN, or about, drumroll... 5.9 percent of Raptor's advertised thrust.

It is quite possible that 230tf is the vacuum thrust of the sea level version of Raptor and that ~215tf is the nominal sea level thrust.

 

It is in the realm of possibility that even this 6.5% shortfall does not exist.

 

 

 

Here is the quote:

Quote

Well, it seems Musk massively overestimated how much thrust their rocket engines can actually produce. This is not surprising; the figures he used to claim were basically impossible.

I would not say that a 6.5% difference is "massively overestimated" nor basically impossible to make up. Either Will is referring to one of Elon's old comments of "Maybe we can get to X number" as gospel, or doesn't know what he is talking about.

He then goes on to once again state that the 4-8 tons of Starlink simulators is "too much stress for the engines."

He then goes on to state that he believes that Musk was stating the (Starship only) expendable figure for Starship V1. He then assumes Starship can launch 45 tons with the ship expended for the rest of the article.

 

Steve's verdict on Deadly Sin #1: Hogwash. There are  nuggets of truth in here. TWR is very important for this architecture and there is evidence where one of the possible conclusions is Raptor making a little less thrust than advertised. However, Will assumes the worst, pins all of the underperformance on Raptor, connects the vibration problems to 4-8 tons of payload, and baselessly assumes that 45 tons is the expendable number (based solely on how he believes that the ship's vibration problems were caused by the 4-8 tons of starlink simulators). That doesn't compute as those vibration problems would happen in expendable mode also but I think that's what he's saying.

 

Will's Starship Deadly Sin #2: Safety Factor
 

Spoiler

Will states that the way to solve Starship's failures is to significantly increase the factor of safety. I mean. In a sense that's right but that ignores the reasons things are failing and ignores other ways they could be fixed.

Like, a structural element in Starship being rated for 10 tons of force with a factor of safety of 2, and actually experiencing 22 tons of force in flight and failing? Sure, increase factor of safety and make that strut thicker. Starship's hinges burning through due to poorly understood hypersonic gas dynamics and possible issues with securing the tiles in place? To me that screams "rethink the tile attachment design and take a look at the reliability of the operations used to attach them" and "Redesign the flaps with a better understanding of the regime" and not "Make the heat shield thicker."

He then makes several laughably incorrect statements:

Quote

It is longer than 1st version to accommodate more propellant (likely to make up for reduced thrust during landing)

Ah yes. 25% more propellant to make up for a (possible) 6.5% reduced landing thrust despite the fact that landing takes a few hundred m/s of Delta-V tops.

Quote

But, and this is hilarious, SpaceX is going to somehow make a 3rd version that is significantly longer than the second, with somehow 68% more thrust, and magically weigh less than the 2nd version. These numbers seem to be plucked out of thin air and are not backed up by any of the test flights or physics, for that matter. The only way SpaceX can even try to achieve this is by reducing the safety factor even further than it already is, rendering the rocket totally unreliable.

The mass claim is unsourced so I will not address it.

But the thrust? Come on, Will. "The only way they can do this is by reducing the factor of safety" The thrusts for Raptor 2 and Raptor 3 are available and with some ratio math you can get an approximate idea of the relative thrusts.

 

V2 has 3 sea level raptor 2s and 3 vacuum raptor 2s, the naive math using the stated numbers on spacex.com gives us 1464 tons. Notably this doesn't match either the 1250 number or the 1600 number shown above but ehh let's go with it for rough math.

V3 has 3 SL R3s, and 6 vacuum R3s.

Raptor 3 is designed for 280 tons of thrust, and apparently they are hoping to later get to 300, but let's say 280. If RVac also has a proportional 22% increase like RSL, we get 2725 tons. An 86 percent increase. "Somehow 68% more thrust" Like come on. Do the damn math yourself, Will.

Steve's Verdict on Deadly Sin #2, Safety Factor: Complete hogwash.

 

Will's Starship Deadly Sin #3: Human Space Flight Certification
 

Spoiler

Will asserts that Starship is not safe enough for human flight, and that it achieving that level of safety is "totally impossible."

Like Will, I also have concerns about Starship's safety for human spaceflight. There is a real discussion to be had here. But instead of making actual good arguments, he starts with an incorrect premise and makes bad faith arguments:

Quote

Most of Starship’s contracts are to take Humans to the Lunar surface, return to Earth, and land safely with the crew onboard.

Starship does not have a single contract to do that. HLS does not return to the surface of Earth.

Quote

But Starship can’t be rated for human space flight. Firstly, it is exploding mid-flight far too often.

The reliability of the system now has little bearing on ratings hundreds of flights from now.

Quote

But, even after 8 test flights, Starship has failed to land its final stage from space even once.

Starship has yet to attempt landing its final stage from space as they want to land on water to prove they won't shower Mexico with debris, and they want to prove they can do a de-orbit burn before going all the way to orbit (which they are required to stay in for around a day unless they do weird orbit things in order to land back at the launch site). They have achieved 2 successful ocean splashdowns and 1 off-target ocean splashdown, out of 8 attempts, 3 of which made it through re-entry.

 

He then explains how landing Starship is hard because of the kinetic energy. This is correct and I will skip that quote. But he again uses "exponentially" to describe a quadratic relationship. That is a massive pet peeve of mine.

 

Quote

But, managing Starship’s gargantuan kinetic energy while dealing with reentry aerodynamics and ensuring a safe landing is orders of magnitude harder than any landing SpaceX has ever done, and even the easier landings it does do are not reliable enough to land humans from space this way. Starships have no landing abort system, so to be certified for human space flight, they need to be able to land safely from orbit over 99% of the time, and all the evidence points to that being totally impossible.

Again, there is a real discussion to be had here. But he says "Falcon can't get to that level of accuracy, so therefore a system designed to learn from, build upon, and exceed Falcon cannot get to that level of accuracy!" and baselessly calls it "totally impossible."

Quote

This has no quick fix. Starship is lightyears away from ever reaching human space flight certification, leaving most of its contracts and the nearly $3 billion NASA poured into Starship for them totally stranded.

The $3 billion does not require safe enough landings for humans, only safe enough landings to make refueling possible.

Steve's verdict on Deadly Sin #3, human space flight certification: Bad-faith. I share many of his concerns but he goes out of his way to twist the facts to make it seem like the problem is represented in as damning of a light as possible, and to make it seem like the problem is an immediate showstopper, rather than one that simply needs addressing before Starship flies with crew in several years time.

 

Will's Starship Deadly Sin #4: Price

Spoiler

Will first takes the 5 billion 2024 operations cost, says "about 2bn is for vehicles", divides that by the four flights they made, and comes up with 500 million per launch.

He then checks that against Falcon 9, by taking its construction cost per  dry kg and scaling that up to Starship levels to find Starship's cost.

That is just...  What?

Falcon 9's exact dry mass is unknown. He says it is 25.6 tons. The most well sourced number I can find is about 28 tons. A lower mass number here is in favor of Will but whatever. Then he says, with no source, that a full Falcon 9 stack costs about 35 million dollars to manufacture. Like there are people who think Falcon's internal reused cost is higher than this. But whatever. So about $1367 per kg of rocket.

He estimates Starship + Super Heavy to be 330 tons dry combined, and comes up with 451 million dollars a stack this way.

His justification for the apples to oranges comparison?

Quote

Starship uses similar technology, just scaled up.

Ah yes. Aluminum-lithium alloy stir friction welding, titanium grid fin forging, and carbon fiber composite structures vs. Stainless Steel welding.

Starship is like literally the definition of trading performance for a cheaper simpler assembly process.

Quote

But, this is an underestimate, as Starship is far more complex than the Falcon 9, requiring vastly more plumbing, heat shields, tougher materials, more landing surfaces and control systems, etc,

He has a point with the upper stage's re-entry hardware. But I would argue that everything else is simpler on Starship.

Firstly "more plumbing" is expected to scale with scale to an extent so I will ignore it.

As for things that reduce complexity and are not scale dependent: No helium pressurization system and all the associated hardware. No landing leg systems anywhere on the whole rocket. The grid fins don't need to retract, you don't need the complex pneumatic separation piston, no custom cold gas RCS system, just vents to the tank, and more I haven't thought of.

 

Okay so he takes this production estimate of 500 million and then is like "Ok so it can be reused" and here is how he accounts for reusability reducing costs:

Quote

Okay, so let’s be generous and say that SpaceX can land a Starship and reuse it. Let’s also be extremely generous and say that these rockets are capable of 10 reflights with minimal refurbishment (despite the extra stress of landing from orbit),

For the booster 10 flights is low for being a system designed to exceed a system on which they've gotten to like 25 or something. The ship, that is to be determined, we will see.

Quote

can carry Elons’s stated 45 tonnes to LEO

This is the v1 number and bad faith arguing.

Quote

and the fuel, minor refurbishment and operational costs per flight are around $20 million(this may seem expensive, but we have to take into account landing pad repairs, chopstick repairs, and more complex pre-flight checks).

The fuel is like 2m or so last I checked, refurb is supposed to be zero (though probably won't be for heat shield reasons for a while), there is no landing pad to repair, the chopsticks shouldn't really need that much work (though some launch pad wear and tear is expected until they have the design nailed down), and I don't think the pre-flight checks will be worse than Falcon as there are less systems to check (at least on the booster). 20 million is an absurd estimate for this IMO.

Quote

That would give Starship a flight cost per kg to LEO of $1,555;

50m amortization per flight, 20 million fixed cost per flight, 70m per flight, 45 tons, so 1555, that checks out based on Will's flawed numbers but at least he can do division right.

Quote

meanwhile, the Falcon Heavy, which has been operational since 2018, costs customers $1,700 per kg to LEO, including around 30%-40% profit for SpaceX. That means Falcon Heavy’s operational costs are only around $1,190 per kg to LEO, or 23% lower than a realistic estimation for Starship’s costs.

FH expendable: 150 million, 63800kg. 2351 $/kg.

FH reusable: 90 million, <50,000kg. 1800 $/kg.

If we use the FH reusable cost and assume the 57000kg "core expended" number, we do get $1580/kg.

I don't know where he is getting his Falcon Heavy numbers from. But he is using a best case scenario number for Falcon (possibly using a reusable cost number and a partially expendable payload number) while consistently giving Starship the short end of the stick at every turn - very high construction costs, a number of reuses falling short of even Falcon, ridiculously high refurbishment costs, and the payload capacity of an early v1 ship.

There is a discussion to be said here on profit margin and whether the upper stage can meet its reuse targets within the amount of time and money SpaceX has to put into it, and whether they really can hit zero refurb. But instead of doing that Will consistently assumes the numbers most convenient to his argument.

Steve's verdict on Deadly Sin #4, Price: Hogwash. Will consistently pulls numbers out of thin air that are not sourced nor likely to be correct and assumes Starship will fail to even meet the bar set by Falcon 9. There is some validity to the method of total cost divided by number of flights but at best that is a flawed methodology and is only particularly relevant for finding the marginal cost of another mission once the system is mature, fully developed, and flying often.

 

Will's Starship Deadly Sin #5: Economics And Demand
 

Spoiler

Will's argument is that Starship's economics are only possible with massive production and that there is no demand for this massive scale, therefore Starship will not work out.

In principle I agree with a lot of what he is saying: "The giant factories pumping out hundreds of starships per year with are only justifiable if you want to build a self sustaining city on Mars."

He does say a few questionable things, such as:

Quote

Musk’s claim that Starship only costs $100 million to build is likely only for the upper stage (i.e. Starship only, not the Suoper Heavy Booster) and once production has reached its economy of scale.

and:

Quote

Now, Earth’s orbits are already full, with not much extra capacity before we run into Kesler Syndrome. Not only that, but for cost-saving and space debris measures, modern satellites are designed to last a lot longer than they used to. On top of all that, as we covered, Starship is so far away from being human space flight certified it is almost funny.

But yeah. They aren't hitting the mythical "2 million dollars per launch" unless they scale to Mars levels. That is not a surprise to anyone.

Steve's Verdict on Deadly Sin #5, Economics and Demand:  Somewhat true, but misleading. I have no problem with Will's assertion that the claimed long term figures are only possible with the demand of a Mars colony, but I do take issue with how Will implies that Starship cannot work for any level of demand. All it takes is Starship beating Falcon in launch costs and the Starship economics will work out. Will seems to believe this is impossible and I believe that Starship's sticker price will never be higher than Falcon 9's sticker price (currently $69.75 million). Time will tell who is correct.

 

Will's Starship Deadly Sin #6: Past Orbit
 

Spoiler

Will uses his heavily skewed numbers to paint a case against refueling being viable.

 

He uses:

• Block 2's 1500 ton propellant load
• Flight 3's 45 ton payload capacity (which was an early v1 ship with 1200 tons of propellant)
• The 70 million dollars per launch number which I tore into earlier

And shows that Starship would take 33 launches to be refueled.

Quote

As such, it would take 33 launches to refuel a Straship, costing $2.31 billion, putting the total mission launch costs to the Moon or Mars at $2.38 billion.

That is only marginally cheaper than NASA’s SLS, which can get to the Moon for $2.5 billion and do it way more reliably. But, get this, the Saturn V took 50 tonnes to the Moon (that is 11% more than our hypothetical Starship) for the equivalent of just $1.4 billion in today’s money.

 

Firstly: You don't need to fill a Starship (or Straship as he calls it, he also misspelled Super Heavy as Souper Heavy another place) all the way up to get to Mars. That cuts the cost down significantly, especially if we are only taking 45 tons to Mars. I will not count landing here as he is comparing it to the SLS which can't land, but let's say Starship still maintains its Will-estimated 130 ton dry mass for the reusable version and for good measure give our ship a comically low isp of 330. That only requires 9 refuelings even with Will's ridiculous numbers. 700 million dollars for 45 tons to trans Mars injection.

NASA's SLS, I'll unwisely take that 2.5 billion dollar price tag at face value. I'll grant Will the reliability argument (though Starship will have far more flight history by the time anything gets sent to Mars). I will steel man SLS. Block 2 can theoretically get >46,000kg to TLI. I will assume it can get at least 45 tons to TMI.

So even with his ridiculous numbers and steel manning SLS, we get 2.5 billion for SLS and 700 million for Starship and not questioning his cost conversions, 1.4 billion for Saturn V.

Steve's Verdict on Deadly Sin #6, Past Orbit: Hogwash. There is an interesting discussion to be had about the reliability and feasibility of large scale orbital refilling but he generously assumes that's a given and instead, not only does garbage-in, garbage-out math with mission cost, but assumes a Starship must be fully refilled in order to go to the Moon or Mars. If we correct for the refueling error, even his garbage cost numbers come out ahead of SLS and Saturn V by significant margins.

 

Will's Starship Deadly Sin #7: No Backstop
 

Spoiler

Will asserts:

Quote

By now, it is apparent to many that landing Starship and reusing the final stage while having a useful payload is impossible. Which would render all the hypothetical scenarios we have just talked about moot.

While I disagree with this, that is not the point of this section. Will's argument is that SpaceX's backup plan of relying on an expendable Starship upper stage and a reusable Super Heavy if they can't crack full reuse doesn't work economically.

So now he runs through what he believes the numbers are for an expendable Starship:

Quote

Let’s be incredibly generous and assume a Starship with an expendable final stage can take 100 tonnes to LEO (Again, I believe Musk’s 40–50 tonnes estimate was for an expendable Starship, knowing how he twists figures).

Musk himself has said that it could be over 200 but ehh whatever maybe he's lying and Will is the beacon of truth here.

He then proceeds to take the cost/kg estimate of what it costs to build Falcon 9 and scales it up to Starship's presumed 130 ton dry mass.

This was highly questionable even for a reusable vehicle. It is complete BS for an expendable version. Unless Will here thinks they would add a heat shield and flaps to an expendable version.

We know the heat shield is about 11 tons. The flaps can't be below 10. All of that structural reinforcement to keep the payload bay and flaps attached during re-entry can be deleted. The aft skirt can be attached to Super Heavy instead of Starship as the engines no longer need protection. The header tanks can be deleted as can their fuel lines. If we want, we can even make a detachable fairing.

There is no way this comes out to 130 tons.

And even if it did, the only point in Will's favor (and there were many against) of maintaining Falcon 9's estimated cost per dry kg and applying it to Starship, was the added complexity of Starship's re-entry hardware, which we have now removed!

So this guy thinks that a steel cylinder with a few Raptors on the bottom costs, get this, 178 MILLION DOLLARS! That's more than entire expendable Falcon Heavy!

They've built like 35 of them by now (yeah they skipped a few but I'm not going to count), does that mean they've spent 6.2 billion dollars on ships alone by now?

Remember that BS 20 million refurb number? If that's anywhere near correct, the vast majority of that would be made up by ship refurb costs I'd wager. But he does not adjust this number.

Anyway, he comes up with 225.2 million dollars before profit margin.

Steve's Verdict on Deadly Sin #7, Past Orbit: My words are too strong for a PG rated forum. I don't need to tell you how ridiculous this guy's conclusions are.

 

[Ultimate Steve]

To be clear, my point was less about Elon himself and more about a general trend I've noticed.

People seem to want to put people into boxes these days. "This person did something good so therefore this other thing this person did is probably good" and "This person did something bad so therefore this other thing this person did is probably bad."

I see this happening with Elon a lot in both directions, which is part of why I talked about him. But my point in general is not about Elon, though I could have worded this a lot better.

There seems to be an ongoing death of nuanced thinking and a draw towards the black and white.

If the person is important enough there's also an endless stream of media supporting either side, and algorithms mean that you would really only ever see one side unless you went out looking for the other. Will Lockett's articles would absolutely convince someone who knew nothing about spaceflight that Starship is doomed to fail and assuming they were already on that side of the debate this would in their eyes reinforce their biases.

To rephrase:

I believe that it is okay to have a positive or negative opinion of someone. I do not believe that it is okay to make that opinion pre-emptively decide your perception of that person's other actions. I strongly believe that it is abhorrent to write articles that use misleading or hogwash claims to reinforce people's perception and contribute to polarization.

Edited Monday at 01:56 AM by Ultimate Steve

[darthgently]

11 hours ago, Minmus Taster said:

I think raising an eyebrow at a major political figure's "pendant salute" shouldn't be considered  as "FUD"

If only it were merely raising an eyebrow and not torching things