SpaceX should withdraw Starship as an Artemis lunar lander.

tahanson43206 · 2023-08-20 10:22:36

Part 5
But there is a whale of a lot more to a vehicle than just its engines.
Part 5

tahanson43206 · 2023-08-20 10:25:07

Part 6
Commercial break.
Part 6

tahanson43206 · 2023-08-20 10:26:42

Part 7

A l o t o f f o l k s f o r g e t t h a t. <<== accepted by Apache

Part 7

Update later: the original text still generates the error! Amazing!

(th)

tahanson43206 · 2023-08-20 10:27:44

Part 8

There is also the issue of “Musk time” versus actual time. That is a factor of about 3, if not higher. He promises results too soon, and always has. Too many folks forget that, too. If Musk really was an engineer, he would be far less likely to make that mistake. He is not an engineer, I checked his credentials. He is a great dreamer with really good overall goals. With SpaceX, he hired people competent enough to make those goals come true. They did it, not him. That is something you must understand about him, when you hear those promises he makes.

The Starship upper stage has flown by itself suborbitally multiple times, and went through several vehicle-loss failures before actually making a successful flight all the way through to a landing. This was an incomplete experimental airframe, not at all fitted out like an operational Starship is projected to be! For one thing, the landing legs are utterly inappropriate for a rough-field landing. It still has no tested heat shield, and last I heard, had problems with heat shield tiles popping off unexpectedly. There is as yet no verification of its expectation-of-survival at realistic LEO entry conditions, and (as yet) no reason at all to suspect that a windward-only shield will work at entry speeds nearer escape, than low orbit speeds. That has to work coming back from high orbit, much less the moon or Mars. Clearly, the vehicle technology is quite immature! It still needs to fly multiple times, and in a configuration closer to what is intended. And it needs to fly in space, multiple times, before anybody trusts it for any missions at all. Plus, it has to have a similarly-proven Superheavy to do any of that.

As for Superheavy, it has only flown once, and that one failed quite early in the ascent, most likely due to a stupid decision by Musk to launch a Nova-class vehicle without a water-deluge flame deflector, when nothing from Atlas-1 onward ever did so. Upward-flung debris is what likely damaged multiple engines, directly causing the loss. And that loss precluded getting very much in the way of a first stage evaluation-as-a-vehicle out of that flight. One bad flight damaged at launch actually proves very little about Superheavy. It needs to fly multiple times before anybody trusts it for anything, either.

So, that's a lot of testing that needs to be done to bring this innovative vehicle to maturity. I do not see it being tested very frequently, probably due to bureaucratic resistance of the FAA, after SpaceX multiply violated the terms of their previous licenses to fly. That can be fixed, although it takes time and some top management decision-making changes, to restore the FAA’s trust. They are also trying to install and prove out their water-deluge flame diverter, and it will take several test fires before they get that right. It took that with the thrust stands so-equipped at McGregor.

You simply cannot do that much flight testing, with a scope that broad, in a year! Period! End-of-issue! I know, I have done flight testing in jet aircraft. You might get it done in 3 years. Maybe. If money were no object. And without a government mandate and blank check (as with Apollo), money IS an object here! It might take longer than 3 years, but shorter? No way!

Quite frankly, I don't see it as remotely possible that Starship/Superheavy could be tasked with anything but a completely-experimental flight test mission, before about 2026. It'll take at least that long to find and fix all the problems, and there will be many crashes and explosions along the way. Very few of these things will fully succeed during that process. You may safely bet that it still has a LOT of problems! It would not surprise me if it took closer to 5 years to get this thing reliable and ready for “routine” use!

Expecting otherwise is VERY unrealistic! No matter what Musk says!

But that pretty much rules out trusting a manned lunar landing to a Starship variant until after 2026, maybe closer to 2028, doesn't it?

GW

End of Quotation.

(th)

RobertDyck · 2023-08-20 11:17:36

Falcon 1 and original Falcon 9 used the same aluminum-lithium alloy as other rockets. It was manufactured using friction stir welding, the same as all rockets that use that alloy. Actually it's required for that alloy because lithium burns, traditional stick welding would burn off all the lithium at the weld. Merlin engines use LOX/RP1, a fuel mixture used for the first stage of Saturn V and many rockets since including Atlas V. Merlin engines are manufactured entirely with 3D printing, a technology that existed before SpaceX, just used more for Merlin's. Starship uses stainless steel, the same alloy used for Atlas A rockets. The rocket that launched John Glenn into orbit. Robert Zubrin and his partner David Baker included methane/LOX rockets in Mars Direct in 1990. Delta-Clipper aka DC-X was the first reusable rocket to land on its tail.

There is no radical new technology used by SpaceX. What SpaceX is good at is management. Elon Musk has proven to be very good at management. Yea launching Starship/SuperHeavy without a flame trench or water deluge system was a mistake. Compare that to mistakes made by Old Space. One great management decision was hiring Gwynne Shotwell. So don't criticize the fact he isn't an engineer; that's not what he does, he's a great profitable business manager. He gets things done when others just dream.

GW Johnson · 2023-08-20 12:30:43

Rob:

I have to disagree with you about Musk's management abilities. At SpaceX, his promises are for things 3 or 4 times faster than Shotwell and her crew can deliver. It's been that way since their founding about 2 decades ago. One would think he would have learned better by now, but he very most clearly has not.

Per Musk, SpaceX only hires people under the age of 40-45. That is in part to support chronic (meaning perpetual) underpaid overtime at the 70-80 hour/week level, which people over 45 cannot endure, and Musk knows that. (That's a labor law violation, by the way, and in more than one country.)

People that young have had no opportunity to learn one-on-one from the old-timers (because there aren't any in their workplace) the art of flying rocket vehicles, which is 50+% of the total knowledge, the "art" being the part that was never written down. What was written down (the "science") is under 40% of the total (required) knowledge. Which in turn is part of why they are driven to "break-it/try again" as their approach. That is more for teaching (by school of hard knocks) the youngsters that they hire the full knowledge, than it is any other reason. That is good management? No, I don't think so. (And I am qualified to know how to properly manage engineering enterprises, because I did so, and way more successfully than most.)

Shotwell and her team are good at management, I quite agree, as long as Musk does not over-rule them, which (unfortunately) he does (see lack of flame diverter for Superheavy as the most egregious example to date). As for the business management ability of Musk himself, look at what he has done with Twitter. In about a year from now, when that gigantic dead dinosaur finally falls over, he will have lost his $44B that he spent to acquire it. How in bloody hell is THAT good management?

Or look at Tesla, which has repeatedly gone under federal scrutiny for killing people on the public highways with that AI-based self-driving software (that Musk promises again and again) that is so VERY CLEARLY NOT ready for prime time. Between that and ChatGPT falling quickly into routinely lying to you when you use it, tells me that the term "AI" is an oxymoron, for sure! And using that kind of crap that kills people on public roads is "good management"? Hell, no, it is NOT!!!!

GW

Last edited by GW Johnson (2023-08-20 12:47:06)

RobertDyck · 2023-08-20 13:55:27

Others have tried to manufacture electric cars. GM built the EV1. All failed. Tesla succeeded. Success of Tesla has forced other car companies to develop electric cars. As Robert Zubrin said, only Elon could make money from electric cars.

As for pushing AI... everyone makes mistakes. He sees that as the next great technological leap. He's working to stay ahead of the curve. Self-parking cars (parallel parking) do work quite well. Self-driving cars were part of the "vision of the future" at the 1939 World's Fair. The GM exibit. But that model depicted dedicated highways for self-driving cars, and the car switched to normal control by a driver once you leave the highway. Pedestrians not allowed on the highway, and no manual control allowed either. So strict separation between self-driving and manual. I think that makes more sense.

As for Twitter... well. He made a major mistake buying at that price. He didn't do his due diligence. But this has greatly benefited society. Ensuring one of the major platforms for social media emphasizes free speech. Mark Zuckerberg had been non-partisan and non-biased, ensuring Facebook is a platform for free speech. But he caved to pressure by governments to support issues of by the current government of the day, And Woke issues supported by certain rich people. Facebook bought Instagram so convincing Me Zuckerberg to return to non-partisan and free speech would have wide ranging effect.

GW Johnson · 2023-08-21 07:48:32

Rob:

A little over a century ago there were a lot of electric cars on the road. The advent of the gasoline engine as a longer range, higher-speed option outcompeted lead-acid battery cars. Today, we have so complicated the gasoline car to reduce the emissions it produces, which we found to be harmful, that they are becoming unaffordable, they have too many failure modes that cause high repair costs. The lithium-ion battery electrics have the speed and power, and can approach the range at the costs of heavy batteries and lithium fires. Let's just say the competitive playing field has leveled once again. Musk's Tesla led the way, but he is no longer alone, offering electric cars.

Self-driving software can only do what its programmers put into it, however they get it in there. What they do not (or can not) anticipate, the software cannot deal with. Which is what kills people. Which is also why the 1955-vintage Disney vision of the self-driving car road (a reprise pf the 39 World's Fair vision) with very restricted access is the only thing that makes any sense at all. That is the only way we humans have of eliminating what we cannot anticipate. I find it disappointing that so many have failed to learn a lesson that is 70+ years old.

Scientists have identified and documented an asymmetry between the spread of mis/disinformation between folks of what we call "conservative" mindsets versus what we call "liberal" mindsets. If you don't believe me, go look in a recent issue of AAAS's "Science" research journal magazine. It's there, supported with real data. The "conservatives" are more likely to believe and spread lies, most often under the excuse of absolutist free speech rights, when the right of free speech is NOT absolute, and never has been. (Yelling "fire" in a crowded theater when there is none gets you arrested, and rightly so.) Musk deleted the efforts to remove mis/disinformation on Twitter under that excuse of absolutist free speech rights, and the rise in its spread on Twitter has been dramatic and documented.

GW

PS -- here is the reference:

About dis/misinformation on social media G W Johnson 8-21-2023

“Conservatives” today are much more likely that today’s “liberals” to believe and spread dis/misinformation gained in social media “echo chambers, such lies presented as news, when they are not. When presented with more factual information, minds of either persuasion do not change.

Source:

AAAS “Science” Magazine for 28 July 2023 Volume 381, Issue 6656. Special section on social media and elections. Introduction on page 386; policy forum on page 388; research report articles on pages 392, 398, and 404. AAAS is the American Association for the Advancement of Science, and the magazine is the research publication journal of that society.

Last edited by GW Johnson (2023-08-21 12:09:30)

GW Johnson · 2023-09-08 11:07:15

I saw two little news articles related to SpaceX and Musk.

SpaceX has been prepping to launch another Starship/Superheavy, just waiting on the launch license from FAA. FAA has finally finished its investigation into what-all went wrong in the first launch, and has reportedly issued SpaceX a list of some 63 things that have to be corrected, before they can fly again. The news article did not provide an actual list, but buried in the words were the very things we have been corresponding about here on the forum. (1) more durable launch pad, (2) fix the flight termination system, (3) stop the propellant leaks that have been a continuing fire risk.

I saw nothing in the news article about fixing any engine faults, so I suspect the FAA reached the same conclusion I did: debris flung from the disintegrating launch pad damaged multiple engines at liftoff. The multiple non-functioning engines issue is not about engine reliability, it is all about debris impact damage.

The other article was about Ukraine being mad at Musk for thwarting their attack on the Russian navy. Boiling down a torrent of words, it appears Ukraine was going to guide their weapons in some way using Starlink. Musk says he turned nothing off, but it appears he deliberately failed to turn on the specific Starlink system or item that they were going to use (details not clear to me). The motive appears to be that he did not want to be associated with an attack on the Russians.

Musk says and does a lot of stuff most of us would call “extreme-conservative”. What he did wrecking Twitter and trying to re-brand it as “X” is but one example. I hate to say it, but I think he actually is one of those far-right types. But it all fits together: the right-wing extremists get their “news” and their “facts” from echo chambers that are well-known for misinformation and disinformation, to include lies and propaganda planted there by Russia (and others).

I have traced some of that misinformation/disinformation about the Ukraine war (and some other topics) back to Russian sources, so I know this to be true! The effect I claim it has on people in those echo chambers, is also true: the proof is the “pro-Putin wing of the GOP” that wants to quit funding Ukraine. That wing overlaps rather strongly with the Trump leader cult (about 40% or thereabouts), whose members usually loudly spout Qanon-type conspiracy theories and culture-war crap as if they were facts, when they are not. We’ve all seen them doing it.

Anyhow, I rather doubt SpaceX will be launching its Starship/Superheavy again anytime soon! The news article described many of these “63 things to be fixed” under the words “vehicle redesign”. Looks to me like FAA will be holding SpaceX’s feet to the fire to “do it right”, every single time they fly, and that’s a good thing for public safety, as well as technical success! They clearly have a lot of work and re-work to do, before there is any hope of a license to launch again.

Shotwell had better be making the top-level decisions from this point, not Musk. If he screws it up again, they may never fly again at all! And SpaceX has “bet their company farm” on Starship / Superheavy as their future! So this is VERY serious from their viewpoint, as well as the FAA’s viewpoint! Screw this up, and they may go out of business, although that takes time to occur. "Large dinosaurs fall over slowly after death" is the effect I am talking about.

NASA is going to need something else to land astronauts on the moon in 2025 or 2026, if they even make the attempt that quickly (I will believe it when I see it). As with politicians, do not listen to what large government organizations say, look at what they actually do! That interpretation applies to large private organizations, too (such as Boeing and a bunch of others). Words are cheap and meaningless. Only actual results matter.

GW

Last edited by GW Johnson (2023-09-08 11:13:46)

RobertDyck · 2023-09-08 12:21:34

GW Johnson wrote:

NASA is going to need something else to land astronauts on the moon in 2025 or 2026

Cough cough
Moon mission today - Dragon & Mars hab

RobertDyck · 2023-09-08 12:43:03

Article GW Johnson referenced. Directly from the FAA
FAA Closes SpaceX Starship Mishap Investigation

Friday, September 8, 2023
The FAA has closed the SpaceX Starship Super Heavy mishap investigation. The final report cites multiple root causes of the April 20, 2023, mishap and 63 corrective actions SpaceX must take to prevent mishap reoccurrence. Corrective actions include redesigns of vehicle hardware to prevent leaks and fires, redesign of the launch pad to increase its robustness, incorporation of additional reviews in the design process, additional analysis and testing of safety critical systems and components including the Autonomous Flight Safety System, and the application of additional change control practices.
The closure of the mishap investigation does not signal an immediate resumption of Starship launches at Boca Chica. SpaceX must implement all corrective actions that impact public safety and apply for and receive a license modification from the FAA that addresses all safety, environmental and other applicable regulatory requirements prior to the next Starship launch.
Contact SpaceX for additional information. Learn more about mishap investigations.

RGClark · 2023-09-09 06:33:39

To me this is the big one in the FAA news release:

“Corrective actions include redesigns of vehicle hardware to prevent leaks and fires,…”

That sounds to me the FAA wants SpaceX to solve that issue before being granted another launch license. People watching replays seeing the engines catch on fire just say, “That’s interesting; it looks like some engines caught on fire.” They don’t realize how bad that looks to actual rocket engineers. A rocket engine leaking fuel and catching on fire during its normal flight regime is NOT normal.

The Raptor has been leaking fuel and catching fire all through the years of its development, including on that April test launch. I don’t think SpaceX is going to be solve that overnight when they haven’t been able to solve it over the years of the Raptor development. They are not going to be able to solve it by keep launching the SuperHeavy/Starship until it stops exploding.

Instead of following the infamous Soviet N-1 approach, they should follow the Apollo approach to developing the Saturn V first stage. Build a separate static test stand capable of full up, full thrust, full flight duration test burns of all 33 engines of the Superheavy. Do incremental testing gradually building up to full thrust, full flight duration tests. When all 33 engines can pass these test together, then proceed to actual test flights.

Robert Clark

Last edited by RGClark (2023-09-09 06:35:11)

GW Johnson · 2023-09-09 09:36:55

Hi Bob:

There's a lot more to the troubles with Starship/Superheavy than just leaks and fires around the engines. Bad as those are, the launch pad and fire-protection mistakes were far worse.

There's leaks, yes, because they use liquid methane as fuel. There's very little leak potential with kerosene, and not so very much with liquid oxygen (although the consequences can be catastrophic), which is the experience base they are coming from.

Remember, they have a bad not-invented-here culture, and they do not hire older experienced guys. Anything outside their experience base is a really serious problem to overcome, which they have approached with the expensive-but-fast "fly it-break it-fly it again" strategy. They don't know any better until they experience it. Some of us old hands actually do know better, but we are not asked, and they do not want to hear from us.

Methane is not quite as notoriously leaky as hydrogen, but it is almost as bad, and it is FAR worse than oxygen about leaks. Handling such an easy leaker is WAY (to hell and gone) outside their in-company experience base! Seeing methane leak problems crop up should surprise no one. And we have seen it, in their Raptor test videos, to be sure.

Leaking fuel (of any type) that burns with air is not necessarily a fatal problem, if your hardware is designed to withstand it. The problem occurs when liquid oxygen leaks into the fuel-air fire, causing an immediate and devastating explosion.

We've all seen it before. Every space shuttle that ever flew had a hydrogen-air fire burning against the base of the center tank, flameholding in the wake zone behind the tank, all the way to main engine shutdown. The only one that blew up was Challenger, when the oxygen tank got ruptured by the unsecured booster and dumped LOX into the base fire. The base of the tank had heat shield insulation on it, to protect it from the heat of the base-burning fire. NASA's engineers knew about this. It was designed that way from the beginning.

Look closely at Raptor-1 vs Raptor-2. The Raptor-1 had a real rat's nest of exposed plumbing around its chamber. Raptor-2 has a much cleaner installation of plumbing, but it is still exposed. So is the wiring. The troubles with methane-air fires on Raptors (-1 or -2) trace directly to exposed plumbing and wiring. They have talked about covering it up, but they have not done it. The wiring is the most vulnerable item, that's the control system. Lose that, and everything goes wrong.

Exposed plumbing is a target of flung launch debris, as well as the engine bells. Whack the plumbing with a piece of debris, and you have a big methane (or oxygen) leak. I'm not sure the plumbing got hit on that initial launch, because any oxygen leak would have precipitated an immediate and devastating explosion, and we did not see that. But it could happen!

Whack the bell with a piece of debris, and you have a big methane leak, plus a plume that goes off axis out through the damage zone. You get a big methane-air base burn, with subsonic methane-air flames shrouding the supersonic plumes. We saw exactly that. We also saw at least 3 engines with plumes sharply off-axis, especially toward the end just before the tumbling vehicle exploded.

Another vulnerable item to overheat is the basic engine mounting structure itself. Overheat it, while an engine is thrusting, and it WILL bend. That points the plume off-axis even with an undamaged bell. And, as I said, we saw exactly that.

The actual explosion happened some 41 seconds after they sent the destruct signal (proof positive the destruct system didn't work). It happened as the vehicle tumbled end-over-end, falling back into denser air way below staging altitude. The broadside air loads crush the tankage, releasing propellants, particularly LOX, which goes right into the base-burning methane-air fire. Voila! Massive explosion! EXACTLY what we saw happen.

Superheavy can tolerate some methane leakage, as long as the control wiring, the plumbing, and the engine mount structures, plus that aft tank dome, get wrapped in some insulation. But a massive methane leak from engine bells damaged by flung debris, that is simply WAY beyond the pale.

Yeah, there's Raptor reliability problems here, but they rank FAR behind the top three idiocies committed by SpaceX with that first launch: (1) a vulnerable launch pad flinging debris into engine bells as it disintegrates, (2) wiring, plumbing, thrust mounts, and tank aft dome unprotected by any insulation against a base-burning methane-air fire, and (3) a self-destruct system that is demonstrably unreliable in actual practice.

My guess is that those 3 items are at or near the top of FAA's list of 63 fixes required before they can fly again.

GW

Last edited by GW Johnson (2023-09-09 10:21:36)

kbd512 · 2023-09-09 14:18:52

GW,

The fact that you brought up your political / ideological beliefs again in a thread about a giant rocket illustrates your own cognitive biases. The continual personal attacks against Elon Musk are clear evidence of that. No matter what you think about Elon Musk, SpaceX has done more to advance affordable and sustainable human space exploration than any other company, or NASA, during my entire lifetime.

If someone else is more qualified to get this job done than Elon Musk, then they've never demonstrated their abilities by starting a company from scratch and producing three real flying reusable orbital class rockets, a cargo ferry, a space capsule, and space suits. Until Elon Musk came along, all the other aerospace engineers on the planet hadn't formed a company to do what Falcon 9 / Falcon Heavy, and now Starship, are actually capable of doing. You've come up with a list of reasons why they shouldn't be allowed to launch rockets, though.

After objectivity is lost, you're no longer an engineer or a scientist. No amount of education will ever be an antidote to personal biases. You either possess the level of introspection required to recognize when what you say and do is driven by personal beliefs and emotions, or you don't. If you haven't learned that by now, then you never will.

kbd512 · 2023-09-09 14:44:01

I can reduce the unstated but underlying premise behind threads like this to the following statement:

"Someone is doing something of great consequence to humanity, but they're not doing it the precise way I think they should, therefore they must either be forced to do it my way or to stop work."

Do the rest of you actually want to see humans go to Mars in our lifetime, or not?

If so, then SpaceX is presently your best and maybe your only shot at living to see that happen.

Is safety important?

Yes. Obviously. Safety is priority #3, behind getting the job done and doing it on time / within budget.

GW Johnson · 2023-09-09 17:39:36

You got your priorities wrong. When public safety is at risk, safety is priority 1. I was taught that from my freshman year in engineering school. And I knew it long before then.

You also got your entrepreneurs and your actual engineers conflated. They DO NOT mix! Shotwell (and her staff) are the engineers. Musk IS NOT an engineer! He is the entrepreneur. That difference is crucial to understand.

I agree he has done things setting up companies and finances and lofty goals that nobody else has. But HE did NOT actually make the technical things happen. Shotwell and her crew made the technical stuff happen for him.

GW

kbd512 · 2023-09-09 17:49:51

I have one final note on this topic:

Dr. Clark and Dr. Johnson's concerns are valid, but suggesting that SpaceX needs to stop work, or that they have no idea what they're doing because someone in management doesn't have a piece of paper behind their name, or maybe they should be allowed to launch 10 years from now, is precisely why we never went anywhere after the moon. People who thought exactly that way were the ones making the decisions, so we went nowhere but LEO and still killed people anyway. There was far too much emphasis placed on engineering perfection and safety, which frequently involved reinventing the wheel, and not nearly enough on getting the job done in a reasonable amount of time. As I stated in the previous post, safety is the third priority, assuming you intend to actually achieve something on time and within budget.

You're Monday morning quarterbacking SpaceX, the FAA, and NASA, all at the same time, and then suggesting that only your approaches are acceptable. The end result is undermining confidence in both the regulators and the regulatees. There are plenty of people with PhDs behind their names who work at all of those aforementioned corporations and regulating governmental agencies. You're not painting a very pretty picture of the sciences, academia, or the government. The over-the-top bashing really doesn't help convince people who don't already share your opinion. Despite that, we're still supposed to achieve what is (hopefully) a shared goal of getting humans to Mars.

How, exactly, is this alternative approach supposed to work if there's no water deluge system available on the moon or Mars?

For someone bashing conservatism applied elsewhere, it's very strange that liberalism is not allowed in engineering approaches. Conservatism and liberalism are both ideologies- different ways of approaching problem solving. It's not always clear to me which one produces better results, because that depends upon your definition of "better". If either ideology has any merit, then is a little consistency in applying it too much to ask for?

Unless Elon Musk has multiple personality disorder, he can only reasonably be expected to apply one or the other ideology at any given time. If he's willing to try launching a giant rocket without a water deluge system, because his giant Mars rocket is clearly much more sturdily built than the ones built in the 1950s, and water deluge would seem to be the most conservative approach, then he clearly has a very liberal view of how engineering can be applied to solving a problem that will exist when we land the giant rocket on another planet without a pre-built water deluge system.

Is a liberal engineering approach good or bad?

I don't know, but how long should we continue waiting for a conservative engineering approach, from someone who dislikes conservatives and conservatism, to produce a crewed mission to Mars?

If it turns out that we can't apply someone's favored engineering approach to coming and going between different planets, do we just stay here on Earth forever, or can we allow people with different ideas to try them (new to them, maybe not to you or someone else), and fail, repeatedly if need be, until someone who is actually willing to do the hard work comes up with a workable solution?

tahanson43206 · 2023-09-09 18:13:10

For kbd512 re 42

I hope this was NOT your last word on the subject, because (from my perspective) the back-and-forth in this topic is enlightening as well as entertaining.

One point you made caught my eye, and it is one that (with any luck) all three of the major contributors to this topic can pursue with a clear conscience.

You made the point that there is going to be no water deluge system on either the Moon or Mars.

There is a lot of talent available in this forum. I'd like to see a thoughful consideration of the challenge of lifting off with a fully laden Starship from the surface of Mars.

I doubt a fully laden Starship will take off from the Moon without a sturdy pad having been built by prior landers. Perhaps such a pad is needed on Mars as well.

However, taking off with a fully loaded Starship is a more challenging exercise than landing, and that is going to be difficult enough.

I'd like to see posts by RGClark, GW Johnson, and kbd512 with thoughtful, considered analysis of the challenge to be met, and a reasonable solution on offer.

I do not consider recommending a water deluge system to be realistic, but perhaps there is an alternative solution that forum members can identify.

(th)

kbd512 · 2023-09-09 18:19:55

GW,

I'm pretty sure that I do have my priorities correct, they simply don't align with your priorities.

If public safety was the greatest issue at play, there would never be a space program. Deliberately going into an environment where humans don't naturally live will never be safe. Launching giant rockets will never be safe. The government doesn't care about public safety and never has. Sometimes they care about creating the appearance of caring about public safety. Casual observation of what all governments do would lead a reasonable person to believe that any assertions to the contrary are counter-factual to observable reality.

Which came first, Elon Musk creating Tesla and SpaceX, or the tens of thousands of engineering jobs his foresight generated?

kbd512 · 2023-09-09 18:40:45

tahanson43206,

That was my last word on the thrust of what this topic is aiming at, which I think is off the mark, assuming we all share the same end goal of getting humans to Mars. Maybe I'm mistaken to believe that is the goal, but I hope not. The entire notion that there is only one right way to do something, and no other approaches should ever be permissible, is counter-factual to reality. That is my point, which I think stands on its own merits. I will still respond to people.

I happen to agree with Dr Johnson about using a water deluge system here on Earth, because it's the simplest solution proven to prevent "rock tornadoes" as Elon called them. At the same time, I'm not at all opposed to SpaceX trying other approaches, because when we do get to the moon or Mars in our giant rocket, we will not have a water deluge system to work with.

The point that seems to be missed is that SpaceX's giant rocket, which everyone thinks is some kind of failure based upon one data point, managed to not only get airborne after sustaining damage that would turn any other lesser vehicle into confetti, but it basically made it to MECO, and then survived a deliberate attempt to blow it up, which means Starship is pretty darned tough. It's not a flimsy over-glorified beer can. If I'm betting my life on the durability of my giant rocket, then that's the one I want.

SpaceX is actively correcting their mistakes and not repeating them. That's all we can reasonably ask for.

GW Johnson · 2023-09-10 10:01:25

There's a misunderstanding of what "safety" means when you attempt challenging or dangerous things. "Safety" does NOT mean that you decline to attempt them. It means that you do so in a way that does not hurt bystanders and neighbors.

The thrown-debris problem is also a function of rocket thrust, in turn a function of its weight. The evidence has been "in" since 1958 that you do not launch anything larger than an Atlas-1 without a flame-diverter tunnel fitted with the right diverter material AND an enormous water deluge.

Given that collective experience dating back almost 7 decades, launching something twice the thrust of a Saturn-5 without those things in place was simply stupid in the extreme, and you do not need 2020 hindsight to see it. That was Musk over-ruling his own engineering team to rush forward faster with a launch that was very important to him, and not waiting for the diverter deluge they also had in work.

He simply does not do very well considering the consequences his actions have upon others. That is a character flaw he has yet to deal with. He sees government ONLY as the regulatory impediment that he hates (I have heard him say so himself). He simply cannot also see those regulations as something that protects his neighbors from the consequences (intended or not) of what he does. And that lack of dealing with safety for others is EXACTLY why he keeps getting into trouble with the FAA repeatedly over his launch licenses!

I do not now, and I have never, said that he should be stopped. He has done things with SpaceX that make both "old space" and the NASA that still favors them too much, look incompetent. And looks do not deceive. Compared to SpaceX, they really ARE incompetent!

What I have said is that he needs to pay a lot more attention to (1) public safety, and (2) the collective experiences of other outfits current and historical, in deciding how to proceed. Which really means listening to his engineering staff and not over-ruling them for his own perceptions of schedule. That is his failing, and he has demonstrated so far an inability to recognize it in himself, and deal properly with it.

It also means he needs to start adjusting their corporate culture to change from its total "not invented here" restraints. There really are current and historical experiences of other outfits and individuals that could far reduce the number of failures they experience while doing their "fly it/break it/fly another" approach. That would make the whole process even less expensive than they already have! You simply do not need to repeat the known mistakes already made by others before you.

I have not paid as much attention to his Tesla outfit, but I suspect the mounting troubles they face with federal investigations into safety complaints over self-driving software that gets people killed, derives from exactly the same fundamental cause: rushing forward too fast without regard for the consequences upon others.

GW

Last edited by GW Johnson (2023-09-10 10:10:18)

GW Johnson · 2023-09-10 10:19:19

As for "no diverter on the moon or Mars", the thrust at those landings is much less than Superheavy. In point of fact, it is no more, and likely somewhat less, than the thrust of Starship-only in those flight tests. That's down at or under Atlas-1 (only 3 Raptor-1 sea level engines, remember?), and they flew it OK several times without a diverter. It's not just the heat, it's also the force. Although one should NEVER expose concrete to flame, because it explodes into violently-thrown chunks when you do.

It's the exploding action that forces debris more directly upward. Just the jet blast sends it nearer horizontally, radially outward. So the rocks and dirt on the moon or Mars are less of a flung debris threat than exposed concrete is here on Earth. Not zero, but less. Between that and the lower thrust effect, they ought to be able to land there, once they come up with adequate legs to support the weight and dynamic forces of a landing on soft sand with loose rocks. They have yet to address that, or the rough non-level ground with a tall vehicle. Eventually they will have to, or Starship will ever only be an Earth orbital transport.

GW

Last edited by GW Johnson (2023-09-10 10:21:13)

RobertDyck · 2023-09-10 12:55:38

The first rule of engineering has to be safety; but there are limits and exceptions. In Canada there is the ceremony of the Iron Ring after a graduate gains a bachelor degree in engineering. The ceremony involves the new engineer swearing that he/she will not allow anything unsafe to be built. The Iron Ring is worn on the ring finger of the working hand; for someone right-handed that means the right hand. Rings were made of iron scavenged from the Quebec Bridge, which collapsed during construction in 1907. However, metal from that bridge has long since been consumed. That bridge collapsed due to poor planning and design by the overseeing engineers. Unfortunately the bridge collapsed again during construction in 1916. It took more than 30 years to complete, finally opened in 1919. A total of 88 people died during both collapses. However, the story of the Iron Ring only mentions the first collapse.

Yes, yes, we understand. Never again. However development of anything new requires effort, money and risk. That risk must be mitigated to ensure people don't die. That's why the launch site at Boca Chica is miles from any city. SpaceX tried to buy the entire village of Boca Chica. The area is evacuated for each launch. So some chunks of concrete were thrown into a swamp. I don't see that as an issue. If any wildlife were killed my response would be a BBQ. My maternal grandfather took my father hunting when I was a child, we had wild deer, goose, and duck. They're delicious. Adequate safety measures WERE taken.

SpaceNut · 2023-09-10 17:02:26

There is a huge laundry list of items to fix before4 any flights will be granted by the FAA, so in one way Musk did it to himself by flying unsafely. Even in an area that was pretty safe all in all. Testing is almost always proving the tolerance to which a design can take the stresses of actually flying.
Mars launch of a starship from the unprepared surface will be just as damaging a quite possibly so will the landing.

Void · 2023-09-10 17:50:39

Truely a concern Spacenut, but I make note that the Starship will have 6 engines, or maybe 9 engines, so less than 1/3rd the engines. Also the Superheavy not being in use, probably the Starship weight ~~~1/3rd the weight of the full stack. Also gravity on Mars being ~1/3rd of that of Earth, the thrust needed to get off the ground will be much less.

So, 1/27th of the problem??? Well, I am not so sure about my math, it may be quite fuzzy.

Also, I think that the main concern would be that rocks blasted out, might hit other equipment, maybe even the rocket, but the rocket thrust might keep rocks away. A hole in the ground after launch might not matter that much.

But an interesting idea....Super Heavy on Mars. You would have to get it to Earth orbit somehow, tow it to Mars, and the only way I think you could land it would be by chemical thrust, you could not use that much air braking.

But if the infrastructure on Mars could eventually support it, it could do some serious lifting I would think.

Done.

Last edited by Void (2023-09-10 17:55:29)

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