Jeff Wright,

Cost and capability are not cleanly separable. If one desires a capability to fly both frequently and at low cost, for example, SLS is a complete non-starter.

The SLS core stage is not reusable and cannot be made so. It is also larger and heavier than it needs to be owing to the quite sub-optimal use of LH2 as a booster propellant, which has barely better Isp than methalox at sea level and low altitude.

You try to compensate for these fundamental limitations by positing that the SLS core stage should be tricked out as a wet workshop and flown all the way to orbit where it will be used for… what, exactly? You have now traded the problems of excessive mass, under-performance and non-reusability for the problem of figuring out a use case for a wet workshop on every launch. The wet workshop use case problem is at least no more frequently faced than SLS can launch – which is not very often. Whoopee!

Glacial production and launch cadence and insane cost also makes any Golden Dome-related military job a laughable non-starter for SLS. Those “battle stations” in LEO will have to be quite numerous and Mr. Trump would like to see at least a minimal-coverage number of them up by the time he leaves office. SLS can be of no help whatsoever on that score if it still has to fly Artemis 3.

What will, of course, be able to deploy hundreds or thousands of space-based interceptors is Starship. As the interceptors themselves will be about the size of a medium or large air-launched tactical missile, those “battle stations” will likely be flat “cigarette cases” that host a modest number of interceptors apiece and which might well be deployable using the same Starships that also deploy Starlink V3 sats.

Propellant slosh does not seem to be a problem with Starship. Landing burn prop has always been contained in separate header tankage where slosh is quite limited. Anent the mechanical force of slosh, stainless steel actually increases in mechanical toughness when chilled to cryo temps.

Super Heavy V2 seemed to have no slosh-related problems except possibly the persistent failure of one particular engine on the middle ring to re-light for boost-back. The entire prop feed system of V3 boosters has been redesigned. In a few weeks we’ll get to see if these changes have chased the erstwhile re-light bug.

As to winged spaceplanes, if there is a decent use case that cannot reasonably be addressed in any other way than via such a vehicle, then someone will build one.

Shuttle was not, in the end, a success. Neither was Buran. Dream Chaser seems to be fading in the stretch. All other winged spaceplane concepts – X-37B notably excepted – have failed to get much beyond the PowerPoint or artist’s concept stages. Often, as with DynaSoar, this has occurred because the notional use case – manned orbital surveillance – proved not to be as useful as a simpler, cheaper alternative – unmanned orbital surveillance.

Jeff is trolling us, blaming us for not knowing SpaceX’s proprietary information about the sloshing in the booster stage when it flips around. That is the crux of his question. He seems to believe that the company has programed the first stage (Super Heavy) turnaround in such a way that the propellants are guaranteed to cause problems rather than having spent these past several launch tests learning how to do it with minimal disturbance to the propellants in the tanks. Hot staging seems to have been one part of the solution, and it seems to have improved performance quite a bit, too.

Minimal disturbance is desirable, because sloshing can cause undesired motions to the stage or stack as the center of mass moves around and as the propellants push against the sides of the vehicle. It is why the Saturn V’s second stage retained the interstage ring for so long; they were waiting for these motions to settle out because the ring was so close to the engines that there was a great risk of the ring striking one as it separated.

Sloshing is as old as staging, and I wouldn’t be surprised if it had some effect on the pitchover of earlier rockets.

There is often baffling in smaller tanks and a form of baffling in the main tanks of the booster stage and most or all upper stages, but it is a bit limited on these large tanks.

I try to avoid Reddit–too ugly.

The fact remains that slosh is an issue (assuming that phys.org article wasn’t a hit piece on LNG ships).

If it is accurate, as I suspect—it might be something the Bocans can look at. I seem to remember some discussion about inner conduits getting abuse

This is one reason I like winged flybacks and parallel staging.

Rockets are not fighter airplanes…and my first instinct is that LVs don’t need to be subjected to violent maneuvers. Parallel staging as with ALS/NLS could alleviate concerns.

Falcon is a narrow vehicle…and that may make more of a difference. Were SuperHeavy simply a Saturn IB-ish cluster of Falcon cores–might that have been more well behaved?

The severe cold about to hit the Southeast is more concerning to me at the moment

The irony is that SpaceX has put great priority on engineering, disregarding schedule. Starship’s schedule slips to the right, and SpaceX does not sweat. The worst part is how everyone is putting heavy pressure for Starship to be ready to land on the Moon in time for Artemis III. Once again, much of the people in charge put schedule ahead of engineering. The President and Congress have expressed an absolute need to land Artemis III in 2028 at the latest, and NASA has put out another request for lunar landers to replace Starship, thinking that it will not be ready in time.

Why the rush? So that Congress can Beat the Chinese™ to a goal that the Chinese lost half a century ago, and so that the President can make a call to the astronauts on the Moon and take credit for the mission, like Nixon did (Nixon didn’t mention Kennedy). Stan W. is correct: NASA, of course, has to satisfy presidents and Congresses, so it does as it is told, and that means that the U.S. space program is riskier than it needs to be. (However, I do not share Stan’s confidence in the understanding of the heat shield. Otherwise NASA would not have redacted virtually the entire investigation report. Clearly, NASA lacks confidence that its own report is persuasive.)

Thank goodness that the U.S. space program is switching hands to the commercial space companies, specifically SpaceX for now.

The Starship development program is extensive because the engineers are studying the problems that occur under a variety of untried conditions, such as turning around in flight, the sloshing that occurs, and the formation of ice in the propellant tanks. They are working hard to solve thermal protection problems similar to those that the Space Shuttle had and to make sure that the reentry vehicle is still safe if a tile falls off before or during reentry. We have seen many tiles fall off during launch and during the reentry of several test flights, and many of the test vehicles survived nonetheless. They are testing the missions for the vehicle, such as dispensing satellites and transferring propellants in microgravity conditions.
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Jeff Wright gives us plenty of red herrings, then won’t let go of them. Many of us here know that Mr. Wright is un-convincible, but we respond to him in order to hone our own thoughts and arguments. He lives in a world that is free from all economic considerations, and any past or future project works perfectly as intended, and the more it relies upon the efficiencies of hydrogen fuels, the more he likes it.

He wrote: “This is one more reason Americans should demand a Buran type Shuttle 2.”

We should make a copy of a copy of a kluge that didn’t perform as we had expected? Even the Space Shuttle (Space Transportation System, or STS) was not designed for coherent missions but was designed like its offspring, the Space Launch System (SLS), for a certain capability, and the hope was that missions could be created that met that capability. Both systems failed to ignite the imaginations and enthusiasm of the American people, especially the taxpayers.

Instead, how about we design our launch vehicles so that they can efficiently and effectively perform the tasks that we want them to perform? Sure, we may need many different types, as we already have in the past and present, but that is no different than the automotive industry, where the autos come in different types and sizes, from motorcycles to sedans, to vans, to trucks to trains, to ships, to aircraft, and now to spacecraft.

“That SLS flew a successful mission debunks that [the SLS isn’t a reliable vehicle, and never will be].”

Robert’s point is made in that one sentence. This is exactly the thinking that NASA had when it didn’t fix the problems it saw with the Space Shuttle, resulting in both Challenger and Columbia. Nothing went wrong, so it must be safe, right? Right?

It is too bad that Jeff won’t follow Robert’s rules and will eventually go away. It was sometimes fun to read his stuff.
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Nate P wrote: “It’s very, very easy to say paper vehicles will outcompete real ones, but nature isn’t quite so kind.”

We sometimes have difficulty knowing the performance of the real launch vehicles. The Buran never flew a second time, demonstrating that it was too expensive for its own space program. It never flew with a crew or a payload. All we really know about it is that it could survive launch, a few orbits, and reentry and landing, but we don’t know how much refurbishment was required for reuse or what its actual capabilities were, including turnaround time.

Starship is being designed to solve a large number of problems, whereas SLS and Orion were not. Instead, we are soon going to launch Artemis II on a wing and a prayer.
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Milt wrote: “…That said, I think that we have to respect the judgement of the Artemis crew about whether or not this mission constitutes an acceptable risk for them and abide by their wishes.”

The crew is unlikely to turn down a mission. NASA astronauts rarely do (but have). The real problem is that this mission is in our name, at our expense, and risks our reputation. We the People deserve as safe a mission as possible so that we do not have yet another historical disaster to lament for the rest of our lives and for generations to come.

If NASA will not apply the lessons that have been learned in the past, then what good are they? We are supposed to improve our safety, reliability, and costs (even cost in lives). We should be making progress, not marking time.
http://www.youtube.com/watch?v=GXbdJ3kyVyU (The Deal, 7 minutes, 2011, Bill Whittle, “The Deal”)

As with civil aviation, we learned from these events [Challenger, Columbia], that wishful thinking is a poor substitute for good engineering. So we went back and fixed the engineering, but we lost the stomach for it, because we didn’t go anywhere or do anything new. Part of the deal, you see, is that you pay in blood for progress. If there’s no progress, what’s the point?

Wishful thinking is a poor substitute for good engineering.

We lost the crew of Challenger learning a lesson about using wishful thinking rather than good engineering. We lost the crew of Columbia because the lesson was not applied at NASA. We now are risking the crew of Orion because the lesson still has not been applied, these forty years later.

Richard M confirmed this attitude at Marshall Spaceflight Center. NASA engineers and NASA fans believe that they know best, but they believed that before Apollo 1, Challenger, and Columbia. That is not a good track record for this attitude.

It smacks of hubris in defiance of the gods, leading to nemesis. It happened thrice before, and each occurrence at this time of year.

Here is to a successful Artemis II, and a sobering of NASA if it is successful.

How to test the stack? Shuttle C variant would have been a decent approach, though don’t think it had been proposed by 1980. Cheers –

I also think you have mischaracterized the situation in a way that paints the decision makers in a very harsh light should something go wrong, specifically you emphasize the heat shield has not been fixed, which is true. What ypu do not address is the substantial work and validation that NASA had in understanding the root cause of shield behavior. Understanding root cause allows looking at & re-examining the problem statements in the various failure modes during reentry. The adjusted reentry profile is the result of characterization of what the heat shield can tolerate without failing.

Now how convincing or relevant the testing was to give probabilistic certainty to that decision is also fair game for criticism, but i think serious minds weighed this data with the decision to fly safely. Not mentioning the work done onnroot cause casts those folks making this decision into corner that is not deserved.

I wish a safe return for this upcoming crew, and find similar dissatisfaction in the emptiness of good wishes. More data, and if it cant be fixed for safe flying within the Artemis schedule, cancel it and move to alternates.

To all: Jeff Wright, who appears to work at Marshall or one of the contractors tied to that NASA center, consistently and repeatedly proves the point of my essay here. His comments are just further evidence that the people there are not trustworthy engineers, and who believe their work should be completely divorced from practical economics.

Wherever he works, Jeff isn’t even remotely as bad as the MSFC regulars who *do* post regularly over on the relevant subs (Artemis Program, SLS, etc.) at Reddit, where even my most diplomatic and focused posts about Orion and its heat shield several days ago got me shredded, repeatedly, for not trusting that “NASA knows what it’s doing,” for not thinking that Charlie Camarda is a complete crank that Isaacman wasted his time inviting in, followed by suggestions that I must enjoy certain sexual acts with Elon Musk. Granted that SpaceX fanboys can sometimes muddy the water, it’s long been clear that some peeps in Hunstville are massively protective of their program there.

That said, it’s not everyone, and I know that there are people working on SLS and Orion that are just guys trying to do their best and appreciate that these vehicles are less than ideal in certain aspects. Like Casey Handmer, I feel sorry for these people, knowing that they are skilled engineers and techs who could be working on much more worthwhile cutting edge commercial space vehicles but instead have their valuable prime working years sucked up by this obsolescent humunculous of an architecture.

As Robert observes, “That’s the last war, long over,” but I’m happy that they are at least doing this. That said, I think that we have to respect the judgement of the Artemis crew about whether or not this mission constitutes an acceptable risk for them and abide by their wishes. Godspeed to these brave men and women.

As an aside, I had a friend who was a candidate / alternate for the Teacher in Space program, and I have no doubt that he weighed the risks of such a flight and chose accordingly. We need more of such people.

GWB: I have had my doubts about Isaacman since last year. Nothing he has done since becoming administrator has eased those doubts.

Dave Walden: some of what he says is technically possible. I think what he means by cost not being the issue is that the federal government can spend trillions of dollars, so in principle NASA could get a much larger budget. That it won’t in practice appears to be irrelevant.

jeff: Charlie Carmada has been talking quite a lot about the heat shield. There’ve been ongoing objections to Artemis 2 for some time now in multiple areas, such as from Casey Handmer, as well.

Edward: when the rhetoric gets stripped away, pretty much.

As a relative novice in my knowledge of “Space,” and the modern adventure triggered by Sputnik in 1957, I relish this site and particularly the regular commentary that is triggered by Robert’s wonderful interest, knowledge and perspective! I learn as much from this commentary as I do from anything I devour!

With regard to one of the latest subjects of interest, as I read the comments by Jeff Wright, together with those who criticize NASA and government’s lavishly funded follies, I admit to finding seeming merit in that which I know little technical understanding, as expressed by Jeff. That was until I read his first line in one of his responses – which I claim to KNOW a great deal about! Jeff began, “Cost isn’t the issue–it is capability.”

Well, Jeff, both are always relevant, but if the cost is prohibitive, then there will be no capability. It is a “causal” relationship as certain as gravity and thermodynamics – unless of course, one is quantumly “challenged.”

Thank you again, Mr Z, for hosting such a marvelous education!

To say just this:

“………. but NASA has stated it has resolved the problem.”

can be viewed as a setup in case something does go wrong.

Jeff: two points: one, I have observed you routinely dodging questions and comments that you don’t want to answer, so complaining about others not responding to your point about slosh rings hollow. It appears as an attempt to get others to shut up rather than an honest concern. Two, if it were an insuperable issue, we would see more damage and less success with Starship flights. There has been a whole string of flights where fuel slosh would have hurt them quite badly if it were a real issue, and it isn’t. You can keep bringing it up if you like, but you won’t be taken any more seriously.

As for Golden Dome, my strong bet is that the SLS will never fly any military hardware. The USSF needs lots of inexpensive, easily replaced spacecraft, with launch vehicles that are actually available to loft payloads when necessary. For now, that means F9 and FH. In the future, it may mean NG, Nova, Eclipse, and other reusable vehicles. It will never mean a rocket that cannot meet even Saturn V’s launch rate, and sans capsule costs as much as 25 Falcon Heavies for a sixteenth of the payload. Read that again. Twenty-five times as expensive, and it can only deliver a sixteenth of the mass. Why would anyone seeking to deploy numerous payloads go with your option, Jeff? You can’t even fall back on your faux argument of ‘it doesn’t work!’ for FH.

No one had a technical response because it’s completely irrelevant. Even Boeing says they can only get the core stage production rate up to one every eight months with any reasonable investment. L3Harris has a similar restriction on new RS-25 engines.

That’s barely enough for the Artemis program as currently envisioned. There’s no excess SLS production to do any of the things you want, let alone the money or the manpower to do them. It’s all just a fantasy — not real.

You have exposed me to a galaxy-class time-hole. Thanks, I think.

This thread looks like Jeff Wright: Unleashed!

Fun!

Jeff Wright wrote, “SLS can put platforms in orbit useful for Golden Dome.”

Giggle. Fantasy land. With the ability to only do one launch at most once every two years, at a cost of $4 billion, I can’t see the Pentagon even considering funding SLS for this purpose. There are far better ways to spend its money. For example, it could launch 40 Falcon Heavies for that price, which by the way has almost the same payload capacity (about 50 tons vs 75). And SpaceX could get those launches done quickly, all probably in four years if necessary.

And if the Pentagon was that stupid to go with SLS, the pace of launch is so slow anything SLS launched would be outdated and obsolete before it even got into space.

But keep pushing Jeff. You keep digging your own grave.

I only put two links per topic.

It is your forum of course Mr. Zimmerman.
The folks at Secret Projects don’t seem to mind links to to other forms of information–so I will no longer post ANY links here of any kind.

And then praise for the sls “ability” to shoot down an ICBM, despite the fact it was never designed to do that.

Yikes.

Copium, I believe, is what the kids call it.

Lawsuits are not evidence, and given Hawthorne’s role in SpaceX’s operations, we’d see the results borne out by increasing problems among Falcon 9 flights, which is not occurring.

Whether some parts of the military wanted Magnum in the past is not relevant to whether any part of the military wants it now. The USSF has been asked and said ‘no’ quite bluntly. You’re building a dream castle. As for a ‘political fix,’ sure, Congress could mandate the USSF fly payloads aboard the SLS, but there isn’t a scrap of evidence that they intend to do so.

1) Will it work over years of operations, as ground teams’ experience in construction, launch, and operation fade because of long gaps?
2) It has no more support than it’s had at any other time. No powerful senators are backing it, there will never be another Shelby supporting the program.
3) Neither is Rocket Lab, Blue Origin, Stoke Space, or any of the other private companies. We don’t need the SLS to have a ‘not-Elon’ option.

And none of this has much to do with Starship, it’s just you twisting a forum towards your own pettiness. You’d be better off with a blog of your own.

Jeff Wright writes, “Mr. Z purports to welcome opposition,” implicating that I am trying to silence him.

Heh. I welcome your comments expressly because they fail so spectacularly in convincing anyone of your faith in SLS and Orion and your dislike of Starship. Your comments, as I noted earlier, also illustrate once again that the bad culture at NASA is still there. You might not work for NASA, but you sure do a great job of taking their position in these matters, in the most unconvincing and confused manner.

What I do not welcome are people who don’t follow my rules. I have told you multiple times that I will not tolerate you posting more than two links on any thread to phys.org or any other site you like. More than two and I said I would delete them.

You don’t seem to care, because you refuse to respect my rules. You not only continue to try to post more than two links in a single thread (forcing me to repeatedly delete those comments), you have now begun sneaking in extra links a week later in the hope I might not notice. I discovered this today and deleted one comment after approving it.

So here is your warning: The next time you send more than two links from any site in any comment, or try to sneak a third in at a later date, I will suspend you for a week. There is no negotiation on this.

If you decide to return afterward, and then do it again, I will ban you permanently. There is also no negotiation on this.

Follow my rules, or go away. That is now your choice.

Not at all.

Z.
“His comments are just further evidence that the people there are not trustworthy engineers”

Nate
“The SLS isn’t a reliable vehicle, and never will be.”

That SLS flew a successful mission debunks that.

Nate (again) in response to my quote
“It is NewSpace that is getting complacent here…letting an unsafe culture rise without question.”

“Where is your evidence for this?”
https://www.the-independent.com/news/world/americas/spacex-elon-musk-workplace-safety-california-lawsuit-b2797542.html

“The military does not want to pay for anything SLS-related.”
there were times DoD as it was called, did want SD-HLLVs (Magnum BMDO) when dullards like Golden didn’t.

A political fix will take care of that.

But the biggest reason SLS isn’t going to do NewSpace noisemakers the very great favor of fading away is three-fold:

1.) it does work
2.) it finally has the political support it deserves
3.) SLS is “not-Elon.”

You had your shot with Jared—and he kissed the ring.

Notice my critics here didn’t argue the technical points I made–about how SLS flight profile doesn’t lend itself to slosh where SS/SH most certainly does.

Instead, he intimated that I was on the take.

Mr. Z purports to welcome opposition.

So what if I did work for them? Then I could take pride that my rocket never rained debris upon the Caribbean. And my employment has nothing to do with the veracity of my statements about slosh hazards anyway—so why even bring it up.

I drive a 1992 Buick beater of a work car–a real luxo boat…uh-huh.

I didn’t even get money from U of A boosters
https://en.wikipedia.org/wiki/Logan_Young

Jeff Wright: all I see from you is a list of hopes with flimsy-if not nonexistent-scaffolding supporting them. You will never see SLS-derived wet workshops, or Shuttle 2s deploying off SLS cores. The military does not want to pay for anything SLS-related. You’re setting yourself up for decades of disappointment by clinging so tightly to this. It’s very, very easy to say paper vehicles will outcompete real ones, but nature isn’t quite so kind. You have to sell the paper better than you are, because your axioms ring false.

“It is NewSpace that is getting complacent here…letting an unsafe culture rise without question.”

Where is your evidence for this?

Who is going to pay the frankly extravagant sums that we’d need to fund even a fraction of your hopes? As for ‘marking off Starship,’ no. Lol, not in a century. Certainly not for the SLS. The SLS isn’t a reliable vehicle, and never will be. Starship will certainly improve, as it has throughout the test campaign.