SpaceX completes successful 6-second static fire test of Superheavy
Screen capture during static fire test
SpaceX today successfully completed a full 5-second static fire test of all 33 Superheavy Raptor-2 engines as well as the deluge system of the launchpad at Boca Chica.
The link goes to the live stream, which is still on-going. The static fire test occurs at about 42 minutes, if you wish to see it.
According to the narrators of the live stream, Elon Musk tweeted that the static fire was a success. It certainly appeared to go for the full five seconds, and it certainly appeared more robust than the previous test. We will have to wait however for confirmation that all 33 engines fired as planned.
The company clearly appears just about ready to do an orbital test flight. Too bad the Biden administration still stands in the way. There is yet no word on when the FAA will approve a launch license, and the decision of the Justice Department yesterday to file a bogus discrimination lawsuit against SpaceX strongly suggests the White House is working hard to figure out ways to squelch this private effort by an American citizen and his company.
Hat tip to Jay, BtB’s stringer.
On Christmas Eve 1968 three Americans became the first humans to visit another world. What they did to celebrate was unexpected and profound, and will be remembered throughout all human history. Genesis: the Story of Apollo 8, Robert Zimmerman's classic history of humanity's first journey to another world, tells that story, and it is now available as both an ebook and an audiobook, both with a foreword by Valerie Anders and a new introduction by Robert Zimmerman.
The ebook is available everywhere for $5.99 (before discount) at amazon, or direct from my ebook publisher, ebookit. If you buy it from ebookit you don't support the big tech companies and the author gets a bigger cut much sooner.
The audiobook is also available at all these vendors, and is also free with a 30-day trial membership to Audible.
"Not simply about one mission, [Genesis] is also the history of America's quest for the moon... Zimmerman has done a masterful job of tying disparate events together into a solid account of one of America's greatest human triumphs."--San Antonio Express-News
Screen capture during static fire test
SpaceX today successfully completed a full 5-second static fire test of all 33 Superheavy Raptor-2 engines as well as the deluge system of the launchpad at Boca Chica.
The link goes to the live stream, which is still on-going. The static fire test occurs at about 42 minutes, if you wish to see it.
According to the narrators of the live stream, Elon Musk tweeted that the static fire was a success. It certainly appeared to go for the full five seconds, and it certainly appeared more robust than the previous test. We will have to wait however for confirmation that all 33 engines fired as planned.
The company clearly appears just about ready to do an orbital test flight. Too bad the Biden administration still stands in the way. There is yet no word on when the FAA will approve a launch license, and the decision of the Justice Department yesterday to file a bogus discrimination lawsuit against SpaceX strongly suggests the White House is working hard to figure out ways to squelch this private effort by an American citizen and his company.
Hat tip to Jay, BtB’s stringer.
On Christmas Eve 1968 three Americans became the first humans to visit another world. What they did to celebrate was unexpected and profound, and will be remembered throughout all human history. Genesis: the Story of Apollo 8, Robert Zimmerman's classic history of humanity's first journey to another world, tells that story, and it is now available as both an ebook and an audiobook, both with a foreword by Valerie Anders and a new introduction by Robert Zimmerman.
The ebook is available everywhere for $5.99 (before discount) at amazon, or direct from my ebook publisher, ebookit. If you buy it from ebookit you don't support the big tech companies and the author gets a bigger cut much sooner.
The audiobook is also available at all these vendors, and is also free with a 30-day trial membership to Audible.
"Not simply about one mission, [Genesis] is also the history of America's quest for the moon... Zimmerman has done a masterful job of tying disparate events together into a solid account of one of America's greatest human triumphs."--San Antonio Express-News
Over in the NSF L2 forums, it has been stated by the supposedly informed posters there that SpaceX is expecting to achieve launch readiness on a date that is coming up very soon now. It has also been reported that the FAA approval is expected to be weeks, not months (my translation of their more precise prediction), later than SpaceX is ready for it. We’ll see, I have my doubts. But if these people are even close, and they weren’t too far off on the dates for the first launch attempt, we can still expect a launch in 2023.
David Eastman: As I have said over and over again, I sincerely hope my pessimism is wrong. However, we must remember that all that has to happen to delay things further, even if the FAA wants to approve, is for some higher official in the White House to insist on the right to review that decision. And based on the behavior of the Biden administration, we should not assume this will not happen.
There are some good videos from SpaceX on SpaceX’s X/Twitter account. The static fire ran 6 seconds and only two engines dropped out this time. I hope they can find the root cause of those “failures” and cure them. I expect to see another static fire once they do that.
As to the launch. Elon and SpaceX have not paid their baksheesh to the Democrats and therefore will be slow rolled on all future launch licenses for Starship/Superheavy. I don’t expect S25/B9 to launch until… well, maybe never.
As a casual observer, I have a question for a steely eyed rocket man/woman. Is it possible to launch the Starship on a
suborbital test that would involve only a partial filling of the propellant tanks?
A lighter ship could still test out a lot of the systems, and mitigate some risk factors, or so I think….
By the way, a slow walk of this system may not be such a bad thing. The power of this system is enormous. It may be profitable to take this a bit more slowly.
I got my ticket to Rocket Ranch
I wonder if the shut down problem is caused by vibration cavitation of the fuels in the lines?
That ship has got to vibrate quite a bit.
As for a lighter ship making a suborbital flight.
Musk could just have them make a shorter first stage and fly an empty second stage. But part of what he is testing is the structural strength of the first stage. On the last flight it buckled and didn’t separate from the second stage the correct way.
He could easily add some structural members to the outside of the first stage to make it stiffer. Or start using thicker sheet metal skins on the outside of the tank/body since the tank is the body..
Greg M, If the FAA has legitimate concerns it want’s SpaceX to address, that’s one thing. We expect and accept that. But that’s not “slow walking”. Slow walking is “the law says I can take 90 days to respond to this inquiry, so I’m going to take 90 days even though I had all the answers on day one.” or, as Bob mentioned above, some administrative flak or staffer far removed from the actual issues sticking his nose in and saying “I want these concerns answered” even though they aren’t actually reasonable concerns, or have already been answered, but now people that could be doing real work have to spend two days writing up a polite letter laying out the facts in a way that doesn’t get them a poor review…
We’ve already seen representative Marie Perez (D-Boeing) try and inject language into budget bills that would require the FAA to involve her committee in any licensing reviews pertaining to Boca Chica, for example.
Perez should have no standing in this.
I wonder if flow problems are behind this.
Ristroph at NYU had an article in phys.org about how fluid flow in the lowly drinking straws surprised him.
Those of you with math chops might want to read that.
It does seem Raptors tested individually do better for some reason. Water hammer?
I think it’s impossible for an outsider to have enough engineering knowledge of the systems under test, and data to speculate on the cause of the two engines shutting down. Entire teams are pouring over a lot of telemetry in a piecemeal, organized analysis. All the transducers: temperature, pressure, strain, acceleration & vibration, and who knows what else; have to be studied after the data has been verified and validated.
That being said it was probably a tubopump.
There is an anonymous SpaceX engineer posting over in the SpaceX subreddits, who indicated that the Boca Chica team is situated for a launch “currently in ~3 weeks depending on the regulatory affairs.”
He later gave this assessment of the static fire: “Very smooth test. 31 fired for a full duration test. Engines seem to have performed well. Ship comes back to the pad soon. Should be able to proceed with stack testing now for integration tests, cryo, WDR etc.”
https://www.reddit.com/user/space_rocket_builder/
They seem not to be too worried about the two engine early shutdown. I guess we’ll see.
Greg M asked: “I have a question for a steely eyed rocket man/woman. Is it possible to launch the Starship on a
suborbital test that would involve only a partial filling of the propellant tanks?”
A steely-eyed rocket man/woman is a rare thing, but some of the rest of us can try to answer.
It is possible, but testing a partial assembly would be done only if it gives answers that support the test of a larger assembly. SpaceX is at the phase of development where it makes sense to test the whole-up assembly. It was the test of the whole system that brought out the problems with the pad, and the failure of the whole-up system showed a terrible flaw in the flight termination system, which may not have been discovered if a smaller test unit had succeeded in its mission (the Starship landing tests didn’t). Since this is a development program, discovering problems and flaws is the point of the testing. Only after the development is complete and operational units are being tested do we want to mitigate risk factors and to demonstrate that the unit is built and operates correctly. At this point, SpaceX has different objectives in its test program, it is pushing limits and trying to do new things and sometimes do seemingly impossible things. This is why they wanted to test that bizarre rotation-separation concept, to prove the concept was feasible and perhaps could be made practical and economical.
And, yes, a slow walk is a bad thing. As we saw, SpaceX was not really a year readier for its integrated test than had they been able to do it the year before. In essence, they are a year behind where they could have been, and the rest of us will receive the benefits of an active space industry a year later than we could have. Space manufacturing of goods and pharmaceuticals is a year farther down range than it should be. There is no profit in that for anyone.
From my test-engineering days: when you are ready to test, then test. There is no benefit in waiting.
Among many goals of the latest static test, the success of the water cooled base under full 33 engine heat load seemed apparent, although I have seen no confirmation. My concern is, looking at videos of the first integrated vehicle, the duration of exposure to the full exhaust blast during liftoff is perhaps twice as long as the static test. Any thoughts?
My concern is, looking at videos of the first integrated vehicle, the duration of exposure to the full exhaust blast during liftoff is perhaps twice as long as the static test. Any thoughts?
Yeah, an actual launch is going to be a sterner test of the flame deflector system: Higher thrust, for longer.
But so far, it has held up very well through two static fires.
Eric Elsam asked: “Any thoughts?”
Since you ask, my recollection is that SpaceX said they had kept Starship on the launch mount a couple of extra seconds in order to make sure things were going well enough to be fairly certain it would clear the tower without too much risk of running into it or engine shutdown before being far enough that a failure wouldn’t bring it crashing down onto the pad. Thus, the static fire would not be quite as long as the amount of time the first integrated test stayed on the pad. The next launch may not hesitate those extra couple of seconds.
Once released from the hold downs, there is still some amount of time that the “world’s largest blow torch” is close to the ground, blow torching the launch pad and the water deluge system. And the launch mount and the tower. So, I agree with Richard M, the next launch will be a serious test of the system.
Although the pad has held up very well through two static fires, the concrete didn’t do so badly, either, giving everyone the false sense of confidence that the pad would be only mildly damaged — but still needing serious repairs — during the April test. This was another case of SpaceX trying to do the impossible, but that time it really was impossible. Sometimes you win, and sometimes you lose. The wins are definitely worth the losses.
While I’m spouting off with my thoughts:
Richard M wrote: “They seem not to be too worried about the two engine early shutdown.”
I see two possibilities. Super Heavy may not depend upon all the engines running at full power to get to orbit. Let’s assume that they run their 33 engines at 90% power. Then they could conceivably still reach orbit even with three engines out at launch by running the remaining 30 engines at 100%.
A second possibility is that SpaceX is willing to run the test with a couple of engines out in order to get additional engineering information as to why they failed to ignite or why they were shut down just after ignition. They may not be getting enough information during their static tests or they may just want the flight time on their engines.
I wouldn’t be surprised if it were a third possibility that I don’t see.
There are a few possibilities for the cause of the early shutdowns, such as pogo, which could be one form of Jeff’s suggestion of flow problems, or John’s suggestion of turbopump problems (also a form of Jeff’s flow-problem suggestion). If the failing engines are in different locations for each test, then it may be a problem with the individual engines rather than a flow problem. Perhaps they have an assembly (quality control) problem, or maybe they are pushing the engines just a bit too hard (operational problem). Without inside knowledge, we are just speculating (isn’t it fun to speculate?), and hopefully SpaceX will eventually tell us what the problem(s) was, once they solve it.
Waiting for perfection is why SLS took so long to launch. But then, SLS’s first launch was an operational acceptance or certification test, not a development test. It had to work right the first time. SpaceX is in development testing, so working right is not really expected, and it would not teach the engineers much about their rocket. The lessons come from something not working as expected, such as o-ring blow-by, or thermal protection tiles coming off, or external tank insulation falling off during launch. When things work right, you assume that you know why, so when it suddenly does not work right on another launch, you are surprised. It worked right not because you designed it right but because you designed it close enough for the conditions seen for that launch, not for the launch where it worked less than right.
If SpaceX waits until they have a perfect system before performing their development tests then they, too, would be running certification testing, not development testing. During development testing you fly a test article that will teach you something. Otherwise, you are not able to advance the development of the system. It is why Musk does not announce that a launch is expected to reach orbit but has a fifty percent chance (or less) of reaching orbit (or successfully landing on a barge).
Sometimes you just have to test the new concept, new hardware, new method, or new system in order to find out where it goes wrong and what needs improvement.
I somehow get the idea that Space X held off on the destruct button for so long in order to get more data.
The rocket was not heading in a dangerous direction at that moment.
Or maybe they just wanted to use up all the fuel they could before the big boom.
My bet is the democrats allow Starship to fly without much delay.
Elon is showing himself to be a bit inept politically by the heavy handed way he is dismantling Twitter to create his X app. Counter intuitively, the democrats fear him less now that he has made a large number of Twitter users unhappy with the changes he is forcing on them. Notice how Elon is more subdued in his public appearances now than he was at the start of the year.
With the inept republican presidential candidates I think the ruling democrat coalition figures it can win the presidency and the house in 2024. Why stir things up by hassling Elon now?
pzatchok wrote: “I somehow get the idea that Space X held off on the destruct button for so long in order to get more data.”
This was my first thought, too.
However, it turns out that the button was pushed, the destruct mechanism punched holes in the propellant tanks, but the expected destruction did not happen as expected but happened 40 or so seconds later. I cannot imagine what was going through the range safety officer’s head during that time, perhaps the longest 40 seconds of his entire life. If the range safety officer waits until the rocket is headed in a dangerous direction, it is too late, as the debris may come down within inhabited areas. No matter when the destruction happened, the Starship upper stage would still be filled with fuel and oxidizer.
I posted this over a Rand Simberg’s place:
When Boeing builds a new airliner, do they need FAA authorization for each test flight? Anyone know?
Or do they get an R&D Experimental certificate with a proposed flight test schedule which gets modified by experience and just fly as required?
To Edward:
Thanks for the info.
Not knowing any better, I’d still like to test that pad before going all the way. That’s why I asked. If it cannot be tested on a static fire, then maybe a partial fill of the tanks.
As I mentioned, I’m not anything but a casual observer. Maybe the questions are dumb, but I’d like the answers anyway.
Not saying that anybody called me dumb, but when you open your mouth, you can remove all doubt like the saying goes.
Greg M: As I used to tell my film students at NYU, the only stupid question is the one you don’t ask.
Greg M,
The popular test mantra these days is “Test as you fly” or something like that.
Deviating from an actual flight configuration adds unknowns and testing is al about managing unknows so flying with partially filled fuel tanks just makes the results less specific to an actual flight.
And also, Yes! to that RSO being freaked out by the rocket surviving the pyros. That’s just the kind of thing the FAA uses to justify acting like a bunch of school crossing guards.
Thank you Edward
Here is the paper I was referring to:
https://www.cambridge.org/core/journals/journal-of-fluid-mechanics/article/hydrodynamics-of-finitelength-pipes-at-intermediate-reynolds-numbers/D7BBD977E0A615A3194E664D8752E1CB
From:
https://phys.org/news/2023-03-uncover-fluid-laws-straws.html
Also of interest—-this talks about N-1
https://link.springer.com/article/10.1007/s00348-023-03573-3
See the bottom citations here:
https://www.sciencedirect.com/science/article/abs/pii/S0094576517307695?via%3Dihub
An unexpected boundary layer?
https://phys.org/news/2023-08-sudden-generation-boundary-layer.html
Related?
https://phys.org/news/2023-04-storms-dangerous-urban-geysers.html
Lastly…a knot of turbulence was formed which persisted:
https://phys.org/news/2023-06-tempest-teacup-physicists-breakthrough-turbulence.html
That may not just explain ball lightning.
Note this isolated knot was formed by many outlets discharging…a complex plumbing situation. Perhaps a knot or two was formed and injested at some kinks.
Even medical studies into circulation may help here.
I wonder if anyone thought to have propellant flows in a Fermat Spiral.
That might smooth things.
Pawn:
It’s those unknowns that worry me. If you can only static fire to 50%, there’s a pretty big gap of unknown with respect to
what the launch table can handle.
Hopefully there’s a way to manage that unknown without incurring too great of a risk of a really bad day. I know of no answers. Hence the questions. I’d really hate to hear things like that there’s no answers, so just light that candle and find out.
“I don’t expect S25/B9 to launch until… well, maybe never.”
yep this is reality now… elections have consequences
“Why stir things up by hassling Elon now?”
he broke their echo chamber
besides, they’re the Party of Stirring Things Up By Hassling
“Why stir things up by hassling Elon now?”
The Dems have built and nurtured a core constituency that hates Musk, and pleasing that group gives them a warm satisfaction that they confuse with electoral success.
I see some chinks though. One Democrats out west wants space solar power. Ro Khanna and Vivek may both be Musk fans. There are a lot of transplants here from India with a pro-tech bent.
I hope both rise in their respective parties.
Cornel West is key here. Many African Americans see the DNC as a Greens Only club where rich white Northeasterners use tax dollars to travel overseas to tell brown people they can’t have electricity.
I remember when progressives wanted folks in the Third World to live as we do.
That script has been flipped.
pawn wrote: “The popular test mantra these days is “Test as you fly” or something like that.”
This is true. However, it is phrased grammatically correct, but the meaning is more: “test like you fly, fly like you test.”
I worked for a company that used that mantra, the one I quoted, but one employee noted that using the word “like” was grammatically incorrect. To summarize a very long response, the company believed that the grammatically correct phrasing would be misinterpreted too often by the general public. I bet almost everyone here interpreted pawn’s phrase as test while you fly.
A certain amount of testing can occur on the ground, before flight tests. This means that the testing should accurately represent the flight conditions. Not doing this is why the Mars Polar Lander failed during landing. The legs sprung open and the momentum flung them so much farther open that they triggered the engine shutdown switch, which was supposed to only be tripped when the legs splayed farther open on touchdown. The engine shut itself down at altitude and the probe crashed onto the surface. The test of the legs happened without the upper part of the probe, the part to which they mounted the switch, so they missed this important flaw in the design and the plan. They didn’t test like (in the configuration) they were going to fly.
Oh, no. I got started …
Designing a test can be much harder than one might think. So, no, Greg M, the question was not dumb. You have to know what you want to test, not just the item but the reaction of that item to the conditions/environment/whatever. If you don’t know those conditions, you don’t know how to test. You also have to know in advance what is successful and what is failure, what is an acceptable reaction and what isn’t.
I was once asked by an engineer to do a shake test on a small gizmo. That was all he said: “just shake it.” I needed to know other details, such as how long to shake it and how hard to shake it. It needed to see vibrations greater than expected during launch (otherwise we don’t know that it will survive launch) but not greater than it was designed to survive (otherwise I might break a perfectly good gizmo). I also didn’t want to assume that he just wanted to make sure it didn’t break, that success could be that it still worked properly after the test (but I was not asked to perform that test). The point is that designing a test was more complicated than my colleague thought.
When SpaceX did their static fire test this past winter/spring, they saw some minor damage to the concrete pad below the rocket. They concluded that the special concrete that they used was almost good enough but that they were trying to do more than even that special concrete could handle. It was a good try, on their part, and may be excellent advertising for that concrete, but they didn’t imagine that the full thrust launch, the April launch, would cause damage to more than the first layer of concrete. They realized that they needed their deluge system, but didn’t realize how necessary it really was. My guess is that they didn’t bother with a pass/fail criterion for that part of the pad, because they already knew it would not be able to pass.
______________
Jeff Wright,
I will look over a couple of those papers later tonight. Thanks for passing them along.
Thank you for that.
Usually…one designs the engines and the plumbing to them straightforward.
Has the opposite approach been looked at?
First, design propellant lines with the best flow characteristics—then the engine plumbing to match…a helical form all the way down?
There is a part of me that thinks Boeing and SpaceX are each building the other guys rocket.
Boeing–at it’s height–could have made the Starship/SuperHeavy like Space Freighter.
A stage-and-a-half SLS type rocket? Say with two Falcons as strap-ons?
I bet Musk could stack those like cordwood.
Four Raptors and cheap tankage means cost savings even if he chunked the big core…as long as he gets strap-ons back.
Less plumbing headaches.
Jeff Wright,
“Has the opposite approach been looked at?”
I don’t work at SpaceX, so I don’t know their process.
“There is a part of me that thinks Boeing and SpaceX are each building the other guys rocket.”
I don’t think so. SLS’s goal is to launch 100 tons or so into orbit. Using it for Artemis is only because it is a super heavy lift rocket. SLS is its own end, just as Atals V and Delta IV were. They all were available for future unknown projects that required launching heavy payloads to orbit, and for SLS, that payload is the Artemis project.
SpaceX has designed Starship and its systems with a very different goal in mind. The goal is to economically build a colony on Mars. As part of that goal, they need a super heavy rocket that can accomplish a variety of tasks. That Starship can also be used for other heavy payloads is a bonus that pays the bills while the Martian colony is planned and built.
Also as part of that goal, Starship has to be able to launch many times during the Mars transit window season, getting as many people and as much cargo on the way to Mars as possible. This is why SpaceX aspires to launch three times from each pad each day, an eight-hour turnaround time. Using strap on boosters for a stage-and-a-half design slows down that process at the critical times of the season.
“Less plumbing headaches.”
All the headaches (plumbing or otherwise) go away once the bugs in the system are worked out. It is all part of the development phase.
____________________
Jeff Wright,
The papers you linked are quite interesting. I had not heard of the second, internal, boundary layer generated by the sudden acceleration of a flow. What fun the aeronautical scientists must be having investigating this. I’m not sure that water hammer is a problem for SpaceX, as it tends to happen when a flow stops, not starts.
The paper that used straws as a mnemonic was fun and makes me wonder if straws were intentionally designed to operate near the triple point or if it just turned out that way through trial and error from user feedback. Or maybe these straws were designed for the thicker milk shakes that some restaurants sell. There is one place I have eaten that has a thinner straw, harder to get a similar flow, but has no viscous shake to flow through the straw.
The lingering, isolated “ball” of turbulence sounds like they have found a new way to study turbulence, but I doubt that this is a problem for Super Heavy’s manifold or plumbing. It sounds like this “ball” of turbulence is formed when flows are added, not separated, as happens in Super Heavy’s manifold.
I don’t know what the Raptor engines’ problems are, but plumbing is not the only difference between testing a single engine on the McGregor stand and running 33 of them on one rocket. It is an obvious one, but there are possible reasons for engine trouble other than fluid flow. Even though they are all of the same design, maybe they have personalities more like Robert Downey Jr.’s Iron Man, who doesn’t play well with others. They test them individually, then fly them in a group. This could be yet another case of not testing like they fly and not flying like they tested.
On the other hand, the flight test is a test, too.
Aggressive testing I certainly agree with…I have never trusted computer modeling.
I lament that our STS wasn’t an Energia Buran modular model: EELV class strap-ons. HLLV with side mount….all engines visible…wide outsized cargo side mount….so huge boilerplates could be released off 747 ferry for low speed tests…and released off a side mount SLS for re-entry tests.
Then a true RLV could be planned from the data collected.
Elon is doing it all at once.
Jeff Wright,
“Has the opposite approach been looked at?”
I don’t work at SpaceX, so I don’t know their process.
“There is a part of me that thinks Boeing and SpaceX are each building the other guys rocket.”
I don’t think so. SLS’s goal is to launch 100 tons or so into orbit. Using it for Artemis is only because it is a super heavy lift rocket. SLS is its own end, just as Atals V and Delta IV were. They all were available for future unknown projects that required launching heavy payloads to orbit.
SpaceX has designed Starship and its systems with a very different goal in mind. The goal is to economically build a colony on Mars. As part of that goal, they need a super heavy rocket that can accomplish a variety of tasks. That Starship can also be used for other heavy payloads is a bonus that pays the bills while the Martian colony is planned and built.
Also as part of that goal, Starship has to be able to launch many times during the Mars transit window season, getting as many people and as much cargo on the way to Mars as possible. This is why SpaceX aspires to launch three times from each pad each day, an eight-hour turnaround time. Using strap-on boosters for a stage-and-a-half design slows down that process at the critical times of the season.
“ Less plumbing headaches.”
The headaches go away once the bugs in the system are worked out.
____________________
The papers you linked are quite interesting. I had not heard of the second, internal, boundary layer generated by the sudden acceleration of a flow. What fun the aeronautical scientists must be having with this. I’m not sure that water hammer is a problem for SpaceX, as it tends to happen when a flow stops, not when it starts.
The paper that used straws as a mnemonic was fun and makes me wonder if straws were intentionally designed to operate near the triple point* or if it just turned out that way through trial and error from user feedback. Or maybe these straws were designed for the thicker milk shakes that restaurants sell, because there is one place I have eaten that has a thinner straw, harder to get a similar flow, but this one place has no viscous shake that has to flow through the straw.
The isolated “ball” of lingering turbulence sounds like they have found a new way to study turbulence, but I doubt that this is a problem plaguing Super Heavy’s manifold or plumbing. It seems to be a phenomenon of combining flows, not separating into multiple flows.
I don’t know what the Raptor engines’ problems are,** but plumbing is not the only difference between testing a single engine on the McGregor stand and running 33 of them on one rocket. Flow is an obvious difference, but there are possible reasons for engine trouble other than fluid flow. Even though the Raptor engines are all of the same design, maybe they have personalities more like Robert Downey Jr.’s Iron Man, who doesn’t play well with others. They test them individually, then fly them in a group. This could be yet another case of not testing like they fly and not flying like they tested.
_____________-
* for those who haven’t read the paper, this triple point refers to the Naiver-Stokes equation, not the water phase chart.
** Wild speculation: the engine control system may have issues. Maybe the best part (no part) isn’t quite as good as SpaceX thinks, and they removed something that helps in a situation that occasionally occurs in multiple engine scenarios, and the company needs to either correct that occasional situation or “get rid of” that particular “best part” by returning a whatchamacallit that they removed.
Or maybe the engines are installed, some have a slight problem, and SpaceX chooses to not replace them before performing a test and instead merely does not ignite them, allowing for a test sooner rather than later. It all depends upon what they need to learn from each test. At this point in development, they may not need perfection at the start of each test.
Jeff Wright,
Yes, I would have preferred a different for STS (Space Shuttle) design, as well. The original concept of a small vehicle that had only a pallet bay rather than a payload bay was excellent. It most likely would not have had the tile problem that cost so much in budget, number of flights, and enthusiasm for reusability. Payloads could have continued to be carried by regular rockets until someone decided that the (hypothetical) economical smaller Shuttle was worth emulating for unmanned payload launch vehicles, too.
Ah, what could have been, if only our politicians not been such terrible control freaks but had been more conducive to the idea of commercial space rather than a Soviet style space program, top down control from a single national government agency. Isn’t government supposed to make our lives easier, not harder? What are we paying them for, anyway?