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Oldfart1939:
Re post 48: if they learn, it won't be an entirely-wasted test. But this is something that they should have already run into with their Falcon-1 and Falcon-9/-Heavy experiences. The Falcon-1 staging debacle nearly bankrupted SpaceX at its outset.
However, the older hands who got through that debacle are no longer there, since people over about age 45 cannot sustain chronic 70-80 hour weeks, meaning that's the "normal", there is no respite. At that kind of workload, the older hands have no time to teach the newbies how they really did it, since most of knowledge is never written down because managers do not want to pay for that.
Between that effect, and the "not invented here" effect that prevents learning the lessons of other outfits, I am unsurprised that they did not think their way through this hot staging change to Starship/Superheavy. The computer simulations are no better than the input data (the "GIGO" law), and my guess is they forgot to include the jet blast effects of Starship upon Superheavy.
If I had to guess, I'd say too many of their engineering staff only know how to run software codes that others wrote, and do not themselves know how to think their way through a problem pencil-and-paper. I do see an awful lot of people like that these days, far more than I used to see, decades ago. Which tells me the engineering schools are making a really bad mistake by focusing almost entirely on software codes, not pencil-and-paper design analysis.
SpaceX was trying to do exactly what I suggested: use 3 engine's thrust to settle the Superheavy propellants during hot staging, but it didn't work when the jet blast forces decelerated the Superheavy, and thereby unsettled the propellants into a giant surge forward, uncovering the suctions. That starved and probably destroyed the 3 engines they had burning.
Here's my bet: they'll never admit to that in public! But that's quite probably what happened.
I am confident that one way or another, they will resolve the Superheavy ullage issue. What concerns me a lot more is what happened to Starship? It got through staging and went several minutes further along the ascending elliptical orbit toward circular orbit altitude. Then it just disappeared. No one seems to know why, or what happened. Everyone at SpaceX seems very closed-mouthed about it, too.
It could have been an ullage issue at re-light for the circular orbit insertion burn, except that as best I understand it, they weren't going to circularize on this flight test. If that supposition is true, then "something else" happened. And whatever that was, is the real question!
GW
Last edited by GW Johnson (2023-12-21 09:42:04)
GW Johnson
McGregor, Texas
"There is nothing as expensive as a dead crew, especially one dead from a bad management decision"
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For GW Johnson re #51
The guest speakers at the recent NSS North Houston meeting gave a presentation on flight control for space craft flying in the United States aircraft control regions.
I came away from that talk with an understanding that every bit of a flight (successful or not) is tracked in real time by various government agencies. Government agencies are under no obligation to keep commercial flight records secret.
A request for information about the recent Starship flight should be honored. I'd be interested in seeing the result of a request for information about that particular flight. I am confident that every physical part of that ship was tracked until it landed in the Gulf, or wherever it landed.
Freedom of Information ... the name of the request finally showed up in memory.
Please consider filing a Freedom of Information request, and let us know what happens!
(th)
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An article appeared in the news feed ...
https://www.yahoo.com/news/faa-closes-i … 43037.html
Reuters
FAA closes investigation into SpaceX Starship explosion
David Shepardson and Joey Roulette
Mon, February 26, 2024 at 7:46 PM EST·2 min read
1SpaceX's next-generation Starship spacecraft atop its powerful Super Heavy rocket is launched
By David Shepardson and Joey RouletteWASHINGTON (Reuters) - The U.S. Federal Aviation Administration said Monday it has closed the investigation into an explosion during SpaceX's Starship Super Heavy Orbital Test flight in late 2023, agreeing with the company on new procedures for future flights.
The Super Heavy booster, the rocket system’s towering first half that launches the upper Starship stage toward space, exploded after several engines failed to properly reignite during its return for a landing, said SpaceX, which led the investigation into the incident.
The uncrewed spacecraft, developed to carry astronauts to the moon and beyond, failed in its second test last November, but it made it further than an earlier attempt that ended in an explosion.
The vehicle breakup occurred more than three and a half minutes into the flight over the Gulf of Mexico.
SpaceX identified, and the FAA accepted the root causes of the incident and 17 corrective actions in SpaceX’s mishap report, including vehicle hardware redesigns, updated control system modeling, re-evaluation of engine analyses, updated engine control algorithms, operational changes, flammability analysis updates and installation of additional fire protection.
SpaceX said it has implemented hardware "to improve leak reduction, fire protection, and refined operations associated with the propellant vent to increase reliability."
Prior to the next launch, SpaceX must implement corrective actions and receive a license modification from the FAA addressing safety, environmental and other regulatory requirements.
The FAA said it is evaluating SpaceX’s license modification request and expects SpaceX to submit additional required information before a final determination.
"More Starships are ready to fly, putting flight hardware in a flight environment to learn as quickly as possible," the company said.
(Reporting by David Shepardson and Joey Roulette in Washington Shivansh Tiwary in Bengaluru; Editing by Shailesh Kuber and Michael Perry)
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This appears to be a fairly recent development.
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SpaceX Gets List of Starship Upgrades Needed Before Launch
The Federal Aviation Administration ordered 17 corrective actions, including hardware redesigns for its Super Heavy Booster and additional fire protection and upgrades for its Starship vehicle.
Engines shutting down early with 1 engine blowing up...
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I dunno about any filter.
We've all speculated about an ullage problem causing engine failures on Superheavy. What's said in press releases is often not nearly as accurate as it should be.
However, that is the very first probable cause as to why the Starship upper stage just disappeared. "Fires destroying wiring connecting computers" or some such, is what I read. And that's the first peep in public I have heard about it. Sounds very serious, enough to to least conceptually cause a computer to decide on a self destruct from loss of control. But it's really hard to understand what actually did happen, press releases being no more truthful than they usually are.
GW
GW Johnson
McGregor, Texas
"There is nothing as expensive as a dead crew, especially one dead from a bad management decision"
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