totm nov 2023 SpaceX Discussion Thread

[CatastrophicFailure]

1 hour ago, RCgothic said:

This isn't the first time the FAA have issued a nothing-burger statement like this as I recall.

It's not news the next launch license needs to wait on the mishap investigation and this statement says nothing about timescale. It's just their standard "Stop hassling us. It'll be done when it's done," press release.

Yup. As someone deep in that X thread said, this would be the FAA’s response whether it was the day after IFT-1 or the day before the new launch license was granted. 

Bit fun tho to scroll through the comments and watch, sigh, “both sides” blow it all out of proportion. 

[mikegarrison]

Trying to pressure the FAA into giving their approval for something is often a bad idea.

[Exoscientist]

On 9/5/2023 at 5:13 PM, Spaceception said:

Predictions for this one? I think it'll make it to stage separation and ignition of Starship. Bit more iffy whether it'll burn the full duration to its semi-orbit, and definitely uncertain if it'll survive reentry. The booster should make boostback, and possibly a soft ocean landing after.

And the pad will survive.

Overall, it'll be a much smoother test than IFT-1, even if I still don't think it'll meet its objectives.

I’m taking bets on the number of Raptors that will fail during the flight.

  Robert Clark

On 9/6/2023 at 12:01 PM, tater said:

The risks are similar enough to liftoff that there is not much to gain. The fact that they don't suggests that whatever the early shutdowns were, they worked the issue.

And much to lose as it increases the chance of explosion.

  Robert Clark

Edited September 8, 2023 by Exoscientist

[tater]

19 minutes ago, Exoscientist said:

Ad much to lose as it increases the chance of explosion.

?

Filling any rocket completely to test it has pretty much identical risk to launch, not an increased chance. None of us knows what the data was from the early shut downs. The did not swap the engines, so it might have been literally anything, GSE, a sensor, overly constrained parameters on shutdown (to mitigate risk), whatever.

The FAA statement I agree was just a "you'll know when we approve it when we approve it" statement.

 

[Ultimate Steve]

20 hours ago, CatastrophicFailure said:

Yup. As someone deep in that X thread said, this would be the FAA’s response whether it was the day after IFT-1 or the day before the new launch license was granted. 

Case in point:

https://www.faa.gov/newsroom/faa-closes-spacex-starship-mishap-investigation

Update from SpaceX website:

Quote

The first flight test of a fully integrated Starship and Super Heavy was a critical step in advancing the capabilities of the most powerful launch system ever developed. Starship’s first flight test provided numerous lessons learned that are directly contributing to several upgrades being made to both the vehicle and ground infrastructure to improve the probability of success on future Starship flights. This rapid iterative development approach has been the basis for all of SpaceX’s major innovative advancements, including Falcon, Dragon, and Starlink. SpaceX has led the investigation efforts following the flight with oversight from the FAA and participation from NASA and the National Transportation and Safety Board.

Starship and Super Heavy successfully lifted off for the first time on April 20, 2023 at 8:33 a.m. CT (13:33:09 UTC) from the orbital launch pad at Starbase in Texas. Starship climbed to a maximum altitude of ~39 km (24 mi) over the Gulf of Mexico. During ascent, the vehicle sustained fires from leaking propellant in the aft end of the Super Heavy booster, which eventually severed connection with the vehicle’s primary flight computer. This led to a loss of communications to the majority of booster engines and, ultimately, control of the vehicle. SpaceX has since implemented leak mitigations and improved testing on both engine and booster hardware. As an additional corrective action, SpaceX has significantly expanded Super Heavy’s pre-existing fire suppression system in order to mitigate against future engine bay fires.

The Autonomous Flight Safety System (AFSS) automatically issued a destruct command, which fired all detonators as expected, after the vehicle deviated from the expected trajectory, lost altitude and began to tumble. After an unexpected delay following AFSS activation, Starship ultimately broke up 237.474 seconds after engine ignition. SpaceX has enhanced and requalified the AFSS to improve system reliability.

SpaceX is also implementing a full suite of system performance upgrades unrelated to any issues observed during the first flight test. For example, SpaceX has built and tested a hot-stage separation system, in which Starship’s second stage engines will ignite to push the ship away from the booster. Additionally, SpaceX has engineered a new electronic Thrust Vector Control (TVC) system for Super Heavy Raptor engines. Using fully electric motors, the new system has fewer potential points of failure and is significantly more energy efficient than traditional hydraulic systems.

SpaceX also made significant upgrades to the orbital launch mount and pad system in order to prevent a recurrence of the pad foundation failure observed during the first flight test. These upgrades include significant reinforcements to the pad foundation and the addition of a flame deflector, which SpaceX has successfully tested multiple times.

Testing development flight hardware in a flight environment is what enables our teams to quickly learn and execute design changes and hardware upgrades to improve the probability of success in the future. We learned a tremendous amount about the vehicle and ground systems during Starship’s first flight test. Recursive improvement is essential as we work to build a fully reusable launch system capable of carrying satellites, payloads, crew, and cargo to a variety of orbits and Earth, lunar, or Martian landing sites.

Interesting, primary cause of failure was fires in the engine bay, N-1 style. From what I saw, the primary problem was suspected to be in the hydraulic system, by the public at least..

[Kerwood Floyd]

Wow, Very interesting reading. Unless the leaks that led to the fires were caused by flying pad debris, it sounds like the disintegration of the pad had little to do with the in-flight engine failures. 

 

[PakledHostage]

1 hour ago, Kerwood Floyd said:

Wow, Very interesting reading. Unless the leaks that led to the fires were caused by flying pad debris, it sounds like the disintegration of the pad had little to do with the in-flight engine failures. 

 

Sounds to me like SpaceX has some homework to do... Let's hope that they're A-students and were already on it like a fly on poo last Tuesday.

[CatastrophicFailure]

1 hour ago, PakledHostage said:

Sounds to me like SpaceX has some homework to do... Let's hope that they're A-students and were already on it like a fly on poo last Tuesday.

Sounds to me like they’ve already done it. 

[mikegarrison]

3 hours ago, Ultimate Steve said:

Interesting, primary cause of failure was fires in the engine bay, N-1 style. From what I saw, the primary problem was suspected to be in the hydraulic system, by the public at least..

Not that I want to sound like I knew it all or whatever, but if you go back in this forum I think you'll find that I was concerned right from the start about packing so many engines together so closely. That's a known risk on airplanes, and is one of the reasons why engines on pods hanging off the wing or fuselage are so popular. When fighters have twin engines buried in the fuselage, they often have a massive piece of structure between them to try and isolate one engine from the result of failure of the other.

Edited September 8, 2023 by mikegarrison

[CatastrophicFailure]

Meanwhile, across the pad…

Ship 26 has been rolled out for testing. Quite the head-scratcher, this. Lots of speculation that it’s a prototype expendable tanker/orbiting fuel depot/fuel-transfer tester, but in any of those cases it’s odd that it still has tile pins and mounting hardware for fins.

 

Just now, mikegarrison said:

 When fighters have twin engines buried in the fuselage, they often have a massive piece of structure between them to try and isolate one engine from the result of failure of the other.

IIRC there’s upgrades on this booster specifically for that.

[Exoscientist]

On 9/6/2023 at 5:33 PM, tater said:

They either got the data they needed, or they didn't.

More static fires just to kill time is needless. Each one presents a nonzero RUD risk—as any WDR/static fire/launch does. The failure modes just short of actual launch are all there. So it's a balancing act of what useful data can they gather vs risk—even if the risk is low.

 
So you agree with me more static fires increase the risk of explosions.

   Robert Clark

[Exoscientist]

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.
https://www.faa.gov/newsroom/faa-closes-spacex-starship-mishap-investigation

This is the big one:

The corrective actions include: “redesigns of vehicle hardware to prevent leaks and fires,…

 SpaceX has been having leaks and fires on the Raptor all through its development, including on the April test launch. I don’t think they are going to make it by doing full-scale test launches, like the (in)famous N-1 rocket did. They’ll have to do instead an incremental approach by building a separate full-up, full thrust, full flight duration static test stand and not certify the rocket for launch until all 33 engines can fire for the full flight duration.

  Like the guys with Apollo did it.

   Robert Clark

[magnemoe]

3 hours ago, Kerwood Floyd said:

Wow, Very interesting reading. Unless the leaks that led to the fires were caused by flying pad debris, it sounds like the disintegration of the pad had little to do with the in-flight engine failures. 

 

I see that as very unlikely, that debris would have to pass up trough the rocket flame and between the engines. Note that all the energy in the debris was from the rocket in the first place. 

[tater]

59 minutes ago, Exoscientist said:

So you agree with me more static fires increase the risk of explosions.

Operating vehicles has nonzero risk. That's why they have closures. If you are arguing in favor of just launching, I agree.

46 minutes ago, Exoscientist said:

SpaceX has been having leaks and fires on the Raptor all through its development, including on the April test launch. I don’t think they are going to make it by doing full-scale test launches, like the (in)famous N-1 rocket did. They’ll have to do instead an incremental approach by building a separate full-up, full thrust, full flight duration static test stand and not certify the rocket for launch until all 33 engines can fire for the full flight duration.

  Like the guys with Apollo did it.

If this is true they might as well quit, and the rest of us can wait for China to do something interesting, because it will never happen here in that case. When the Apollo people did it, they could have done it however they liked, BTW. They would not have faced a decades long environmental review, and no one cared about turtle nests, nor hardly any other pollution (all the engineers were likely smoking into the bargain). If you want Apollo era testing, first get Apollo era regulations, and the same sorts of permissions someone from Apollo would have had... they complain up the chain, LBJ gets on the horn and swears at them, problem solved.

Full flight static testing is useless. Having it blow up in a test stand is unquestionably worse than having it do so 40km up.

Little of the full duration testing is useful. How do the engines behave at increasing g loads? Who knows? How is the engine TPS able to deal with expansion and turbulent areas we always see at the base of rockets in low pressure areas with increasing altitude? No idea.

The reality is they will check off the 63 boxes and fly.

Edited September 8, 2023 by tater

[Kerwood Floyd]

7 minutes ago, magnemoe said:

I see that as very unlikely, that debris would have to pass up trough the rocket flame and between the engines. Note that all the energy in the debris was from the rocket in the first place. 

Is my memory playing tricks on me? I remember in the immediate aftermath of IFT-1 seeing a lot of speculation that flying debris might have been the culprit.

[Exoscientist]

4 hours ago, Kerwood Floyd said:

Wow, Very interesting reading. Unless the leaks that led to the fires were caused by flying pad debris, it sounds like the disintegration of the pad had little to do with the in-flight engine failures. 

 

 

 I don’t find it surprising. Considering the number of times the Raptor has leaked fuel and caught fire all through its developing including on the April test launch. What’s surprising is it took the FAA this long to recognize the fact that a rocket engine leaking fuel and catching fire during its normal flight regime is NOT normal.

    Robert Clark

Edited September 8, 2023 by Exoscientist

[magnemoe]

Just now, Kerwood Floyd said:

Is my memory playing tricks on me? I remember in the immediate aftermath of IFT-1 seeing a lot of speculation that flying debris might have been the culprit.

Yes, but I have serious problems seeing how it could happen. You could perhaps damage an engine bell on the other ring if something ricocheted of the launch tower side somehow but that would be an golden BB. 
Once you enter the supersonic flame front strong enough to dig an hole in concrete how are thing supposed to go up into it, that is if you only power came from the same flame front down at the ground. 

[darthgently]

33 minutes ago, Exoscientist said:

 

 I don’t find it surprising. Considering the number of times the Raptor has leaked fuel and caught fire all through its developing including on the April test launch. What’s surprising is it took the FAA this long to recognize the fact that a rocket engine leaking fuel and catching fire during its normal flight regime is NOT normal.

    Robert Clark

I'm not a space historian extraordinaire, but it seems to me not outrageously abnormal for first full test flights with double digits of engines pushing well past common chamber pressures of the day.  Just the number of fuel handling components, lines, and fittings involved in a cluster that large changes the situation quite a bit.  This is a big tradeoff with large numbers of engines: engine-out robustness vs more parts to fail.  But key terminology is test flight.  Not the same as an engine stand with a lot more acoustic and inertial stuff going on

And they did test the engine out capability whether it was in the plan or not.  It needs testing also

Edited September 8, 2023 by darthgently

[mikegarrison]

47 minutes ago, tater said:

Operating vehicles has nonzero risk. That's why they have closures. If you are arguing in favor of just launching, I agree.

If this is true they might as well quit, and the rest of us can wait for China to do something interesting, because it will never happen here in that case. When the Apollo people did it, they could have done it however they liked, BTW. They would not have faced a decades long environmental review, and no one cared about turtle nests, nor hardly any other pollution (all the engineers were likely smoking into the bargain). If you want Apollo era testing, first get Apollo era regulations, and the same sorts of permissions someone from Apollo would have had... they complain up the chain, LBJ gets on the horn and swears at them, problem solved.

Full flight static testing is useless. Having it blow up in a test stand is unquestionably worse than having it do so 40km up.

Little of the full duration testing is useful. How do the engines behave at increasing g loads? Who knows? How is the engine TPS able to deal with expansion and turbulent areas we always see at the base of rockets in low pressure areas with increasing altitude? No idea.

The reality is they will check off the 63 boxes and fly.

I think we live in a better world when people care about turtle nests.

[tater]

31 minutes ago, mikegarrison said:

I think we live in a better world when people care about turtle nests.

I never said otherwise. My point was that the resources behind Apollo, combined with what we would all call an utter disregard for—all kinds of things we value—means that asking for Apollo-era operations with none of the countervailing simplifications is essentially asking for the program to come to a standstill.

"Why can't SpaceX do it exactly the same as a national program spending 4% of the Federal budget, and given carte blanche to run roughshod over, well, anything they like while also having far less money, and zero ability to run roughshod?"

 

Edited September 8, 2023 by tater

[tater]

Useful illumination.

[CBase]

From https://arstechnica.com/space/2023/09/faa-says-spacex-has-more-to-do-before-starship-can-fly-again/

Quote

"The FAA has been provided with sufficient information and accepts the root causes and corrective actions described in the mishap report," wrote Marcus Ward, manager of the FAA's safety assurance division, in a letter to SpaceX. "Consequently, the FAA considers the mishap investigation that SpaceX was required to complete to be concluded."

This is basically good news: There are no additional actions required that SpaceX didn't already prepare for. So yes I am pretty sure that SpaceX can now proceed to have all 63 actions verified. But I doubt they get FAA to approve all this paperwork within next week.

Quote

"The closure of the mishap investigation does not signal an immediate resumption of Starship launches at Boca Chica," the FAA said in a statement

My guess: 2-3 weeks delay

[SunlitZelkova]

4 hours ago, Exoscientist said:

SpaceX has been having leaks and fires on the Raptor all through its development, including on the April test launch. I don’t think they are going to make it by doing full-scale test launches, like the (in)famous N-1 rocket did. They’ll have to do instead an incremental approach by building a separate full-up, full thrust, full flight duration static test stand and not certify the rocket for launch until all 33 engines can fire for the full flight duration.

  Like the guys with Apollo did it.

The N1 was actually just fine, and they made improvements in every launch. If the KORD engine control computer hadn’t malfunctioned on the 4th flight, it actually could have made it to orbit on the remaining engines it had.

It’s been speculated the N1 would have finally had a successful flight if the program wasn’t cancelled in 1974. It’s been compared to Proton, which also had many early launch failures but later became a reliable vehicle.

I don’t think the alarm needs to be sounded here. Starship-Superheavy’s development might look a little like the R-7, Proton, or even F9 landing attempts, but eventually it will succeed- like all those other rockets did.

[tater]

It's literally had 1 flight, and is unique on so many levels.

Note that all the old-school testing in the world on Shuttle had the first flights succeed! Except in retrospect they decided something like the first 20 flights were at a LOV risk of ~1:9. Shockingly high—and a crew vehicle into the bargain.

[RCgothic]

The vehicle's already been redesigned. Check. Send.