totm nov 2023 SpaceX Discussion Thread

[darthgently]

56 minutes ago, tater said:

I don't think it's anything loony, it was likely a plumbing problem

Likely, but I bet that the actual investigation goes beyond just engineering and manufacturing issues and will also take possible security aspects into account.  As it should be.

There have been two other bomb threats at Boca Chica over the years that I just learned about and the FBI is still investigating all three of them, apparently.

Loonies do loony things

[Superpluto126]

I think its safe to say that Flight 8 Catch is off

[darthgently]

Just now, Superpluto126 said:

I think its safe to say that Flight 8 Catch is off

Catch went fine other than engine out on boost back. 

[Minmus Taster]

41 minutes ago, Ultimate Steve said:

 

Yeah right, no way the FAA isn't clamping down after this, unless Elon's "friends" (lets keep this apolitical as possible) step in which I suppose is possible.

[Superpluto126]

3 minutes ago, darthgently said:

Catch went fine other than engine out on boost back. 

Talking about the Ship Catch

[Minmus Taster]

6 minutes ago, darthgently said:

Catch went fine other than engine out on boost back. 

I think they mean a ship catch attempt

This is actually quite frightening, this could have been ugly.

Edited 18 hours ago by Minmus Taster

[JoeSchmuckatelli]

 

SX has a working very large 1st stage.  Three successful launches with two RTLS catches.  They could commercialize Booster. 

Question is - how much is the cost of expendable second stages?  Like, cool factor aside, is Starship actually necessary? 

Can we get a lot more weight to the moon and Mars now using traditional-style upper and payload staging ideas matched to the size Booster now allows? 

Or do we really need Starship to work, too? 

(is it a nice to have or a need to have?) 

[Minmus Taster]

2 minutes ago, JoeSchmuckatelli said:

 

SX has a working very large 1st stage.  Three successful launches with two RTLS catches.  They could commercialize Booster. 

Question is - how much is the cost of expendable second stages?  Like, cool factor aside, is Starship actually necessary? 

Can we get a lot more weight to the moon and Mars now using traditional-style upper and payload staging ideas matched to the size Booster now allows? 

Or do we really need Starship to work, too? 

(is it a nice to have or a need to have?) 

Been pondering this to, but Starship's primary focus will probably end up being Earth orbit and quick turnarounds and reusing hardware are essential to dominate the market with such a large vehicle.

 

[tater]

28 minutes ago, Minmus Taster said:

Yeah right, no way the FAA isn't clamping down after this, unless Elon's "friends" (lets keep this apolitical as possible) step in which I suppose is possible.

They have no need to "clamp down," the point of a mishap/anomaly investigation is to establish cause, and subsequent changes to mitigate. As has happened with other investigations, since the FAA is not in fact qualified to do much of either of those things for spacecraft, SpaceX will in fact drive the efforts. Present the problems observed, causes, and planned mitigations. They already seem to have the cause.

29 minutes ago, Minmus Taster said:

This is actually quite frightening, this could have been ugly.

That debris was no where near that aircraft, and given it burning from heating, it was way above any air traffic—presumably ATC diverts aircraft away from the flight path of the debris, which in this case would be some miles east of the fireballs.

29 minutes ago, JoeSchmuckatelli said:

Like, cool factor aside, is Starship actually necessary? 

Yea, they could throw a fairing on it, expend upper stages, and use it for Starlinks now I wager. There are probably some payloads for customers where this might be a thing as well. It's not what they want, however, and there's no real commercial reason past Starlink to bother—it's not about making money.

27 minutes ago, Minmus Taster said:

Been pondering this to, but Starship's primary focus will probably end up being Earth orbit and quick turnarounds and reusing hardware are essential to dominate the market with such a large vehicle.

The market is chump change. Starship has nothing at all to do with that aside from Starlink. Starlink alone has the potential to grossly exceed the revenue in the TAM (total addressable market) for launches. That's at most some lowball billions (10? 20?) even capturing all of it.

[Spaceception]

43 minutes ago, JoeSchmuckatelli said:

is Starship actually necessary? 

Yes. Full reuse is the name of the game, not back pedaling to partial reuse. And from the sound of it, this failure wasn't caused by anything in the vehicle contributing to reusability, so whether or not SpaceX wanted to expend it, this failure probably would've happened.

Starship is more expensive than Falcon 9's upper stage, and the cost floor will be higher if they have to build a new one each flight, limiting commercial opportunities beyond Starlink, while also lowering the potential flight rate.

I also believe that HLS benefits more from full reuse than without. In theory, you can refuel with expendable tankers, but it will take longer, and cost more. Plus, HLS will be closer to the intended version of Starship anyway, so it's good to commit to reuse for the entire architecture, rather than a bespoke lander.

SpaceX shouldn't put full reusability on the backburner, they had to retrofit it onto Falcon 9, and while they made some huge strides, it's ultimately constrained by its original design choices. Starship is still experimental, and they've had 3 mostly successful reentries so far. The Starship catch was supposed to be shortly after this flight (I'm not expecting it until flight 9 or 10 now though), but still, they are trying to make quick strides to recover the entire vehicle. They shouldn't stop when they're this close because of an unexpected failure.

[Ultimate Steve]

Interesting tangent:

Starship seemed to carry on just fine with this engine configuration for several seconds (Still accelerating enough to probably not be spinning) before ultimately failing. This surprised me as I was under the impression that Starship (the upper stage) had minimal to no engine out capability. I don't have perfect numbers, but I did shove my numbers into a spreadsheet and I came up with the following:

Assuming my numbers are right, immediately throttling the two Raptor vacuum engines down to minimum and gimbaling to the limit of 10 degrees might be enough to cancel out the torque from the uneven engine distributions in this vehicle configuration.

On the surface the math says if the CoM is more than ~21.9m from the base of the vehicle it should be stable, but the propellant will slosh towards the side of the vehicle with the engines in this case, which causes all three engines to produce less "vertical torque" and would beneficially reduce this number, by how much I am unsure. 

Admittedly my source is just some guy on Discord, but I'm told that Raptor can normally gimbal to 15 degrees, but that the current engine shielding limits that to 10 or 11 degrees. Interestingly, for future ships using Raptor 3, the full 15 degrees would be available and this puts the minimum CoM height at only about 15.8m, though future versions of the ship may have to limit their gimbals to avoid hitting the vacuum engine bells.

I don't know if the resulting thrust (of roughly 30% of normal thrust) (though if the CoM is higher than the minimum you can throttle the Vactors up more than 40%) would be enough to get into orbit for any situation aside from very late in the upper stage burn, but I find it very interesting that Starship can (at least theoretically) survive under some conditions with only 3 engines running, all on the same side of the vehicle, only one of which can gimbal.

Assuming I did my math right, of course, it has been a while since I took statics.

Edited 17 hours ago by Ultimate Steve

[Hotel26]

1. As long as engines don't RUD, their reliability seems analogous to the widepsread use these days of SD memory, which is always degrading but error-corrected.  It's overall system performance/economics that count.
2. I expect that the economics of the current state of the art (making it perfect immediately) compared to the economics of simply reserving some flight lane bandwidth (time and space) for the benefit of human progress in space flight (e.g. SpaceX) is going to argue that it will or should be the FAA/DOT that takes compensatory future action to prevent  reoccurrence of mutual hazard.  (You could actually say it is the fault of those controlling authorities, but what matters is only how those now react to the data.)  This situation is analagous to the shootdown of MH17 over the Ukraine (Donbas) in 2014.  The (impossibly) idealistic solution might have been proposed of stopping that war (still continuing (and looking mighty like ww3 already in progress, summing all told around the world)) but the actual solution applied was to ban commercial overflights of the area until such time as deemed safe to resume.

Edited 16 hours ago by Hotel26

[tater]

That map I showed was some guy's guestimate of debris, SpaceX apparently has a different view:

Quote

Following stage separation, the Starship upper stage successfully lit all six Raptor engines and performed its ascent burn to space. Prior to the burn’s completion, telemetry was lost with the vehicle after approximately eight and a half minutes of flight. Initial data indicates a fire developed in the aft section of the ship, leading to a rapid unscheduled disassembly.

Starship flew within its designated launch corridor – as all U.S. launches do to safeguard the public both on the ground, on water and in the air. Any surviving pieces of debris would have fallen into the designated hazard area. If you believe you have identified a piece of debris, please do not attempt to handle or retrieve the debris directly. Instead, please contact your local authorities or the SpaceX Debris Hotline at 1-866-623-0234 or at [email protected].

 

[Nuke]

2 hours ago, Minmus Taster said:

Yeah right, no way the FAA isn't clamping down after this, unless Elon's "friends" (lets keep this apolitical as possible) step in which I suppose is possible.

i think they may be concerned with the dogepocalypse that threatens to eat bureaucrats alive, with heel dragers and boat rockers being the juiciest prey. however the faa are one of the few three letter agencies that actually do a useful job. they will want the usual analysis and mitigation write-up before they grant the next license. that may take a little while to complete, but i dont see it as a major obstacle. spacex want to make reusable launch vehicles, not expensive fireworks.

[Nuke]

2 hours ago, JoeSchmuckatelli said:

 

SX has a working very large 1st stage.  Three successful launches with two RTLS catches.  They could commercialize Booster. 

Question is - how much is the cost of expendable second stages?  Like, cool factor aside, is Starship actually necessary? 

Can we get a lot more weight to the moon and Mars now using traditional-style upper and payload staging ideas matched to the size Booster now allows? 

Or do we really need Starship to work, too? 

(is it a nice to have or a need to have?) 

the booster has proven to be reliable, with the catch failure of the previous launch more being a tower issue. workaround for that is to have a spare tower or two in case the first one takes damage during launch. they could pivot to a disposable second stage, but the only fundamental difference between landing the first stage and the second is re-entry, and this was not a re-entry failure. it seems like a kneejerk reaction to abandon the concept when the thing that failed is something they have done right in many other launches. what were seeing here is the growing pains of moving to a new ss design.

[CatastrophicFailure]

Full statement from SpaceX:

https://www.spacex.com/launches/mission/?missionId=starship-flight-7

Also, more context:

 

And while I’m at it…

9 hours ago, GuessingEveryDay said:

Hmm, maybe they accidentally borrowed a few faulty Cybertruck motors from Austin? There was a Cybertruck that blew up in Las Vegas.

It did not blow up, it was blown up, deliberately, by the driver via fireworks and gasoline in the bed. 

[Ultimate Steve]

5 hours ago, JoeSchmuckatelli said:

Question is - how much is the cost of expendable second stages?  Like, cool factor aside, is Starship actually necessary? 

Can we get a lot more weight to the moon and Mars now using traditional-style upper and payload staging ideas matched to the size Booster now allows? 

Or do we really need Starship to work, too? 

(is it a nice to have or a need to have?) 

Sure, you can hurl a decent amount of mass to Mars with an expendable variant. Maybe up to 100 tons in a single lanuch if fairly optimistic numbers are used. However (assuming the goal is humans to mars) then you need a Mars lander, which needs a heat shield, RCS, engines, fuel tanks, guidance systems, power systems... Possibly aero surfaces too. Then you'll need a habitat for the crew, requiring a large pressurized volume,  with enough space and power for life support systems, airlocks, elevators, and cargo... Huh. That sounds an awful lot like what you would do for a reusable LEO system.

So the question now is "Why don't they bother making a custom lander for all of that stuff and skip it for LEO?" And the answer is because they are aiming for an out of the park home run, however wise or unwise that is. They don't want to get to Mars once, they want to make it affordable,  pretty much necessitating reusability and orbital refilling and commonality between the Mars vehicle and their other vehicles.

If the goal is payload to Mars per launch, yes, an expendable upper stage on modern-ish Super Heavy is absolutely the play, likely with a further third stage on top of that. The targets they appear to be aiming for are payload to Mars per dollar, and per-pad/booster/ship throughput.

Now as for the Moon. You run into a lot of the same problems as Mars - You can get ~100 tons to TLI depending on what numbers you assume. Then you need to at that point have a vehicle with engines, fuel tanks, navigation, power...

Though sticking with Starship is less solid than it is for the Mars example. Starship is very much not a Lunar optimized architecture and it shows. It was picked as it reused a lot of effort from internal SpaceX projects they were self funding, and it could therefore be shoehorned into the role of a Moon lander for a lower cost than clean sheet designs. I wonder if SpaceX will ever consider a ground up Lunar optimized architecture. It would likely look quite different from the existing vehicle.

[Flavio hc16]

9 hours ago, tater said:

Plus side is FTS seems to have been very effective vs previous use—which might be something interesting to look at per something Scott Manley posted. It might be worth looking into the descent of one, giant piece of debris, vs thousands of smaller chunks. When FTS was triggered by humans, this is harder to do, but when the computer does it, it could certainly have parameters to decide when/if to open the vehicle. If the current trajectory puts it into empty ocean, let it stay intact, if the trajectory might be concerning, disassemble it. It's actually a complex decision which would be best, a far lower chance of being hit by an intact SS, or a shotgun blast of birdshot with a higher % chance of a hit that does far less damage.

This is something that should get talked more IMHO. If the trajectory isn't over populated areas, let the ship remain intact and glide/bellyflop for as long as possible so that it has less energy and there is less chance it hits something, it would be also easier to avoid.

 

Ofc if it is falling over risky areas, blow it up, it better to have a lot of debris than a Rods from Gods type situation with a 150/200 tons meteor.

Edited 11 hours ago by Flavio hc16
Grammar

[farmerben]

Why did the upper stage blow?  Was it a heat shield -  reentry failure?

[darthgently]

5 minutes ago, farmerben said:

Why did the upper stage blow?  Was it a heat shield -  reentry failure?

 

[Deddly]

11 hours ago, GuessingEveryDay said:

  

Hmm, maybe they accidentally borrowed a few faulty Cybertruck motors from Austin? There was a Cybertruck that blew up in Las Vegas.

That explosion was fireworks and a very tragic event.

[darthgently]

Related

 

[K^2]

10 hours ago, JoeSchmuckatelli said:

Two experimental rockets - both huger than anything else that has flown since Apollo... Both having had some measure of success?  Booster catch is amazing and SX potentially having a competitor for heavy lift - plus potential size of future science missions?

My concern is that, based purely on preliminary, the part that failed is not related to systems that have been changed for this flight. The failure happened due to insufficient safety margin on systems that have already passed the tests. And as a consequence, some of the new changes still need to be first-tested on the next flight on top of things that need to be improved for the parts that failed. Technical debt has gone up, not down, as an outcome of this flight.

There is a part of the design process where you move fast and break things. But you have to ramp it down gradually. You're not going to arrive at a working model by changing everything every time. You have to arrive at smaller and smaller changes as time goes on. Sometimes, that means flying with something imperfect knowing it will work well enough and get the mission to results. This is something that all good engineers understand, and something we've seen with Falcon's design process. They've flown older engine configs when they were itching to test new ones, because there were other flight systems that had to be checked first.

I'm not seeing that with Starship. Now, maybe, it's still very far away from completion. Maybe nobody expects it to even remotely reliably until flight 100-something, and I'm expecting too much consistency from flight 7, and SpaceX is happy to burn $100M per flight to keep doing these tests where they overhaul multiple major systems for each flight. But that's not congruent with the promises that SpaceX is making on the schedule. And it sounds like the team's under pressure to test more things in every flight precisely because management is trying to cut cost by flying fewer tests. Which is, predictably, backfiring.

And even that isn't a huge deal if all that happens is that SpaceX burns more money. But we've seen how self-driving on Tesla was handled. The progress was slow, and instead of that resulting in more tests, the company pushed a raw product around the safety checks that should have prevented it. Hopefully, I'm wrong here, but it sounds like SpaceX is making all the same mistakes that Boeing has been, from how they cut corners, to how they handle tests and safety, except that SpaceX now has an ability to bully its project through by using the gov't connections leverage, regardless of the safety in ways that even Boeing couldn't.

 

If that is the case, this largest rocket might also turn into the largest disaster with loss of human life.

 

Maybe I'm being too pessimistic here. I am confident that the Starship project is not in as good of a shape as the PR tries to show it, but some delays and overruns aren't the worst thing in the world - so long as appropriate steps are taken when it starts to become unsafe. Given how close the debris track came with threatening a few airliners this time, hopefully, we'll see FAA take steps to increase the safety in the future by requiring that the airspace is properly cleared. That will put additional costs and constraints on SpaceX. If the SpaceX plays along - good. They're taking responsibility and eating the costs. If not, and they bully FAA into allowing the future launches to continue putting passenger flights at risk instead, then we should all start being way, way more concerned about how SpaceX is handling the Starship project.

 

8 hours ago, tater said:

They have no need to "clamp down," the point of a mishap/anomaly investigation is to establish cause, and subsequent changes to mitigate. As has happened with other investigations, since the FAA is not in fact qualified to do much of either of those things for spacecraft, SpaceX will in fact drive the efforts. Present the problems observed, causes, and planned mitigations. They already seem to have the cause.

FAA's investigation shouldn't be into why the rocket failed. Rockets do that sometimes. It's into why airliners managed to make it so close to the debris track. The warning to traffic was only given for the area immediately around the launch site, presumably, because the rocket was above relevant flight levels. That's fine if you have a well-established rocket with known failure characteristics. It's irresponsible if you're flying an experimental rocket that may fail in novel ways, like what just happened.

Clearly, the simplified procedures were some sort of an agreement with FAA that SpaceX takes responsibility for keeping the launches safe to air traffic. That didn't happen. FAA must clamp down on that. It is part of the agency's direct responsibility.

And yes, if that doesn't happen, we should be worried about influence of corporate interests over regulatory agency, because that's putting all of us at risk. Especially in light of the Boeing's recent failures on that front.

Edited 9 hours ago by K^2

[RCgothic]

Scott Manley thinks the explosion was FTC activation 2-3 minutes after loss of telemetry, on automated detection of deviation from flight corridor.

He thinks the FTC was uncalled for in this instance, and only had the effect of spreading the debris over a larger area. Luckily the ship was entering the atmosphere at the time. If FTC detonation had occured in space on an upward trajectory the debris field could have been extremely large.

Potentially Starship could have attempted to glide to a pre-programmed safe splashdown, (varying depending on flight stage) although this may not have been possible with a loss of attitude control.

All this counter-balanced against the risk of a large un-FTC'd chunk surviving an uncontrolled re-entry.

[Lukaszenko]

Not really sure why everyone's freaking out here. Yeah it exploded, yeah it's not ideal, but I don't see how it created a dangerous situation, and I don't see how it goes outside of SpaceX's development philosophy, which seems have to been working out so far. It was after all a test, and even operational Falcon 9s failed on occasion, trying to stick a landing or otherwise

Edited 7 hours ago by Lukaszenko