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Re: Astronomy and Space
Posted: Sat Apr 22, 2023 5:30 pm
by jimbob
Pishwish wrote: ↑Sat Apr 22, 2023 4:21 pm
Chris Hadfield offers some
perspective. I still wouldn't call it a success, but how can you not be impressed by the maiden launch of what is by far the most powerful rocket ever built? Obviously we will have to wait a while before we know all the facts, but the most likely cause seems to be engine loss due to debris from pad damage. It seems that SpaceX intended to put a water-cooled
plate under the launch mount, but thought that the concrete would withstand a single launch. It may be that the rocket took longer to get of the pad than expected, exposing the concrete to more forces, but I really don't think that the static fire was an adequate means of determining resilience. As for stage separation, it is unlikely that that was attempted because the flight control system would have to hit speed and altitude targets, because the engines were still running, and because you can't always rely on the launch commentary to be accurate, it is to some extent scripted.
I have seen claims that installing flame trenches would take 2-3 years (and as much as 7) due to environmental permitting. A deluge system would presumably require some permitting too. I think that Boca Chica is a test/development site, so maybe that's why SpaceX were looking at simpler solutions. As the launch mount took a beating, and some of the storage tanks took some hits, it will probably take more than a couple of months before the next launch at Boca Chica.
Even if a subsequent test launch is successful, SpaceX still has to carry out many more launches to gain confidence in novel technologies/procedures. Will the heat shields work? can the booster and Starship prove reliable enough to be crew-rated?, will the chopsticks catch each rocket?, will low-Earth orbit fuel transfer work? can the rockets be refurbished/refueled fast enough to suit the mission plans?
Brilliant. But he has had at least two years to put in the flame trenches, as he mentioned it in 2020 as possibly being a mistake (paraphrase).
He also learned less than he would have done from a proper set of testing to show that the flame trench was needed (which observers had already spotted and told him).
He got away lightly. Given the damage to the launch pad and the range the debris flew, there could have been a severe incident. And there's plenty of evidence that Musk is very keen to take risks with other people's wealth, property and health.
It looks like he decided to launch on 4/20 (given the cultural implications), rather than when the launch system was ready.
Re: Astronomy and Space
Posted: Sat Apr 22, 2023 5:31 pm
by Grumble
bjn wrote: ↑Sat Apr 22, 2023 5:07 pm
Ouch…
Is that from debris or the blast wave?
Re: Astronomy and Space
Posted: Sat Apr 22, 2023 5:32 pm
by jimbob
bjn wrote: ↑Sat Apr 22, 2023 5:07 pm
Ouch…
what is that showing please?
Re: Astronomy and Space
Posted: Sat Apr 22, 2023 6:47 pm
by insignificant
oops
Re: Astronomy and Space
Posted: Sat Apr 22, 2023 7:24 pm
by Gfamily
jimbob wrote: ↑Sat Apr 22, 2023 5:32 pm
what is that showing please?
Storage containers at the SpaceX launch facility at Boca Chica after the launch.
Re: Astronomy and Space
Posted: Sat Apr 22, 2023 7:39 pm
by Pishwish
These are the storage tanks I mentioned. They mainly store liquid oxygen and nitrogen. They are double walled, except perhaps for one that might be a water tank.
I think the coverage of the problems has been slightly slanted. The "debris" that has fallen on the nearby town is dust, the lumps of concrete that slammed into the sea, the tank farm (?) and the camera van were all within the evacuation area as far as I know. The broken window in the town could have been due to ground shaking or air pressure. Didn't Concorde used to break windows from time to time?
It is also worth mentioning that the rocket that was launched was already obsolescent; SpaceX continues to make changes even as rockets are under construction and has scrapped several examples that became too obsolete. This could explain the eagerness to launch (there are 2 pretty much complete rockets at Bocca Chica).
Re: Astronomy and Space
Posted: Sun Apr 23, 2023 5:11 am
by bjn
Having large lumps of your launch pad slam into critical infrastructure, whether it was in or out of an exclusion zone, means you f.cked up somewhere. So does simply having large lumps of you launch pad become airborne in the first place. The f.ck up looks to have been completely avoidable. Now those next Starships will have to wait a while, possibly a long while, to launch.
Re: Astronomy and Space
Posted: Sun Apr 23, 2023 8:25 am
by TimW
Pishwish wrote: ↑Sat Apr 22, 2023 4:21 pm
... As for stage separation, it is unlikely that that was attempted because the flight control system would have to hit speed and altitude targets, because the engines were still running, and because you can't always rely on the launch commentary to be accurate, it is to some extent scripted.
If it wasn't attempted, why not? Hopefully they won't get a load of opportunities to test emergency separation so it seems odd not to try. Settling for "everyone dies" because the booster was failing is not encouraging.
Re: Astronomy and Space
Posted: Sun Apr 23, 2023 8:41 am
by Sciolus
bjn wrote: ↑Fri Apr 21, 2023 5:59 pm
Apparently they didn't initially want all that as it would need a complex environmental impact statement.
In civilised countries, and also the UK, EIA regulations require assessment of "the risks to human health, cultural heritage or the environment (for example due to accidents or disasters)". No wonder he wanted to avoid that process.
Re: Astronomy and Space
Posted: Sun Apr 23, 2023 8:54 am
by EACLucifer
Pishwish wrote: ↑Sat Apr 22, 2023 7:39 pm
These are the storage tanks I mentioned. They mainly store liquid oxygen and nitrogen. They are double walled, except perhaps for one that might be a water tank.
I think the coverage of the problems has been slightly slanted. The "debris" that has fallen on the nearby town is dust, the lumps of concrete that slammed into the sea, the tank farm (?) and the camera van were all within the evacuation area as far as I know.
There wasn't meant to be any debris raining down on a nearby town. Things did not go as they were meant to. They wouldn't have had to have gone very differently for the debris to have been a lot more damaging. In addition, the debris knocked out several engines. If it had knocked out more, especially if they had mostly been on one side, the rocket itself would have been a hazard to that nearby town.
There are good engineers at Space X, but this was a serious f.ckup that could have become catastrophic had things only been a little different, and it appears that's due to cost cutting due to the utter bellend of a CEO, and perhaps a desire to rush to launch because of his pathetic, childish obsession with cannabis memes.
Re: Astronomy and Space
Posted: Sun Apr 23, 2023 1:29 pm
by dyqik
Dust is a significant health hazard, and can damage infrastructure.
Re: Astronomy and Space
Posted: Sun Apr 23, 2023 6:26 pm
by bjn
New rockets blow up, often before they even leave the ground. It takes time and repeated effort to sort all the unknowns out (both know and unknown ones). Shotwell and her team at SpaceX have proven with the Falcon 9 that they can make a reliable reusable launch system. However quite a few of those went boom in the process of getting there. So it is not unreasonable for the first of the SpaceX’s new generation of rockets to fail, in fact it should probably be expected, but if you learn from that failure something is gained. Also, the degree of instrumentation on modern rockets gives you a huge amount of information to dig through to analyse failures or spot potential problems, way more than a Saturn V say. That allows you to learn and iterate faster than before. So the thing going boom is not a biggy, though if it would have been nice to get right the first time.
What was stupid is building a substandard launch stand that has the potential to cause your rocket to catastrophically fail and that this fact was well known.
Re: Astronomy and Space
Posted: Sun Apr 23, 2023 7:07 pm
by Gfamily
I'm not sure if I've posted this here already, but I found this (long) blog post by Everyday Astronaut very informative on rocket engine design - and in particular, the features of the Raptor rocket engine design.
https://everydayastronaut.com/raptor-engine/
Re: Astronomy and Space
Posted: Sun Apr 23, 2023 8:06 pm
by Pishwish
TimW wrote: ↑Sun Apr 23, 2023 8:25 am
Pishwish wrote: ↑Sat Apr 22, 2023 4:21 pm
... As for stage separation, it is unlikely that that was attempted because the flight control system would have to hit speed and altitude targets, because the engines were still running, and because you can't always rely on the launch commentary to be accurate, it is to some extent scripted.
If it wasn't attempted, why not? Hopefully they won't get a load of opportunities to test emergency separation so it seems odd not to try. Settling for "everyone dies" because the booster was failing is not encouraging.
I'm not an expert on this, my "knowledge" is mainly half-remembered stuff from NASAspaceflight forums. Normally a rocket is blown up if it strays out of its expected flight corridor, this prevents the rocket from crashing into populated areas. (I am not sure if this is autonomous, flight control decisions are generally pre-programmed). As for emergency flight separation, that is something that would have its own specific
test flight. The sort of all-up testing that was done during the Apollo program is not typical and was seen as a bit risky at the time; there is a lot to be said for not testing too many things in a single test flight. I think the main goal of this test was the booster's first flight. They could have just put a lump of metal on top of the booster and launched it, but why not add a Starship stage that would otherwise have to be scrapped? The staging, flight, and reentry of the Starship stage would have been great to see, though.
Settling for "everyone dies" because the booster was failing is not encouraging
Look, I get that people don't like Musk, but this is just nonsense.
However, I do not know if SpaceX or the authorities have properly assessed the effects of a fully fueled Superheavy explosion. The
explosion of the N1 rocket in 1969 was one of the largest non-nuclear explosions in history. (The Pepcon disaster, also on that list, was also spaceflight related, in that the Challenger disaster caused that company to stockpile solid rocket fuel during the grounding of the Shuttle fleet). It may be that a LOX and liquid methane explosion (deflagration?) might be less explosive than these examples (the activation of the flight termination system in this flight would seem to suggest this).
Re: Astronomy and Space
Posted: Mon Apr 24, 2023 6:06 am
by jimbob
Via ISF
https://www.youtube.com/watch?v=wmCy7UoGIuE
Video of the local damage.
Also some worrying observations, like it taking a minute and 19 seconds from when the rocket started tumbling to it being destroyed
(Just over 8 mins into the video)
Re: Astronomy and Space
Posted: Mon Apr 24, 2023 3:44 pm
by Gfamily
Did anyone else see the aurorae last night?
We are at a Star Party in the Bannau Brycheineiog and some people could see them naked eye - I could only pick them up on the camera.
Re: Astronomy and Space
Posted: Thu Apr 27, 2023 12:42 pm
by FlammableFlower
NASA wants you to listen to space:
https://listen.spacescience.org/
Re: Astronomy and Space
Posted: Thu Apr 27, 2023 3:18 pm
by monkey
Are they testing the "no one can hear you scream" hypothesis?
More seriously, isn't this the sort of thing machine learning is supposed to be good at? Is this really just the learning bit?
Re: Astronomy and Space
Posted: Sun Apr 30, 2023 2:15 pm
by bjn
Thorough take down of the Starship launch.
https://www.youtube.com/watch?v=ErDuVomNd9M
Re: Astronomy and Space
Posted: Sun Apr 30, 2023 8:31 pm
by jimbob
Nice video and I notice the author quotes his predictions from before the launch, and compares them to what happened.
I wasn't following this, but I am seriously unimpressed with the approach to engineering at
SpaceX companies where Musk calls the shots. Yes, they might move fast and break things, but a lot of the time, they're moving fast to achieve something that has little benefit for their goal.
Re: Astronomy and Space
Posted: Sun Apr 30, 2023 8:52 pm
by bjn
SpaceX did well with the Falcon family of rockets, but that mainly seems to be Glynn Shotwell running the show and handling Musk so as not to f.ck it up. When Musk gets his micro managing 2p in is when it usually goes wrong, such as the launch strand and removing radar from Teslas.
Re: Astronomy and Space
Posted: Sun Apr 30, 2023 9:01 pm
by jimbob
bjn wrote: ↑Sun Apr 30, 2023 8:52 pm
SpaceX did well with the Falcon family of rockets, but that mainly seems to be Glynn Shotwell running the show and handling Musk so as not to f.ck it up. When Musk gets his micro managing 2p in is when it usually goes wrong, such as the launch strand and removing radar from Teslas.
It's Musk trying to be a particularly aggressive engineer and not realising that if you want to move quickly, you don't take needless risks or at least don't put those with marginal benefits on the critical path of the project.
And when Musk does this, he ends up harming other people (and not actually paying the full cost for his decision)
Re: Astronomy and Space
Posted: Sun Apr 30, 2023 9:16 pm
by EACLucifer
jimbob wrote: ↑Sun Apr 30, 2023 9:01 pm
bjn wrote: ↑Sun Apr 30, 2023 8:52 pm
SpaceX did well with the Falcon family of rockets, but that mainly seems to be Glynn Shotwell running the show and handling Musk so as not to f.ck it up. When Musk gets his micro managing 2p in is when it usually goes wrong, such as the launch strand and removing radar from Teslas.
It's Musk trying to be a particularly aggressive engineer and not realising that if you want to move quickly, you don't take needless risks or at least don't put those with marginal benefits on the critical path of the project.
And when Musk does this, he ends up harming other people (and not actually paying the full cost for his decision)
Slow is smooth, smooth is fast.
Re: Astronomy and Space
Posted: Sun Apr 30, 2023 10:02 pm
by jimbob
EACLucifer wrote: ↑Sun Apr 30, 2023 9:16 pm
jimbob wrote: ↑Sun Apr 30, 2023 9:01 pm
bjn wrote: ↑Sun Apr 30, 2023 8:52 pm
SpaceX did well with the Falcon family of rockets, but that mainly seems to be Glynn Shotwell running the show and handling Musk so as not to f.ck it up. When Musk gets his micro managing 2p in is when it usually goes wrong, such as the launch strand and removing radar from Teslas.
It's Musk trying to be a particularly aggressive engineer and not realising that if you want to move quickly, you don't take needless risks or at least don't put those with marginal benefits on the critical path of the project.
And when Musk does this, he ends up harming other people (and not actually paying the full cost for his decision)
Slow is smooth, smooth is fast.
It certainly is if you are doing something complicated where there are lots of dependencies. Prior preparation prevents piss poor performance. And deciding that you'll have a launch pad that had been shown to be marginal at best for a smaller rocket, and which is not necessary for testing the launch is foolhardy
Re: Astronomy and Space
Posted: Sun Apr 30, 2023 10:42 pm
by Pishwish
I wouldn't trust any video by "common sense skeptic," he makes videos with bad-faith arguments written to please an anti-elon audience. This video isn't as bad as his earlier ones on Starship, but why waste time on an unreliable source? (Same goes for any video by Thunderf00t on SpaceX).
Speaking of unreliable sources, Musk gave an interview that I haven't watched but has been summarized in a twitter
thread, these are some excerpts:
"The vehicle's structural margins appear to be better than we expected, as we can tell from the vehicle actually doing somersaults towards the end and still staying intact." ..."The longest item on that is probably requalification of the flight termination system ... it took way too long to rupture the tanks."
Time for AFTS to kick in "was pretty long," about "40 seconds-ish."
..."There were 3 engines that we chose not to start," so that's why Super Heavy booster lifted off with 30 engines, "which is the minimum number of engines."
The 3 engines "didn't explode," but just were not "healthy enough to bring them to full thrust so they were shut down" ."Rocket kept going through T+62 seconds" with the engines continuing to run. Lost thrust vector control at T+85 seconds.
"It was actually good to get this vehicle off the ground because we've made so many improvements" in Super Heavy Booster 9 "and beyond."
"Really just needed to fly this vehicle and then move on to the much improved booster."
"Got pretty close to stage separation ... if we had maintained thrust vector control and throttled up, which we should have ... then we would have made it to staging."
"Definitely don't" expect lunar Starship (under the HLS project) to be the longest lead item for the Artemis III mission.
"We will be the first thing to really be" ready.
there is a transcript halfway down this forum page, the flight termination system problem is more evident:
The longest lead item on that is probably re-qualification of the flight termination system.
Because we did initiate the flight termination system, but it was not enough to...
it took way too long to rupture the tanks.
So we need a basically a much...
we need more detonation cord to lines up the tanks at altitude and ensure that basically the rocket explodes immediately if there's a flight termination is necessary.
So re-qualification of the...
I'm just guessing here that re-qualification of the much longer detonation cord to lines up the rocket in a bad situation is probably the long lead item.
What was the time lag? It was pretty long.
I think it was on the order of 40 seconds-ish.
So quite long.
The yeah, so now the rocket was in a relatively low air density situation.
So the aerodynamic forces that I was experiencing were would be less than if it was at a lower, you know, lower down in the atmosphere.
And so the aerodynamic forces would have, I think, at lower point in the atmosphere aided in the destruction of the vehicle.
And in fact that's kind of what happened when the vehicle got to a low enough altitude that the atmospheric density was enough to cause structural failure.
But I mean this is obviously something that we want to make super sure is solid before proceeding with the next flight.