Total Members Voted: 1034
Voting closed: 07/06/2020 03:20 pm
Quote from: meberbs on 06/02/2020 04:07 pmQuote from: tssp_art on 06/02/2020 03:53 pmSpaceX’s Starship explosion explained by Elon Musk - https://www.teslarati.com/spacex-starship-explosion-explained-elon-musk/Nothing new to see here, just explanation and extrapolation around the single statement we already heard:“What we thought was going to be a minor test of a quick disconnect ended up being a big problem.”I read the article and I saw mentioned that they disconnected and reconnected the QD(quick disconnect). That didn't seem to me to be correct? Anybody?
Quote from: tssp_art on 06/02/2020 03:53 pmSpaceX’s Starship explosion explained by Elon Musk - https://www.teslarati.com/spacex-starship-explosion-explained-elon-musk/Nothing new to see here, just explanation and extrapolation around the single statement we already heard:“What we thought was going to be a minor test of a quick disconnect ended up being a big problem.”
SpaceX’s Starship explosion explained by Elon Musk - https://www.teslarati.com/spacex-starship-explosion-explained-elon-musk/
Quote from: tssp_art on 06/02/2020 03:53 pmSpaceX’s Starship explosion explained by Elon Musk - https://www.teslarati.com/spacex-starship-explosion-explained-elon-musk/As usual Teslarati writes a long article based on a single short phrase tweeted by Musk. There is no additional information in the article - no official information from Spacex and certainly nothing more than has been discussed here at length.
Quote from: fael097 on 06/02/2020 04:20 pmQuote from: samgineer on 06/02/2020 12:20 pmQuote from: Alvian@IDN on 06/02/2020 02:11 amQuote from: bocachicagal on 06/02/2020 12:21 amA two ring high sleeve was put over the dome.Hmm, curious as to the two ring instead of 3. Will this indicates that this is actually another bopper instead of full SN7 to test corrected quick disconnect? Kinda doesn't make sense since there's SN5 & SN6 full-size isn't it? (or will they actually jump the test campaign to SN7 bopper, and keeping the already-assembled SN5 & SN6 for nosecone, flaps (for the latter) and three-engine tests?)What if they will use use lap weld to add stiffness to fairing? Like I illustrated in image below. We saw fairing 5 stack collapse and also they welded in circular stiffeners. It isn't maybe most efficient way how to do, but if it will be sufficient, this is easier to mass produce than weld something inside.they probably just welded stiffeners so it wouldn't collapse again from wind. nosecones #1 and #2 were welded onto single rings for testing, and they used lap welds, although that's probably not enough stiffness for the fairing as that thing should be able to keep its shape unpressurized, and also support the weight of the fwd fins, header tank+lox, and transfer the loads on the fins during reentry.They might pressurize the fairing during fueling LOX header and flight and definitely on reentry. So it has to support static weight of fins and nose cone.
Quote from: samgineer on 06/02/2020 12:20 pmQuote from: Alvian@IDN on 06/02/2020 02:11 amQuote from: bocachicagal on 06/02/2020 12:21 amA two ring high sleeve was put over the dome.Hmm, curious as to the two ring instead of 3. Will this indicates that this is actually another bopper instead of full SN7 to test corrected quick disconnect? Kinda doesn't make sense since there's SN5 & SN6 full-size isn't it? (or will they actually jump the test campaign to SN7 bopper, and keeping the already-assembled SN5 & SN6 for nosecone, flaps (for the latter) and three-engine tests?)What if they will use use lap weld to add stiffness to fairing? Like I illustrated in image below. We saw fairing 5 stack collapse and also they welded in circular stiffeners. It isn't maybe most efficient way how to do, but if it will be sufficient, this is easier to mass produce than weld something inside.they probably just welded stiffeners so it wouldn't collapse again from wind. nosecones #1 and #2 were welded onto single rings for testing, and they used lap welds, although that's probably not enough stiffness for the fairing as that thing should be able to keep its shape unpressurized, and also support the weight of the fwd fins, header tank+lox, and transfer the loads on the fins during reentry.
Quote from: Alvian@IDN on 06/02/2020 02:11 amQuote from: bocachicagal on 06/02/2020 12:21 amA two ring high sleeve was put over the dome.Hmm, curious as to the two ring instead of 3. Will this indicates that this is actually another bopper instead of full SN7 to test corrected quick disconnect? Kinda doesn't make sense since there's SN5 & SN6 full-size isn't it? (or will they actually jump the test campaign to SN7 bopper, and keeping the already-assembled SN5 & SN6 for nosecone, flaps (for the latter) and three-engine tests?)What if they will use use lap weld to add stiffness to fairing? Like I illustrated in image below. We saw fairing 5 stack collapse and also they welded in circular stiffeners. It isn't maybe most efficient way how to do, but if it will be sufficient, this is easier to mass produce than weld something inside.
Quote from: bocachicagal on 06/02/2020 12:21 amA two ring high sleeve was put over the dome.Hmm, curious as to the two ring instead of 3. Will this indicates that this is actually another bopper instead of full SN7 to test corrected quick disconnect? Kinda doesn't make sense since there's SN5 & SN6 full-size isn't it? (or will they actually jump the test campaign to SN7 bopper, and keeping the already-assembled SN5 & SN6 for nosecone, flaps (for the latter) and three-engine tests?)
A two ring high sleeve was put over the dome.
Quote from: rsdavis9 on 06/02/2020 04:24 pmQuote from: fael097 on 06/02/2020 04:20 pmQuote from: samgineer on 06/02/2020 12:20 pmQuote from: Alvian@IDN on 06/02/2020 02:11 amQuote from: bocachicagal on 06/02/2020 12:21 amA two ring high sleeve was put over the dome.Hmm, curious as to the two ring instead of 3. Will this indicates that this is actually another bopper instead of full SN7 to test corrected quick disconnect? Kinda doesn't make sense since there's SN5 & SN6 full-size isn't it? (or will they actually jump the test campaign to SN7 bopper, and keeping the already-assembled SN5 & SN6 for nosecone, flaps (for the latter) and three-engine tests?)What if they will use use lap weld to add stiffness to fairing? Like I illustrated in image below. We saw fairing 5 stack collapse and also they welded in circular stiffeners. It isn't maybe most efficient way how to do, but if it will be sufficient, this is easier to mass produce than weld something inside.they probably just welded stiffeners so it wouldn't collapse again from wind. nosecones #1 and #2 were welded onto single rings for testing, and they used lap welds, although that's probably not enough stiffness for the fairing as that thing should be able to keep its shape unpressurized, and also support the weight of the fwd fins, header tank+lox, and transfer the loads on the fins during reentry.They might pressurize the fairing during fueling LOX header and flight and definitely on reentry. So it has to support static weight of fins and nose cone.Crew variant should have the crew cabin pressurized to human acceptable levels, which means equal to ambient sea level pressure (or even lower than 1 bar if similar to the cabin of an airliner). That doesn't increase structural integrity. I should also mention that crew cabin volume isn't equal to the entire volume of the fairing, and some areas might remain unpressurized.Therefore, fairing structural integrity will rely entirely on its own shape/thickness and likely additional support structures, and not on pressure like the tanks.Also, there's no need for the cargo or tanker variants to have a pressurized fairing, nitrogen is heavy, could easily weigh more than a tonne when filling the entire fairing, and helium is expensive.
Pressure does increase structural integrity. Makes it less likely to buckle.
Quote from: rsdavis9 on 06/02/2020 05:20 pmPressure does increase structural integrity. Makes it less likely to buckle.
Quote from: fael097 on 06/02/2020 05:26 pmQuote from: rsdavis9 on 06/02/2020 05:20 pmPressure does increase structural integrity. Makes it less likely to buckle. A structure pressurized to one atmosphere should have higher structural strength in a vacuum than one that's not pressurized, what am I missing?
Quote from: Thunderscreech on 06/02/2020 05:29 pmQuote from: fael097 on 06/02/2020 05:26 pmQuote from: rsdavis9 on 06/02/2020 05:20 pmPressure does increase structural integrity. Makes it less likely to buckle. A structure pressurized to one atmosphere should have higher structural strength in a vacuum than one that's not pressurized, what am I missing? I think you're missing the fact that they have to manufacture, load, board and fuel it on earth.
Interview with Hans Königsmann (mostly about crew dragon) about plans for Starship Schedulehttps://www.spiegel.de/wissenschaft/weltall/spacex-chefingenieur-zum-stat-des-crew-dragon-wilde-party-kommt-noch-a-998ff592-1071-44d5-9972-ff2b73ec8fb6...
SPIEGEL: In Texas, SpaceX is already building the next largest spaceship, the "Starship". This is also supposed to be suitable for trips to the moon and Mars. But another prototype has just been destroyed during a test. Is the program still on course?Königsmann: The program is clearly separated from our work with the "Crew Dragon". It's all about research. We want to see how far you can go with certain things. The goal is to learn as much as possible in a short time. If there are setbacks in the process, that naturally slows us down. But that is part of it.SPIEGEL: So when does the Starship fly for the first time?Königsmann: I expect the first test flights at an altitude of, let's say, 150 metres in the coming weeks. We'll do that a few times. If everything works out, we want to enter Earth orbit at the end of the year. But maybe it will take a little longer.SPIEGEL: SpaceX is to deliver technology to Nasa for the moon landing. Will it really be possible to have an American on the lunar surface by 2024?Königsmann: That is ambitious and won't be easy. But if we get the appropriate resources, it is quite possible.SPIEGEL: You once said in an interview that you would feel too old for a Mars flight. Would you at least have ambitions for the moon?Königsmann: I'd like to take back what I said about Mars. If it goes quickly, maybe I'm not too old after all. And I could also imagine the moon.Translated with www.DeepL.com/Translator (free version)
Quote from: Magical Trevor on 06/01/2020 08:29 pmHandrails have appeared on the mystery fabrications from a couple of weeks ago; work platforms/walkways, then?[zubenelgenubi: deleted embedded image]IF you look at how there are 2 platforms attached one on top of the next but with the top one extended forward, it's clear they're nose cone work platforms.
Handrails have appeared on the mystery fabrications from a couple of weeks ago; work platforms/walkways, then?[zubenelgenubi: deleted embedded image]
Quote from: fael097 on 06/02/2020 05:37 pmQuote from: Thunderscreech on 06/02/2020 05:29 pmQuote from: fael097 on 06/02/2020 05:26 pmQuote from: rsdavis9 on 06/02/2020 05:20 pmPressure does increase structural integrity. Makes it less likely to buckle. A structure pressurized to one atmosphere should have higher structural strength in a vacuum than one that's not pressurized, what am I missing? I think you're missing the fact that they have to manufacture, load, board and fuel it on earth.And how does this contradict the fact that it becomes even stronger when pressurized?
Quote from: rsdavis9 on 06/02/2020 04:13 pmQuote from: meberbs on 06/02/2020 04:07 pmQuote from: tssp_art on 06/02/2020 03:53 pmSpaceX’s Starship explosion explained by Elon Musk - https://www.teslarati.com/spacex-starship-explosion-explained-elon-musk/Nothing new to see here, just explanation and extrapolation around the single statement we already heard:“What we thought was going to be a minor test of a quick disconnect ended up being a big problem.”I read the article and I saw mentioned that they disconnected and reconnected the QD(quick disconnect). That didn't seem to me to be correct? Anybody?It's a reasonable assumption. A QD only has those two fundamental actions. And it had to have been connected for the fueling that preceded the static fire. So the simplest test from that partially-fueled state is a disconnect, followed by a reconnect for detanking. The timing of the test also points to that. SX would likely want to do one or more maximum fidelity tests of the QD before the hop.
...Normally a quick release umbilical would not need to be designed to reattach under pressure. It only detaches as the rocket leaves the pad and is attached only to an empty rocket when it can presumably be done manually in safety. A mechanism intended for automatic attachment under pressure implies they are getting ahead and developing a combination mechanism that can also operate for on-orbit refuelling.
Quote from: Lars-J on 06/02/2020 05:50 pmQuote from: fael097 on 06/02/2020 05:37 pmQuote from: Thunderscreech on 06/02/2020 05:29 pmQuote from: fael097 on 06/02/2020 05:26 pmQuote from: rsdavis9 on 06/02/2020 05:20 pmPressure does increase structural integrity. Makes it less likely to buckle. A structure pressurized to one atmosphere should have higher structural strength in a vacuum than one that's not pressurized, what am I missing? I think you're missing the fact that they have to manufacture, load, board and fuel it on earth.And how does this contradict the fact that it becomes even stronger when pressurized? He's claiming the fairing won't be pressurized on the pad. I'm not convinced myself, since that skin is pretty floppy. I have to think they'll pressurize it some on the pad for launch. It's not like 1 1/2 bar absolute inside will do anything but pop a few ears.
For cargo models, they could add internal aluminium stiffeners (weld steel tabs to hull, rivet Al rods to them) in a way that doesn't interfere with cargo capacity and won't remove too much payload margin
Quote from: Slothman on 06/02/2020 07:30 pmFor cargo models, they could add internal aluminium stiffeners (weld steel tabs to hull, rivet Al rods to them) in a way that doesn't interfere with cargo capacity and won't remove too much payload marginUsing Al would require the tabs to be pretty long or the rivet joints to have insulation. One of the points of stainless is that it can take much more reentry heat than Al.
That fairing (or parts of it) have to be depressurized for cargo load and unload for some periods on the pad (or Moon, Mars).If not, than all loading ops have to be done through airlocks.
The idea that the QD is indeed a Quick Disconnect (under pressure) but is only intended to reconnect without the pressure of a partially filled tank might point to a process error or human error as the cause of this failure.