Astronomy and Space

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monkey
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Re: Astronomy and Space

Post by monkey » Thu Apr 20, 2023 7:30 pm

Splodey.

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TimW
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Re: Astronomy and Space

Post by TimW » Fri Apr 21, 2023 6:02 am

The fact that separation failed doesn't look good. I'm assuming that separation is essential to crew survival, and would therefore be designed with appropriate failsafes so that if it goes wrong then a backup mechanism enables the Starship to still fly a bit while the booster is sacrificed. Apparently not.

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Re: Astronomy and Space

Post by EACLucifer » Fri Apr 21, 2023 11:50 am

TimW wrote:
Fri Apr 21, 2023 6:02 am
The fact that separation failed doesn't look good. I'm assuming that separation is essential to crew survival, and would therefore be designed with appropriate failsafes so that if it goes wrong then a backup mechanism enables the Starship to still fly a bit while the booster is sacrificed. Apparently not.
There's that, and there's also the fact that the pictures all seem to show some of the engines not functional. I'd have thought getting the engines working reliably is something one would do before launch.

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Re: Astronomy and Space

Post by dyqik » Fri Apr 21, 2023 12:46 pm

TimW wrote:
Fri Apr 21, 2023 6:02 am
The fact that separation failed doesn't look good. I'm assuming that separation is essential to crew survival, and would therefore be designed with appropriate failsafes so that if it goes wrong then a backup mechanism enables the Starship to still fly a bit while the booster is sacrificed. Apparently not.
I vaguely saw in passing that tumbling started due to engine failures before separation was attempted. If that was the case, it would be sufficient to prevent a clean separation. And tumbling is likely to lead to fatal consequences of some kind.

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Re: Astronomy and Space

Post by dyqik » Fri Apr 21, 2023 12:50 pm

EACLucifer wrote:
Fri Apr 21, 2023 11:50 am
TimW wrote:
Fri Apr 21, 2023 6:02 am
The fact that separation failed doesn't look good. I'm assuming that separation is essential to crew survival, and would therefore be designed with appropriate failsafes so that if it goes wrong then a backup mechanism enables the Starship to still fly a bit while the booster is sacrificed. Apparently not.
There's that, and there's also the fact that the pictures all seem to show some of the engines not functional. I'd have thought getting the engines working reliably is something one would do before launch.
In this case, I think the launch was intended to prove that they could get sufficient engines functional to clear the launch tower. Which it did. So this was really a test of and a step towards getting the engines working reliably more than anything else. Anything beyond that was a "success oriented schedule", I think.

The more sensible people at SpaceX have said several times that if they aren't losing some fraction of test rockets, they aren't pushing hard enough. Which is a strategy you can take if you aren't a government entity.

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Re: Astronomy and Space

Post by TimW » Fri Apr 21, 2023 1:14 pm

dyqik wrote:
Fri Apr 21, 2023 12:46 pm
I vaguely saw in passing that tumbling started due to engine failures before separation was attempted. If that was the case, it would be sufficient to prevent a clean separation. And tumbling is likely to lead to fatal consequences of some kind.
The last bit of in-house commentary before announcing something was wrong was "Beginning the flip for stage separation". The turn is supposed to be what propels the stages apart, I gather.

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Re: Astronomy and Space

Post by TimW » Fri Apr 21, 2023 1:38 pm

This article from 2021 wrote:Sidestepping decades of precedent, Musk says that Starship will have no separation mechanism at all. Instead, at some point during the design or testing process, Musk decided that a separation mechanism was entirely superfluous and that the same effect could be more or less replicated by using existing systems on Super Heavy. By using the booster’s gimballing Raptor engines to impart a small but significant rotation on the rocket moments before separation, Super Heavy could effectively flick Starship away from it – a bit like how SpaceX currently deploys Starlink satellites from Falcon by spinning the upper stage end over end and letting the spacecraft just float away thanks to centripetal forces.

Because Starship is something like five times heavier than Super Heavy at stage separation, the ship would effectively float away from the booster in a straight and stable line, use cold gas thrusters to settle its propellant, and ignite its six Raptor engines to head to orbit. In return for the slightly unorthodox deployment profile, if this new approach works, SpaceX can entirely preclude the development of a pusher/spring system capable of pushing a ~1300 ton Starship away from Super Heavy. That approach is possible on Starship in large part because the ship’s six Raptor engines are completely tucked away inside a skirt, meaning that there is zero chance of nozzles being damaged by impacting the booster interstage.
Well that's lovely.

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Re: Astronomy and Space

Post by jimbob » Fri Apr 21, 2023 1:50 pm

TimW wrote:
Fri Apr 21, 2023 1:38 pm
This article from 2021 wrote:Sidestepping decades of precedent, Musk says that Starship will have no separation mechanism at all. Instead, at some point during the design or testing process, Musk decided that a separation mechanism was entirely superfluous and that the same effect could be more or less replicated by using existing systems on Super Heavy. By using the booster’s gimballing Raptor engines to impart a small but significant rotation on the rocket moments before separation, Super Heavy could effectively flick Starship away from it – a bit like how SpaceX currently deploys Starlink satellites from Falcon by spinning the upper stage end over end and letting the spacecraft just float away thanks to centripetal forces.

Because Starship is something like five times heavier than Super Heavy at stage separation, the ship would effectively float away from the booster in a straight and stable line, use cold gas thrusters to settle its propellant, and ignite its six Raptor engines to head to orbit. In return for the slightly unorthodox deployment profile, if this new approach works, SpaceX can entirely preclude the development of a pusher/spring system capable of pushing a ~1300 ton Starship away from Super Heavy. That approach is possible on Starship in large part because the ship’s six Raptor engines are completely tucked away inside a skirt, meaning that there is zero chance of nozzles being damaged by impacting the booster interstage.
Well that's lovely.
Um.

Musk doesn't seem to be the engineer he thinks he is. That might have made a decent backup for a more conventional separation system I'd have thought
Have you considered stupidity as an explanation

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Re: Astronomy and Space

Post by bjn » Fri Apr 21, 2023 5:59 pm

The base of the launch stand was massively eroded, with chunks of concrete being blasted all over the place. It looks like that may have done some damage to several of the engines in the process, which were not firing. There was no flame trench and the active cooling system (ie: spraying lots and lots of water) was only recently fitted, it all appears to have been inadequate. Apparently they didn't initially want all that as it would need a complex environmental impact statement.

Crater at the base of the tower...

Image

Some engines not burning...
Screenshot 2023-04-21 at 18.57.19.png
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Re: Astronomy and Space

Post by EACLucifer » Fri Apr 21, 2023 8:20 pm

bjn wrote:
Fri Apr 21, 2023 5:59 pm
The base of the launch stand was massively eroded, with chunks of concrete being blasted all over the place. It looks like that may have done some damage to several of the engines in the process, which were not firing. There was no flame trench and the active cooling system (ie: spraying lots and lots of water) was only recently fitted, it all appears to have been inadequate. Apparently they didn't initially want all that as it would need a complex environmental impact statement.

Crater at the base of the tower...

Image

Some engines not burning...
Screenshot 2023-04-21 at 18.57.19.png
That makes more sense than the engines just being unreliable. Even Musk would probably be unable to stop decent engineers from testing the engines thoroughly before using the design. On the other hand cutting corners with the launch pad to the point the whole thing fails in a way that would have been unavoidably fatal to anyone on board due to corners cut with the separation mechanism seems very Musk...

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Re: Astronomy and Space

Post by EACLucifer » Fri Apr 21, 2023 8:34 pm

If only someone had told him...oh wait

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Re: Astronomy and Space

Post by dyqik » Fri Apr 21, 2023 9:25 pm

Related:

https://twitter.com/marinakoren/status/ ... YCnMw&s=19

SpaceX redistributed the launch pad over a nearby town.

Hopefully this is a gifted version of the New York Times article

SpaceX’s Starship Kicked Up a Dust Cloud, Leaving Texans With a Mess https://www.nytimes.com/2023/04/21/us/s ... Rx7izg0XDs
Last edited by dyqik on Fri Apr 21, 2023 9:27 pm, edited 1 time in total.

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Re: Astronomy and Space

Post by dyqik » Fri Apr 21, 2023 9:27 pm

Ignore
Last edited by dyqik on Fri Apr 21, 2023 9:27 pm, edited 1 time in total.

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Re: Astronomy and Space

Post by dyqik » Fri Apr 21, 2023 9:27 pm

Ignore

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Re: Astronomy and Space

Post by EACLucifer » Fri Apr 21, 2023 9:41 pm

dyqik wrote:
Fri Apr 21, 2023 9:25 pm
Related:

https://twitter.com/marinakoren/status/ ... YCnMw&s=19

SpaceX redistributed the launch pad over a nearby town.

Hopefully this is a gifted version of the New York Times article

SpaceX’s Starship Kicked Up a Dust Cloud, Leaving Texans With a Mess https://www.nytimes.com/2023/04/21/us/s ... Rx7izg0XDs
I can't be the only one bothered that a rocket that large was launched with that little care regarding safety that near people, can I?

It also looks like Space X have set back their schedule somewhat. I guess move fast and break things doesn't work so well when you break the things needed to move fast.

That said, Musk was claiming they would have tourist flights ludicrously soon, so it's quite clear that that claimed schedule was, like a lot of things Musk claims are in the pipeline, a straightforward f.cking lie from a pathetic lying fraud.

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Re: Astronomy and Space

Post by jimbob » Fri Apr 21, 2023 10:10 pm

EACLucifer wrote:
Fri Apr 21, 2023 9:41 pm
dyqik wrote:
Fri Apr 21, 2023 9:25 pm
Related:

https://twitter.com/marinakoren/status/ ... YCnMw&s=19

SpaceX redistributed the launch pad over a nearby town.

Hopefully this is a gifted version of the New York Times article

SpaceX’s Starship Kicked Up a Dust Cloud, Leaving Texans With a Mess https://www.nytimes.com/2023/04/21/us/s ... Rx7izg0XDs
I can't be the only one bothered that a rocket that large was launched with that little care regarding safety that near people, can I?

It also looks like Space X have set back their schedule somewhat. I guess move fast and break things doesn't work so well when you break the things needed to move fast.

That said, Musk was claiming they would have tourist flights ludicrously soon, so it's quite clear that that claimed schedule was, like a lot of things Musk claims are in the pipeline, a straightforward f.cking lie from a pathetic lying fraud.
Yup, and so very Musk.

Of you want to get a new, untested technology released quickly, you don't cut corners where you don't have to. You release the technology as fast as you can, using tried technology combinations wherever possible and once you have it working, you look at how to make it (or its successor) cheaper.


And there have been lots of tweets since his 2020 tweet with people pointing out the erosion of the concrete from far smaller rockets. So he was using something that was proven inadequate
Have you considered stupidity as an explanation

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Re: Astronomy and Space

Post by jimbob » Fri Apr 21, 2023 10:28 pm

EACLucifer wrote:
Fri Apr 21, 2023 9:41 pm
dyqik wrote:
Fri Apr 21, 2023 9:25 pm
Related:

https://twitter.com/marinakoren/status/ ... YCnMw&s=19

SpaceX redistributed the launch pad over a nearby town.

Hopefully this is a gifted version of the New York Times article

SpaceX’s Starship Kicked Up a Dust Cloud, Leaving Texans With a Mess https://www.nytimes.com/2023/04/21/us/s ... Rx7izg0XDs
I can't be the only one bothered that a rocket that large was launched with that little care regarding safety that near people, can I?

It also looks like Space X have set back their schedule somewhat. I guess move fast and break things doesn't work so well when you break the things needed to move fast.

That said, Musk was claiming they would have tourist flights ludicrously soon, so it's quite clear that that claimed schedule was, like a lot of things Musk claims are in the pipeline, a straightforward f.cking lie from a pathetic lying fraud.
Also, given the debris did damage houses, and the nature of the debris, there must have been a non-negligible risk of that causing the rocket to explode on launch.

It should give investors pause for thought. A very public demonstration of recklessness and potential liabilities.
Have you considered stupidity as an explanation

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Re: Astronomy and Space

Post by dyqik » Sat Apr 22, 2023 1:05 am

The lack of noise suppression apparently knocked out at least five engines at launch.

Friday I was sat at a table with a new colleague, who used to work on sound suppression for launches at NASA Marshall Spaceflight Center. Water suppression is worth a 75% reduction in vibration experienced by payloads at the top of the rocket, and presumably much more at the bottom of the rocket.

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Re: Astronomy and Space

Post by Grumble » Sat Apr 22, 2023 6:18 am

dyqik wrote:
Sat Apr 22, 2023 1:05 am
The lack of noise suppression apparently knocked out at least five engines at launch.

Friday I was sat at a table with a new colleague, who used to work on sound suppression for launches at NASA Marshall Spaceflight Center. Water suppression is worth a 75% reduction in vibration experienced by payloads at the top of the rocket, and presumably much more at the bottom of the rocket.
Intuitively I would have thought less vibration at the bottom, because the top is effectively at the end of a lever. Top stories of towers sway more than the bottom.
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Re: Astronomy and Space

Post by bjn » Sat Apr 22, 2023 7:02 am

Grumble wrote:
Sat Apr 22, 2023 6:18 am
dyqik wrote:
Sat Apr 22, 2023 1:05 am
The lack of noise suppression apparently knocked out at least five engines at launch.

Friday I was sat at a table with a new colleague, who used to work on sound suppression for launches at NASA Marshall Spaceflight Center. Water suppression is worth a 75% reduction in vibration experienced by payloads at the top of the rocket, and presumably much more at the bottom of the rocket.
Intuitively I would have thought less vibration at the bottom, because the top is effectively at the end of a lever. Top stories of towers sway more than the bottom.
I'd guess that you'd have higher frequencies at the bottom which would be damped out somewhat by the time they get to the top.

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Re: Astronomy and Space

Post by jimbob » Sat Apr 22, 2023 8:44 am

dyqik wrote:
Sat Apr 22, 2023 1:05 am
The lack of noise suppression apparently knocked out at least five engines at launch.

Friday I was sat at a table with a new colleague, who used to work on sound suppression for launches at NASA Marshall Spaceflight Center. Water suppression is worth a 75% reduction in vibration experienced by payloads at the top of the rocket, and presumably much more at the bottom of the rocket.
This sounds like another predicted risk on something separate from the key technology, but which Musk decided to gamble on being fine if removed.


There seems to be a problem with the approach to risk of organisations where Musk takes decisions. See also Tesla's removal of radar and the remote disabling of radar on cars already sold. An engineering decision taken by Musk against the experts in the company.

https://www.carscoops.com/2023/03/elon- ... -bad-idea/
Engineers feared that the removal of such important sensors could lead to an uptick in crashes, noting that the cameras couldn’t be relied upon if they were obscured by raindrops or bright sunlight.

Tesla engineers went as far as to contact a trusted former executive to advise them on how to talk Musk out of it. He wouldn’t budge and in May 2021, Tesla announced it was eliminating radar on its new cars. What’s more, it then started to disable the radars already installed in customer-owned vehicles.
I can foresee a class action lawsuit about that. You buy a car with radar crash avoidance and to satisfy the ego of the company owner, the company subsequently remotely disables its functionality.
Former Tesla employees say the decision to remove radar immediately caused problems. Complaints filed with regulators reveal that vehicles were allegedly “stopping for imaginary hazards, misinterpreting street signs, and failing to detect obstacles” including emergency vehicles. An uptick in owners also reported cases of phantom braking with 107 complaints made over three months compared to 34 complaints made in the 22 months prior to radar being removed.
Have you considered stupidity as an explanation

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Re: Astronomy and Space

Post by dyqik » Sat Apr 22, 2023 1:39 pm

bjn wrote:
Sat Apr 22, 2023 7:02 am
Grumble wrote:
Sat Apr 22, 2023 6:18 am
dyqik wrote:
Sat Apr 22, 2023 1:05 am
The lack of noise suppression apparently knocked out at least five engines at launch.

Friday I was sat at a table with a new colleague, who used to work on sound suppression for launches at NASA Marshall Spaceflight Center. Water suppression is worth a 75% reduction in vibration experienced by payloads at the top of the rocket, and presumably much more at the bottom of the rocket.
Intuitively I would have thought less vibration at the bottom, because the top is effectively at the end of a lever. Top stories of towers sway more than the bottom.
I'd guess that you'd have higher frequencies at the bottom which would be damped out somewhat by the time they get to the top.
Yeah. You'd get higher peak loads, because the frequencies from strongly peaked transients are all still in phase, and all the high frequencies present.

A triangle wave displacement will still look like a triangle wave at the base (and delta function like a delta function), but will have been damped to closer to a sine wave near the top. And acceleration and thus force is the second differential of the displacement, so is much higher when there are sharp peaks on the displacement.

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Re: Astronomy and Space

Post by Pishwish » 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?

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Re: Astronomy and Space

Post by dyqik » Sat Apr 22, 2023 5:00 pm

I think it's very likely that the FAA won't approve another launch from the site without a water suppression system and flame trenches in place, because of the risk to the public.

This launch covered nearby towns in debris, and damaged the vehicle to the point of making it unsafe.

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Re: Astronomy and Space

Post by bjn » Sat Apr 22, 2023 5:07 pm

Ouch…
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