"SpaceX launches Starship, world's most powerful rocket, but flight ends
in explosion | full video"
https://www.youtube.com/watch?v=wsKyM1Raeu4

Wow, that was beautiful even if it did end in a Unplanned Rapid
Disassembly !

Looks like they had a shutdown failure in the Booster rocket with
subsequent failure to separate.

And only 28 of the 33 rockets in the Booster lit up. I'll bet that they
had some fuel tank cavitation issues.

Lynn

On Thursday, April 20, 2023 at 3:56:52 PM UTC-4, Lynn McGuire wrote:
> "SpaceX launches Starship, world's most powerful rocket, but flight ends
> in explosion | full video"
> https://www.youtube.com/watch?v=wsKyM1Raeu4
>
> Wow, that was beautiful even if it did end in a Unplanned Rapid
> Disassembly !
>
> Looks like they had a shutdown failure in the Booster rocket with
> subsequent failure to separate.
>
> And only 28 of the 33 rockets in the Booster lit up. I'll bet that they
> had some fuel tank cavitation issues.

On the SpaceX reddit, people are thinking the blast broke up the concrete
under the rocket - post launch photos show a crater under the
platform, and a camera truck got seriously smashed hundreds of yards away by
a chunk of concrete.

These debris caused enough damage that some of the engines exploded.
Fuel continued to pour into the damaged engines, uncontrollably.

There was enough thrust and vectoring to get off the pad, but only slowly,
perhaps leading to more debris damage.

When it came time for stage separation, that failed. Perhaps the damaged
engines still produced some thrust which could not be turned off, and that
prevented stage separation.

What no one expected was that the stack would remain intact while tumbling
a couple times before the Flight Termination System was activated. You'd
expect aerodynamic forces to rip it apart earlier. That ship and booster are
tougher than expected.

A failure at this early stage was almost expected. I'm just happy that it
didn't ruin the 'Stage 0' ground equipment.

pt

In article <82789209-b039-4e19-a42a-daa4bb8e55aan@googlegroups.com>,
pete...@gmail.com <petertrei@gmail.com> wrote:

snip

>On the SpaceX reddit, people are thinking the blast broke up the concrete
>under the rocket - post launch photos show a crater under the
>platform, and a camera truck got seriously smashed hundreds of
>yards away by
>a chunk of concrete.
>
Shades of the incident during the early US space program where
the press were located too close to the launch and parts of the
ceiling came down on them.

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In article <82789209-b039-4e19-a42a-daa4bb8e55aan@googlegroups.com>,
pete...@gmail.com <petertrei@gmail.com> wrote:
>What no one expected was that the stack would remain intact while tumbling
>a couple times before the Flight Termination System was activated. You'd
>expect aerodynamic forces to rip it apart earlier. That ship and booster are
>tougher than expected.

I recall a story about one of the early Atlas (I think) tests,
where due to some failure, it was flying sideways. One of the
engineers said "It shouldn't be able to hang together while
flying sideways! That means we can shave off more weight!"

Though, with SpaceX going for reusability, more structural
robustness is probably in order than for something that's
strictly one-use.
--
Mike Van Pelt | "I don't advise it unless you're nuts."
mvp at calweb.com | -- Ray Wilkinson, after riding out Hurricane
KE6BVH | Ike on Surfside Beach in Galveston

Lynn McGuire <lynnmcguire5@gmail.com> wrote:
>"SpaceX launches Starship, world's most powerful rocket, but flight ends
>in explosion | full video"
> https://www.youtube.com/watch?v=wsKyM1Raeu4
>
>Wow, that was beautiful even if it did end in a Unplanned Rapid
>Disassembly !

The usual term is RUD for Rapid Unplanned Disassembly, though a few
has new jokingly suggested that it now also means Rapid Unplanned
Digging - there's now a massive crater in the launch mount!

>Looks like they had a shutdown failure in the Booster rocket with
>subsequent failure to separate.

There's a distinct possibility that the separation system had
hydraulic issues probably due to various lines being punctured by
concrete fragments (see below).

It DID make it through Max-Q first which is a monumental achievement -
far from all first launches do and they're going with a "test real
hardware" approach.

SpaceX already they have two more SH+SS stacks mostly ready, the limit
is going to be repair work AND some kind of deluge system. Both were
known already, most of the parts for a deluge system has already been
seen but not installed.

But it'll take a few months at least, but then it probably would take
that just from crunching all the data.

>And only 28 of the 33 rockets in the Booster lit up. I'll bet that they
>had some fuel tank cavitation issues.

The first engine "map" shows up at 00:16 with 3 engines out, we don't
know how many lit up, the previous test ground control shut down one
and IIRC "engine management" shut down one or two more. I suspect they
would have delayed the launch rather than launch with ground-disabled
engines but some or all of the three might have be shut down by their
engine management. So probably not cavitation during start.

Later more engines stopped, at one point they were down 6 but if I
understood them correctly they apparently successfully restarted one
of them - very neat if true! Should give them even more good data, not
sure anyone has actually relit engines that way before!

We see one engine doing the "green exhaust" aka "engine rich exhaust",
which indicates that it was running too hot and melting the engine
nozzle (IIRC the green is from the copper). I think that was one of
the 6 mentioned above.

If we look at the early footage footage we can see massive concrete
slabs going past the side of the rocket much faster than the rocket is
going at that time. Yes, some goes nearly straight up at fairly high
speeds.

So a number of people are wondering if there might have been some
engine and hydraulic pipe damage from concrete debris strikes, it's
definitely a possibility.

On Thu, 20 Apr 2023 14:56:45 -0500, Lynn McGuire wrote:

> "SpaceX launches Starship, world's most powerful rocket, but flight ends
> in explosion | full video"
> https://www.youtube.com/watch?v=wsKyM1Raeu4
>
> Wow, that was beautiful even if it did end in a Unplanned Rapid
> Disassembly !
>
> Looks like they had a shutdown failure in the Booster rocket with
> subsequent failure to separate.
>
> And only 28 of the 33 rockets in the Booster lit up. I'll bet that they
> had some fuel tank cavitation issues.
>
> Lynn

Or maybe numerology issues?

On Saturday, April 22, 2023 at 3:12:36 AM UTC-4, Charles Packer wrote:
> On Thu, 20 Apr 2023 14:56:45 -0500, Lynn McGuire wrote:
>
> > "SpaceX launches Starship, world's most powerful rocket, but flight ends
> > in explosion | full video"
> > https://www.youtube.com/watch?v=wsKyM1Raeu4
> >
> > Wow, that was beautiful even if it did end in a Unplanned Rapid
> > Disassembly !
> >
> > Looks like they had a shutdown failure in the Booster rocket with
> > subsequent failure to separate.
> >
> > And only 28 of the 33 rockets in the Booster lit up. I'll bet that they
> > had some fuel tank cavitation issues.
> >
> > Lynn
> Or maybe numerology issues?

The only numerology I've heard invoked is that Elon may have delayed
the second try until 4/20. He's fond of puerile jokes.

Pt

On Saturday, April 22, 2023 at 2:14:04 PM UTC-4, pete...@gmail.com wrote:
> On Saturday, April 22, 2023 at 3:12:36 AM UTC-4, Charles Packer wrote:
> > On Thu, 20 Apr 2023 14:56:45 -0500, Lynn McGuire wrote:
> >
> > > "SpaceX launches Starship, world's most powerful rocket, but flight ends
> > > in explosion | full video"
> > > https://www.youtube.com/watch?v=wsKyM1Raeu4
> > >
> > > Wow, that was beautiful even if it did end in a Unplanned Rapid
> > > Disassembly !
> > >
> > > Looks like they had a shutdown failure in the Booster rocket with
> > > subsequent failure to separate.
> > >
> > > And only 28 of the 33 rockets in the Booster lit up. I'll bet that they
> > > had some fuel tank cavitation issues.
> > >
> > > Lynn
> > Or maybe numerology issues?
> The only numerology I've heard invoked is that Elon may have delayed
> the second try until 4/20. He's fond of puerile jokes.
>
Didn't Elon claim that the flight would be considered successful if it got off and didn't destroy the launch pad? II guess it was half a success.

On 4/24/2023 10:52 AM, John Halpenny wrote:
> On Saturday, April 22, 2023 at 2:14:04 PM UTC-4, pete...@gmail.com wrote:
>> On Saturday, April 22, 2023 at 3:12:36 AM UTC-4, Charles Packer wrote:
>>> On Thu, 20 Apr 2023 14:56:45 -0500, Lynn McGuire wrote:
>>>
>>>> "SpaceX launches Starship, world's most powerful rocket, but flight ends
>>>> in explosion | full video"
>>>> https://www.youtube.com/watch?v=wsKyM1Raeu4
>>>>
>>>> Wow, that was beautiful even if it did end in a Unplanned Rapid
>>>> Disassembly !
>>>>
>>>> Looks like they had a shutdown failure in the Booster rocket with
>>>> subsequent failure to separate.
>>>>
>>>> And only 28 of the 33 rockets in the Booster lit up. I'll bet that they
>>>> had some fuel tank cavitation issues.
>>>>
>>>> Lynn
>>> Or maybe numerology issues?
>> The only numerology I've heard invoked is that Elon may have delayed
>> the second try until 4/20. He's fond of puerile jokes.
>>
> Didn't Elon claim that the flight would be considered successful if it got off and didn't destroy the launch pad? II guess it was half a success.

Apparently a steel launchpad is in the works but did not make it in time
for this launch. Hopefully it will have trenches and water cooling.

Lynn

On Monday, April 24, 2023 at 3:21:52 PM UTC-4, Lynn McGuire wrote:
> On 4/24/2023 10:52 AM, John Halpenny wrote:
> > On Saturday, April 22, 2023 at 2:14:04 PM UTC-4, pete...@gmail.com wrote:
> >> On Saturday, April 22, 2023 at 3:12:36 AM UTC-4, Charles Packer wrote:
> >>> On Thu, 20 Apr 2023 14:56:45 -0500, Lynn McGuire wrote:
> >>>
> >>>> "SpaceX launches Starship, world's most powerful rocket, but flight ends
> >>>> in explosion | full video"
> >>>> https://www.youtube.com/watch?v=wsKyM1Raeu4
> >>>>
> >>>> Wow, that was beautiful even if it did end in a Unplanned Rapid
> >>>> Disassembly !
> >>>>
> >>>> Looks like they had a shutdown failure in the Booster rocket with
> >>>> subsequent failure to separate.
> >>>>
> >>>> And only 28 of the 33 rockets in the Booster lit up. I'll bet that they
> >>>> had some fuel tank cavitation issues.
> >>>>
> >>>> Lynn
> >>> Or maybe numerology issues?
> >> The only numerology I've heard invoked is that Elon may have delayed
> >> the second try until 4/20. He's fond of puerile jokes.
> >>
> > Didn't Elon claim that the flight would be considered successful if it got off and didn't destroy the launch pad? II guess it was half a success.
> Apparently a steel launchpad is in the works but did not make it in time
> for this launch. Hopefully it will have trenches and water cooling.

A water cooled steel launchpad is under construction, but wasnt ready in time. A trench
is difficult, since the water table is very close to the surface: the crater left behind immediately
started to flood.

Pt

On Mon, 24 Apr 2023 19:02:14 -0700 (PDT), "pete...@gmail.com"
<petertrei@gmail.com> wrote:

>On Monday, April 24, 2023 at 3:21:52?PM UTC-4, Lynn McGuire wrote:
>> On 4/24/2023 10:52 AM, John Halpenny wrote:
>> > On Saturday, April 22, 2023 at 2:14:04?PM UTC-4, pete...@gmail.com wrote:
>> >> On Saturday, April 22, 2023 at 3:12:36?AM UTC-4, Charles Packer wrote:
>> >>> On Thu, 20 Apr 2023 14:56:45 -0500, Lynn McGuire wrote:
>> >>>
>> >>>> "SpaceX launches Starship, world's most powerful rocket, but flight ends
>> >>>> in explosion | full video"
>> >>>> https://www.youtube.com/watch?v=wsKyM1Raeu4
>> >>>>
>> >>>> Wow, that was beautiful even if it did end in a Unplanned Rapid
>> >>>> Disassembly !
>> >>>>
>> >>>> Looks like they had a shutdown failure in the Booster rocket with
>> >>>> subsequent failure to separate.
>> >>>>
>> >>>> And only 28 of the 33 rockets in the Booster lit up. I'll bet that they
>> >>>> had some fuel tank cavitation issues.
>> >>>>
>> >>>> Lynn
>> >>> Or maybe numerology issues?
>> >> The only numerology I've heard invoked is that Elon may have delayed
>> >> the second try until 4/20. He's fond of puerile jokes.
>> >>
>> > Didn't Elon claim that the flight would be considered successful if it got off and didn't destroy the launch pad? II guess it was half a success.
>> Apparently a steel launchpad is in the works but did not make it in time
>> for this launch. Hopefully it will have trenches and water cooling.
>
>A water cooled steel launchpad is under construction, but wasnt ready in time. A trench
>is difficult, since the water table is very close to the surface: the crater left behind immediately
>started to flood.

So, what they had turned out to be water-cooled after all ...
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