Space and Science BS Thread

I’m actually more concerned about this now that it seems confirmed that water won’t be supplied to a large arc of the plate except what flows across from the manifolds on the opposite side. This guarantees a pressure drop across the plate and uneven flow out of the holes. Combined with cavitation(supply flow is at 90 degrees to the output spray) it could seriously make a hot mess of the spray pattern. I’m in no way a fluid dynamics engineer so this is pure speculation but as complicated as the plate is it just seems to get sideways to common sense. I suppose if they fill the system to the point of a small amount of flow to eliminate any trapped air and ramp up the pressure just in advance of the thrust pressure it might last long enough but my intuition is telling me that the spray will be uneven at very low pressure then even out some as the pressure climbs but become erratic beyond a certain point. Maybe the flow across the plate is slow enough to both prevent cavitation and allow for a more even pressure gradient. Ten fingers crossed on this one and I hope and expect to see them test a range of pressure profiles to gauge performance both before and during the SF campaigns.

 

I have a theory that runs a bit contrary to the NSF video on how the plate might be supplied more evenly. If you look at the latest NSF flyover image(~2:37:00) showing the rebar there are two canopies (one blue and one white) opposite the ILT where they might have already buried a supply pipe under the rebar to feed sections there. In another image(~(2:34:00) there’s a grey circle approximately 4’ or 5’ across in about that location and no canopy. That position has access to 3 of the tower leg openings while the orange tarp side can only access 2 because of the tower and doghouse cryo plumbing. If this is the case it would allow for alternating plate supplies or 2 pairs of adjoining plate supplies and even out the pressure across the plates dramatically. We’ll see.

Edit- I went back and reviewed the videos going back to the launch and couldn’t find any sign that a pipe had been laid under or behind the doghouse area and on top of that the rebar has no depressed area to allow for supply pipes on the berm side. I think it could have been done after the pilings were poured and before the cryo pipes to the doghouse were replaced but for whatever reason it wasn’t. I hope this wasn’t a mistake.

 

Fireworks = Science

 

A Starship has more than 1-3 times the volume if you convert the Lox and CH4 tanks to space station as well.

With the weir pipes, I imagine that the plate will stay full between launches. That will help with the water supply issue, I think.

 

Which NSF video was this?

 

The problem is fast moving water can cavitate(dissolved gasses form bubbles) and the shower head analogy might not apply beyond a certain flow rate. Supply from one side doubles the flow rate on the supply side. And it’s not just cavitation, pressure drops the farther it has to travel. It’s not whether they can supply enough water but whether they can maintain even enough pressure across the whole plate for the jets to surpass the engine thrust everywhere. Since the area is completely obscured during even low power, short duration static fires the only way to know would be to run tests on the plate alone and measure the output pressure at different flow rates. Jet height might be all they need to compare.

 

Starbase Weekly 80. The earlier time stamp showed the grey circle and the later one had the blue and white canopies. They’ve been doing their launch site coverage last so these are at 2 hrs 34 minutes and 2 hrs 37 minutes respectively. There’s definitely something there but I no longer think it’s part of the water system.

 

And then there were none.
https://m.youtube.com/watch?v=rIE-a2de7Gg&pp=ygUIbGFicGFkcmU=

 

https://twitter.com/spacedotcom/status/1676924517598347264?s=46

 

SpX - 7(plus 1 for DM-2, and a few others)
Starliner - 0
https://twitter.com/spacedotcom/status/1677286654845886468?s=46

 

OH! You mean the RGV Aerial stream. I gotcha. I went back and looked and I see what you mean.

 

Cool moon guide from NASA:
https://moon.nasa.gov/moon-observation/daily-moon-guide/

 

https://twitter.com/nasahistory/status/1677329131095113738?s=46

 

One of these days I will share the troubles of some of these other missions, but that day isnt today.
We just keep rolling along, one top secret mission at a time.

 

Unrelated, this would speed things up for the next Starship launch if granted…
https://twitter.com/spacedotcom/status/1677619261852864513?s=46

 

That would be nice but given the lack of cleanup anywhere but on the launch site itself I’m doubtful. They made a mess and being able to prevent another one probably doesn’t exonerate them from dealing with this one. Musk hates dealing with bureaucracies but we may have to wait for more excitement until this is dealt with meaningfully. The FAA is concerned with flight risks but the mess is on Parks and Wildlife Refuge land.
https://techcrunch.com/2023/04/19/a... the debris site to monitor clean-up efforts.
It’s a pain but it still has to get done and this was even before the actual launch test. It’s the other shoe dropping when Spacex decided to go ahead with the launch rather than wait for the plates and plumbing to be ready. The fact that they were in production argues against the notion that the existing pad would hold up with nothing else protecting it.

 

The wind must have made this fun.
https://m.youtube.com/watch?v=H6PXHqOErvs

 

So this is kinda disheartening to me. I thought SpX considered themselves part of the community and would make right any wrongs..

 

I doubt it’s black and white but it does exemplify some of the reasons for and difficulties of needing and dealing with watchdog agencies. Spacex wants to fly and while willing to help mitigate the consequences of their operations doesn’t have that as the primary focus or they wouldn’t be nearly as fast. They’re going full speed ahead with tunnel vision until told what to do differently. The agencies involved (and I don’t pretend to know them all) being bureaucracies don’t operate at this pace let alone as a group and the short notice road closures made it impossible for them to coordinate clean up efforts going back through the various sub orbital tests. I’m sure frustration has been growing steadily and this lawsuit seems to be necessary in order to force everyone to get their acts together to figure out how to make it work. I think it has less to do with the pad failure than with the failure of whatever plan was in place. Lawsuits seek relief so I doubt it will be dismissed with all the rubble lying around demonstrating what that relief is for.
To me what’s disappointing is that they’ve pissed away a perfect opportunity to do the cleanup and wasted it on legal wrangling.

 

It's not SpaceX, it's bureaucracy. Look at the article. The final piece was a 1500 lb actuator, and SpaceX had to submit their retrieval plan for approval before going in and getting it. They likely had to do that with every piece larger than a soda can. So a cleanup job that should have taken a small team about a week to complete turned into a massive ordeal that took ages.