SpaceX Starship : First Flight : Starbase, TX : 20 April 2023 - DISCUSSION

[woods170]

Hey. I'm finding it hard to get accurate answers about this.

In this tweet, Zack Golden mentions that this many LN2/LOX/CH4 tankers are needed to replenish the Tank Farm after this kind of WDR.
<snip>
Is it accurate in any way? One would think they wouldn't need as much CH4.

Zack's numbers are way off. As in way too high, particularly for LN2.

And no, SpaceX doesn't vent all of the propellants when they detank the vehicle. It is just that during tanking, stable replenishment and detanking, a LOT of the cryogenics warm up to the point that they change phase from fluid to gas. To prevent over pressure in the vehicle tanks, storage tanks and all of the plumbing in-between, the gaseous oxygen, nitrogen and methane need to be vented.
SpaceX does employ recondensors to turn some of the gaseous stuff back to fluids, but those are far from 100% effective.

Given the massive amounts of LOX and liquid methane involved, it is inevitable that many truckloads worth of LN2, LOX and liquid methane are required to top off the tank farm.

[eeergo]

There's a very illustrative slide (applied to LH2, but still of huge quantitative value) regarding liquid hydrogen balances during STS in this article from last year, credited to “NASA Experience with Large Scale Liquid Hydrogen” presentation at the Hydrogen Liquefaction and Storage Symposium, University of Western Australia, September 26, 2019. Presented by William Notardonato NASA KSC:

https://www.nasaspaceflight.com/2022/04/sls-wet-dress-rehearsal/
Of course, LH2 shall always be more "lossy" than warmer, bigger-molecule propellants such as LOX or LNG. On the other hand, KSC infrastructure may be more leak-tight than Boca Chica's, both because of the amounts involved as well as the speed of operations and such factors. Maybe a 30% overall loss rate is the ballpark of what they're experiencing, with a 10-15% load loss as per the slide's breakdown?

[CrazySpace]

I wonder, what will they do differently this time in the valve so that it doesn't freeze again? if it's the same model it could happen again...
??

[clongton]

Launch control box in foreground.

What is this?

Some immature person's sick idea of a stupid joke

[ThatOldJanxSpirit]

It is so sad to see this forum declining to the abject level of Reddit or the Ars Technica comments section.

They tried to launch on the 17th. They are recycling to the 20th for good technical reasons. Are people really suggesting that they should rush or delay the recycle to avoid a meme.

[ugordan]

It is so sad to see this forum declining to the abject level of Reddit or the Ars Technica comments section.

They tried to launch on the 17th. They are recycling to the 20th for good technical reasons. Are people really suggesting that they should rush or delay the recycle to avoid a meme.

And it's not like there's a high chance of it launching on that date, either, let's be realistic here.

[edzieba]

In the attached screengrab from engineering cameras under the booster in the OLM I see what appears to be frosted tubing extending from the launch mount to each engine.  They are put in after the explosion in December and are not part of the LN2 stage zero connectors for engine spin-up.  What are these for? Are they directly connected to each engine and how are they disconnected at launch or do they just tear off at launch?

Those are flex lines and are torn off at launch. Temporary thing. This only applies to B7. On B9 et al. a different solution is applied.

Thanks, I added a clip from CSI Starbase that mentions that the booster can't launch like that.  But if they are designed to tear away, then I'm good

CSI Starbase is not an authoritative source. Much pure speculation is presented as fact.

[Chris Bergin]

It is so sad to see this forum declining to the abject level of Reddit or the Ars Technica comments section.

They tried to launch on the 17th. They are recycling to the 20th for good technical reasons. Are people really suggesting that they should rush or delay the recycle to avoid a meme.

Not to pick you out, but the point made.....I'm not sure what posts like this do to solve that. Yes, there were a fair amount of absolutely pointless posts, but thankfully some members here don't quote bad posts and says "bad post" creating two bad posts. They report to mod and we can clean up the crap.

That's this thread, not "this forum". A thread that is a discussion, not update, thread, on a subject that is about the most talked about thing in this subject matter, on the internet, full of people with different opinions and styles of getting their point across.

And on that note, everything think before posting, because some certainly didn't. 1000s of people are reading your posts, so try not to embarrass yourself when hitting post, because some of the three word doozies I removed we very much in the style Janx complained about. Any repeat offenders will find they'll be in read only for a month.

Carry on (plus I'll start a new thread for Attempt 2).

[Chris Bergin]

By the way, I saw people quoting numbers for yesterday, and totally wrong.  It was a lot more.

SpaceX got 5.2m views.

NSF got 3.3m (on a longer stream of course).

[saturnsky]

Has Space X indicated weather requirements for next launch attempt?  Are they using data from 37th Space Wing, private weather service or NWS?  Weather Thursday may not be the best......

[rdale]

I don't think there is a 37th Space Wing? They have their own meteorologists.

[Tomness]

By the way, I saw people quoting numbers for yesterday, and totally wrong.  It was a lot more.

SpaceX got 5.2m views.

NSF got 3.3m (on a longer stream of course).

That's crazy,  almost 1:1 sub/view ratio

[wannamoonbase]

By the way, I saw people quoting numbers for yesterday, and totally wrong.  It was a lot more.

SpaceX got 5.2m views.

NSF got 3.3m (on a longer stream of course).

I joined on April 10, 2006 and have seen the growth and interest.  To have that many views with a such a historic rocket, could not have been imagined 17 years ago.

Chris, it's epic what you have built here.

[Slothman]

By the way, I saw people quoting numbers for yesterday, and totally wrong.  It was a lot more.

SpaceX got 5.2m views.

NSF got 3.3m (on a longer stream of course).

That's crazy,  almost 1:1 sub/view ratio

I was also curious about the concurrent viewers since the chat just lagged my browser tab (with 32 GB system RAM) and the most viewers I saw were about 250.000 on the NSF stream. Mind you, that's concurrent viewers at the same time. Not individual viewers over the whole stream. And I was seriously impressed by that number. More than Tim Dodd's stream when I checked.

[cuddihy]

I don't think there is a 37th Space Wing? They have their own meteorologists.

There are no US Space Force "Wings", only Deltas. Space Launch Delta 45 supports launches at the Eastern Range out of Patrick Space Force Base, FL. The 45th Weather Squadron (45WS) supports the Eastern Range, but far as I know no USSF supports the Texas launch site, they rely on National Weather Service entirely. Any USSF folks out there know better?

[Alberto-Girardi]

By the way, I saw people quoting numbers for yesterday, and totally wrong.  It was a lot more.

SpaceX got 5.2m views.

NSF got 3.3m (on a longer stream of course).

That's crazy,  almost 1:1 sub/view ratio

I was also curious about the concurrent viewers since the chat just lagged my browser tab (with 32 GB system RAM) and the most viewers I saw were about 250.000 on the NSF stream. Mind you, that's concurrent viewers at the same time. Not individual viewers over the whole stream. And I was seriously impressed by that number. More than Tim Dodd's stream when I checked.

Indeed in my post I meant the most viewers at a given instant. Not the total, but I'm not sure about how youtube calculates that.

[whitelancer64]

By the way, I saw people quoting numbers for yesterday, and totally wrong.  It was a lot more.

SpaceX got 5.2m views.

NSF got 3.3m (on a longer stream of course).

The numbers quoted yesterday were for view counts at the time. Obviously as time passes the view count goes up as more people watch it.

[FutureSpaceTourist]

https://twitter.com/alexphysics13/status/1648326879076597760

To me the most exciting thing of yesterday was finally putting together all the times for certain key events on Starship's countdown. When SpaceX had published their timeline, there had been certain events that were not in there and we finally got to know some of them

I put together the script for this video we did last week at NSF analyzing the times from SpaceX's timeline and correlating it to things we could see. Some stuff I got very close, a few others... not so much. But hey it was worth a shot:

https://twitter.com/alexphysics13/status/1648327665051480070

Based on all the stuff we've learned and seen so far, I've put together an updated timeline with more information and posted it on NSF's discord on the Starship channel so if you're in there pop in and search for it for Thursday's event.

And maybe... we'll use it next time 🤔

[cuddihy]

Hi folks, under the impression autogenous pressurization means Starship/SH doesn't need helium, so a helium pressurization valve being frozen confused me. I've done some googling on this forum, wikipedia, & media, it's very hard to get to ground truth as SpaceX's approach appears to have shifted a lot from the beginning of the program, and their public info & wikipedia mentions autogenous pressurization a lot. What I believe the current state is that:

-Autogenous pressurization is used to maintain pressure in the tanks once the engines are running for Super Heavy
-Autogenous pressurization is used to maintain pressure in the tanks once Starship deploys from the SH.
-there are no helium tanks on either vehicle.
WHAT I THOUGHT:
-self pressurization (evaporation) maintains pressure on the pad when both SS & SH are loaded, but clearly that is not the case

So trying to puzzle out:
1. Is helium only used during loading ops or through the launch up to engine start?
2. Is it just on SS, just on SH, or on both?

Any pointers would be appreciated.

[kdhilliard]

The only He mention we've seen was in MZ's tweet, right?
Perhaps he misspoke.