NASASpaceFlight.com Forum

SpaceX Vehicles and Missions => SpaceX Super Heavy/Starship (BFR/BFS) - Earth to Deep Space => Topic started by: Chris Bergin on 09/13/2021 01:17 pm

Title: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: Chris Bergin on 09/13/2021 01:17 pm
New thread (23) for discussion of the Starship (and Booster) prototypes being built in Boca Chica, Texas.  Previous posts on these prototypes can be found in these threads:

Discussion 1 (https://forum.nasaspaceflight.com/index.php?topic=47184.0)

Discussion 2 (https://forum.nasaspaceflight.com/index.php?topic=48894.0)

Discussion 3 (https://forum.nasaspaceflight.com/index.php?topic=49114.0)

Discussion 4 (https://forum.nasaspaceflight.com/index.php?topic=49602.0)

Discussion 5 (https://forum.nasaspaceflight.com/index.php?topic=49998.0)

Discussion 6 (https://forum.nasaspaceflight.com/index.php?topic=50240.0)

Discussion 7 (https://forum.nasaspaceflight.com/index.php?topic=50453.0)

Discussion 8 (https://forum.nasaspaceflight.com/index.php?topic=50620.0)

Discussion 9 (https://forum.nasaspaceflight.com/index.php?topic=50773.0)

Discussion 10 (https://forum.nasaspaceflight.com/index.php?topic=51290.0)

Discussion 11 (https://forum.nasaspaceflight.com/index.php?topic=51474.0)

Discussion 12 (https://forum.nasaspaceflight.com/index.php?topic=51736.0)

Discussion 13  (https://forum.nasaspaceflight.com/index.php?topic=52205.0)

Discussion 14  (https://forum.nasaspaceflight.com/index.php?topic=52396.0)

Discussion 15  (https://forum.nasaspaceflight.com/index.php?topic=52606.0)

Discussion 16  (https://forum.nasaspaceflight.com/index.php?topic=52701.0)

Discussion 17  (https://forum.nasaspaceflight.com/index.php?topic=52940.0)

Discussion 18  (https://forum.nasaspaceflight.com/index.php?topic=53212.0)

Discussion 19  (https://forum.nasaspaceflight.com/index.php?topic=53361.0)

Discussion 20  (https://forum.nasaspaceflight.com/index.php?topic=53471.0)

Discussion 21  (https://forum.nasaspaceflight.com/index.php?topic=53935.0)

Discussion 22  (https://forum.nasaspaceflight.com/index.php?topic=54342.0)

Thread 23 - you're in it!

UPDATES:

SpaceX BFS : Phase 2 - Starship Orbital Prototype(s) - Photos and Updates -3 (https://forum.nasaspaceflight.com/index.php?topic=51332.0) (Previous)

SpaceX Boca Chica - Production Updates - MASTER Thread (4) (https://forum.nasaspaceflight.com/index.php?topic=52398.0)

Also standalone threads for key vehicles and missions.

---

Follow NSF Twitter:
https://twitter.com/NASASpaceflight

---

NSF Youtube Channel with hundreds of original Starship videos:
https://www.youtube.com/channel/UCSUu1lih2RifWkKtDOJdsBA

Supporting NSF and the team

Members of Red Team or higher get early clips pre-edit and more. Capcom and higher get access to our team Discord.

Subscribe and hit notifications for instant alerts of new videos as that'll be the first you'll see for a new video going live.

--

L2 Boca Chica (intense level updates - Master Thread from Day 1 to today) (https://forum.nasaspaceflight.com/index.php?topic=47107.0)
Now with advanced clips from Mary's videos and unique content.

*Also now with standalone L2 threads for Starships and Boosters, etc*

---

Store, with Boca Chica merch:

https://shop.nasaspaceflight.com/

---

RULES

There are 10s of millions of views on these Starship threads, so remember when you post your post is being viewed by a lot of people. Make sure you're posting something interesting:

Stay on topic (don't wander, use new or other threads). This is ONLY about discussing the prototypes
Make sure your post is useful and adding something. Failure to do so will see your post removed.

This Starship Section has many millions of views, and threads with a lot of bandwidth/data (we're not text only like Reddit (who also make a ton of money), we have photos and files hosted on our servers here. If you can support this site, please do via L2. It's a very expensive place to host and only viable if we have enough L2 support).
Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: Okie_Steve on 09/13/2021 04:19 pm
So, given the apparent tile damage from flexing when ship 20 was llifted for the fit check, what has likely changed during replacement to prevent a repeat going forward? Barring major changes like internal bracing or pressurization, all I can think of is tweaks to placement and tolerances to "pre-compensate" for the stress/strain of lifting, now that they have hard data on it.
Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: cscott on 09/13/2021 04:21 pm
So, given the apparent tile damage from flexing when ship 20 was lifted for the fit check

{{Citation needed}}

How many tiles are we taking about and how sure are you that they were installed correctly before the lift?

Also, this discussion belongs in its dedicated thread:

Just for fun, someone should start poll or a contest to guess number of tiles that will fall off from before its next lift to the time it is stacked.
Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: Okie_Steve on 09/13/2021 04:53 pm
NSF articles have extensively covered the colored tape marking and replacement of damaged tiles which were primarily on the nosecone and not the barrel section. Let's not rehash that discussion or make cheap shot shuttle comparison, please. My point is that something presumably unexpected happened to lots of tiles during the fit check and SpaceX has smart people who are also presumably making sure it does not happen again during restack.

How?

I though about both the heat shield thread and the engineering thread but given this is a discussion about an existing prototype and the changes might be more procedural and wider ranging than I can imagine I brought it here. If the mods disagree they can move or delete the whole subthread.
Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: ETurner on 09/13/2021 05:26 pm
So, given the apparent tile damage from flexing when ship 20 was llifted for the fit check, what has likely changed during replacement to prevent a repeat going forward? Barring major changes like internal bracing or pressurization, all I can think of is tweaks to placement and tolerances to "pre-compensate" for the stress/strain of lifting, now that they have hard data on it.
I doubt that the double-curved surface of the nosecone flexes much. The sheet metal canít bend significantly without outright buckling, and it doesnít do that (the cylindrical sides pop in and out easily, but theyíre single-curved). By tile-tolerance standards, stretching of the steel will be negligible. I think that the tile damage requires a different explanation.
Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: edzieba on 09/13/2021 05:27 pm
My point is that something presumably unexpected happened to lots of tiles during the fit check and SpaceX has smart people who are also presumably making sure it does not happen again during restack.
That presumption has no backing: we have no way to tell when the tiles were damaged (at fit check? After? Before transport? Before tile install (i.e. reject tiles installed because they were ready and the flight tiles were not, as with the Raptors on BN4) beyond that the tiles were labelled as damaged after SN20 was placed on the suborbital pad.
The claim that the tiles were damaged as a result of the fit check is unsupported.
Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: Okie_Steve on 09/13/2021 06:40 pm
My point is that something presumably unexpected happened to lots of tiles during the fit check and SpaceX has smart people who are also presumably making sure it does not happen again during restack.
That presumption has no backing: we have no way to tell when the tiles were damaged (at fit check? After? Before transport? Before tile install (i.e. reject tiles installed because they were ready and the flight tiles were not, as with the Raptors on BN4) beyond that the tiles were labelled as damaged after SN20 was placed on the suborbital pad.
The claim that the tiles were damaged as a result of the fit check is unsupported.

Fair point, I retract the assertion.
Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: yakman2020 on 09/13/2021 07:11 pm
Respecting the retraction,
still, if they tiles were damaged by the fit test one would expect most of the damage would have been at the very bottom or top of the vehicle, rather than pretty uniformly throughout.

I wonder if they simply started inspecting the placement, or whether they tiles had been placed experimentally, with a lot of failures, but different techniques, then repaired as expected as a post-process.
Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: Vettedrmr on 09/14/2021 10:29 am
OTOH, this is a discussion thread about the prototypes.  Literally *everything* topic you mentioned can be considered relevant to the prototypes.
Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: cpushack on 09/14/2021 06:25 pm
Its a good sign to see SpaceX continuing to build boosters while waiting for the eventual B4 testing.
We now see B5 stacking has commenced, and bits and pieces of B6 being made.

Have we seen similar progress on S21/22? I don't recall seeing pics for them but probably missed some

Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: Okie_Steve on 09/14/2021 07:16 pm
Boosters B1 to B4  had major changes for each one. Now we are seeing B4, B5 and B6 which *appear* to be more of a similar series along the lines of 3 or 4 builds between major iterations like they did with Starship for a while. I think that means things are stabilizing a bit. Which makes sense with the push to orbit. Of course while S21 is building, even before S20 flys, Musk has mentioned changes to smaller, more leeward "body flaps" so not stabilizing too much  ::)  yet.

Edit2 - Fix leeward/windward correctly this time
Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: rsdavis9 on 09/14/2021 07:26 pm
Boosters B1 to B4  had major changes for each one. Now we are seeing B4, B5 and B6 which *appear* to be more of a similar series along the lines of 3 or 4 builds between major iterations like they did with Starship for a while. I think that means things are stabilizing a bit. Which makes sense with the push to orbit. Of course while S21 is building, even before S20 flys, Musk has mentioned changes to smaller, more windward "body flaps" so not stabilizing too much  ::)  yet.

Edit - Fix leeward -> windward

Leeward is what elon said.

https://twitter.com/elonmusk/status/1437163979953016832?s=20
Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: daavery on 09/15/2021 02:22 am
(https://forum.nasaspaceflight.com/assets/52398.0/2059078.jpg)


actually  - booster transport stand
Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: Hamish.Student on 09/15/2021 05:01 am
I wonder if we could see B5/B6 and S21/S22 leapfrog B4/S20 to the first orbital flight if construction ends up going faster than regulatory approval. 
Just by nature of how fast they are moving, by the time the govt gives the go ahead we could already be several vehicles behind the most recent version.
Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: sferrin on 09/15/2021 11:19 am
Anybody know how they plan to heatshield the lifting points on S20?  I'd have thought they'd have had some kind of cover.  ???
Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: WiresMN on 09/15/2021 11:38 am
Anybody know how they plan to heatshield the lifting points on S20?  I'd have thought they'd have had some kind of cover.  ???

These are prototypes and to not require fancy covers. When stacked, remove the lift points and tile over the areas. It will be a while before they need a better solution.
Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: JamesH65 on 09/15/2021 11:48 am
Anybody know how they plan to heatshield the lifting points on S20?  I'd have thought they'd have had some kind of cover.  ???

These are prototypes and to not require fancy covers. When stacked, remove the lift points and tile over the areas. It will be a while before they need a better solution.

How do they get to them to remove them? They are needed to stack the SS on the SH, but once up there, there are no cherry pickers that go that high. Could they use the grabber arms I wonder?
Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: eriblo on 09/15/2021 11:54 am
Anybody know how they plan to heatshield the lifting points on S20?  I'd have thought they'd have had some kind of cover.  ???

These are prototypes and to not require fancy covers. When stacked, remove the lift points and tile over the areas. It will be a while before they need a better solution.

How do they get to them to remove them? They are needed to stack the SS on the SH, but once up there, there are no cherry pickers that go that high. Could they use the grabber arms I wonder?
The same way that they get there to disconnect the lifting slings/cables? The suggestion has been a crane suspended personell platform (aka man basket).
Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: SkyRate on 09/15/2021 12:08 pm
Anybody know how they plan to heatshield the lifting points on S20?  I'd have thought they'd have had some kind of cover.  ???

These are prototypes and to not require fancy covers. When stacked, remove the lift points and tile over the areas. It will be a while before they need a better solution.

How do they get to them to remove them? They are needed to stack the SS on the SH, but once up there, there are no cherry pickers that go that high. Could they use the grabber arms I wonder?

Same thing applies to releasing the SS from the lift harness in the first place. I assume they can lift someone in a construction basket using the whip line of Frankencrane for both.
Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: SkyRate on 09/15/2021 12:16 pm
Anybody know how they plan to heatshield the lifting points on S20?  I'd have thought they'd have had some kind of cover.  ???
These are prototypes and to not require fancy covers. When stacked, remove the lift points and tile over the areas. It will be a while before they need a better solution.
Strongly agree. The current solution is not suitable for regular operations. Regardless of whether SS is caught or lands on legs, they'll want to stack it using the same method as SH. Something that requires no manual handling high in the air and that lets SS be precisely clocked and positioned.
Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: WiresMN on 09/15/2021 12:59 pm
Strongly agree. The current solution is not suitable for regular operations. Regardless of whether SS is caught or lands on legs, they'll want to stack it using the same method as SH. Something that requires no manual handling high in the air and that lets SS be precisely clocked and positioned.

After watching the Everyday Astronaut interview with Elon, I was stuck how far SpaceX has taken the agile method. You could see the annoyance on Elon's face when he was asked about questions he found irrelevant or out of touch with the current push. To me it all makes sense, don't optimize or design a part that may not exist in a week or so. It is wasted effort at best and can lead to poor design choices in the future.

Just wait, within a star ship or two it is all going to change. This is SO much fun to watch.
Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: eriblo on 09/15/2021 01:27 pm
Anybody know how they plan to heatshield the lifting points on S20?  I'd have thought they'd have had some kind of cover.  ???
These are prototypes and to not require fancy covers. When stacked, remove the lift points and tile over the areas. It will be a while before they need a better solution.
Strongly agree. The current solution is not suitable for regular operations. Regardless of whether SS is caught or lands on legs, they'll want to stack it using the same method as SH. Something that requires no manual handling high in the air and that lets SS be precisely clocked and positioned.
S21 S20 already has what could very well be two other sets of lifting points; one beneath each forward fin and a second pair further down the side. So the nose points could be used for initial section stacking and lifting (for static fires and such) and then closed out before final stacking on SH using the chopsticks.

A corresponding crane lift rig should not be too hard (especially if the forward fins move leeward) and would allow the TPS to be completed at the production site. Lifting by the nose would then be just a short term fix for these first prototypes until the GSE is ready to take over.

Regarding the first question - these points are set well below the surface of the TPS tiles perpendicular to the flow and would be quite hefty bare steel. There should be no need for any extra protection.

EDIT: Corrected ship number.
Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: beelsebob on 09/15/2021 10:52 pm
I guess I had incorrect expectations, but I'm surprised that the QD arm is below the level of the top of the booster.  I was expecting it to be holding onto the base of the starship, with the QD fueling port on it.  I guess the fueling port has to be mounted on top of the arm by a few meters.
Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: VaBlue on 09/16/2021 02:04 pm
I guess I had incorrect expectations, but I'm surprised that the QD arm is below the level of the top of the booster.  I was expecting it to be holding onto the base of the starship, with the QD fueling port on it.  I guess the fueling port has to be mounted on top of the arm by a few meters.

Yeah, me too!  I expected it to latch on above the grid fins, where it could also hold onto to SS and it's QD attachment.  Whatever...  You'd think we know to not presume what SpaceX is doing by now, right?  So the new question is: does SS require stabilization, or just the booster?  And how does the QD get to SS?
Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: meekGee on 09/16/2021 02:11 pm
I guess I had incorrect expectations, but I'm surprised that the QD arm is below the level of the top of the booster.  I was expecting it to be holding onto the base of the starship, with the QD fueling port on it.  I guess the fueling port has to be mounted on top of the arm by a few meters.

Yeah, me too!  I expected it to latch on above the grid fins, where it could also hold onto to SS and it's QD attachment.  Whatever...  You'd think we know to not presume what SpaceX is doing by now, right?  So the new question is: does SS require stabilization, or just the booster?  And how does the QD get to SS?
Musk said the stated purpose of the QD arm was to stabilize the booster so the ship can be stacked.

Relative to the ship, it will be at the same height as the launch stand when the ship stands directly on it.

The QD mechanism will pop up, much like it does from the base of the OLS for booster.
Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: intamin on 09/16/2021 05:08 pm
Here's a good one. Is the latest aerocover now like the Cybertruck? Linear edges, very few curves. Perhaps for ease of heat shield tile design? Or something else?

Src Nic of NSF:

(https://forum.nasaspaceflight.com/assets/52398.0/2059626.jpg)
Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: abaddon on 09/16/2021 05:30 pm
Aerocovers are for the booster which has no heat shield tiles.  Probably just easier to make this way.
Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: grndkntrl on 09/16/2021 05:46 pm
Aerocovers are for the booster which has no heat shield tiles.  Probably just easier to make this way.

These ones are for a Starship though. Note the rounded part which covers the top of the flap hinge.
Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: eriblo on 09/16/2021 06:11 pm
Aerocovers are for the booster which has no heat shield tiles.  Probably just easier to make this way.

These ones are for a Starship though. Note the rounded part which covers the top of the flap hinge.
Yep, it is the forward -Y (starboard) fin tip fairing, this post (https://forum.nasaspaceflight.com/index.php?topic=52398.msg2270083#msg2270083) shows the same delivery for S20 and this one (https://forum.nasaspaceflight.com/index.php?topic=52398.msg2271518#msg2271518) shows the installation of the +Y one for S20.
Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: intamin on 09/16/2021 06:46 pm
Aerocovers are for the booster which has no heat shield tiles.  Probably just easier to make this way.

These ones are for a Starship though. Note the rounded part which covers the top of the flap hinge.
Yep, it is the forward -Y (starboard) fin tip fairing, this post (https://forum.nasaspaceflight.com/index.php?topic=52398.msg2270083#msg2270083) shows the same delivery for S20 and this one (https://forum.nasaspaceflight.com/index.php?topic=52398.msg2271518#msg2271518) shows the installation of the +Y one for S20.

So they did update the design from smooth to angular. Must help with tiles, I'd think...
Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: RocketLover0119 on 09/17/2021 04:32 pm
I believe this stand that was brought to the launch site today is the raptor stand for the orbital table mount for the booster.

Saw an extension test of this I believe a little while back
Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: Cheapchips on 09/17/2021 06:26 pm
Since SpaceX know a licence is months away, will they fly with B5 and S21 instead?  I'm sure they have a laundry list changes they would include since they have that opportunity.
Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: oldAtlas_Eguy on 09/17/2021 07:48 pm
Since SpaceX know know a licence is months away, will they fly with B5 and S21 instead?  I'm sure they have a laundry list changes they would include since they have that opportunity.
I see the production and readiness for launch of the three sets of flight hardware B4S20, B5S21 and B6S22 to be something like the following which includes time doing the preliminary tests prior to launching:

B4S20 - 1 Oct

B5S21 - mid Nov

B6S22 - mid Jan 2022

Basically at least a new set every 60 days for a launch every 60 days. And if the first launch is likely to be Dec. Then the next could be Dec Jan 2022, the 3rd launch Feb 2022, and the 4th Mar 2022. With the 5th launch a possibility of May 2022. For a total of a possible 10 launches in 2022. By 2023 the build rates for all the flight hardware should be fast enough to do a 1 a month launch.

The likely Dec launch is based on an optimistic but not an overly optimistic one of the EA schedule of events. The public comment period closes 18 Oct. A month to process and do the Final EA is then mid Nov. With the next being approximately a week to issue the Launch License (NOTE is that the AST is not the drivers seat for the FAA work on the EA they only provide assistance to the part of the EA for the unique bits associated with launch vehicles). So once AST get their hands on the Final(Final) they should have no difficulty in writing up the provisions for the Launch License. Hence the duration of a week. That puts earliest possible very late Nov/early Dec. More likely would be mid Dec. So everyone can then go have a very happy Holidays regardless of the flight outcome.
Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: Svisloch on 09/17/2021 08:34 pm
We seem to have test-length road closures for next week, but have we seen any gas deliveries to the suborbital prop farm in the last two weeks?
Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: dgkimpton on 09/18/2021 10:55 am
Since SpaceX know a licence is months away, will they fly with B5 and S21 instead?  I'm sure they have a laundry list changes they would include since they have that opportunity.
I would imagine that will entirely depend on what they learn (and have already learnt) during B4/S21 development and exactly how much time elapses. Static fires of these current units will either confirm their designs or throw spanners in the works. If the issues turn out to be big enough then sure, we've seen SpaceX be ready to abandon vehicles in favour of a better path. What I don't see happening is anything that slows down the path to first-flight unless the issues are insurmountable - Elon knows that getting that first one up there will teach the most important lessons.
Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: capoman on 09/18/2021 12:52 pm
I wouldnít be surprised if we start seeing acceleration of builds soon The GSE tank builds have been taking away a lot of production capacity that can soon be reassigned back to the builds.
Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: Herb Schaltegger on 09/18/2021 01:04 pm
I wouldnít be surprised if we start seeing acceleration of builds soon The GSE tank builds have been taking away a lot of production capacity that can soon be reassigned back to the builds.

Or, depending on the testing timelines, begin working on the tank farm for the second orbital launch platform/tower complex.
Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: OTV Booster on 09/18/2021 03:12 pm
I wouldnít be surprised if we start seeing acceleration of builds soon The GSE tank builds have been taking away a lot of production capacity that can soon be reassigned back to the builds.

Or, depending on the testing timelines, begin working on the tank farm for the second orbital launch platform/tower complex.
This struck me as wrong at first, but with the new bay a building, maybe not. Invest some build capacity now to support a new pad and have the new pad come on line as the new bay multiplies current build capacity.
Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: FutureSpaceTourist on 09/19/2021 06:59 am
https://twitter.com/starship_sults/status/1439425657721659392

Quote
StarBase Weekly Development timeline.
Sep 12 Ė Sep 18

This is the last StarBase Weekly timeline. Next, SpaceX timelines, including falcon and StarBase updates together.

@elonmusk @SpaceX
#Starship #Starbase
Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: lykos on 09/19/2021 11:26 am
I wouldnít be surprised if we start seeing acceleration of builds soon The GSE tank builds have been taking away a lot of production capacity that can soon be reassigned back to the builds.

Or, depending on the testing timelines, begin working on the tank farm for the second orbital launch platform/tower complex.
This struck me as wrong at first, but with the new bay a building, maybe not. Invest some build capacity now to support a new pad and have the new pad come on line as the new bay multiplies current build capacity.

No need for that now!
The ground of orbital pad B is still deep swamp!
Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: Herb Schaltegger on 09/19/2021 01:30 pm
I wouldnít be surprised if we start seeing acceleration of builds soon The GSE tank builds have been taking away a lot of production capacity that can soon be reassigned back to the builds.

Or, depending on the testing timelines, begin working on the tank farm for the second orbital launch platform/tower complex.
This struck me as wrong at first, but with the new bay a building, maybe not. Invest some build capacity now to support a new pad and have the new pad come on line as the new bay multiplies current build capacity.

No need for that now!
The ground of orbital pad B is still deep swamp!
Elon says next year.

Having said that, and by your same logic, thereís no need to keep building more booster rings and domes indefinitely before they start launching, because they donít have room to store them all.
Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: oldAtlas_Eguy on 09/19/2021 05:56 pm
The current build rate of complete flight set SH+SS and therefore flight-rate without reuse occurring is 1 every 2 months. This seems to currently match the EA limit of 5/yr. Have not confirmed the 5/yr EA limit yet though. But also in the early flights is the probable need of design upgrades. Even though most would be minor (can be done in a 60 day cycle between launches) some may need significant time to implement. These would have to be implemented at an earlier point in the flight set manufacture which currently looks to be about a 5 month process from start to finish. So these more significant upgrades may be delayed a flight or two before showing up while other simpler upgrades are tested on the last of the previous already in process builds are flown.

Such that in a practical sense is that after 3 flights would be seen a significant upgrade on the next flight. Or 2 significant vehicle version changes a year for the first couple of years. This much faster than Falcon did its significant version changes. NOTE is that R2 is coming up soon and is likely to bring in significant  structural changes to both SH and SS.
Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: winkhomewinkhome on 09/19/2021 11:22 pm
Regarding why B3 is still hanging around...

Use what is left of it as a test article for the launch tower "Mechazilla" equipment?
Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: cdebuhr on 09/20/2021 01:13 am
Regarding why B3 is still hanging around...

Use what is left of it as a test article for the launch tower "Mechazilla" equipment?
Nope - B3 had very different lift points, and besides, the top half (i.e., the part that interfaces with "Mechazilla") is missing (they scrapped it already).  My guess is that they've been busy, they haven't need suborbital pad A for anything else, and they just haven't gotten around to it.

Edit: typos
Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: Ben Baley on 09/20/2021 02:35 am
With the  release of the draft PEA for public comment we are finally seeing some progress towards the necessary permits required for the test flight of SS/SH 4/20.

My question is how far can SpaceX advance the testing campaign under the current permits?

IIRC they are limited to a thrust equivalent to a FH for static fires, if so then a full engine count static fire of Super Heavy won't be allowed until the new permits are finalized.

If anyone has some better information on what exactly is currently allowed it would be much appreciated.
Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: Adriano on 09/20/2021 10:45 pm
Probably they will use the chopsticks to pick up the starship from the ground and Place it on top of the Superheavy. We have not seen yet the lift points under the forward flaps. Do you think they plan to have workers walking on the chopsticks if any manual adjustment is needed? I would not want to be the oneÖ
Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: CamiloPasin on 09/21/2021 12:34 am
Probably they will use the chopsticks to pick up the starship from the ground and Place it on top of the Superheavy. We have not seen yet the lift points under the forward flaps. Do you think they plan to have workers walking on the chopsticks if any manual adjustment is needed? I would not want to be the oneÖ

Of course we have seen the lifting points, they have been there since always.
Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: Hamish.Student on 09/21/2021 02:09 am
With the  release of the draft PEA for public comment we are finally seeing some progress towards the necessary permits required for the test flight of SS/SH 4/20.

My question is how far can SpaceX advance the testing campaign under the current permits?

IIRC they are limited to a thrust equivalent to a FH for static fires, if so then a full engine count static fire of Super Heavy won't be allowed until the new permits are finalized.

If anyone has some better information on what exactly is currently allowed it would be much appreciated.
 
 
All these questions and more are answered over in the permitting thread and the launch site thread, among others.   

https://forum.nasaspaceflight.com/index.php?topic=52656.0 
https://forum.nasaspaceflight.com/index.php?topic=54355.0 
 
Enjoy  :)
Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: TomH on 09/21/2021 03:17 am
With the  release of the draft PEA for public comment we are finally seeing some progress towards the necessary permits required for the test flight of SS/SH 4/20.

My question is how far can SpaceX advance the testing campaign under the current permits?

IIRC they are limited to a thrust equivalent to a FH for static fires, if so then a full engine count static fire of Super Heavy won't be allowed until the new permits are finalized.

If anyone has some better information on what exactly is currently allowed it would be much appreciated.

Discussion of that topic is here (https://forum.nasaspaceflight.com/index.php?topic=52656.0). Please take the inquiry to that thread.
Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: WormPicker959 on 09/21/2021 03:33 am
Probably they will use the chopsticks to pick up the starship from the ground and Place it on top of the Superheavy. We have not seen yet the lift points under the forward flaps. Do you think they plan to have workers walking on the chopsticks if any manual adjustment is needed? I would not want to be the oneÖ

Of course we have seen the lifting points, they have been there since always.

I'm not sure what you're referring to. I don't even think SpaceX knows definitively:

https://twitter.com/elonmusk/status/1432276054664744961?s=20
Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: JoerTex on 09/21/2021 06:43 pm
There's word in Austin that OSHA has been asked to inspect and assess the work processes at Boca Chica.  No information on time/schedule.
Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: schuttle89 on 09/21/2021 07:13 pm
There's word in Austin that OSHA has been asked to inspect and assess the work processes at Boca Chica.  No information on time/schedule.

Elon's going to have to start wearing a hard hat.
Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: CruddyCuber on 09/21/2021 07:28 pm
There's word in Austin that OSHA has been asked to inspect and assess the work processes at Boca Chica.  No information on time/schedule.

Elon's going to have to start wearing a hard hat.

He'll have to get some hearing/eye protection for Marvin too.
Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: CamiloPasin on 09/21/2021 10:50 pm
Probably they will use the chopsticks to pick up the starship from the ground and Place it on top of the Superheavy. We have not seen yet the lift points under the forward flaps. Do you think they plan to have workers walking on the chopsticks if any manual adjustment is needed? I would not want to be the one…

Of course we have seen the lifting points, they have been there since always.

I'm not sure what you're referring to. I don't even think SpaceX knows definitively:

https://twitter.com/elonmusk/status/1432276054664744961?s=20

Musk is talking about CATCHING the ship, if you look at any pictures from the side of the ship, on the very first time s20 roll out quite a while ago to this day, you will be able to see the load points the catch arms will interface with the ship to stack it.

Btw, that's not only confirmed by the new FAA renders, but it's quite obvious as there's just no crane at all on that tower... It shouldn't even be up to debate.
Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: copper8 on 09/21/2021 10:58 pm
https://twitter.com/rgvaerialphotos/status/1440416375978086411

Quote
New parts delivered to the Launch Site just now.

Looks like a gear box/speed reducer attached to a long ball screw.
Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: baking on 09/22/2021 02:48 am
https://twitter.com/rgvaerialphotos/status/1440416375978086411

Quote
New parts delivered to the Launch Site just now.

Looks like a gear box/speed reducer attached to a long ball screw.
So two really, really long linear actuators.  What is so big that they can't use hydraulics?  All I can think of is Mechazilla's chopsticks.  Each arm needs to be controlled individually and the independent speed of actuation is critical for aiming.  Of course, they would need to be protected from the rockets.

EDIT:  Sorry, meant to post this to the launch site thread.
Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: M.E.T. on 09/22/2021 05:08 am
Is there any sense that things have slowed down since Elonís tweet about a month ago that they would be good to go in ďabout two weeks?Ē

Eric Ralph even speculated that Booster 4 and Ship 20 might not even launch, given the work done on the next iterations already. Is there any information that issues have been discovered precluding Ship 20 /Booster 4ís launch?

Or is everything still looking pretty good to go for testing and launch as soon as the FAA approval comes through?
Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: [email protected] on 09/22/2021 06:16 am
Probably environmental assessment process makes them to not need the rush yet
Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: sferrin on 09/22/2021 12:05 pm
Probably environmental assessment process makes them to not need the rush yet


IMO launching in 2021 sailed long ago.  It's going to be stalled at the FAA for months. (Hopefully not years.  Depends on how much response they got.  If BO sent in terabytes of crap to sift through. . . ;) )
Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: Rocket Surgeon on 09/22/2021 01:15 pm
Is there any sense that things have slowed down since Elonís tweet about a month ago that they would be good to go in ďabout two weeks?Ē

Eric Ralph even speculated that Booster 4 and Ship 20 might not even launch, given the work done on the next iterations already. Is there any information that issues have been discovered precluding Ship 20 /Booster 4ís launch?

Or is everything still looking pretty good to go for testing and launch as soon as the FAA approval comes through?

Slowed down? No.

Elon is incredibly optimistic with his time scales but people who work on this stuff for a living were always saying, even back when the goal for launch was July, that October would be at best when things were ready, and even then thats a big IF.

The reality is they still need ALOT finished before they can launch, and then it would probably be smart of them to finish off the remainder (I.E. the chopsticks). Bulding any sort of engineering project like this is always looks from the outside to go really slow when they lay the foundation, really fast when the structure goes up, then really slow again as things are finished off on the inside.

Will it launch this year... possibly but I give it 50/50 odds. Will it launch next year? Definitely
Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: FutureSpaceTourist on 09/23/2021 12:20 pm
https://youtu.be/PpsEkl8Y1ew
Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: philw1776 on 09/24/2021 05:03 pm
We're stuck in some perverse quantum state of 2 weeks to static fire
Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: alugobi on 09/24/2021 06:20 pm
Xeno's static fire.
Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: ETurner on 09/24/2021 09:48 pm
Urgent: Must shut down discussion board to allow progress!
Quote
Quantum Zeno effect (https://en.wikipedia.org/wiki/Quantum_Zeno_effect)
Sometimes this effect is interpreted as "a system cannot change while you are watching it".
Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: Sciencefan on 09/24/2021 10:17 pm
Urgent: Must shut down discussion board to allow progress!

The Elon's week is not over yet.
Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: Hamish.Student on 09/25/2021 03:49 pm
Bringing things back to this topic of this thread.   
 
If someone wants to know what sacks of Perlite look like, they are the white ones with pink bands. The Perlite kiln can be seen behind them.
 
 
Can I ask what the kiln would be for in this context? 
 
These two white tanks are currently on the move
Via NSF 24/7 Starbase Livestream
 
 
Assuming these are the tanks from the Sanchez site that were delivered a few weeks back and that were previous covered in blue tarps?
Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: raivo45 on 09/25/2021 04:21 pm
Bringing things back to this topic of this thread.   
 
If someone wants to know what sacks of Perlite look like, they are the white ones with pink bands. The Perlite kiln can be seen behind them.
 
 
Can I ask what the kiln would be for in this context? 
 
These two white tanks are currently on the move
Via NSF 24/7 Starbase Livestream
 
 
Assuming these are the tanks from the Sanchez site that were delivered a few weeks back and that were previous covered in blue tarps?

Both of these are off topic here tbh and belong in the launch site thread.   :)

The "kiln" is used to expand perlite, basically making popcorn from volcanic rock. (Used as insulation for cryogenic tanks.)

The tanks delivered to the launch site aren't the ones that are covered with blue tarps. The ones covered with blue tarps are absorbtion/purification columns for CH4 production as far as I understand.
Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: FutureSpaceTourist on 09/26/2021 07:20 am
https://twitter.com/starship_sults/status/1441959797650198537

Quote
SpaceX weekly timeline.
Sep 19 Ė Sep 25.
@elonmusk #SpaceX
#starship #falcon9
Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: SDSmith on 09/28/2021 09:37 am
From the 09/28 daily video I see this large diameter pipe under SN20 (in red oval). To me it appears to be under one of the rvacs. Could it be a thrust ram?
Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: raivo45 on 09/28/2021 11:57 am
From the 09/28 daily video I see this large diameter pipe under SN20 (in red oval). To me it appears to be under one of the rvacs. Could it be a thrust ram?

Yes, they're thrust rams for RVac mounts, there's 3 of them.
Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: RocketLover0119 on 10/01/2021 12:00 pm
Quick word of edit to the NSF video teamÖ

This is not the B6 common dome but rather the B5 aft dome
Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: Alberto-Girardi on 10/01/2021 03:04 pm
Quick word of edit to the NSF video teamÖ

This is not the B6 common dome but rather the B5 aft dome

The pace is just incredible seeing b5, if they were building b6 too it would be even more incredible.
Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: cpushack on 10/01/2021 04:39 pm
Quick word of edit to the NSF video teamÖ

This is not the B6 common dome but rather the B5 aft dome

The pace is just incredible seeing b5, if they were building b6 too it would be even more incredible.

I'm sure they are, at least the longer lead pieces of it.
Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: OTV Booster on 10/02/2021 10:08 pm
Question: that SN21 nosecone, it it the new design or the old. Can't tell with the TPS in the way. I think I remember it being the old design, but I can't remember where I put my glasses half the time.  ::)
Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: beelsebob on 10/03/2021 03:13 am
I've not seen one of these before:

(https://forum.nasaspaceflight.com/index.php?action=dlattach;topic=52398.0;attach=2062770;image)

My thought though is that this is a support structure for the bottom of SuperHeavy to mount all the plumbing for the outer 20 engines to.  It doesn't *quite* make sense though - I could 15 holes facing Mary, (plus 2 at the bottom) - that makes 30 holes (34 including the bottom ones).  You'd expect 40 for the outer 20 engines.

Actually, scratch that, I think 15 is a trick of perspective.  There's 9 (plus one at the bottom) per panel.  4 panels means 40 total holes, so just right for this to be a mounting bracket for superheavy outer engine plumbing.

Any other thoughts on what this thing is?
Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: FutureSpaceTourist on 10/03/2021 05:35 am
https://twitter.com/starship_sults/status/1444500332659175428

Quote
SpaceX weekly timeline.
Sep 26 Ė Oct 2.
Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: raivo45 on 10/03/2021 08:12 am
I've not seen one of these before:

(https://forum.nasaspaceflight.com/index.php?action=dlattach;topic=52398.0;attach=2062770;image)

My thought though is that this is a support structure for the bottom of SuperHeavy to mount all the plumbing for the outer 20 engines to.  It doesn't *quite* make sense though - I could 15 holes facing Mary, (plus 2 at the bottom) - that makes 30 holes (34 including the bottom ones).  You'd expect 40 for the outer 20 engines.

Actually, scratch that, I think 15 is a trick of perspective.  There's 9 (plus one at the bottom) per panel.  4 panels means 40 total holes, so just right for this to be a mounting bracket for superheavy outer engine plumbing.

Any other thoughts on what this thing is?

Looks like there's 3 panels not 4. The one facing camera + the one on the right have 9 holes and the one on the left has 12 holes, so 30 upper holes(+ 4 in the bottom?). 33 holes for engines and 1 filling line? I assume they changed the size of the CH4 downcomer(The huge pipe that was lifted up in the Highbay and presumably installed inside Booster 5 could be the new CH4 downcomer) to act as a "header tank" and this is the bottom end of the downcomer. The original SH downcomer was around 70-75cm in diameter, this thing seems a lot bigger in diameter.

You don't need 40 pipes for the outer engines, only the CH4 lines connect to the downcomer!
Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: equiserre on 10/03/2021 11:39 am
Was looking at the recent gridfin photos, and it is marvelous how agricultural and practical all Starship construction looks. You dont see high precision cmnponents everywhere like on other rockets, even Falcon 9. Only where needed.
Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: FlattestEarth on 10/03/2021 03:12 pm

Looks like there's 3 panels not 4. The one facing camera + the one on the right have 9 holes and the one on the left has 12 holes, so 30 upper holes(+ 4 in the bottom?). 33 holes for engines and 1 filling line? I assume they changed the size of the CH4 downcomer(The huge pipe that was lifted up in the Highbay and presumably installed inside Booster 5 could be the new CH4 downcomer) to act as a "header tank" and this is the bottom end of the downcomer. The original SH downcomer was around 70-75cm in diameter, this thing seems a lot bigger in diameter.

You don't need 40 pipes for the outer engines, only the CH4 lines connect to the downcomer!

20 top row holes for outer ring, 10 slightly lower holes for the inner ring, 3 lower holes for the center cluster?  We haven't seen a 13 engine thrust puck yet though.  Lower holes could also be lox infeed for center cluster.

Edit: someone on Reddit spotted the 13 engine thrust puck on the road so should be arriving soon.
Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: raivo45 on 10/04/2021 12:47 pm
Edit: someone on Reddit spotted the 13 engine thrust puck on the road so should be arriving soon.

Photo of the thrust puck:
Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: Dappa on 10/04/2021 01:32 pm
Edit: someone on Reddit spotted the 13 engine thrust puck on the road so should be arriving soon.

Photo of the thrust puck:
Appreciate the picture, but do you have the source for that?  A link where you found it perhaps?
Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: raivo45 on 10/04/2021 03:16 pm
Edit: someone on Reddit spotted the 13 engine thrust puck on the road so should be arriving soon.

Photo of the thrust puck:
Appreciate the picture, but do you have the source for that?  A link where you found it perhaps?
I have it but I don't want to post the link here directly because the person(older guy) shared the photo from his Google Photos that has his full name.

What's interesting is that one of the 9 raptor thrust pucks was spotted in Bellevue, Washington and this new one was spotted in Michigan.
Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: grndkntrl on 10/04/2021 03:19 pm
Edit: someone on Reddit spotted the 13 engine thrust puck on the road so should be arriving soon.

Photo of the thrust puck:
Appreciate the picture, but do you have the source for that?  A link where you found it perhaps?

not the same photo from the same person, but it was also spotted on the road by someone else on reddit and posted in the master update thread here: https://forum.nasaspaceflight.com/index.php?topic=52398.msg2295108#msg2295108
Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: r1279 on 10/04/2021 03:57 pm
I've not seen one of these before:

(https://forum.nasaspaceflight.com/index.php?action=dlattach;topic=52398.0;attach=2062770;image)

My thought though is that this is a support structure for the bottom of SuperHeavy to mount all the plumbing for the outer 20 engines to.  It doesn't *quite* make sense though - I could 15 holes facing Mary, (plus 2 at the bottom) - that makes 30 holes (34 including the bottom ones).  You'd expect 40 for the outer 20 engines.

Actually, scratch that, I think 15 is a trick of perspective.  There's 9 (plus one at the bottom) per panel.  4 panels means 40 total holes, so just right for this to be a mounting bracket for superheavy outer engine plumbing.

Any other thoughts on what this thing is?

Looks similar to part of the thrust puck / downcomer distribution we've seen before (without the plumbing or rest of the structure, just that initial cylinder) [source post (https://forum.nasaspaceflight.com/index.php?topic=52398.msg2240489#msg2240489)]

Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: Crispy on 10/04/2021 04:00 pm
Edit: someone on Reddit spotted the 13 engine thrust puck on the road so should be arriving soon.

Photo of the thrust puck:
Appreciate the picture, but do you have the source for that?  A link where you found it perhaps?

not the same photo from the same person, but it was also spotted on the road by someone else on reddit and posted in the master update thread here: https://forum.nasaspaceflight.com/index.php?topic=52398.msg2295108#msg2295108 (https://forum.nasaspaceflight.com/index.php?topic=52398.msg2295108#msg2295108)
They are different pucks. Note the different truck beds: The 8-ring one has a bed with circular holes and tidy hazard stripes. The 10-ring one has a bed with triangular holes and hardly any hazard stripes. The support frame is also slightly different. You can also just count and infer the number of holes.
https://forum.nasaspaceflight.com/index.php?action=dlattach;topic=54775.0;attach=2063051;image (https://forum.nasaspaceflight.com/index.php?action=dlattach;topic=54775.0;attach=2063051;image)
https://preview.redd.it/cyty8r7s0dq71.jpg?width=4032&format=pjpg&auto=webp&s=972b272558fa7013907026dd1512ea8dc4dc4646 (https://preview.redd.it/cyty8r7s0dq71.jpg?width=4032&format=pjpg&auto=webp&s=972b272558fa7013907026dd1512ea8dc4dc4646)
Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: AU1.52 on 10/04/2021 04:33 pm
Edit: someone on Reddit spotted the 13 engine thrust puck on the road so should be arriving soon.

Photo of the thrust puck:
Appreciate the picture, but do you have the source for that?  A link where you found it perhaps?

not the same photo from the same person, but it was also spotted on the road by someone else on reddit and posted in the master update thread here: https://forum.nasaspaceflight.com/index.php?topic=52398.msg2295108#msg2295108 (https://forum.nasaspaceflight.com/index.php?topic=52398.msg2295108#msg2295108)
They are different pucks. Note the different truck beds: The 8-ring one has a bed with circular holes and barely any hazard stripes. The 10-ring one has a bed with triangular holes and tatty hazard stripes. The support frame is also slightly different. You can also just count and infer the number of holes.
https://forum.nasaspaceflight.com/index.php?action=dlattach;topic=54775.0;attach=2063051;image (https://forum.nasaspaceflight.com/index.php?action=dlattach;topic=54775.0;attach=2063051;image)
https://preview.redd.it/cyty8r7s0dq71.jpg?width=4032&format=pjpg&auto=webp&s=972b272558fa7013907026dd1512ea8dc4dc4646 (https://preview.redd.it/cyty8r7s0dq71.jpg?width=4032&format=pjpg&auto=webp&s=972b272558fa7013907026dd1512ea8dc4dc4646)


The body of medusae. Just missing her many arms!
Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: beelsebob on 10/04/2021 05:59 pm
I've not seen one of these before:

(https://forum.nasaspaceflight.com/index.php?action=dlattach;topic=52398.0;attach=2062770;image)

My thought though is that this is a support structure for the bottom of SuperHeavy to mount all the plumbing for the outer 20 engines to.  It doesn't *quite* make sense though - I could 15 holes facing Mary, (plus 2 at the bottom) - that makes 30 holes (34 including the bottom ones).  You'd expect 40 for the outer 20 engines.

Actually, scratch that, I think 15 is a trick of perspective.  There's 9 (plus one at the bottom) per panel.  4 panels means 40 total holes, so just right for this to be a mounting bracket for superheavy outer engine plumbing.

Any other thoughts on what this thing is?

Looks like there's 3 panels not 4. The one facing camera + the one on the right have 9 holes and the one on the left has 12 holes, so 30 upper holes(+ 4 in the bottom?). 33 holes for engines and 1 filling line? I assume they changed the size of the CH4 downcomer(The huge pipe that was lifted up in the Highbay and presumably installed inside Booster 5 could be the new CH4 downcomer) to act as a "header tank" and this is the bottom end of the downcomer. The original SH downcomer was around 70-75cm in diameter, this thing seems a lot bigger in diameter.

You don't need 40 pipes for the outer engines, only the CH4 lines connect to the downcomer!

You're right ofc, 40 pipes was dumb.  Why would the bottom of the downcomer increase so much in diameter though?  I guess it could be just to make manufacturing easier, but if the downcomer diameter increases so much, wouldn't it then make it harder to get the O2 supply in to the centre engines?

One possibility:  Perhaps the existing diameter of downcomer would block plumbing for the 32 raptor version. Perhaps that lower hole is not the fueling line, but the O2 supply for the centre 3 engines, and there will be an internal oxygen 'downcomer' inside the CH4 downcomer.

Something like this:

(https://i.imgur.com/fOO2er9.png)

p.s. I love the idea of the bottom of the downcomer being known as "the medusa".
Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: warp99 on 10/05/2021 10:24 am
I've not seen one of these before:

(https://forum.nasaspaceflight.com/index.php?action=dlattach;topic=52398.0;attach=2062770;image)

My thought though is that this is a support structure for the bottom of SuperHeavy to mount all the plumbing for the outer 20 engines to.  It doesn't *quite* make sense though - I could 15 holes facing Mary, (plus 2 at the bottom) - that makes 30 holes (34 including the bottom ones).  You'd expect 40 for the outer 20 engines.

Actually, scratch that, I think 15 is a trick of perspective.  There's 9 (plus one at the bottom) per panel.  4 panels means 40 total holes, so just right for this to be a mounting bracket for superheavy outer engine plumbing.

Any other thoughts on what this thing is?

Looks like there's 3 panels not 4. The one facing camera + the one on the right have 9 holes and the one on the left has 12 holes, so 30 upper holes(+ 4 in the bottom?). 33 holes for engines and 1 filling line? I assume they changed the size of the CH4 downcomer(The huge pipe that was lifted up in the Highbay and presumably installed inside Booster 5 could be the new CH4 downcomer) to act as a "header tank" and this is the bottom end of the downcomer. The original SH downcomer was around 70-75cm in diameter, this thing seems a lot bigger in diameter.

You don't need 40 pipes for the outer engines, only the CH4 lines connect to the downcomer!

You're right ofc, 40 pipes was dumb.  Why would the bottom of the downcomer increase so much in diameter though?  I guess it could be just to make manufacturing easier, but if the downcomer diameter increases so much, wouldn't it then make it harder to get the O2 supply in to the centre engines?

One possibility:  Perhaps the existing diameter of downcomer would block plumbing for the 32 raptor version. Perhaps that lower hole is not the fueling line, but the O2 supply for the centre 3 engines, and there will be an internal oxygen 'downcomer' inside the CH4 downcomer.

Something like this:

(https://i.imgur.com/fOO2er9.png)

p.s. I love the idea of the bottom of the downcomer being known as "the medusa".
Yes pretty much like that but with three separate LOX pipes feeding the three center engines rather than a branching header. 

* Ten holes visible at the top of the cylinder showing half of the liquid methane feed pipes to the 20 fixed outer engines. 

* Five holes visible below them showing half of the liquid methane feed pipes for the 10 gimbaling engines on the outer edge of the thrust puck 

* Two holes at the bottom at 120 degree offset for the LOX feed pipes to the three central gimbaling engines 

Congratulations - the first solid confirmation of the 20-10-3 booster engine layout
Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: edzieba on 10/05/2021 12:44 pm
https://twitter.com/NASASpaceflight/status/1445030243236990983
I don't think it had been confirmed before what the business in the front party in the back 'Superheavy at the top Starship at the base' article's purpose was.
Presumably it can be stacked on top of Superheavy to test the Superheavy-side pushers, or used as a base to stack Starship onto to test Starship-side separation systems (e.g. data connections, latches).
Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: CorvusCorax on 10/05/2021 01:00 pm

Something like this:

<404 - file not found>


Minor off-topic nitpick, if you post an image you made, please attach it to the post directly, don't link 3rd party sites. These have a tendency to go away over time, or get blocked by add-blockers, create a privacy issue as they allow 3rd parties to monitor who reads this thread, to list some of the issues. It's highly encouraged to attach materials like that directly to the post whenever possible!
Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: CamiloPasin on 10/05/2021 03:54 pm
https://twitter.com/NASASpaceflight/status/1445030243236990983
I don't think it had been confirmed before what the business in the front party in the back 'Superheavy at the top Starship at the base' article's purpose was.
Presumably it can be stacked on top of Superheavy to test the Superheavy-side pushers, or used as a base to stack Starship onto to test Starship-side separation systems (e.g. data connections, latches).

It can not be stacked on top of a superheavy, the bottom of the hybrid article is not able to interface with the stage sep nor would it fit.

Also there is no pushers on any of the stages in stage sep, nor does it have data connections.

About the latches, theres no need to build an entire article with scraps just to test something they already tested with the actual ship on "fit checks and photo ops".
Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: Tangilinear Interjar on 10/05/2021 04:00 pm
I suspect that the odd hybrid piece is for testing the new Super Heavy can crusher rig. The reason they used a SS bottom dome is simply because it was cheaper, available, and irrelevant for the type of testing and calibration that they need to do.
Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: beelsebob on 10/06/2021 12:59 am
I suspect that the odd hybrid piece is for testing the new Super Heavy can crusher rig. The reason they used a SS bottom dome is simply because it was cheaper, available, and irrelevant for the type of testing and calibration that they need to do.
It would surprise me - the can crusher is configured with rams for 29 engines.  The Starship thrust puck is not designed for that.

Not impossible though.
Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: grndkntrl on 10/06/2021 01:18 am
I suspect that the odd hybrid piece is for testing the new Super Heavy can crusher rig. The reason they used a SS bottom dome is simply because it was cheaper, available, and irrelevant for the type of testing and calibration that they need to do.
It would surprise me - the can crusher is configured with rams for 29 engines.  The Starship thrust puck is not designed for that.

Not impossible though.

If you look closely at any of Mauricio's aerial photos, or the detailed shots of it from Mary & Nic, you can see that the 20 rams around the perimeter of the crusher aren't in the positions for the 20 RBoost mounts.

These rams are a fair bit further out than the ~9m diameter required for them to do that, and they have a hammerhead/T-shaped head on the ram, which corresponds to having a looped strap going from one arm of the T up to the top cap of the crusher, through one of the 20 eyelets, and then back down to the other arm of the T of the same ram.

There are hold-down clamps in the usual 9m diameter for the rim of the booster.

This way they can apply load to both the top & bottom of a booster and simulate both the thrust of the engines from below and the load from a Starship on top.

The internal volume of the crusher is open so they can just drop in a thrust ram with either 9 or 13 rams, depending on how many RCenters the booster under test is built to have.
Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: alugobi on 10/06/2021 03:54 am
I wonder how many times they'll have to use it before they get mfg configured to produce what they need in a validated process. 
Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: grndkntrl on 10/06/2021 11:25 am
I wonder how many times they'll have to use it before they get mfg configured to produce what they need in a validated process.

I think - given how much reinforced concrete they put into the inner base of the structure, and then all of the plumbing to/from it to the mini GSE tank, the long horizontal compressed air/hydraulic reservoir(?) tank and other supporting hardware around it on its pad - it's going to be a permanent feature to interrogate test all boosters that come off of the production line.
Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: rsdavis9 on 10/06/2021 12:46 pm
I wonder how many times they'll have to use it before they get mfg configured to produce what they need in a validated process.

I think - given how much reinforced concrete they put into the inner base of the structure, and then all of the plumbing to/from it to the mini GSE tank, the long horizontal compressed air/hydraulic reservoir(?) tank and other supporting hardware around it on its pad - it's going to be a permanent feature to interrogate test all boosters that come off of the production line.

Maybe not every booster. Just the ones with large structural changes. Which might be everyone for a while.
Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: samgineer on 10/06/2021 02:27 pm
Can crusher will be likely used to test design margins and optimize structures. Actual boosters and starships are overbuild by idea "dumb but it works" and it's fast. For more advanced vehicles, meant to be not too heavy but durable and reliable they need test and iterate and find out how much material shaved is too much. Best example is Falcon 9, at first build fast, cheap and reliable enough, today after many iteration, much more money spent and structural testing they done at McGregor  it's very well optimized vehicle by weight, reliability, reusability and cost. Even B3 and B4 are very different, for example B3 had stringers in LCH4 lank, B4 is without them. 
Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: livingjw on 10/06/2021 03:42 pm
The Super Heavy is under compression during launch so buckling margins need to be determined. Buckling analysis has considerable uncertainty so testing is called for; hence, the can crusher. Once actual margins are known, they can probably shave some weight.

John
Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: edzieba on 10/07/2021 10:32 am
I would expect to see the 'can crusher' used in the same way as the smaller scale structural test stands at McGregor for Falcon: structural tests for every new design or significant design change, no need to test every single vehicle when the design is stable. Like with the early Falcons, Super Heavy iterations will be almost every booster near the start of the programme, but as the design stabilises we will start to see boosters that do not need static testing.
Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: capoman on 10/07/2021 12:39 pm
I would expect to see the 'can crusher' used in the same way as the smaller scale structural test stands at McGregor for Falcon: structural tests for every new design or significant design change, no need to test every single vehicle when the design is stable. Like with the early Falcons, Super Heavy iterations will be almost every booster near the start of the programme, but as the design stabilises we will start to see boosters that do not need static testing.

That pretty well jives with comments made by Elon about eliminating unnecessary in-process testing.
Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: FutureSpaceTourist on 10/10/2021 10:17 am
https://twitter.com/starship_sults/status/1447038745799274496

Quote
SpaceX weekly timeline.
Oct 3rd Ė Oct 9th
Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: Fizrock on 10/10/2021 01:28 pm
https://twitter.com/AustinDeSisto/status/1447190114568970245
 
 
This Raptor appears to be sporting a protective skirt. That's new. I wonder if it'll get a full boot of they'll leave it at that.
Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: maquinsa on 10/10/2021 01:40 pm
https://twitter.com/AustinDeSisto/status/1447190114568970245
??? ??? ???
Ok this has thrown me off.
Is that thing around the throat the wheel looking thing in the starship thrust puck?

if it is, I'm going to have to rethink how the hell RVacs attach to the starship thrust puck.
It leaves me with so many question:

- is the powerhead embeded in the low fuel tank?
- is the engine atached to the starship through the throat like on pic 1 or through the top of the lox turbopump
  assembly as normal raptors are attached (pic 2).
- if its like in pic 2 the thing around the throat could be to stabilize the engine through a mecanism like the one in pic
  3

have I somehow missed something??
please help me!!

edit: just saw Fizrock's post. A protective skirt makes a lot of sense. That would be similar to pic 3
Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: Eer on 10/10/2021 02:56 pm
Pic 3 combined with the really flat thrust puck we’ve seen would seem to go together.
Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: cdebuhr on 10/10/2021 03:43 pm
Pic 3 combined with the really flat thrust puck weíve seen would seem to go together.
The "really flat thrust puck" you refer to is for the centre cluster of 9 (or now 13, in the latest arrival) raptors on Superheavy.  No Rvacs there, and nothing to do with Starship itself.  This new addition to Rvac is pretty clearly the start of some sort of power-head shielding for the engines.  I won't be surprised at all to see it (or something like it) start to appear on all the raptors soon.
Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: GHogan on 10/11/2021 06:25 pm
NASA has published a document about observing Starship during reentry.
 
https://ntrs.nasa.gov/citations/20210020835 
 
Of note:
 
- NASA is making a special imaging system to view the reentry with an infrared camera mounted on a WB-57.
- Starship's heat tiles are called "Starbricks". 
- NASA is targeting a Starship reentry observation in March of 2022.
Someone should start a poll. Will this be S20, 21, 22, 23, later? never? I will guess S22. (Sorry for first posting this on Master Thread. I moved it.)
Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: steveleach on 10/11/2021 06:31 pm
NASA has published a document about observing Starship during reentry.
 
https://ntrs.nasa.gov/citations/20210020835 
 
Of note:
 
- NASA is making a special imaging system to view the reentry with an infrared camera mounted on a WB-57.
- Starship's heat tiles are called "Starbricks". 
- NASA is targeting a Starship reentry observation in March of 2022.
Someone should start a poll. Will this be S20, 21, 22, 23, later? never? I will guess S22. (Sorry for first posting this on Master Thread. I moved it.)
Interesting. Can NASA justify working on this even though they don't have any Starship projects they are officially allowed to work on? They may need another special imaging system to probe the legal grey areas here.
Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: DanClemmensen on 10/11/2021 06:53 pm
NASA has published a document about observing Starship during reentry.
 
https://ntrs.nasa.gov/citations/20210020835 
 
Of note:
 
- NASA is making a special imaging system to view the reentry with an infrared camera mounted on a WB-57.
- Starship's heat tiles are called "Starbricks". 
- NASA is targeting a Starship reentry observation in March of 2022.
Someone should start a poll. Will this be S20, 21, 22, 23, later? never? I will guess S22. (Sorry for first posting this on Master Thread. I moved it.)
Interesting. Can NASA justify working on this even though they don't have any Starship projects they are officially allowed to work on? They may need another special imaging system to probe the legal grey areas here.
The NASA effort has nothing to do with Starship (wink wink non nod). It is merely a target for testing their new thermal imaging system.
Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: sferrin on 10/11/2021 06:55 pm
NASA has published a document about observing Starship during reentry.
 
https://ntrs.nasa.gov/citations/20210020835 (https://ntrs.nasa.gov/citations/20210020835) 
 
Of note:
 
- NASA is making a special imaging system to view the reentry with an infrared camera mounted on a WB-57.
- Starship's heat tiles are called "Starbricks". 
- NASA is targeting a Starship reentry observation in March of 2022.
Someone should start a poll. Will this be S20, 21, 22, 23, later? never? I will guess S22. (Sorry for first posting this on Master Thread. I moved it.)
Interesting. Can NASA justify working on this even though they don't have any Starship projects they are officially allowed to work on? They may need another special imaging system to probe the legal grey areas here.


Could be Starship is just a target of opportunity.  In other words, NASA may be just taking advantage of the opportunity, not assisting SpaceX with development.
Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: equiserre on 10/11/2021 07:01 pm
NASA has published a document about observing Starship during reentry.
 
https://ntrs.nasa.gov/citations/20210020835 
 
Of note:
 
- NASA is making a special imaging system to view the reentry with an infrared camera mounted on a WB-57.
- Starship's heat tiles are called "Starbricks". 
- NASA is targeting a Starship reentry observation in March of 2022.
Someone should start a poll. Will this be S20, 21, 22, 23, later? never? I will guess S22. (Sorry for first posting this on Master Thread. I moved it.)
Interesting. Can NASA justify working on this even though they don't have any Starship projects they are officially allowed to work on? They may need another special imaging system to probe the legal grey areas here.
Spacex has a contract with Nasa for this, previous to HLS. Think it was one of those batches of technical assistance with no money involved
Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: alugobi on 10/11/2021 07:28 pm
The latest flyover shows that they moved B4 over a little on to the new deep foundation that they poured there.  Looks like it's still on a transporter, but we'll see if they lower it on to the concrete.
Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: joek on 10/11/2021 07:59 pm
Spacex has a contract with Nasa for this, previous to HLS. Think it was one of those batches of technical assistance with no money involved
Cite please. If there was "no money involved", that would most likely fall under an SAA (Space Act Agreement). Last SAA amendment was Mar-2017 (https://www.nasa.gov/sites/default/files/atoms/files/saa-qa-14-18882_ffd_amendment_1_02-24-2017_final-signed-redacted.pdf) which, as far as I can tell, would not include such.
Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: joek on 10/11/2021 08:06 pm
Could be Starship is just a target of opportunity.  In other words, NASA may be just taking advantage of the opportunity, not assisting SpaceX with development.

Yes. NASA wants data related to EDL; SpaceX wants whatever data NASA can provide related to EDL. Win-win. NASA development of observational capability is worth their investment to obtain accurate observations. Win-win.
Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: Reynold on 10/11/2021 08:23 pm
I do wonder if the photo of the thermal protection tiles on the Starship on the upper right of the NASA poster in that Starship reentry proposal came from NSF, or if they had their own person out in TX taking a photo of it.  Does anyone recognize the exact photo? 
Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: joek on 10/11/2021 08:25 pm
The NASA effort has nothing to do with Starship (wink wink non nod). It is merely a target for testing their new thermal imaging system.

That's rather disingenuous. Do you really think: (a) NASA has a pet project using this as an target-excuse to develop-deploy; or (b) that NASA is truly interested in collecting data which requires that capability? I would argue the latter; if the former, you're going to have to do better than "wink wink non nod" innuendo. It may not be exclusive to SS, but certainly inclusive of other efforts. (Please note that NASA has deployed similar assets-capabilities for EDL information gathering exclusive of individual missions.)
Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: DanClemmensen on 10/11/2021 08:57 pm
The NASA effort has nothing to do with Starship (wink wink non nod). It is merely a target for testing their new thermal imaging system.

That's rather disingenuous. Do you really think: (a) NASA has a pet project using this as an target-excuse to develop-deploy; or (b) that NASA is truly interested in collecting data which requires that capability? I would argue the latter; if the former, you're going to have to do better than "wink wink non nod" innuendo. It may not be exclusive to SS, but certainly inclusive of other efforts. (Please note that NASA has deployed similar assets-capabilities for EDL information gathering exclusive of individual missions.)

I was unclear, sorry.  NASA is developing a new imaging system. SpaceX cannot prevent NASA from testing it during  this opportunity. SpaceX also cannot prevent NASA from using publicly available information about the target system, and I don't think NASA can prevent SpaceX from accessing the results unless there is a national security classification. The only possible objection would be some sort of wacko objection raised by the BO suing machine.

With no inside information at all, I speculate that SpaceX already has a plan to deploy the appropriate imaging systems of their own at all re-entry sites and that they will not change these plans based on the existence of a new experimental NASA system that may or may not be able to acquire additional data at one site.
Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: WormPicker959 on 10/11/2021 09:03 pm
The nasa link contains some extra information, but I don't have the expertise to properly figure it out.

The "Funding Numbers" for the SCIFLI project are listed as "WBS: 571232.04.32.23" and "WBS: 571232.04.49.23". From what I can gather WBS is the 20180000844.pdf]numbering system for project management used at NASA (https://explorers.larc.nasa.gov/HPMIDEX/pdf_files/08_[NASA_WBS_Handbook_). The first number is the main project number, associated with either Spaceflight or Technology Development, then the next number is the main subcategory, and then after than the numbers seem to be specific to the project/program etc. I don't know what project "571232" corresponds to, but other technical reports with that same project number are various sorts of tech development happening at NASA facilities, so I'm guessing it's project bomber associated with Technology Development. That would mean "04" refers to... "Technology Development" (as opposed to "project management", "analysis", etc. (see attached screenshot).

tl;dr: the numbers give a clue as to what this is. It's a technology development project at a NASA facility (NASA Langley), similar to projects involving advanced Hall thrusters, 3d printing engine parts, and friction stir welding advances.
Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: eriblo on 10/11/2021 09:03 pm
I do wonder if the photo of the thermal protection tiles on the Starship on the upper right of the NASA poster in that Starship reentry proposal came from NSF, or if they had their own person out in TX taking a photo of it.  Does anyone recognize the exact photo?
If it is not this one by Jack Beyer from this post (https://forum.nasaspaceflight.com/index.php?topic=52398.msg2234346#msg2234346) it is taken from the same place in identical light (SN15 on 2021-05-07). Amusingly, the first image search result is a very similar crop in this r/SpaceXMasterRace post:
https://old.reddit.com/r/SpaceXMasterrace/comments/n6fnoq/news_be_like_sn15_considered_failure_after_heat/
Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: WormPicker959 on 10/11/2021 09:09 pm
The NASA effort has nothing to do with Starship (wink wink non nod). It is merely a target for testing their new thermal imaging system.

That's rather disingenuous. Do you really think: (a) NASA has a pet project using this as an target-excuse to develop-deploy; or (b) that NASA is truly interested in collecting data which requires that capability? I would argue the latter; if the former, you're going to have to do better than "wink wink non nod" innuendo. It may not be exclusive to SS, but certainly inclusive of other efforts. (Please note that NASA has deployed similar assets-capabilities for EDL information gathering exclusive of individual missions.)

I was unclear, sorry.  NASA is developing a new imaging system. SpaceX cannot prevent NASA from testing it during  this opportunity. SpaceX also cannot prevent NASA from using publicly available information about the target system, and I don't think NASA can prevent SpaceX from accessing the results unless there is a national security classification. The only possible objection would be some sort of wacko objection raised by the BO suing machine.

With no inside information at all, I speculate that SpaceX already has a plan to deploy the appropriate imaging systems of their own at all re-entry sites and that they will not change these plans based on the existence of a new experimental NASA system that may or may not be able to acquire additional data at one site.

Just to chime in here. I think it's silly to think that NASA and SpaceX are not already talking about several aspects of Starship, and have been for some time. There's plenty of evidence of it, and the two entities have a long (and ongoing) track record of cooperation.

Starship is part of an official NASA headline program for chrissakes. Of course they'll collaborate on technology development.
Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: AnalogMan on 10/11/2021 09:12 pm
Spacex has a contract with Nasa for this, previous to HLS. Think it was one of those batches of technical assistance with no money involved
Cite please. If there was "no money involved", that would most likely fall under an SAA (Space Act Agreement). Last SAA amendment was Mar-2017 (https://www.nasa.gov/sites/default/files/atoms/files/saa-qa-14-18882_ffd_amendment_1_02-24-2017_final-signed-redacted.pdf) which, as far as I can tell, would not include such.

Might be related to these attached documents.

From the second doc:

"NASA Langley Research Center will use reasonable efforts to:

1.  Lead biweekly (or as necessary) team meetings via teleconference to identify
    requirements to enable surface temperature from infrared measurements during the
    flight/reentry of the Starship vehicle."

[...]
Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: WormPicker959 on 10/11/2021 09:14 pm
Spacex has a contract with Nasa for this, previous to HLS. Think it was one of those batches of technical assistance with no money involved
Cite please. If there was "no money involved", that would most likely fall under an SAA (Space Act Agreement). Last SAA amendment was Mar-2017 (https://www.nasa.gov/sites/default/files/atoms/files/saa-qa-14-18882_ffd_amendment_1_02-24-2017_final-signed-redacted.pdf) which, as far as I can tell, would not include such.

Might be related to these attached documents.

From the second doc:

"NASA Langley Research Center will use reasonable efforts to:

1.  Lead biweekly (or as necessary) team meetings via teleconference to identify
    requirements to enable surface temperature from infrared measurements during the
    flight/reentry of the Starship vehicle."

[...]


Nice find! Can you share how/where you found them? I did some really basic sleuthing and came up with very little...
Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: StevenOBrien on 10/11/2021 09:44 pm
The NASA effort has nothing to do with Starship (wink wink non nod). It is merely a target for testing their new thermal imaging system.

That's rather disingenuous. Do you really think: (a) NASA has a pet project using this as an target-excuse to develop-deploy; or (b) that NASA is truly interested in collecting data which requires that capability? I would argue the latter; if the former, you're going to have to do better than "wink wink non nod" innuendo. It may not be exclusive to SS, but certainly inclusive of other efforts. (Please note that NASA has deployed similar assets-capabilities for EDL information gathering exclusive of individual missions.)

I was unclear, sorry.  NASA is developing a new imaging system. SpaceX cannot prevent NASA from testing it during  this opportunity. SpaceX also cannot prevent NASA from using publicly available information about the target system, and I don't think NASA can prevent SpaceX from accessing the results unless there is a national security classification. The only possible objection would be some sort of wacko objection raised by the BO suing machine.

With no inside information at all, I speculate that SpaceX already has a plan to deploy the appropriate imaging systems of their own at all re-entry sites and that they will not change these plans based on the existence of a new experimental NASA system that may or may not be able to acquire additional data at one site.

Just to chime in here. I think it's silly to think that NASA and SpaceX are not already talking about several aspects of Starship, and have been for some time. There's plenty of evidence of it, and the two entities have a long (and ongoing) track record of cooperation.

Starship is part of an official NASA headline program for chrissakes. Of course they'll collaborate on technology development.
I think Dan's comments were in reference to the ongoing litigation against NASA over the HLS contract. While the litigation is ongoing, the HLS team is prevented from working on Starship with SpaceX in any official capacity.
Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: steveleach on 10/11/2021 10:33 pm
The NASA effort has nothing to do with Starship (wink wink non nod). It is merely a target for testing their new thermal imaging system.

That's rather disingenuous. Do you really think: (a) NASA has a pet project using this as an target-excuse to develop-deploy; or (b) that NASA is truly interested in collecting data which requires that capability? I would argue the latter; if the former, you're going to have to do better than "wink wink non nod" innuendo. It may not be exclusive to SS, but certainly inclusive of other efforts. (Please note that NASA has deployed similar assets-capabilities for EDL information gathering exclusive of individual missions.)

I was unclear, sorry.  NASA is developing a new imaging system. SpaceX cannot prevent NASA from testing it during  this opportunity. SpaceX also cannot prevent NASA from using publicly available information about the target system, and I don't think NASA can prevent SpaceX from accessing the results unless there is a national security classification. The only possible objection would be some sort of wacko objection raised by the BO suing machine.

With no inside information at all, I speculate that SpaceX already has a plan to deploy the appropriate imaging systems of their own at all re-entry sites and that they will not change these plans based on the existence of a new experimental NASA system that may or may not be able to acquire additional data at one site.

Just to chime in here. I think it's silly to think that NASA and SpaceX are not already talking about several aspects of Starship, and have been for some time. There's plenty of evidence of it, and the two entities have a long (and ongoing) track record of cooperation.

Starship is part of an official NASA headline program for chrissakes. Of course they'll collaborate on technology development.
I think Dan's comments were in reference to the ongoing litigation against NASA over the HLS contract. While the litigation is ongoing, the HLS team is prevented from working on Starship with SpaceX in any official capacity.
Though the SAA that AnalogMan found, above, shows that this imaging work is not part of the HLS contract and so presumably unaffected by that litigation.
Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: DanClemmensen on 10/11/2021 11:08 pm
NASA has published a document about observing Starship during reentry.
 
https://ntrs.nasa.gov/citations/20210020835 
 
Of note:
 
- NASA is making a special imaging system to view the reentry with an infrared camera mounted on a WB-57.
- Starship's heat tiles are called "Starbricks". 
- NASA is targeting a Starship reentry observation in March of 2022.
Someone should start a poll. Will this be S20, 21, 22, 23, later? never? I will guess S22. (Sorry for first posting this on Master Thread. I moved it.)
As a side note, I find it interesting that NASA is flying this system on an airframe that was designed before the first satellite was launched and  manufactured before the first Apollo mission.
Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: su27k on 10/12/2021 03:12 am
Spacex has a contract with Nasa for this, previous to HLS. Think it was one of those batches of technical assistance with no money involved
Cite please. If there was "no money involved", that would most likely fall under an SAA (Space Act Agreement). Last SAA amendment was Mar-2017 (https://www.nasa.gov/sites/default/files/atoms/files/saa-qa-14-18882_ffd_amendment_1_02-24-2017_final-signed-redacted.pdf) which, as far as I can tell, would not include such.

Might be related to these attached documents.

From the second doc:

"NASA Langley Research Center will use reasonable efforts to:

1.  Lead biweekly (or as necessary) team meetings via teleconference to identify
    requirements to enable surface temperature from infrared measurements during the
    flight/reentry of the Starship vehicle."

[...]


Press release when this was announced last year: https://www.nasa.gov/directorates/spacetech/2020_NASA_Announcement_of_Collaboration_Opportunity_ACO_Selections/

Quote from: NASA
Space Exploration Technologies Corp. (SpaceX) of Hawthorne, California

SpaceX will partner with Langley to capture imagery and thermal measurements of its Starship vehicle during orbital re-entry over the Pacific Ocean. With the data, the company plans to advance a reusable thermal protection system, which protects the vehicle from aerodynamic heating, for missions returning from low-Earth orbit, the Moon, and Mars.
Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: Vultur on 10/12/2021 05:11 am
I wonder where March 2022 comes from? I wouldn't have thought anyone (even SpaceX) could reliably predict Starship flight timelines, since there are still regulatory steps that need to be done.
Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: Oersted on 10/12/2021 08:20 am
NASA has published a document about observing Starship during reentry.
 
https://ntrs.nasa.gov/citations/20210020835 
 
Of note:
 
- NASA is making a special imaging system to view the reentry with an infrared camera mounted on a WB-57.
- Starship's heat tiles are called "Starbricks". 
- NASA is targeting a Starship reentry observation in March of 2022.
Someone should start a poll. Will this be S20, 21, 22, 23, later? never? I will guess S22. (Sorry for first posting this on Master Thread. I moved it.)
As a side note, I find it interesting that NASA is flying this system on an airframe that was designed before the first satellite was launched and  manufactured before the first Apollo mission.

I found this page on one of the WB-57 airframes. It was BUILT before or during 1952! Wings replaced at a later date, it seems.

https://www.aerialvisuals.ca/AirframeDossier.php?Serial=140386
Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: Snail on 10/12/2021 10:55 am
I wonder where March 2022 comes from?

They said they are still developing the infrared imaging system. Maybe said system will be ready no earlier than March:

twitter.com/thesheetztweetz/status/1447613057161736193/photo/1
Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: sferrin on 10/12/2021 11:51 am
NASA has published a document about observing Starship during reentry.
 
https://ntrs.nasa.gov/citations/20210020835 (https://ntrs.nasa.gov/citations/20210020835) 
 
Of note:
 
- NASA is making a special imaging system to view the reentry with an infrared camera mounted on a WB-57.
- Starship's heat tiles are called "Starbricks". 
- NASA is targeting a Starship reentry observation in March of 2022.
Someone should start a poll. Will this be S20, 21, 22, 23, later? never? I will guess S22. (Sorry for first posting this on Master Thread. I moved it.)
As a side note, I find it interesting that NASA is flying this system on an airframe that was designed before the first satellite was launched and  manufactured before the first Apollo mission.


It's all about payload to altitude.  The WB-57 beats the U-2 in that regard.


(RB-57F, with extra engines.)
Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: OTV Booster on 10/13/2021 01:04 am
NASA has published a document about observing Starship during reentry.
 
https://ntrs.nasa.gov/citations/20210020835 (https://ntrs.nasa.gov/citations/20210020835) 
 
Of note:
 
- NASA is making a special imaging system to view the reentry with an infrared camera mounted on a WB-57.
- Starship's heat tiles are called "Starbricks". 
- NASA is targeting a Starship reentry observation in March of 2022.
Someone should start a poll. Will this be S20, 21, 22, 23, later? never? I will guess S22. (Sorry for first posting this on Master Thread. I moved it.)
As a side note, I find it interesting that NASA is flying this system on an airframe that was designed before the first satellite was launched and  manufactured before the first Apollo mission.
Hmm. Makes me wonder if there will be a few 9m Starships still kicking around in 60-70 years. Maybe highly modified, stripped down and no longer certified for EDL.
Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: ChrisC on 10/13/2021 03:24 am
Two Raptor Boost engines, removed from Booster 4, were loaded onto the RaptorVan for delivery to McGregor. Meanwhile, Ship 20 waits for its first Static Fire attempt. Video and Pictures from Mary (@BocaChicaGal), Nic (@nicansuini) and the NSF Robots

Just wanted to say, THANK YOU for getting this daily video out quickly.  Lately the daily video releases have been slipping past midnight Eastern time (LOL not EST :) ) which means I don't get to watch it until sometime the next day ...  Thank you NSF production team!
Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: Tangilinear Interjar on 10/13/2021 03:25 pm
Something interesting showed up on the Super Heavy, a hard point like the SS has. I went back and checked some pictures and it looks like the spacing from this part to the lift point on both vehicles is the same (roughly 6.5 rings, you pixel counters can double check me).

I've also noticed some structure on the bottom of the chopsticks that doesn't have anything attached yet but does have a couple hydraulic circuits routed to that makes me think there's going to be a positive hold and control mechanism that attaches to the vehicles for more precise control during placement.

All pictures from Boca Chica Gal.
Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: WiresMN on 10/13/2021 03:39 pm
Something interesting showed up on the Super Heavy, a hard point like the SS has. I went back and checked some pictures and it looks like the spacing from this part to the lift point on both vehicles is the same (roughly 6.5 rings, you pixel counters can double check me).

I've also noticed some structure on the bottom of the chopsticks that doesn't have anything attached yet but does have a couple hydraulic circuits routed to that makes me think there's going to be a positive hold and control mechanism that attaches to the vehicles for more precise control during placement.

All pictures from Boca Chica Gal.

Nice find! I had seen the hard point on SS, but had missed it on SH. This answers one of my questions I have had since first seeing the single lift point on SH. How do you prevent this thing from becoming a very large pendulum?
Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: gdipasquale on 10/13/2021 06:35 pm
Guys,
does that means Booster 5's Grid Fins will be able to rotate?
I don't remember seeing this mechanic in Booster 4 ???
Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: WiresMN on 10/13/2021 06:39 pm
Guys,
does that means Booster 5's Grid Fins will be able to rotate?
I don't remember seeing this mechanic in Booster 4 ???

Yes, it was also discussed in Everyday Astronaut's interview with Elon. They can rotate but do not fold flat.
They have changed the outer brackets for the grid fins. The new attachment looks clean compared to the one on #4
Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: grndkntrl on 10/13/2021 06:40 pm
Guys,
does that means Booster 5's Grid Fins will be able to rotate?
I don't remember seeing this mechanic in Booster 4 ???

Booster 4's grid fins can also rotate. This is long confirmed, with Elon also referring to it in his interview with Tim.
Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: xvel on 10/13/2021 07:07 pm
Gridfins ROTATE on every spacex rocket but on superheavy they DON'T FOLD as opposed to Falcon 9 where they do fold down.
Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: alugobi on 10/13/2021 07:35 pm
They must rotate in order function as intended. 
Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: warp99 on 10/13/2021 07:50 pm
Guys,
does that means Booster 5's Grid Fins will be able to rotate?
I don't remember seeing this mechanic in Booster 4 ???

Yes, it was also discussed in Everyday Astronaut's interview with Elon. They can rotate but do not fold flat.
They have changed the outer brackets for the grid fins. The new attachment looks clean compared to the one on #4
The question is whether they can rotate 180 degrees so that the grid fins are facing upwards during ascent to minimise drag. 

The previous mounting design limited the grid fin rotation to about 60 degrees either way which meant they would be facing backwards during ascent which would lead to higher drag at transonic speeds.
Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: Vettedrmr on 10/13/2021 08:05 pm
No, they don't rotate 90 degrees (which is what I think you meant).  180 degrees would give you essentially the same drag profile as 0 degrees.  F9's only rotated about +/- 20 degrees (basing that on the AoA the booster achieves during the re-entry/landing phase).
Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: TomH on 10/13/2021 10:17 pm
No, they don't rotate 90 degrees (which is what I think you meant).  180 degrees would give you essentially the same drag profile as 0 degrees.  F9's only rotated about +/- 20 degrees (basing that on the AoA the booster achieves during the re-entry/landing phase).

He may well have meant 180į as that would mean that pointed edges would be pointed up into the airflow as opposed to blunt edges, for better aerodynamics while V is positive on the z axis. During EDL, V is negative on the z axis and those points interface the air before the main body of the grid. The same question has been posed before.
Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: Stan-1967 on 10/13/2021 11:46 pm

The question is whether they can rotate 180 degrees so that the grid fins are facing upwards during ascent to minimise drag. 

The previous mounting design limited the grid fin rotation to about 60 degrees either way which meant they would be facing backwards during ascent which would lead to higher drag at transonic speeds.

IIRC the grid fins are scalloped on the leading edges to manage the shock front and choking of the flow through the fin lattice.  Functionality is not about minimizing drag, it is about maximizing control moment for a given size & mass.  The choice of how much they can rotate is likely about keeping the system simple as possible

I would guess SpaceX has likely weighed these losses against the more simple design & this resulted in the current configuration.  That being said, I would not be surprised if they change it back to the F9 style fins, or even scallop the leading edges of the grids as oriented for the ascent.
Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: cdebuhr on 10/14/2021 01:39 am

The question is whether they can rotate 180 degrees so that the grid fins are facing upwards during ascent to minimise drag. 

The previous mounting design limited the grid fin rotation to about 60 degrees either way which meant they would be facing backwards during ascent which would lead to higher drag at transonic speeds.

IIRC the grid fins are scalloped on the leading edges to manage the shock front and choking of the flow through the fin lattice.  Functionality is not about minimizing drag, it is about maximizing control moment for a given size & mass.  The choice of how much they can rotate is likely about keeping the system simple as possible

I would guess SpaceX has likely weighed these losses against the more simple design & this resulted in the current configuration.  That being said, I would not be surprised if they change it back to the F9 style fins, or even scallop the leading edges of the grids as oriented for the ascent.
I would.  As you say, they've decided the mass penalty of the more complex mechanism more than offsets the potential drag savings.  As for scalloping the leading edges, if that truly is all about increasing control authority, then there really would be no point.  They neither want nor need grid fin control authority on the way up - they've got more control than they need from Raptor TVC.
Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: Stan-1967 on 10/14/2021 02:00 am

As for scalloping the leading edges, if that truly is all about increasing control authority, then there really would be no point.  They neither want nor need grid fin control authority on the way up - they've got more control than they need from Raptor TVC.

The idea of scalloping the gridfins for the way up ( top edges) would not be for control authority, as you correctly note, it would be to possibly have a quicker transition through the subsonic-transonic-supersonic regime.  If you can initiate & stabilize the shock front sooner & resume flow through the lattice, you may save on aero losses and peak torque loading on the gridfin, which may also save some mass.
Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: zodiacchris on 10/15/2021 04:09 pm
Well, after the crazy rush of getting the launch table, S20 and B4 finished and then the blink and you miss it stacking, I guess we all figured that things would feel really slow afterwards. And I know, they are still crazily busy building Stage 0 and GSE while waiting for the permits to come through and in no way am I complaining or feel entitled or whateverÖ

But boy, I feel like an eight year old the day before Xmas, worse, the permit for Xmas could still be months away and watching barrel sections and raptors being shuffled around just isnít doing the trick. Checking progress on NSF is like looking at the clock on the wall, only to find that what feels like hours has only been five minutesÖ

With the launch probably slipping into next year and maybe S20 and B4 suffering virgin deaths as s21 and B5 are breathing down their necks patience is a virtue, I know. And itĎll be absolutely awesome to see the full stack finally launch but right now Iím suffering from serious withdrawal symptoms.

This is probably the least relevant post in my 11 year membership, Iíll see myself outÖ ::)
Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: Vultur on 10/15/2021 08:58 pm
Any idea why the static fire might have been canceled at the "last minute" last night?

I'm kind of surprised there's no closure for tonight to try again...
Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: Lars-J on 10/15/2021 11:06 pm

The question is whether they can rotate 180 degrees so that the grid fins are facing upwards during ascent to minimise drag. 

The previous mounting design limited the grid fin rotation to about 60 degrees either way which meant they would be facing backwards during ascent which would lead to higher drag at transonic speeds.

IIRC the grid fins are scalloped on the leading edges to manage the shock front and choking of the flow through the fin lattice.  Functionality is not about minimizing drag, it is about maximizing control moment for a given size & mass.  The choice of how much they can rotate is likely about keeping the system simple as possible

I would guess SpaceX has likely weighed these losses against the more simple design & this resulted in the current configuration.  That being said, I would not be surprised if they change it back to the F9 style fins, or even scallop the leading edges of the grids as oriented for the ascent.

Or they could do something even simpler... If the fins do not fold, then why use grid fins at all? That was the main reason for grid fins in the first place, unless I am mistaken. I would not be surprised to see them revert to a plain (New Glenn-style) fin.

But perhaps grid fins have some other advantage, like control authority in the transonic speeds?
Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: Redclaws on 10/15/2021 11:07 pm

The question is whether they can rotate 180 degrees so that the grid fins are facing upwards during ascent to minimise drag. 

The previous mounting design limited the grid fin rotation to about 60 degrees either way which meant they would be facing backwards during ascent which would lead to higher drag at transonic speeds.

IIRC the grid fins are scalloped on the leading edges to manage the shock front and choking of the flow through the fin lattice.  Functionality is not about minimizing drag, it is about maximizing control moment for a given size & mass.  The choice of how much they can rotate is likely about keeping the system simple as possible

I would guess SpaceX has likely weighed these losses against the more simple design & this resulted in the current configuration.  That being said, I would not be surprised if they change it back to the F9 style fins, or even scallop the leading edges of the grids as oriented for the ascent.

Or they could do something even simpler... If the fins do not fold, then why use grid fins at all? That was the main reason for grid fins in the first place, unless I am mistaken. I would not be surprised to see them revert to a plain (New Glenn-style) fin.

But perhaps grid fins have some other advantage, like control authority in the transonic speeds?

I thought grid fins were particularly well suited to supersonic control, and lighter for the control authority provided?
Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: S.Paulissen on 10/16/2021 12:24 am

The question is whether they can rotate 180 degrees so that the grid fins are facing upwards during ascent to minimise drag. 

The previous mounting design limited the grid fin rotation to about 60 degrees either way which meant they would be facing backwards during ascent which would lead to higher drag at transonic speeds.

IIRC the grid fins are scalloped on the leading edges to manage the shock front and choking of the flow through the fin lattice.  Functionality is not about minimizing drag, it is about maximizing control moment for a given size & mass.  The choice of how much they can rotate is likely about keeping the system simple as possible

I would guess SpaceX has likely weighed these losses against the more simple design & this resulted in the current configuration.  That being said, I would not be surprised if they change it back to the F9 style fins, or even scallop the leading edges of the grids as oriented for the ascent.

Or they could do something even simpler... If the fins do not fold, then why use grid fins at all? That was the main reason for grid fins in the first place, unless I am mistaken. I would not be surprised to see them revert to a plain (New Glenn-style) fin.

But perhaps grid fins have some other advantage, like control authority in the transonic speeds?

Absolutely incorrect. Grid fins were used for their excellent supersonic and subsonic performance while also having a short chord compared to a traditional fin of similar control authority. Short chord reduces the force needed to twist the fin for maneuvering.

Their major weakness is transonic performance because the grid fin openings become choked, and the scallops alleviate some of that reduction.
Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: alugobi on 10/16/2021 01:12 am
Quote
Or they could do something even simpler...

Umm, this is SpaceX we're talking about.  They look for the simple solutions.  Grid fins are it.
Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: matthewkantar on 10/16/2021 01:18 am
Does the steel for the new highbay seem to be hot dip galvanized? Not cheap!
Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: Lars-J on 10/16/2021 02:53 am
Quote
Or they could do something even simpler...

Umm, this is SpaceX we're talking about.  They look for the simple solutions.  Grid fins are it.

I certainly don’t think SpaceX have fallen into the trap of thinking “we are doing it so it must be the simplest”.

One needs to understand why grid fins were chosen in the first place. Being able to fold was a major reason. Now that folding is no longer necessary, that reason goes away. I suspect the trades are being done (or have been done) and a decision has been made. What it is, I don’t know.

I’m just stating that I would not be shocked *IF* in a few weeks we see “normal” fins being delivered for BN6.
Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: Nevyn72 on 10/16/2021 03:50 am
Quote
Or they could do something even simpler...

Umm, this is SpaceX we're talking about.  They look for the simple solutions.  Grid fins are it.

I certainly donít think SpaceX have fallen into the trap of thinking ďwe are doing it so it must be the simplestĒ.

One needs to understand why grid fins were chosen in the first place. Being able to fold was a major reason. Now that folding is no longer necessary, that reason goes away. I suspect the trades are being done (or have been done) and a decision has been made. What it is, I donít know.

Iím just stating that I would not be shocked *IF* in a few weeks we see ďnormalĒ fins being delivered for BN6.

How about no fins?

I'm pretty sure that was an option mentioned by Elon during his interview with Tim Dodd.
I think the suggestion was that ullage gas thrusters could possibly be used instead....
Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: Vettedrmr on 10/16/2021 10:21 am
I certainly donít think SpaceX have fallen into the trap of thinking ďwe are doing it so it must be the simplestĒ.

One needs to understand why grid fins were chosen in the first place. Being able to fold was a major reason. Now that folding is no longer necessary, that reason goes away. I suspect the trades are being done (or have been done) and a decision has been made. What it is, I donít know.

Iím just stating that I would not be shocked *IF* in a few weeks we see ďnormalĒ fins being delivered for BN6.

How about no fins?

I'm pretty sure that was an option mentioned by Elon during his interview with Tim Dodd.
I think the suggestion was that ullage gas thrusters could possibly be used instead....

IIRC grid fins are used because of their control authority at hyper- and supersonic speeds, not because of their ability to fold.  It made/makes sense to fold them on F9 because it made sense at the time, or their drag contribution to F9's total drag is pretty large, etc.  Apparently that contribution on SH is small enough to not be worth the added complexity of folding.
Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: ppb on 10/16/2021 06:02 pm
I certainly don’t think SpaceX have fallen into the trap of thinking “we are doing it so it must be the simplest”.

One needs to understand why grid fins were chosen in the first place. Being able to fold was a major reason. Now that folding is no longer necessary, that reason goes away. I suspect the trades are being done (or have been done) and a decision has been made. What it is, I don’t know.

I’m just stating that I would not be shocked *IF* in a few weeks we see “normal” fins being delivered for BN6.

How about no fins?

I'm pretty sure that was an option mentioned by Elon during his interview with Tim Dodd.
I think the suggestion was that ullage gas thrusters could possibly be used instead....

IIRC grid fins are used because of their control authority at hyper- and supersonic speeds, not because of their ability to fold.  It made/makes sense to fold them on F9 because it made sense at the time, or their drag contribution to F9's total drag is pretty large, etc.  Apparently that contribution on SH is small enough to not be worth the added complexity of folding.
As another poster up thread noted, grid fins minimize the chord length perpendicular to the rotation axis. To get the same force from a conventional fin for the same deflection, the chord must be much longer: just check out the size of the fins on New Glenn. A larger chord means the rotation axis must be somewhere mid-chord (usually close to the aerodynamic center) to minimize actuator torque. This means the motors, levers and structural mounts could no longer be housed above the CH4 dome in the interstage region of the current design. Perhaps they could be mounted in faired external housings farther down the sides of the tank, but that may be a heavier solution. Big fins hanging farther down the sides also create complications for the catching interface with the tower chopsticks (I’m still anxious to see how they’re solving that one for Starship and it’s huge Elonerons). They also would lose the nice failsafe of landing on the grid fins if they somehow missed the grappling pins. It would probably wreck the grid fins and their mounting interface, but given how beefy that structure is, it would probably hold and prevent a crash. I doubt flat fins would be quite as strong.
Also, I doubt no fins will ever work, particularly with weak ullage pressure nozzles. They already tried that with stronger relative authority N2 thrusters on Falcon 9 and were unable to make it work, hence the advent of grid fins.
Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: aip on 10/16/2021 09:38 pm
Does the steel for the new highbay seem to be hot dip galvanized? Not cheap!

For super thick parts like structural steel, hot dip is a tiny cost. Even at $0.50/lb finished steel, a 4000 lb beam is only $2000 to coat. And with Elon $13B richer this past week (!) due to Tesla stock rising, it's really insignificant.

Even if it were 100x more expensive, they'd still have to do it. Boca Chica is close enough to the ocean to get salt spray during storms, and hot dip is the most reliable way to protect against corrosion.
Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: DistantTemple on 10/16/2021 09:49 pm
Does the steel for the new highbay seem to be hot dip galvanized? Not cheap!

For super thick parts like structural steel, hot dip is a tiny cost. Even at $0.50/lb finished steel, a 4000 lb beam is only $2000 to coat. And with Elon $13B richer this past week (!) due to Tesla stock rising, it's really insignificant.

Even if it were 100x more expensive, they'd still have to do it. Boca Chica is close enough to the ocean to get salt spray during storms, and hot dip is the most reliable way to protect against corrosion.
Pretty certain we haven't seen galvanized beams before this. Maybe this building is expected to be a more "final" design and much longer lasting.
Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: aip on 10/16/2021 09:57 pm
Does the steel for the new highbay seem to be hot dip galvanized? Not cheap!

For super thick parts like structural steel, hot dip is a tiny cost. Even at $0.50/lb finished steel, a 4000 lb beam is only $2000 to coat. And with Elon $13B richer this past week (!) due to Tesla stock rising, it's really insignificant.

Even if it were 100x more expensive, they'd still have to do it. Boca Chica is close enough to the ocean to get salt spray during storms, and hot dip is the most reliable way to protect against corrosion.
Pretty certain we haven't seen galvanized beams before this. Maybe this building is expected to be a more "final" design and much longer lasting.
Probably, but I'd also guess they are starting to see surface rust on other structures too.
Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: Okie_Steve on 10/16/2021 10:09 pm
I believe the original high bay is on part of the Stargate property owned by UTRGV, so maybe a 5, 10 or 20 year lease/design lifetime was baked in from the beginning for that building while the new higher, wider bay is intended to be "permanent"?
Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: edzieba on 10/19/2021 01:12 pm
Mary's view of the preburner test:

https://twitter.com/NASASpaceflight/status/1450320970414178305


LabPadre's Rover Cam also had a great view of the preburner test from the beach:

https://www.youtube.com/watch?v=n6cJXB7OZrQ
Second angle of the LabPadre view very much looks like a green puff and some sparks at shutdown, indicating a small amount of something copper-rich got pretty toasty. As always though, colour balance in video without a white reference can be deceiving.
Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: abaddon on 10/19/2021 03:56 pm
Looks like a single RVac being lit at the start?

[EDIT] More confident on the "single" than the "Rvac" though.
Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: StevenOBrien on 10/20/2021 11:08 am
Second angle of the LabPadre view very much looks like a green puff and some sparks at shutdown, indicating a small amount of something copper-rich got pretty toasty. As always though, colour balance in video without a white reference can be deceiving.

I wouldn't rule out that just being a lens flare. You see similar effects on the LabPadre cams whenever car headlights pass at night time. It doesn't look like it's actually emanating from anywhere, it just appears with the flash of light.
Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: Hamish.Student on 10/21/2021 09:09 am
SpaceX doesn't stop for a silly thing like night, they are still working. The chopsticks assembly was lifter by a foot or so which surprises me as I wouldn't expect an operator in the crane at midnight local time.
 
 
Anytime there is a load on the hook, it is required there be an operator in the crane.
Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: Syl35 on 10/21/2021 03:58 pm
First hints of engine bay thermal protection install starting on Booster 4

https://twitter.com/StarshipGazer/status/1450629832514150401

I think the white braces are just temporary parts (maybe for integration work of raptors), but on the left we can see an inox part that seems to be fixed between RB18 and anothet RB1x on the left. It really looks to a thermalprotection part.

(Image attached cropped from Staship Gazer tweet)
Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: OTV Booster on 10/21/2021 03:59 pm
SpaceX doesn't stop for a silly thing like night, they are still working. The chopsticks assembly was lifter by a foot or so which surprises me as I wouldn't expect an operator in the crane at midnight local time.
 
 
Anytime there is a load on the hook, it is required there be an operator in the crane.
They're set up with four crews running 24/7. SX does not know what an eight hour day is.
Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: jon.amos on 10/21/2021 09:14 pm
SpaceX doesn't stop for a silly thing like night, they are still working. The chopsticks assembly was lifter by a foot or so which surprises me as I wouldn't expect an operator in the crane at midnight local time.
 
 
Anytime there is a load on the hook, it is required there be an operator in the crane.

That is the practice with every lift operation I have been a part of.  While not a lot there have been a few and one involved an overnight load on a crane.
Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: ProToolsWizard on 10/21/2021 10:57 pm
Hey so Iím at Boca Chica today, I was going to check out the static fire but they arenít letting anyone without a SpaceX badge past S Oklahoma on Boca Chica Blvd? Is that normal? I thought they let people go up to the production facility. Itís a public road and the actual road closure is at the Prancing Pony. Any way of getting there before the test today?
Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: AC in NC on 10/21/2021 11:05 pm
Hey so Iím at Boca Chica today, I was going to check out the static fire but they arenít letting anyone without a SpaceX badge past S Oklahoma on Boca Chica Blvd? Is that normal? I thought they let people go up to the production facility. Itís a public road and the actual road closure is at the Prancing Pony. Any way of getting there before the test today?

Thought there was a soft-checkpoint midway from there to Boca where only Residents were allowed further.  Doubt you'd make it close to the Production Facility if you can get past where you are.
Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: RoboGoofers on 10/22/2021 01:29 pm
First hints of engine bay thermal protection install starting on Booster 4

https://twitter.com/StarshipGazer/status/1450629832514150401

I think the white braces are just temporary parts (maybe for integration work of raptors), but on the left we can see an inox part that seems to be fixed between RB18 and anothet RB1x on the left. It really looks to a thermalprotection part.

(Image attached cropped from Staship Gazer tweet)
And looks like the exterior shielding is going up too.
https://forum.nasaspaceflight.com/index.php?action=dlattach;topic=54439.0;attach=2065935;image (https://forum.nasaspaceflight.com/index.php?action=dlattach;topic=54439.0;attach=2065935;image)
Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: edzieba on 10/22/2021 02:35 pm
Hey so Iím at Boca Chica today, I was going to check out the static fire but they arenít letting anyone without a SpaceX badge past S Oklahoma on Boca Chica Blvd? Is that normal?
That's normal. You're not a resident, so you will be kept outside the soft checkpoint. Only SpaceX personnel and Boca Chica residents are permitted inside that, and they still have to remain outside the hard checkpoint.
Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: AC in NC on 10/22/2021 02:38 pm
Hey so Iím at Boca Chica today, I was going to check out the static fire but they arenít letting anyone without a SpaceX badge past S Oklahoma on Boca Chica Blvd? Is that normal?
That's normal. You're not a resident, so you will be kept outside the soft checkpoint. Only SpaceX personnel and Boca Chica residents are permitted inside that, and they still have to remain outside the hard checkpoint.

He reported being blocked at S Oklahoma on Boca Chica Blvd which is here:
Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: edzieba on 10/22/2021 03:29 pm
Sorry, attached the old version.
Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: kevinof on 10/22/2021 04:14 pm
https://twitter.com/elonmusk/status/1451581465645494279

Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: ProToolsWizard on 10/22/2021 06:11 pm
Hey so Iím at Boca Chica today, I was going to check out the static fire but they arenít letting anyone without a SpaceX badge past S Oklahoma on Boca Chica Blvd? Is that normal?
That's normal. You're not a resident, so you will be kept outside the soft checkpoint. Only SpaceX personnel and Boca Chica residents are permitted inside that, and they still have to remain outside the hard checkpoint.

So what happens if you are in the area of the production site prior to the road closure on that day? Do they still check badges and kick people out?
Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: Hamish.Student on 10/22/2021 06:15 pm
Hey so Iím at Boca Chica today, I was going to check out the static fire but they arenít letting anyone without a SpaceX badge past S Oklahoma on Boca Chica Blvd? Is that normal?
That's normal. You're not a resident, so you will be kept outside the soft checkpoint. Only SpaceX personnel and Boca Chica residents are permitted inside that, and they still have to remain outside the hard checkpoint.

So what happens if you are in the area of the production site prior to the road closure on that day? Do they still check badges and kick people out?
 
 
Correct. It is a safety requirement by the FAA. However, I believe that task is left to law enforcement as SpaceX Security have no power over the public.
Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: Alberto-Girardi on 10/23/2021 12:56 pm
Elon Time  ::)

https://twitter.com/elonmusk/status/1451581465645494279?s=21

I too think that we have to convert that one month in Elon time to normal time.  But in the cases similar to this, when the event isn't too far off (unlike when he said by july 1), I think that the timelines he says is wrong, but that instead we misunderstand the "if everything goes well". Surely there are hundreds of smaller thing that we don't notice if one goes wrong, except in the delays. If all of them go well, probably Musk's timelin would be correct. But unlicky it has never happened. I'm not speaking of when the timeline is very unrealistic.
Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: Hamish.Student on 10/23/2021 01:28 pm
The HLS mockup that had the NASA logo painted over yesterday has been hooked up to a crane and moved around. It seems to have gotten shorter over the past 20 minutes, which might indicate it's been removed from its stand or is being cut up.

Per NSF 24/7
 
 
Interesting to note it is exactly one year since the nosecone was painted.
Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: Robotbeat on 10/23/2021 02:24 pm
Aerocovers are for the booster which has no heat shield tiles.  Probably just easier to make this way.

These ones are for a Starship though. Note the rounded part which covers the top of the flap hinge.
Yep, it is the forward -Y (starboard) fin tip fairing, this post (https://forum.nasaspaceflight.com/index.php?topic=52398.msg2270083#msg2270083) shows the same delivery for S20 and this one (https://forum.nasaspaceflight.com/index.php?topic=52398.msg2271518#msg2271518) shows the installation of the +Y one for S20.

So they did update the design from smooth to angular. Must help with tiles, I'd think...
it could have also made it out of a refractory metal alloy based off of Niobium, Molybdenum, or even Tungsten. Or perhaps stainless with a ceramic coating.
Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: BZHSpace on 10/23/2021 02:31 pm
If every administrative issue have been solved orbital flight for next mounth could be reallistic (he add "if all goes well").
Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: grndkntrl on 10/23/2021 02:38 pm
The HLS mockup that had the NASA logo painted over yesterday has been hooked up to a crane and moved around. It seems to have gotten shorter over the past 20 minutes, which might indicate it's been removed from its stand or is being cut up.

Per NSF 24/7
 
 
Interesting to note it is exactly one year since the nosecone was painted.

Yep.

There was possibly (entirely my speculation of course!) some stipulation in the contract that required the mockup to be available for a 12 month period, and now that time has passed, it can be scrapped as it serves no further purpose.
Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: Alastor on 10/23/2021 02:52 pm
The HLS mockup that had the NASA logo painted over yesterday has been hooked up to a crane and moved around. It seems to have gotten shorter over the past 20 minutes, which might indicate it's been removed from its stand or is being cut up.
 
Interesting to note it is exactly one year since the nosecone was painted.
There was possibly (entirely my speculation of course!) some stipulation in the contract that required the mockup to be available for a 12 month period, and now that time has passed, it can be scrapped as it serves no further purpose.

While the observation of the exact dates coincidence is interesting and intriguing, I doubt they would scrap it without NASA approval, and given that NASA hasn't been working on the HLS SpaceX thing for most of that time, I have trouble imagining them being done with it if they estimated they needed it for a year initially.

Any reason why the nosecone mockup might not be up to date anymore and could use a new design shell to be more realistic ?
Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: StuffOfInterest on 10/23/2021 03:00 pm
There was possibly (entirely my speculation of course!) some stipulation in the contract that required the mockup to be available for a 12 month period, and now that time has passed, it can be scrapped as it serves no further purpose.

Why would they go to the trouble of painting over the logo if it is just going to be scrapped?
Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: cdebuhr on 10/23/2021 03:06 pm
There was possibly (entirely my speculation of course!) some stipulation in the contract that required the mockup to be available for a 12 month period, and now that time has passed, it can be scrapped as it serves no further purpose.

Why would they go to the trouble of painting over the logo if it is just going to be scrapped?
That occurred to me too, but it makes sense I think.  I'm sure there are at least a few detractors, politicians, and competitors who would love to get out-of-context pictures of SXs "new NASA rocket" getting cut up.  They'd be firmly in the "nothing to see here" category for anyone paying attention, but we're not the intended audience.
Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: grndkntrl on 10/23/2021 03:12 pm
There was possibly (entirely my speculation of course!) some stipulation in the contract that required the mockup to be available for a 12 month period, and now that time has passed, it can be scrapped as it serves no further purpose.

Why would they go to the trouble of painting over the logo if it is just going to be scrapped?
That occurred to me too, but it makes sense I think.  I'm sure there are at least a few detractors, politicians, and competitors who would love to get out-of-context pictures of SXs "new NASA rocket" getting cut up.  They'd be firmly in the "nothing to see here" category for anyone paying attention, but we're not the intended audience.

Exactly.

Can you just imagine all the rabid haters just itching for another excuse to dogpile on to SpaceX if they cut up something that prominently displayed the flag of the USA, nevermind the NASA logo‽  ::)
Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: Robotbeat on 10/23/2021 03:25 pm
Does the steel for the new highbay seem to be hot dip galvanized? Not cheap!
probably what you want if youíre living next to the sea though
Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: xyv on 10/24/2021 12:40 am
There was possibly (entirely my speculation of course!) some stipulation in the contract that required the mockup to be available for a 12 month period, and now that time has passed, it can be scrapped as it serves no further purpose.

Why would they go to the trouble of painting over the logo if it is just going to be scrapped?
That occurred to me too, but it makes sense I think.  I'm sure there are at least a few detractors, politicians, and competitors who would love to get out-of-context pictures of SXs "new NASA rocket" getting cut up.  They'd be firmly in the "nothing to see here" category for anyone paying attention, but we're not the intended audience.

Exactly.

Can you just imagine all the rabid haters just itching for another excuse to dogpile on to SpaceX if they cut up something that prominently displayed the flag of the USA, nevermind the NASA logo‽  ::)

This^^

When I saw that they were covering the logo earlier this week my first thought was "...time to scrap it..."  Really shows that SpaceX is on game right now.  They are completely open in their development but clearly aware of the potential consequences.  Nearly everything around NASA HSF has political and optics issues that you must deal with if you gonna' play da' game.
Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: nacnud on 10/25/2021 09:57 am
I donít know if this the right thread but it occurs to me that the two new large horizontal tanks at the orbital launch site are very likely for detanking vehicles quickly and safely.

The reason for them being horizontal? It means that any CH4 in a vehicle on the launch mount can flow from the vehicle to the tank under gravity alone which adds a degree of passive safety.

Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: edzieba on 10/25/2021 10:40 am
Not passive: as we saw with SN3, propellant draining or depressurisation (which propellant draining will cause) in an incorrect sequence will result in vehicle failure. In addition, even an empty Starship atop Super Heavy would require Super Heavy to be pressurised, so a fully passive drain would only apply to Starship's tanks. A vehicle collapse during draining results in a mixing of whatever fuel and oxidiser remain in the tanks, definitely not a 'fail safe' condition.
A gravity drain is vulnerable to one less failure mode than a pumped drain (i.e. no pump failure), but still requires active control and sequencing rather than a passive "open the valves and wait".
Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: nacnud on 10/25/2021 12:07 pm
Yes I agree, I was thinking that the amount of pressurant needed is only just enough to keep the vehicle structurally stable and to replace the volume of propellant as it is drained from the tanks. IE less gas is needed than for vertical tanks, less requirement for pumps (best part is no part).

I'm trying to find good reasons for horizontal tanks vs vertical tanks.

The temperature gradient (stratification) is likely to be greater in vertical tanks, possibly useful in sub cooling.
Horizontal tanks have a lower centre of gravity, possibly useful in moving fluids around .

IE what gradients are present in the different configurations and how could this be useful, don't fight physics, use it.


Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: livingjw on 10/25/2021 03:53 pm
.... In addition, even an empty Starship atop Super Heavy would require Super Heavy to be pressurised....

SpaceX has stated that the full stack with payload but with empty tanks is stable without pressurization of any tanks. I did some buckling analysis that seems to confirm this.

John
Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: V42 on 10/25/2021 04:28 pm
.... In addition, even an empty Starship atop Super Heavy would require Super Heavy to be pressurised....

SpaceX has stated that the full stack with payload but with empty tanks is stable without pressurization of any tanks. I did some buckling analysis that seems to confirm this.

John

I don't doubt SX's statement or your results. But given all the visible surface imperfections (wrinkles) routinely seen in the unpressurized tank shells, the best a textbook buckling analysis can show is the upper bounds on buckling capability. A significant knockdown factor would need to be applied to that and/or a more sophisticated non-linear buckling analysis be performed to determine the true buckling capability. Assuming a simple hand analysis is what you did, your results are not surprising, though they are reassuring :)
Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: livingjw on 10/25/2021 04:51 pm
.... In addition, even an empty Starship atop Super Heavy would require Super Heavy to be pressurised....

SpaceX has stated that the full stack with payload but with empty tanks is stable without pressurization of any tanks. I did some buckling analysis that seems to confirm this.

John

I don't doubt SX's statement or your results. But given all the visible surface imperfections (wrinkles) routinely seen in the unpressurized tank shells, the best a textbook buckling analysis can show is the upper bounds on buckling capability. A significant knockdown factor would need to be applied to that and/or a more sophisticated non-linear buckling analysis be performed to determine the true buckling capability. Assuming a simple hand analysis is what you did, your results are not surprising, though they are reassuring :)

Method I used (NASA SP-8007) is known to be conservative.

John
Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: Okie_Steve on 10/25/2021 07:10 pm
Nomadd once mentioned that SpaceX had increased safety distances because they had started keeping the ship prototypes pressurized at all times. Whether that was for wind loads, moisture/corrosion/contamination control or some other reason I do not recall. Is that still the case for ships and/or boosters?

In any event, being structurally stable even when depressurized is indeed reassuring whether or not that is the normal situation.

Edit - Except obviously when working inside the tanks  ::)
Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: V42 on 10/25/2021 08:49 pm
.... In addition, even an empty Starship atop Super Heavy would require Super Heavy to be pressurised....

SpaceX has stated that the full stack with payload but with empty tanks is stable without pressurization of any tanks. I did some buckling analysis that seems to confirm this.

John

I don't doubt SX's statement or your results. But given all the visible surface imperfections (wrinkles) routinely seen in the unpressurized tank shells, the best a textbook buckling analysis can show is the upper bounds on buckling capability. A significant knockdown factor would need to be applied to that and/or a more sophisticated non-linear buckling analysis be performed to determine the true buckling capability. Assuming a simple hand analysis is what you did, your results are not surprising, though they are reassuring :)

Method I used (NASA SP-8007) is known to be conservative.

John

I'm familiar with NASA/SP-8007-2020/REV 2. And that curve for knockdown factor is based on manufacturing practices from from the 1930s to 1960s, so one would expect it to be conservative by today's standards. But it's also hard to imagine it included data from shells as badly wrinkled as even recent examples of SS & SH have shown. A knockdown of 0.2 may seem low, but might not be low enough. Musk's statement may simply imply he expects to improve the manufacturing process in the future to reduce these imperfections and increase buckling strength.

I guess my point is while your rough sizing is a good check, it may not be good enough for the current build quality. Or another way to put it, SX needs to improve built quality to match even your conservative assumptions.
Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: InterestedEngineer on 10/25/2021 11:53 pm
The downcomer for the booster is about the same diameter as an Electron rocket (1.2m)

https://forum.nasaspaceflight.com/index.php?action=dlattach;topic=54984.0;attach=2066294;image
Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: sferrin on 10/26/2021 02:21 pm
They really ought to fly S20 up to 15km a couple times before attempting the 'round the world shot. If a static fire with one engine for a fraction on a second causes tiles to leave what would an actual flight do to them? How many would even be left for reentry? On second thought S20 probably doesn't even have landing gear so no test flight.  They need to figure out the tile situation.
Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: edzieba on 10/26/2021 02:28 pm
Given that the tiles that popped off appear to have... popped off, rather than shattered or delaminated, and that it appears less than 10 have actually been affected (out of thousands of tiles that all held fine), this looks more like an "ah, those were the loose pins, go fix them" problem than any radical change needed. The vibration loads from ground testing will be greater than those of launch or post-staging ignition (because the tail end of the vehicle is clamped in place, and you also have ground reflections of engine sound added to direct conduction).
Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: Coastal Ron on 10/26/2021 02:30 pm
They really ought to fly S20 up to 15km a couple times before attempting the 'round the world shot. If a static fire with one engine for a fraction on a second causes tiles to leave what would an actual flight do to them? How many would even be left for reentry? On second thought S20 probably doesn't even have landing gear so no test flight.  They need to figure out the tile situation.

The tiles on S20 Starship likely fell off because of the conditions of the static fire on the ground, but S20 won't be lighting its engines on the test flight until it has separated from the B4 Booster, so the same conditions won't be present. And the only way to know for sure how well the tiles will do in THAT situation is to fly the mission.

As we've seen so far, SpaceX is fine with iterative learning, and the biggest milestone for the B4 + S20 mission is the launch, and then getting the S20 Starship into orbit. Everything after that is gravy.  :D
Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: CruddyCuber on 10/26/2021 02:43 pm
They really ought to fly S20 up to 15km a couple times before attempting the 'round the world shot. If a static fire with one engine for a fraction on a second causes tiles to leave what would an actual flight do to them? How many would even be left for reentry? On second thought S20 probably doesn't even have landing gear so no test flight.  They need to figure out the tile situation.

SpaceX could do it your way, and use ground testing and suborbital flights to determine the challenges starship may face in an orbital flight.  Alternatively, SpaceX could perform an orbital flight to determine the challenges starship will face in an orbital flight.  Time is the ultimate currency, and one of these options is far cheaper than the other.
Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: Tangilinear Interjar on 10/26/2021 04:28 pm
I noticed in the daily update video that some raceway covers have been installed on the Booster. I don't know how to clip an image from the video and can't find any good pictures of it but for some reason it surprised me that it just stainless sheet screwed on. I know that I shouldn't be surprised that it's that simple but for some reason I was expecting something more interesting.
Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: livingjw on 10/26/2021 05:16 pm
.... In addition, even an empty Starship atop Super Heavy would require Super Heavy to be pressurised....

SpaceX has stated that the full stack with payload but with empty tanks is stable without pressurization of any tanks. I did some buckling analysis that seems to confirm this.

John

I don't doubt SX's statement or your results. But given all the visible surface imperfections (wrinkles) routinely seen in the unpressurized tank shells, the best a textbook buckling analysis can show is the upper bounds on buckling capability. A significant knockdown factor would need to be applied to that and/or a more sophisticated non-linear buckling analysis be performed to determine the true buckling capability. Assuming a simple hand analysis is what you did, your results are not surprising, though they are reassuring :)

Method I used (NASA SP-8007) is known to be conservative.

John

I'm familiar with NASA/SP-8007-2020/REV 2. And that curve for knockdown factor is based on manufacturing practices from from the 1930s to 1960s, so one would expect it to be conservative by today's standards. But it's also hard to imagine it included data from shells as badly wrinkled as even recent examples of SS & SH have shown. A knockdown of 0.2 may seem low, but might not be low enough. Musk's statement may simply imply he expects to improve the manufacturing process in the future to reduce these imperfections and increase buckling strength.

I guess my point is while your rough sizing is a good check, it may not be good enough for the current build quality. Or another way to put it, SX needs to improve built quality to match even your conservative assumptions.

- Respectively disagree. I am pretty sure NASA/SP-8007 included Atlas data which shows similar buckling when not pressurized.

- I also assumed no stringers on the SH methane tank which was built with stringers. Entire SH has stringers so buckling is not an issue. SS did not need stringers at all and had significant margin.

John
Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: Vultur on 10/26/2021 06:36 pm
S20 is not expected to be recovered (it's supposed to fall in the ocean),  so I dont think a totally successful heat shield is necessarily a go/no go for this flight.

If it gets to first stage separation that is valuable in itself as it proves the Super Heavy works. If it gets to orbit, more so. A TPS failure on reentry would provide useful data, and would not really be a mission failure given the stated goal/mission profile. 
Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: Chris Bergin on 10/26/2021 07:09 pm
This is nice work!

https://www.youtube.com/watch?v=wPA4tU4Q_NM
Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: V42 on 10/26/2021 11:38 pm
They really ought to fly S20 up to 15km a couple times before attempting the 'round the world shot. If a static fire with one engine for a fraction on a second causes tiles to leave what would an actual flight do to them? How many would even be left for reentry? On second thought S20 probably doesn't even have landing gear so no test flight.  They need to figure out the tile situation.

The tiles on S20 Starship likely fell off because of the conditions of the static fire on the ground, but S20 won't be lighting its engines on the test flight until it has separated from the B4 Booster, so the same conditions won't be present. And the only way to know for sure how well the tiles will do in THAT situation is to fly the mission.

As we've seen so far, SpaceX is fine with iterative learning, and the biggest milestone for the B4 + S20 mission is the launch, and then getting the S20 Starship into orbit. Everything after that is gravy.  :D

Some of the worst launch loads typically occur during the 15 seconds after first stage ignition (ground reflected acoustics) and Max Q (max dynamic air pressure). Without access to SpaceX's analysis results, there is no way to know if the ground test environment is an over test compared to flight (hopefully they are at least taking advantage of the opportunity to measure it). But Starship engine ignition after booster separation will not likely be the worst loads the tiles see.

I don't know what kind or how much testing SpaceX has done relative to tile loads and their structural capability. These constant tile ground test failures indicate a significant design and/or workmanship problem. What concerns me about relying on only flight experience would be it makes it very hard to determine failure modes if failure results in it burning up on reentry. A key part in a trial-and-error design approach is understanding the error before the next trial.
Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: Keldor on 10/27/2021 12:01 am
They really ought to fly S20 up to 15km a couple times before attempting the 'round the world shot. If a static fire with one engine for a fraction on a second causes tiles to leave what would an actual flight do to them? How many would even be left for reentry? On second thought S20 probably doesn't even have landing gear so no test flight.  They need to figure out the tile situation.

The tiles on S20 Starship likely fell off because of the conditions of the static fire on the ground, but S20 won't be lighting its engines on the test flight until it has separated from the B4 Booster, so the same conditions won't be present. And the only way to know for sure how well the tiles will do in THAT situation is to fly the mission.

As we've seen so far, SpaceX is fine with iterative learning, and the biggest milestone for the B4 + S20 mission is the launch, and then getting the S20 Starship into orbit. Everything after that is gravy.  :D

Some of the worst launch loads typically occur during the 15 seconds after first stage ignition (ground reflected acoustics) and Max Q (max dynamic air pressure). Without access to SpaceX's analysis results, there is no way to know if the ground test environment is an over test compared to flight (hopefully they are at least taking advantage of the opportunity to measure it). But Starship engine ignition after booster separation will not likely be the worst loads the tiles see.

I don't know what kind or how much testing SpaceX has done relative to tile loads and their structural capability. These constant tile ground test failures indicate a significant design and/or workmanship problem. What concerns me about relying on only flight experience would be it makes it very hard to determine failure modes if failure results in it burning up on reentry. A key part in a trial-and-error design approach is understanding the error before the next trial.

There are many components other that the heat shield that need to be tested, and don't depend on the heat shield to function.  Fou can waste a lot of time and money delaying everything else while waiting for one system to be ready, or you can just test a partial prototype system.  Also, it's really not possible to replicate the conditions of reentry on Earth, so there will be unknows all the way up to the first reentry, so again, test early and often.
Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: V42 on 10/27/2021 12:02 am
.... In addition, even an empty Starship atop Super Heavy would require Super Heavy to be pressurised....

SpaceX has stated that the full stack with payload but with empty tanks is stable without pressurization of any tanks. I did some buckling analysis that seems to confirm this.

John

I don't doubt SX's statement or your results. But given all the visible surface imperfections (wrinkles) routinely seen in the unpressurized tank shells, the best a textbook buckling analysis can show is the upper bounds on buckling capability. A significant knockdown factor would need to be applied to that and/or a more sophisticated non-linear buckling analysis be performed to determine the true buckling capability. Assuming a simple hand analysis is what you did, your results are not surprising, though they are reassuring :)

Method I used (NASA SP-8007) is known to be conservative.

John

I'm familiar with NASA/SP-8007-2020/REV 2. And that curve for knockdown factor is based on manufacturing practices from from the 1930s to 1960s, so one would expect it to be conservative by today's standards. But it's also hard to imagine it included data from shells as badly wrinkled as even recent examples of SS & SH have shown. A knockdown of 0.2 may seem low, but might not be low enough. Musk's statement may simply imply he expects to improve the manufacturing process in the future to reduce these imperfections and increase buckling strength.

I guess my point is while your rough sizing is a good check, it may not be good enough for the current build quality. Or another way to put it, SX needs to improve built quality to match even your conservative assumptions.

- Respectively disagree. I am pretty sure NASA/SP-8007 included Atlas data which shows similar buckling when not pressurized.

- I also assumed no stringers on the SH methane tank which was built with stringers. Entire SH has stringers so buckling is not an issue. SS did not need stringers at all and had significant margin.

John

We're in total agreement the use of stringers make a world of difference and the buckling curves should be conservative. But I'm not sure either were intended to account for initial imperfections like this:
Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: livingjw on 10/27/2021 12:33 am
.... In addition, even an empty Starship atop Super Heavy would require Super Heavy to be pressurised....

SpaceX has stated that the full stack with payload but with empty tanks is stable without pressurization of any tanks. I did some buckling analysis that seems to confirm this.

John

I don't doubt SX's statement or your results. But given all the visible surface imperfections (wrinkles) routinely seen in the unpressurized tank shells, the best a textbook buckling analysis can show is the upper bounds on buckling capability. A significant knockdown factor would need to be applied to that and/or a more sophisticated non-linear buckling analysis be performed to determine the true buckling capability. Assuming a simple hand analysis is what you did, your results are not surprising, though they are reassuring :)

Method I used (NASA SP-8007) is known to be conservative.

John

I'm familiar with NASA/SP-8007-2020/REV 2. And that curve for knockdown factor is based on manufacturing practices from from the 1930s to 1960s, so one would expect it to be conservative by today's standards. But it's also hard to imagine it included data from shells as badly wrinkled as even recent examples of SS & SH have shown. A knockdown of 0.2 may seem low, but might not be low enough. Musk's statement may simply imply he expects to improve the manufacturing process in the future to reduce these imperfections and increase buckling strength.

I guess my point is while your rough sizing is a good check, it may not be good enough for the current build quality. Or another way to put it, SX needs to improve built quality to match even your conservative assumptions.

- Respectively disagree. I am pretty sure NASA/SP-8007 included Atlas data which shows similar buckling when not pressurized.

- I also assumed no stringers on the SH methane tank which was built with stringers. Entire SH has stringers so buckling is not an issue. SS did not need stringers at all and had significant margin.

John

We're in total agreement the use of stringers make a world of difference and the buckling curves should be conservative. But I'm not sure either were intended to account for initial imperfections like this:

- That defect seems to be happening less as time progresses.  Also, those shadows sometime exaggerate. Atlas had similar buckling before pressure testing. I think StarShip also showed some permanent improvement after pressure testing. 

John
Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: V42 on 10/27/2021 12:58 am

I'm familiar with NASA/SP-8007-2020/REV 2. And that curve for knockdown factor is based on manufacturing practices from from the 1930s to 1960s, so one would expect it to be conservative by today's standards. But it's also hard to imagine it included data from shells as badly wrinkled as even recent examples of SS & SH have shown. A knockdown of 0.2 may seem low, but might not be low enough. Musk's statement may simply imply he expects to improve the manufacturing process in the future to reduce these imperfections and increase buckling strength.

I guess my point is while your rough sizing is a good check, it may not be good enough for the current build quality. Or another way to put it, SX needs to improve built quality to match even your conservative assumptions.

- Respectively disagree. I am pretty sure NASA/SP-8007 included Atlas data which shows similar buckling when not pressurized.

- I also assumed no stringers on the SH methane tank which was built with stringers. Entire SH has stringers so buckling is not an issue. SS did not need stringers at all and had significant margin.

John

We're in total agreement the use of stringers make a world of difference and the buckling curves should be conservative. But I'm not sure either were intended to account for initial imperfections like this:

- That defect seems to be happening less as time progresses.  Also, those shadows sometime exaggerate. Atlas had similar buckling before pressure testing. I think StarShip also showed some permanent improvement after pressure testing. 

John

Hence my original observation:

"Musk's statement may simply imply he expects to improve the manufacturing process in the future to reduce these imperfections and increase buckling strength"

I'm sure he will, build tolerances will match analysis assumptions, and all will be right with the world ;)
Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: V42 on 10/27/2021 01:17 am
They really ought to fly S20 up to 15km a couple times before attempting the 'round the world shot. If a static fire with one engine for a fraction on a second causes tiles to leave what would an actual flight do to them? How many would even be left for reentry? On second thought S20 probably doesn't even have landing gear so no test flight.  They need to figure out the tile situation.

The tiles on S20 Starship likely fell off because of the conditions of the static fire on the ground, but S20 won't be lighting its engines on the test flight until it has separated from the B4 Booster, so the same conditions won't be present. And the only way to know for sure how well the tiles will do in THAT situation is to fly the mission.

As we've seen so far, SpaceX is fine with iterative learning, and the biggest milestone for the B4 + S20 mission is the launch, and then getting the S20 Starship into orbit. Everything after that is gravy.  :D

Some of the worst launch loads typically occur during the 15 seconds after first stage ignition (ground reflected acoustics) and Max Q (max dynamic air pressure). Without access to SpaceX's analysis results, there is no way to know if the ground test environment is an over test compared to flight (hopefully they are at least taking advantage of the opportunity to measure it). But Starship engine ignition after booster separation will not likely be the worst loads the tiles see.

I don't know what kind or how much testing SpaceX has done relative to tile loads and their structural capability. These constant tile ground test failures indicate a significant design and/or workmanship problem. What concerns me about relying on only flight experience would be it makes it very hard to determine failure modes if failure results in it burning up on reentry. A key part in a trial-and-error design approach is understanding the error before the next trial.

There are many components other that the heat shield that need to be tested, and don't depend on the heat shield to function.  Fou can waste a lot of time and money delaying everything else while waiting for one system to be ready, or you can just test a partial prototype system.  Also, it's really not possible to replicate the conditions of reentry on Earth, so there will be unknows all the way up to the first reentry, so again, test early and often.

Sure, not blowing up the launch pad will be considered a major flight success. My point was you can't test reentry unless all the tiles remain intact up to that point in the flight. And right now, thatís not looking very likely. Even basic component level testing to static fire vibration levels would have uncovered this type of failure. So why efforts like that, which would have little cost but large reward potential, are not given more priority are beyond me.
Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: [email protected] on 10/27/2021 01:41 am
Quote
My point was you can't test reentry unless all the tiles remain intact up to that point in the flight
Jumping to that conclusion seems pretty premature in this early days

These people giving siren in their head aren't new. They also insisted to fly SN6 150 m a lot more before jumping to SN8 just because they didn't know about the trade-off SpaceX has been made
Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: Coastal Ron on 10/27/2021 01:43 am
Sure, not blowing up the launch pad will be considered a major flight success. My point was you can't test reentry unless all the tiles remain intact up to that point in the flight.

I would think that surviving reentry with some tiles missing would be a MAJOR test result, even if the goal is to not lose any tiles during the lifecycle of a Starship.

Quote
And right now, thatís not looking very likely.

Well, what we are seeing is the result of an activity (sea level ship test fire) that won't happen on a normal orbital launch where the ship is stacked on top of the booster.

Quote
Even basic component level testing to static fire vibration levels would have uncovered this type of failure. So why efforts like that, which would have little cost but large reward potential, are not given more priority are beyond me.

Right, all of us have to make guesses.

My guess is that the Starship team is more concerned about tiles falling off during flight, and which ones fall off (i.e. is there a pattern?), and the only way to see that is with a flight.

And more specifically, I think Elon Musk is prioritizing getting to orbit over surviving reentry, meaning tile issues don't have to be fixed for Ship 20. Which makes sense, since if they can't get Ship 20 to orbit they never have to worry about reentry...  :D
Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: InterestedEngineer on 10/27/2021 03:06 am
Quote
My point was you can't test reentry unless all the tiles remain intact up to that point in the flight
Jumping to that conclusion seems pretty premature in this early days

These people giving siren in their head aren't new. They also insisted to fly SN6 150 m a lot more before jumping to SN8

Plenty of discussions about surviving reentry while missing tiles in the Heat Shield thread.

https://forum.nasaspaceflight.com/index.php?topic=50748.0
Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: Lemurion on 10/27/2021 06:24 am

(Snipped)

Sure, not blowing up the launch pad will be considered a major flight success. My point was you can't test reentry unless all the tiles remain intact up to that point in the flight. And right now, thatís not looking very likely. Even basic component level testing to static fire vibration levels would have uncovered this type of failure. So why efforts like that, which would have little cost but large reward potential, are not given more priority are beyond me.

I would say that you can't test reentry without reentering. Everything else is just another variable in the test conditions. You might even get better results on the original test (in terms of the amount of usable data) if you do lose some tiles.
Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: ThatOldJanxSpirit on 10/27/2021 09:23 am
Quote
My point was you can't test reentry unless all the tiles remain intact up to that point in the flight
Jumping to that conclusion seems pretty premature in this early days

These people giving siren in their head aren't new. They also insisted to fly SN6 150 m a lot more before jumping to SN8 just because they didn't know about the trade-off SpaceX has been made

Weíve seen tiles fall off when they move the ship on the SPMT; an incredibly benign environment. That suggests to me that failure of the pins to engage is the dominant failure mode here, rather than mechanical failure of the tile or pin. Also if vibration was the main failure mechanism Iíd expect to see significant damage in the skirt, rather than a fairly random pattern of gaps we have. The best case, supported by an Elon tweet, is that static fires are just acting as an effective QA check of tile engagement.
Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: Rossco on 10/27/2021 09:37 am
Would there be larger vibrations felt in a static fire than actually in 'flight'?
If they are firing single, offset engines and the sound bouncing off the ground?
How much vibrations from the booster will reach the spaceship - would they be less or more by the time the reach the top of the booster.
Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: KBK on 10/27/2021 12:38 pm
Quote
My point was you can't test reentry unless all the tiles remain intact up to that point in the flight
Jumping to that conclusion seems pretty premature in this early days

These people giving siren in their head aren't new. They also insisted to fly SN6 150 m a lot more before jumping to SN8 just because they didn't know about the trade-off SpaceX has been made

Weíve seen tiles fall off when they move the ship on the SPMT; an incredibly benign environment. That suggests to me that failure of the pins to engage is the dominant failure mode here, rather than mechanical failure of the tile or pin. Also if vibration was the main failure mechanism Iíd expect to see significant damage in the skirt, rather than a fairly random pattern of gaps we have. The best case, supported by an Elon tweet, is that static fires are just acting as an effective QA check of tile engagement.

If it is due to no pin engagement due to not being inserted all the way and then locking back 'out' (so to speak), then this might be testable with a small electromagnetic sensor system, custom made.

Akin to a small handheld that simultaneously checks for tile spacing... as that is the lock on point for accuracy in the primary design point of the test device. it locks or sits on tile gaps, at the given corners.

It can, at that point, also check for tile surface accuracy, curvature and so on, with respect to itself - and adjoining tiles.

Then the depth of the pin in the lock mechanism on the tile proper is checked with the device itself, which is akin to a metal detector. Cross fired, custom coils and frequencies/patterns, for a single use device. It might be accurate enough, only way to know is to muse out a prototype and test it.

I don't think it would be all that time consuming to do so, as it's benefit, if deemed minimally functional, could be enormous. IF this tile mounting and application/design are to be kept as the way forward in doing things.

This would not be a heavy or clunky device, and could be kept at the ready for the singular place where it would be used, which is the main body where the tiles and mounting are relatively identical.

we know the pins are metal and all of the same type, so resonances and patterns should be predictable, and rotation would/might show itself. three coils per pin mount might be key here. The trick is that I don't know the pin lock's materials (on the tile proper), which might cloud the issue, depending on what is going on with that aspect.

Additional measurements and usefulness and thus additional found/discovered metrics are possible.

Could be a total waste of time, but might not be. Needs to be assessed from within the knowledge base of the tile project proper.
Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: livingjw on 10/27/2021 01:34 pm
Or you could do a pull test like they did on the Space Shuttle. Requirement was just north of 100 lbs if I remember right.
1) insert tile, 2) check fit, 3) pull test, done.

John
Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: Doom2pro on 10/27/2021 02:01 pm
I wonder if a locking mechanism would work better, one where a strong handheld magnet is needed to disengage it for tile removal. Or is it easier to just break the tile to get it out?
Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: KBK on 10/27/2021 02:48 pm
Or you could do a pull test like they did on the Space Shuttle. Requirement was just north of 100 lbs if I remember right.
1) insert tile, 2) check fit, 3) pull test, done.

John

The usual, John. My team and 1000 lines of code replaced by 10 lines of code from one person. It's why we design in teams. First thoughts don't generally equal outcomes.

But, one thing possibly on my side, is that they are looking to make many a beast, in identical fashion. There, in a production scenario, such a thing..as a form of automation, (either my proposal or your known solution for that environment) may show it's efficacy. If one bad tile = (closely resembles) death, then more data under stable conditions of repeatability... might be the more workable solution. With that many tiles, tiny changes in margin can be everything.
Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: Fish #6 on 10/27/2021 03:27 pm
Or you could do a pull test like they did on the Space Shuttle. Requirement was just north of 100 lbs if I remember right.
1) insert tile, 2) check fit, 3) pull test, done.

John
8 years. 8 years I've happily lurked on this forum, and now I'm forced to the surface. Thank you John for one of many delightfully simple, concise & knowledgeable responses.
Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: ETurner on 10/27/2021 03:28 pm
[...]
We're in total agreement the use of stringers make a world of difference and the buckling curves should be conservative. But I'm not sure either were intended to account for initial imperfections like this:

- That defect seems to be happening less as time progresses.  Also, those shadows sometime exaggerate. Atlas had similar buckling before pressure testing. I think StarShip also showed some permanent improvement after pressure testing. 

John
The ability of pressure to stretch and reshape 304L stainless tanks can be amazing.
See discussion, before-and-after following the 9:00 mark:
https://www.youtube.com/watch?v=6T5RYcNbImk (https://www.youtube.com/watch?v=6T5RYcNbImk)

Can get rid of dents way before this!
Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: AU1.52 on 10/29/2021 12:43 pm
In the daily update video today we saw the thrust puck for the Booster test tank and I was surprised to see it had a ship puck and not a booster puck. Do we know why? The outer ring is Booster but and inner is ship - 3 sea level and 3 vacuum mounts.
Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: Crispy on 10/29/2021 03:53 pm
In the daily update video today we saw the thrust puck for the Booster test tank and I was surprised to see it had a ship puck and not a booster puck. Do we know why? The outer ring is Booster but and inner is ship - 3 sea level and 3 vacuum mounts.
B2.1 is a frankenstein's monster destined for testing only. I imagine it's on the testing mount for fit check only.
Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: Tangilinear Interjar on 10/29/2021 05:07 pm
In the daily update video today we saw the thrust puck for the Booster test tank and I was surprised to see it had a ship puck and not a booster puck. Do we know why? The outer ring is Booster but and inner is ship - 3 sea level and 3 vacuum mounts.
B2.1 is a frankenstein's monster destined for testing only. I imagine it's on the testing mount for fit check only.
I originally had the opinion that 2.1 was just a fit check article but now I don't think so.

They configured the test rams inside new test rig for a Starship and connected them to the test tank. This is a totally different configuration than for the Booster. Also they have installed a number of sensors that kind of look like strain gages to the bottom dome.

I now suspect that they needed this new test jig in order to adequately load the SS thrust puck. Maybe this is the system that will allow them to really test it to failure.
Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: sferrin on 10/29/2021 06:27 pm
They really ought to fly S20 up to 15km a couple times before attempting the 'round the world shot. If a static fire with one engine for a fraction on a second causes tiles to leave what would an actual flight do to them? How many would even be left for reentry? On second thought S20 probably doesn't even have landing gear so no test flight.  They need to figure out the tile situation.

SpaceX could do it your way, and use ground testing and suborbital flights to determine the challenges starship may face in an orbital flight.  Alternatively, SpaceX could perform an orbital flight to determine the challenges starship will face in an orbital flight.  Time is the ultimate currency, and one of these options is far cheaper than the other.
So better to waste a booster AND a Starship or two to find out something you could do with one Starship?  Not seeing how that's a better plan.  Take a Starship to max Q, and lose 50% of the tiles, you can still come back.  Lose 50% of your tiles on your way to orbit and you're done, and you won't be learning much from the fragments you may or may not be able to recover from the ocean.
Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: AU1.52 on 10/29/2021 06:46 pm
In the daily update video today we saw the thrust puck for the Booster test tank and I was surprised to see it had a ship puck and not a booster puck. Do we know why? The outer ring is Booster but and inner is ship - 3 sea level and 3 vacuum mounts.
B2.1 is a frankenstein's monster destined for testing only. I imagine it's on the testing mount for fit check only.


The thing is the Booster testing stand 20 ring mounts look like they can apply load to the boost mounts to test their structural integrity. My concern (which may be unfounded) is how does having a dissimilar (Ship) puck as part of the test tank affect the testing of the 20 outer engine mounts instead of having a booster puck?
Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: Luc on 10/29/2021 06:52 pm

[/quote]
So better to waste a booster AND a Starship or two to find out something you could do with one Starship?  Not seeing how that's a better plan.  Take a Starship to max Q, and lose 50% of the tiles, you can still come back.  Lose 50% of your tiles on your way to orbit and you're done, and you won't be learning much from the fragments you may or may not be able to recover from the ocean.
[/quote]

I think the idea here is that you find out a whole bunch of other stuff as well in parallel, which saves a mountain of time, and time seems to be a priority for Elon.
Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: Herb Schaltegger on 10/29/2021 06:54 pm
So better to waste a booster AND a Starship or two to find out something you could do with one Starship?  Not seeing how that's a better plan.  Take a Starship to max Q, and lose 50% of the tiles, you can still come back.  Lose 50% of your tiles on your way to orbit and you're done, and you won't be learning much from the fragments you may or may not be able to recover from the ocean.

With the telemetry and tracking data available, they would find out quite a bit regardless of what any debris looks like.
Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: envy887 on 10/29/2021 07:02 pm
They really ought to fly S20 up to 15km a couple times before attempting the 'round the world shot. If a static fire with one engine for a fraction on a second causes tiles to leave what would an actual flight do to them? How many would even be left for reentry? On second thought S20 probably doesn't even have landing gear so no test flight.  They need to figure out the tile situation.

SpaceX could do it your way, and use ground testing and suborbital flights to determine the challenges starship may face in an orbital flight.  Alternatively, SpaceX could perform an orbital flight to determine the challenges starship will face in an orbital flight.  Time is the ultimate currency, and one of these options is far cheaper than the other.
So better to waste a booster AND a Starship or two to find out something you could do with one Starship?  Not seeing how that's a better plan.  Take a Starship to max Q, and lose 50% of the tiles, you can still come back.  Lose 50% of your tiles on your way to orbit and you're done, and you won't be learning much from the fragments you may or may not be able to recover from the ocean.

It wouldn't be a waste of a booster if the ship fails - whether the Starship succeeds at reentry will be irrelevant to the booster. The booster flight is still going to be extremely informative. They need to show that the booster is working as expected through all phases of its own flight, and that it is controllable to within a few meters of the intended soft landing target location.
Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: alugobi on 10/29/2021 07:15 pm
SpaceX doesn't waste anything.  They learn by doing.
Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: DanClemmensen on 10/29/2021 07:25 pm

So better to waste a booster AND a Starship or two to find out something you could do with one Starship?  Not seeing how that's a better plan.  Take a Starship to max Q, and lose 50% of the tiles, you can still come back.  Lose 50% of your tiles on your way to orbit and you're done, and you won't be learning much from the fragments you may or may not be able to recover from the ocean.
[/quote]

I think the idea here is that you find out a whole bunch of other stuff as well in parallel, which saves a mountain of time, and time seems to be a priority for Elon.
[/quote]

Unlike certain other organizations, SpaceX seems to be able to do multiple things at the same time. There are several SH and several SS under construction, and basically all of them must be treated as test articles. My guess is that the various tests will be developing independently and launch sequence will depend on flight readiness. Whichever test launches first, its test results will feed into the follow-on tests.
Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: aardvark2z on 10/29/2021 07:37 pm
Anyone know what this large ring and positioned diagonally on the right is ?? Also, are those numerous baffle holes ?

(https://forum.nasaspaceflight.com/index.php?action=dlattach;topic=54984.0;attach=2066888;image)

Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: grndkntrl on 10/29/2021 07:43 pm
Anyone know what this large ring and positioned diagonally on the right is ?? Also, are those numerous baffle holes ?


It's the mount for the RVAC engine.
Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: TergenFlerg on 10/29/2021 07:52 pm
In the daily update video today we saw the thrust puck for the Booster test tank and I was surprised to see it had a ship puck and not a booster puck. Do we know why? The outer ring is Booster but and inner is ship - 3 sea level and 3 vacuum mounts.

My though is that they only need a dome there for structural integrity.  The testing is for the external ring only, they had already tested the booster puck some time ago, and did static fires with B3.  So they had an extra SS aft dome laying around, throw it in this test article instead of using a more complicated (and probably more expensive) booster dome/puck.
Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: StevenOBrien on 10/29/2021 07:55 pm
They really ought to fly S20 up to 15km a couple times before attempting the 'round the world shot. If a static fire with one engine for a fraction on a second causes tiles to leave what would an actual flight do to them? How many would even be left for reentry? On second thought S20 probably doesn't even have landing gear so no test flight.  They need to figure out the tile situation.

SpaceX could do it your way, and use ground testing and suborbital flights to determine the challenges starship may face in an orbital flight.  Alternatively, SpaceX could perform an orbital flight to determine the challenges starship will face in an orbital flight.  Time is the ultimate currency, and one of these options is far cheaper than the other.
So better to waste a booster AND a Starship or two to find out something you could do with one Starship?  Not seeing how that's a better plan.  Take a Starship to max Q, and lose 50% of the tiles, you can still come back.  Lose 50% of your tiles on your way to orbit and you're done, and you won't be learning much from the fragments you may or may not be able to recover from the ocean.
I don't think it would be a waste. They need to test more than just the tile attachments. The booster needs to be tested, stage separation needs to be tested, RVacs need to be tested in flight, OLS needs to be tested, etc. Even if enough tiles fell off on ascent to make successful re-entry impossible, there will probably still be things to learn from just de-orbiting the ship and seeing what happens.

If the tiles do turn out to be a serious enough problem, they have three vehicles that can be used for suborbital tests after B4S20. Those suborbital tests likely won't really be feasible until the OLS is completed at this point anyway.

In a worst case scenario of the tile attachments needing to be completely reworked, making hypersonic tile testing a prerequisite for any orbital flights could mean you have everything other than the tiles sitting around waiting for months doing nothing.
Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: Sciencefan on 10/29/2021 08:30 pm
In the daily update video today we saw the thrust puck for the Booster test tank and I was surprised to see it had a ship puck and not a booster puck. Do we know why? The outer ring is Booster but and inner is ship - 3 sea level and 3 vacuum mounts.
B2.1 is a frankenstein's monster destined for testing only. I imagine it's on the testing mount for fit check only.

This testing with the starship bulkhead was planned a while ago but was on hold probably while they was busy with the chopsticks. Looks they want to get some result regarding the outer booster engines & RVacs setup on the ship at once without another tank.
Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: wannamoonbase on 10/29/2021 08:34 pm
They really ought to fly S20 up to 15km a couple times before attempting the 'round the world shot. If a static fire with one engine for a fraction on a second causes tiles to leave what would an actual flight do to them? How many would even be left for reentry? On second thought S20 probably doesn't even have landing gear so no test flight.  They need to figure out the tile situation.

SpaceX could do it your way, and use ground testing and suborbital flights to determine the challenges starship may face in an orbital flight.  Alternatively, SpaceX could perform an orbital flight to determine the challenges starship will face in an orbital flight.  Time is the ultimate currency, and one of these options is far cheaper than the other.
So better to waste a booster AND a Starship or two to find out something you could do with one Starship?  Not seeing how that's a better plan.  Take a Starship to max Q, and lose 50% of the tiles, you can still come back.  Lose 50% of your tiles on your way to orbit and you're done, and you won't be learning much from the fragments you may or may not be able to recover from the ocean.
I don't think it would be a waste. They need to test more than just the tile attachments. The booster needs to be tested, stage separation needs to be tested, RVacs need to be tested in flight, OLS needs to be tested, etc. Even if enough tiles fell off on ascent to make successful re-entry impossible, there will probably still be things to learn from just de-orbiting the ship and seeing what happens.

If the tiles do turn out to be a serious enough problem, they have three vehicles that can be used for suborbital tests after B4S20. Those suborbital tests likely won't really be feasible until the OLS is completed at this point anyway.

In a worst case scenario of the tile attachments needing to be completely reworked, making hypersonic tile testing a prerequisite for any orbital flights could mean you have everything other than the tiles sitting around waiting for months doing nothing.

I agree, any (flight) test of the full stack that doesn't damage the orbital launch complex is worth while. 

There are so many things to learn that successful re-entry of Starship would be the ultimate cherry on top.  No one has ever flown a booster this big and with 29 engines there is plenty of risk to retire.

Am I the only one concerned that the FAA's limited number of flights will limit the pace of SpaceX's progress?  Because they are going to be able to make a set of booster and starship every 4 to 6 weeks.
Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: aardvark2z on 10/29/2021 11:33 pm
Anyone know what this large ring and positioned diagonally on the right is ?? Also, are those numerous baffle holes ?


It's the mount for the RVAC engine.

But that's the 1st stage booster. It doesn't use RVac engines.
Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: xvel on 10/29/2021 11:46 pm
Anyone know what this large ring and positioned diagonally on the right is ?? Also, are those numerous baffle holes ?


It's the mount for the RVAC engine.

But that's the 1st stage booster. It doesn't use RVac engines.

Ehh, this are rvac mounts because it's a starship thrust dome and the rest is from booster, it's just a test article made from stuff laying around.
Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: OTV Booster on 10/30/2021 02:25 am

So better to waste a booster AND a Starship or two to find out something you could do with one Starship?  Not seeing how that's a better plan.  Take a Starship to max Q, and lose 50% of the tiles, you can still come back.  Lose 50% of your tiles on your way to orbit and you're done, and you won't be learning much from the fragments you may or may not be able to recover from the ocean.

I think the idea here is that you find out a whole bunch of other stuff as well in parallel, which saves a mountain of time, and time seems to be a priority for Elon.


Unlike certain other organizations, SpaceX seems to be able to do multiple things at the same time. There are several SH and several SS under construction, and basically all of them must be treated as test articles. My guess is that the various tests will be developing independently and launch sequence will depend on flight readiness. Whichever test launches first, its test results will feed into the follow-on tests.


That what you get when you go hardware rich. If the results of 20's flight dictate, we may see 21 scrapped and they won't even blink. They've done it before. 22 or 23 will be in the pipeline and begging for improvements.


Edit: quotes & brain farts
Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: aardvark2z on 10/30/2021 05:53 am
Anyone know what this large ring and positioned diagonally on the right is ?? Also, are those numerous baffle holes ?


It's the mount for the RVAC engine.

But that's the 1st stage booster. It doesn't use RVac engines.

Ehh, this are rvac mounts because it's a starship thrust dome and the rest is from booster, it's just a test article made from stuff laying around.

Wow, That very large thick ring that's positioned diagonally on the right side with large triangular holes/baffles seems to be very very different from a sea level engine mount. I don't understand why that large angled thick ring is needed for RVac. I'm extremely sorry if it's obvious to everyone but me. Thanks in advance.
Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: Hyperus on 10/30/2021 07:47 am
Anyone know what this large ring and positioned diagonally on the right is ?? Also, are those numerous baffle holes ?


It's the mount for the RVAC engine.

But that's the 1st stage booster. It doesn't use RVac engines.

Ehh, this are rvac mounts because it's a starship thrust dome and the rest is from booster, it's just a test article made from stuff laying around.

Wow, That very large thick ring that's positioned diagonally on the right side with large triangular holes/baffles seems to be very very different from a sea level engine mount. I don't understand why that large angled thick ring is needed for RVac. I'm extremely sorry if it's obvious to everyone but me. Thanks in advance.

I would assume this mainly due to force distribution, distributing the force over the aft dome is certainly desirable if you don't want to "push" a hole into it.
Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: kevinof on 10/30/2021 10:12 am
First post? Welcome to NSF Hyperus and yes that was my take on the ring. Can't think what else it could be.

Anyone know what this large ring and positioned diagonally on the right is ?? Also, are those numerous baffle holes ?


It's the mount for the RVAC engine.

But that's the 1st stage booster. It doesn't use RVac engines.

Ehh, this are rvac mounts because it's a starship thrust dome and the rest is from booster, it's just a test article made from stuff laying around.

Wow, That very large thick ring that's positioned diagonally on the right side with large triangular holes/baffles seems to be very very different from a sea level engine mount. I don't understand why that large angled thick ring is needed for RVac. I'm extremely sorry if it's obvious to everyone but me. Thanks in advance.

I would assume this mainly due to force distribution, distributing the force over the aft dome is certainly desirable if you don't want to "push" a hole into it.
Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: DanClemmensen on 10/30/2021 09:56 pm
[snip pictures of "catch points:]

Those do not look like "catch" or "lift" structures. They appear to be able to tilt the SS or SH slightly toward or away from the tower ("pitch", for SS). The hydraulics below the rails atop the chopsticks allow tilting toward one or the other chopstick ("yaw" for SS). Added to the other motions, this gives you positioning in all six dimensions (X,Y,Z, pitch, roll, yaw), as will be needed to stack the SH on the pad and the SS on the SH.
Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: SpeakertoAnimals on 10/31/2021 01:04 am
[snip pictures of "catch points:]

Those do not look like "catch" or "lift" structures. They appear to be able to tilt the SS or SH slightly toward or away from the tower ("pitch", for SS). The hydraulics below the rails atop the chopsticks allow tilting toward one or the other chopstick ("yaw" for SS). Added to the other motions, this gives you positioning in all six dimensions (X,Y,Z, pitch, roll, yaw), as will be needed to stack the SH on the pad and the SS on the SH.
or more simply, to stabilize either vehicle against wind. How much would the bottom of the booster move with a 25 mph wind blowing over the pad toward the tower?
Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: Bob Niland on 10/31/2021 02:21 am
SpeakertoAnimals: or more simply, to stabilize either vehicle against wind. How much would the bottom of the booster move with a 25 mph wind blowing over the pad toward the tower?

Or perhaps more alarmingly, what 90į cross-wind would cause the lee side booster or Starship hardpoint to fail to engage, or lift back off the catch fixture?

A stabilizer brace might increase the acceptable range of landing winds allowed. If this conjecture is correct, I wouldn't be surprised to see some sort of curved pad on the end to minimize, if not entirely prevent, tile damage from the brace in the SS scenario, and denting in either.
Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: SpeakertoAnimals on 10/31/2021 02:58 am
SpeakertoAnimals: or more simply, to stabilize either vehicle against wind. How much would the bottom of the booster move with a 25 mph wind blowing over the pad toward the tower?

Or perhaps more alarmingly, what 90į cross-wind would cause the lee side booster or Starship hardpoint to fail to engage, or lift back off the catch fixture?

A stabilizer brace might increase the acceptable range of landing winds allowed. If this conjecture is correct, I wouldn't be surprised to see some sort of curved pad on the end to minimize, if not entirely prevent, tile damage from the brace in the SS scenario, and denting in either.
I was thinking about setting the booster onto the pad with the wind blowing the bottom around.
Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: DanClemmensen on 10/31/2021 05:49 am
SpeakertoAnimals: or more simply, to stabilize either vehicle against wind. How much would the bottom of the booster move with a 25 mph wind blowing over the pad toward the tower?

Or perhaps more alarmingly, what 90į cross-wind would cause the lee side booster or Starship hardpoint to fail to engage, or lift back off the catch fixture?

A stabilizer brace might increase the acceptable range of landing winds allowed. If this conjecture is correct, I wouldn't be surprised to see some sort of curved pad on the end to minimize, if not entirely prevent, tile damage from the brace in the SS scenario, and denting in either.
I was thinking about setting the booster onto the pad with the wind blowing the bottom around.
I think the chopsticks can adjust the tilt in the yaw direction (i.e., a tilt toward one or the other of the arms) by using the hydraulics to raise or lower the rail atop the chopstick arm by a small amount. With appropriate feedback to your PID loops you should be able to damp out  a fair amount of gust-induced yaw oscillation. The new "little" vertical arms can damp out pitch oscillation. There will clearly be wind conditions that  will prevent stacking.
Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: BZHSpace on 10/31/2021 05:50 am
My main concern about orbital test flight is the sturdiness of the separation mechanism during ascend phase, it different to the F9 mechanism so I fear it could break during max Q event.
Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: RotoSequence on 10/31/2021 06:03 am
My main concern about orbital test flight is the sturdiness of the separation mechanism during ascend phase, it different to the F9 mechanism so I fear it could break during max Q event.

Hold-down clamps are the only active mechanism for a staging event. Separation itself will be handled by initiating a booster flip at BECO, followed by clamp release.
Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: Vettedrmr on 10/31/2021 10:05 am
My main concern about orbital test flight is the sturdiness of the separation mechanism during ascend phase, it different to the F9 mechanism so I fear it could break during max Q event.

Hold-down clamps are the only active mechanism for a staging event. Separation itself will be handled by initiating a booster flip at BECO, followed by clamp release.

Where did this info come from?  I *assumed* that they'd initiate separation using a similar mechanism to F9.
Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: grndkntrl on 10/31/2021 10:17 am
My main concern about orbital test flight is the sturdiness of the separation mechanism during ascend phase, it different to the F9 mechanism so I fear it could break during max Q event.

Hold-down clamps are the only active mechanism for a staging event. Separation itself will be handled by initiating a booster flip at BECO, followed by clamp release.

Where did this info come from?  I *assumed* that they'd initiate separation using a similar mechanism to F9.

Photos from Elon (during the rollout of B4 from the High Bay to pad, & the August first stack) clearly showing the 3 clamps (spaced 120į apart) at the top of B4, which engage through slots in the skirt of S20. See attached.

Also Elon confirmed just 10hrs ago, that the spin separation maneuver that they intend to use would be very close to this animation from Erc X, which is based on the method currently used for Starlink deployment, and also mentioned in the interview with Tim:

https://twitter.com/elonmusk/status/1454610184979075079
Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: Spaceman_From_Italy on 10/31/2021 10:22 am
My main concern about orbital test flight is the sturdiness of the separation mechanism during ascend phase, it different to the F9 mechanism so I fear it could break during max Q event.

Hold-down clamps are the only active mechanism for a staging event. Separation itself will be handled by initiating a booster flip at BECO, followed by clamp release.

Where did this info come from?  I *assumed* that they'd initiate separation using a similar mechanism to F9.

Elon's latest interview with Tim Dodd, the Everyday Astronaut
Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: Vettedrmr on 10/31/2021 10:51 am
Thanks to both of you for sharing that.  I vaguely remember EM saying that during Tim's interview, but apparently that brain cell went dormant.

Have a good one,
Mike
Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: Lars-J on 11/05/2021 04:15 pm
My main concern about orbital test flight is the sturdiness of the separation mechanism during ascend phase, it different to the F9 mechanism so I fear it could break during max Q event.

Hold-down clamps are the only active mechanism for a staging event. Separation itself will be handled by initiating a booster flip at BECO, followed by clamp release.

Where did this info come from?  I *assumed* that they'd initiate separation using a similar mechanism to F9.

Elon's latest interview with Tim Dodd, the Everyday Astronaut

And here is a recent tweet were someone posted an animation, and Elon replied "pretty close". With a stack this large, there does not have to be much of a spin to create separation:

https://twitter.com/ErcXspace/status/1454562965173252098
Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: wannamoonbase on 11/07/2021 02:02 pm
We must be in a lull, Iíve never seen so much excitement over a crane.

The animation of the separation video is excellent.  The difference in SH to SS mass really shows.

Canít wait to see how it works.
Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: sferrin on 11/07/2021 08:34 pm
We must be in a lull, Iíve never seen so much excitement over a crane.

The animation of the separation video is excellent.  The difference in SH to SS mass really shows.

Canít wait to see how it works.
The FAA nonsense is a dark cloud over the whole thing.  Until they give the green light I don't see the excitement level changing substantially. 
Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: ETurner on 11/07/2021 09:12 pm
We must be in a lull, Iíve never seen so much excitement over a crane.

The animation of the separation video is excellent.  The difference in SH to SS mass really shows.

Canít wait to see how it works.
Looks wrong. SH and SS share the same angular velocity at separation, but the animation shows the angular velocity of SS go to zero before any thrust is applied.

Knowing that the linear and angular velocities of both SS and SH will be unchanged by merely severing their connection is enough to figure out what happens. Conveniently, the initial motions are along the vehicle axis -- the surfaces just pull straight apart under ďcentrifugal forceĒ.
Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: rickyramjet on 11/07/2021 10:46 pm

The FAA nonsense is a dark cloud over the whole thing.  Until they give the green light I don't see the excitement level changing substantially. 

Even if the FAA gave full approval today, there is still a ton of stuff to do.  A complete SS static fire has not been done, they are still swapping engines.  SS isn't remotely close to being ready, with zero testing so far.  The tank farm has yet to be filled with LOX and LCH4 and tested to fuel a full SS/SH stack.  I don't believe the FAA is the gating item!
Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: schuttle89 on 11/08/2021 01:32 am

The FAA nonsense is a dark cloud over the whole thing.  Until they give the green light I don't see the excitement level changing substantially. 

Even if the FAA gave full approval today, there is still a ton of stuff to do.  A complete SS static fire has not been done, they are still swapping engines.  SS isn't remotely close to being ready, with zero testing so far.  The tank farm has yet to be filled with LOX and LCH4 and tested to fuel a full SS/SH stack.  I don't believe the FAA is the gating item!

You might be the only one here that doesn't think the FAA is the limiting item. It's a fair point that there is plenty to do, but it feels like they could be doing all those things at a much faster pace if it were possible to launch at an earlier time.
Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: Kansan52 on 11/08/2021 01:47 am
Nope he usn't the only one. At least they seem to on a full court press without FAA approval. I worry what happens if the FAA says no more flights from Boca Chica. Huge uptick of work at the Cape would be my guess.
Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: alugobi on 11/08/2021 02:53 am
If they say no to anything, it will be landings, is my guess.
Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: samgineer on 11/08/2021 11:42 am
Iīm not sure if it was posted somewhere, (if so i overlooked) but SpaceX finally started making nosecones, after fine tuning machines and testing, with new big stretched plates instead smaller press formed. I realized when i watched today daily video update. One behind looks like has completed structural welding with header installed (header weld is visible) and one in front of is fully welded top part.  It seems like SN22 will be last starship with small piece nosecone!



Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: Vettedrmr on 11/08/2021 12:12 pm
Nope he usn't the only one. At least they seem to on a full court press without FAA approval. I worry what happens if the FAA says no more flights from Boca Chica. Huge uptick of work at the Cape would be my guess.

Agreed.  BC seems to be running at full speed, just not on stuff we love to watch.  As EM is fond of saying, the biggest problem is not the actual vehicle, but all of the support infrastructure to build and fly them.
Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: edzieba on 11/08/2021 12:55 pm
Iīm not sure if it was posted somewhere, (if so i overlooked) but SpaceX finally started making nosecones, after fine tuning machines and testing, with new big stretched plates instead smaller press formed. I realized when i watched today daily video update. One behind looks like has completed structural welding with header installed (header weld is visible) and one in front of is fully welded top part.  It seems like SN22 will be last starship with small piece nosecone!
The first of these 'cleaner' noses was shown off by Elon during Tim Dodd's site walkthrough.
Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: sferrin on 11/08/2021 01:39 pm

The FAA nonsense is a dark cloud over the whole thing.  Until they give the green light I don't see the excitement level changing substantially. 

Even if the FAA gave full approval today, there is still a ton of stuff to do.  A complete SS static fire has not been done, they are still swapping engines.  SS isn't remotely close to being ready, with zero testing so far.  The tank farm has yet to be filled with LOX and LCH4 and tested to fuel a full SS/SH stack.  I don't believe the FAA is the gating item!
Yes, but at least we'd know there is a light at the end of the tunnel.  Right now everything SpaceX is doing in Boca Chica could be for naught if the FAA says no.
Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: Vettedrmr on 11/08/2021 02:01 pm
Yes, but at least we'd know there is a light at the end of the tunnel.  Right now everything SpaceX is doing in Boca Chica could be for naught if the FAA says no.

The FAA rarely comes out with a direct "No"; but rather a conditional "Yes".  "Yes, once you make A, B, and C changes, and put in D, E, and F limits.  And then the FAA has to verify those changes have been made and those limits are in place.  That's what got SpaceX into hot water with SN-8: the FAA said to have limits in place, SpaceX put them in place, but didn't get FAA signoff on them BEFORE flight.

SpaceX has obviously learned from that mistake.
Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: edzieba on 11/08/2021 02:10 pm
In effect: The FAA already 'approve' of the contents of the PEA (or they would not have published it for public comment, and instead have told SpaceX to make the modifications needed to satisfy them). Any wrinkles at this point would be if the public comment period turns up a substantial issue with the PEA that the FAA have missed.
Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: samgineer on 11/08/2021 02:15 pm
Iīm not sure if it was posted somewhere, (if so i overlooked) but SpaceX finally started making nosecones, after fine tuning machines and testing, with new big stretched plates instead smaller press formed. I realized when i watched today daily video update. One behind looks like has completed structural welding with header installed (header weld is visible) and one in front of is fully welded top part.  It seems like SN22 will be last starship with small piece nosecone!
The first of these 'cleaner' noses was shown off by Elon during Tim Dodd's site walkthrough.

Yes, I know, but it wasn't complete with header and it was only partially build top part. I don't think it was even  fully welded. 
Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: simon82 on 11/08/2021 03:16 pm
Iīm not sure if it was posted somewhere, (if so i overlooked) but SpaceX finally started making nosecones, after fine tuning machines and testing, with new big stretched plates instead smaller press formed. I realized when i watched today daily video update. One behind looks like has completed structural welding with header installed (header weld is visible) and one in front of is fully welded top part.  It seems like SN22 will be last starship with small piece nosecone!

Interesting. I recall some months back that that S24 was going to be the one with the next leap in terms of upgrade, like how 15 and 20 were. When I saw the stretched plates on Tim Dodd's video I assumed that would be one of the S24 upgrades, along with the new smaller flaps. Maybe they'll bring the upgraded cone forward.
Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: JamesH65 on 11/09/2021 09:32 am

The FAA nonsense is a dark cloud over the whole thing.  Until they give the green light I don't see the excitement level changing substantially. 

Even if the FAA gave full approval today, there is still a ton of stuff to do.  A complete SS static fire has not been done, they are still swapping engines.  SS isn't remotely close to being ready, with zero testing so far.  The tank farm has yet to be filled with LOX and LCH4 and tested to fuel a full SS/SH stack.  I don't believe the FAA is the gating item!
Yes, but at least we'd know there is a light at the end of the tunnel.  Right now everything SpaceX is doing in Boca Chica could be for naught if the FAA says no.

The knowledge they have gained on manufacture of the ships, the launch tower, the machinery. That will not be lost if the FAA says no. They just need to move to knowledge to a site they can use. Expensive, but they know how to do it now.
Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: andrewmcleod on 11/09/2021 12:15 pm
Looks wrong. SH and SS share the same angular velocity at separation, but the animation shows the angular velocity of SS go to zero before any thrust is applied.

Knowing that the linear and angular velocities of both SS and SH will be unchanged by merely severing their connection is enough to figure out what happens. Conveniently, the initial motions are along the vehicle axis -- the surfaces just pull straight apart under ďcentrifugal forceĒ.

I don't think that's true - when you define angular velocity you have to define the point you are calculating it around. If, before the separation, you calculate the angular velocity of the Starship around its centre of mass, and the angular velocity of the booster around its centre of mass, they will be different (and they will have different translational velocities). I believe they will retain these different angular velocities and translational velocities after separation, and each will rotate around its centre of mass.

So yes, the Starship should probably have some rotation left after separation, but less than the booster as its movement is more translational than rotational (as it is further from the original centre of rotation of the combined stack). I presume that the animation assumes RCS thrusters will null out the rotation of the Starship prior to engine start - although it would probably be easier to just gimbal the main engines.
Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: Tangilinear Interjar on 11/09/2021 01:22 pm
Iīm not sure if it was posted somewhere, (if so i overlooked) but SpaceX finally started making nosecones, after fine tuning machines and testing, with new big stretched plates instead smaller press formed. I realized when i watched today daily video update. One behind looks like has completed structural welding with header installed (header weld is visible) and one in front of is fully welded top part.  It seems like SN22 will be last starship with small piece nosecone!

Interesting. I recall some months back that that S24 was going to be the one with the next leap in terms of upgrade, like how 15 and 20 were. When I saw the stretched plates on Tim Dodd's video I assumed that would be one of the S24 upgrades, along with the new smaller flaps. Maybe they'll bring the upgraded cone forward.

They are likely to make another structural test nosecone soon, maybe one of these will be it?

Changes they will need to evaluate are the reduced thickness steel, different nose panel design, new forward flaps, and probably a dozen other significant things that we can't see.
Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: cdebuhr on 11/09/2021 01:30 pm
I don't think that's true - when you define angular velocity you have to define the point you are calculating it around. If, before the separation, you calculate the angular velocity of the Starship around its centre of mass, and the angular velocity of the booster around its centre of mass, they will be different (and they will have different translational velocities).
Not quite.  Angular velocity is simply rotation rate around an axis.  Any axis.  For an unsupported body rotating in space that axis will, of course, pass though the center of mass, but that's neither here nor there with respect to the definition of angular velocity.  When ship and booster are coupled.  What does depend on the specific axis is angular momentum.

So just before separation the total system will have a single angular velocity around the common centre of mass which will be moving with some specific translational velocity.   Each part (ship and booster) will have a certain amount of angular momentum, and a translational velocity that will be changing continuously due the rotation of the system as a whole (the accelerations being provided by rigid body forces couples from the other half of the system).  What will happen at the moment of separation of ship and booster is that those translational velocities will stop changing as each component begins conserving translational momentum individually (in addition to conservation in the overall system, obviously).  Each component will also have some fraction of the overall system's angular momentum which my intuition says should result in each component having the same angular velocity vector as the combined system before separation, but to say that definitively is beyond what my current coffee saturation levels will allow.
Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: wannamoonbase on 11/09/2021 01:33 pm
Iīm not sure if it was posted somewhere, (if so i overlooked) but SpaceX finally started making nosecones, after fine tuning machines and testing, with new big stretched plates instead smaller press formed. I realized when i watched today daily video update. One behind looks like has completed structural welding with header installed (header weld is visible) and one in front of is fully welded top part.  It seems like SN22 will be last starship with small piece nosecone!

Interesting. I recall some months back that that S24 was going to be the one with the next leap in terms of upgrade, like how 15 and 20 were. When I saw the stretched plates on Tim Dodd's video I assumed that would be one of the S24 upgrades, along with the new smaller flaps. Maybe they'll bring the upgraded cone forward.

They are likely to make another structural test nosecone soon, maybe one of these will be it?

Changes they will need to evaluate are the reduced thickness steel, different nose panel design, new forward flaps, and probably a dozen other significant things that we can't see.

Might be worth doing a structural nose cone test with the TPS installed.  See how that does going through MAX-Q loads.
Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: wannamoonbase on 11/09/2021 01:43 pm

The FAA nonsense is a dark cloud over the whole thing.  Until they give the green light I don't see the excitement level changing substantially. 

Even if the FAA gave full approval today, there is still a ton of stuff to do.  A complete SS static fire has not been done, they are still swapping engines.  SS isn't remotely close to being ready, with zero testing so far.  The tank farm has yet to be filled with LOX and LCH4 and tested to fuel a full SS/SH stack.  I don't believe the FAA is the gating item!

You might be the only one here that doesn't think the FAA is the limiting item. It's a fair point that there is plenty to do, but it feels like they could be doing all those things at a much faster pace if it were possible to launch at an earlier time.

I think itís both, SpaceX isnít ready but once it is the FAA could still be a ways off.

I donít think there is anything stopping SpaceX from stacking, fueling and doing a static fire on SH.  Until they do that, we know they arenít ready on several fronts.  The launch mount, fueling system, amount of fuel on site, SH readiness. 

Given the size and number of engines on SH they could do a lot of static fires to collect data.  Starting with a few engines and work their way up to a full set.

Itís now November 9, if they have the SH stacked and doing static fire. By 12/31/21 I think that could be considered a win.

I think SS is probably pretty close.  Install the engines, stack and complete the missing TPS tiles.

Edit: Elon will be pushing hard, Iím sure they want to show that FAA could be holding them up.
Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: Okie_Steve on 11/09/2021 02:16 pm
If they end up waiting once all the hardware is ready, operational practice stacking, unstacking and moving the Ship and Booster around the launch site a dozen times would doubtless turn up some things worth tweaking for speed and safety. Just seeing what gets dinged when where how and why would be valuable information going forward to improve handling procedures.

Yes, the goal is to fly but enforced waiting would not be totally wasted time either.
Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: capoman on 11/09/2021 02:57 pm
Aside from orbital flight, I can't wait to see the chopsticks do some stacking. They must have pretty good confidence in it if the LR11000 can't do it, and there's no other option onsite.
Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: RotoSequence on 11/09/2021 03:19 pm
Aside from orbital flight, I can't wait to see the chopsticks do some stacking. They must have pretty good confidence in it if the LR11000 can't do it, and there's no other option onsite.

They'd have to reconfigure it with a longer boom, derrick, and a counterweight tray, but the 11000 could do it.
Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: rsdavis9 on 11/09/2021 03:22 pm
Looks wrong. SH and SS share the same angular velocity at separation, but the animation shows the angular velocity of SS go to zero before any thrust is applied.

Knowing that the linear and angular velocities of both SS and SH will be unchanged by merely severing their connection is enough to figure out what happens. Conveniently, the initial motions are along the vehicle axis -- the surfaces just pull straight apart under ďcentrifugal forceĒ.

I don't think that's true - when you define angular velocity you have to define the point you are calculating it around. If, before the separation, you calculate the angular velocity of the Starship around its centre of mass, and the angular velocity of the booster around its centre of mass, they will be different (and they will have different translational velocities). I believe they will retain these different angular velocities and translational velocities after separation, and each will rotate around its centre of mass.

So yes, the Starship should probably have some rotation left after separation, but less than the booster as its movement is more translational than rotational (as it is further from the original centre of rotation of the combined stack). I presume that the animation assumes RCS thrusters will null out the rotation of the Starship prior to engine start - although it would probably be easier to just gimbal the main engines.

Actually at separation booster weighs 200t and spaceship weighs 1300t so the center of mass will definitely be somewhere in the spaceship.

On separation each center of mass of the booster and spaceship will have some translational velocity which will move them apart and rotate them.
Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: philw1776 on 11/09/2021 04:38 pm

I think itís both, SpaceX isnít ready but once it is the FAA could still be a ways off.

I donít think there is anything stopping SpaceX from stacking, fueling and doing a static fire on SH.  Until they do that, we know they arenít ready on several fronts.  The launch mount, fueling system, amount of fuel on site, SH readiness. 

Given the size and number of engines on SH they could do a lot of static fires to collect data.  Starting with a few engines and work their way up to a full set.

Itís now November 9, if they have the SH stacked and doing static fire. By 12/31/21 I think that could be considered a win.

I think SS is probably pretty close.  Install the engines, stack and complete the missing TPS tiles.

Edit: Elon will be pushing hard, Iím sure they want to show that FAA could be holding them up.

We should do a new Poll "When will Starship reach orbit successfully" in late December for 2022 and beyond, as the overwhelming majority of predictions on the existing poll were way too early.
Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: OTV Booster on 11/09/2021 06:20 pm
If they end up waiting once all the hardware is ready, operational practice stacking, unstacking and moving the Ship and Booster around the launch site a dozen times would doubtless turn up some things worth tweaking for speed and safety. Just seeing what gets dinged when where how and why would be valuable information going forward to improve handling procedures.

Yes, the goal is to fly but enforced waiting would not be totally wasted time either.
They could get the same or better return rotating SN21 and BN5 into service. ;)
Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: Okie_Steve on 11/09/2021 06:42 pm
If they end up waiting once all the hardware is ready, operational practice stacking, unstacking and moving the Ship and Booster around the launch site a dozen times would doubtless turn up some things worth tweaking for speed and safety. Just seeing what gets dinged when where how and why would be valuable information going forward to improve handling procedures.

Yes, the goal is to fly but enforced waiting would not be totally wasted time either.
They could get the same or better return rotating SN21 and BN5 into service. ;)

No argument with that, but they might want to scratch and ding the old models first then improve procedures and delay that first scratch on the new rocket. It is bad enough with a new car  :)
Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: Alberto-Girardi on 11/09/2021 07:57 pm
If they end up waiting once all the hardware is ready, operational practice stacking, unstacking and moving the Ship and Booster around the launch site a dozen times would doubtless turn up some things worth tweaking for speed and safety. Just seeing what gets dinged when where how and why would be valuable information going forward to improve handling procedures.

Yes, the goal is to fly but enforced waiting would not be totally wasted time either.
They could get the same or better return rotating SN21 and BN5 into service. ;)

No argument with that, but they might want to scratch and ding the old models first then improve procedures and delay that first scratch on the new rocket. It is bad enough with a new car  :)
I think that at the end SpaceX might need all of the time, and that no time will be really wasted waiting. They have so many things to do and problems to solve that  there will be, sadly but surely, delays. With S20 we are seeing weeks with little apparent action (expecially in the past), but I'm sure (and I think that many agree )  that they are doing many things under the hood or they can't concentrate fully on S20 because of the other things to do.
Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: wannamoonbase on 11/09/2021 09:00 pm
If they end up waiting once all the hardware is ready, operational practice stacking, unstacking and moving the Ship and Booster around the launch site a dozen times would doubtless turn up some things worth tweaking for speed and safety. Just seeing what gets dinged when where how and why would be valuable information going forward to improve handling procedures.

Yes, the goal is to fly but enforced waiting would not be totally wasted time either.
They could get the same or better return rotating SN21 and BN5 into service. ;)

At a minimum, stacking SN20 and BN4 and doing several static fires with BN4 to learn what is involved there and the vehicles response and staging of engine timing could be worth it, even if 20 & 4 never fly.

I do wonder how long these vehicles can be outside in the elements and remain at a level of readiness.
Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: Chris Bergin on 11/09/2021 09:31 pm
Where it all started :)

https://www.youtube.com/watch?v=Jem5iFXMAhU
Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: Echo_Jex on 11/09/2021 09:44 pm
If they end up waiting once all the hardware is ready, operational practice stacking, unstacking and moving the Ship and Booster around the launch site a dozen times would doubtless turn up some things worth tweaking for speed and safety. Just seeing what gets dinged when where how and why would be valuable information going forward to improve handling procedures.

Yes, the goal is to fly but enforced waiting would not be totally wasted time either.
They could get the same or better return rotating SN21 and BN5 into service. ;)

At a minimum, stacking SN20 and BN4 and doing several static fires with BN4 to learn what is involved there and the vehicles response and staging of engine timing could be worth it, even if 20 & 4 never fly.

I do wonder how long these vehicles can be outside in the elements and remain at a level of readiness.

I get the feeling you were wondering rhetorically, but I'm compelled to think about it like airframe maintenance. Even if SN15 is forever just sitting still and accumulating time, it might get inspected here and there to log how the elemental exposure progresses... but, i dont think that there will be too many headscratchers in the near term, since some heavy airframe isochronal inspections probably translates ok from heavy airframes to SS/SH
Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: ETurner on 11/09/2021 10:01 pm
Each component will also have some fraction of the overall system's angular momentum which my intuition says should result in each component having the same angular velocity vector as the combined system before separation, but to say that definitively is beyond what my current coffee saturation levels will allow.
This is correct. Itís important not to confuse angular momentum with angular velocity.
Camera views at separation should show purely axial motion initially, then sideways shear due to apparent Coriolis ďforcesĒ and actual thruster forces.
Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: Vultur on 11/10/2021 03:21 am

I donít think there is anything stopping SpaceX from stacking, fueling and doing a static fire on SH.  Until they do that, we know they arenít ready on several fronts.  The launch mount, fueling system, amount of fuel on site, SH readiness. 

Given the size and number of engines on SH they could do a lot of static fires to collect data.  Starting with a few engines and work their way up to a full set.

Itís now November 9, if they have the SH stacked and doing static fire. By 12/31/21 I think that could be considered a win.

I agree. They already did a limited static fire with the Ship and are likely to do a full 6 engine one next; building up in the same way for the Booster makes sense.

Then they need to stack the two, maybe other final stuff.

But I don't expect launch license by even Jan, either.
Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: Oersted on 11/10/2021 11:55 am
Where it all started :)

https://www.youtube.com/watch?v=Jem5iFXMAhU

Fantastic video! - I would love to see more historical vids like this, made while all involved can still remember what happened and the emotions and feelings of these early Boca Chica days.
Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: capoman on 11/10/2021 02:10 pm
Where it all started :)

https://www.youtube.com/watch?v=Jem5iFXMAhU

Fantastic video! - I would love to see more historical vids like this, made while all involved can still remember what happened and the emotions and feelings of these early Boca Chica days.

Agree, and it wasn't that long ago.  It's a reminder of how fast things have actually progressed in such a short time. Watching things unfold in real time, we know it's happening quickly, but to look back to that, and realize how short of time it's actually been has been astounding.
Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: oiorionsbelt on 11/10/2021 02:53 pm


Agree, and it wasn't that long ago.  It's a reminder of how fast things have actually progressed in such a short time. Watching things unfold in real time, we know it's happening quickly, but to look back to that, and realize how short of time it's actually been has been astounding.
This is how I have always viewed "Elon time"
Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: VaBlue on 11/10/2021 04:39 pm

I agree. They already did a limited static fire with the Ship and are likely to do a full 6 engine one next; building up in the same way for the Booster makes sense.

Then they need to stack the two, maybe other final stuff.

But I don't expect launch license by even Jan, either.

The bold is mine...  Any chance the FAA grants a one time license for an experimental vehicle (ie: S21/B4) sometime this winter, before the EA is completed?  Because neither vehicle is coming back home, and (pending) successful static fires have occurred, it seems reasonable to me.  Of course, a lot has to go right - successful static fires of all 29 engines on B4 and all 6 on S20, along with a variety of other things.  It's probably a pipe dream, but it seems plausible (until one of the many smart guys here shoot it down)...
Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: edzieba on 11/10/2021 05:29 pm
Any chance the FAA grants a one time license for an experimental vehicle (ie: S21/B4) sometime this winter, before the EA is completed?
None.
Abiding by NEPA is the reason the FAA cannot issue a launch license yet. Until the requirements of NEPA are satisfied, the FAA cannot issue a launch license, no matter if it's 'one off' or not.

Unless the public comment period turned up something that the FAA missed and that the FAA thinks has a material impact on the current PEA, then approval of the final EA for publishing is likely sooner than some people think. Things like the USFWS letter were already received by the FAA long before they published the PEA, which means those had already been taken into account in the FAAs assessment of whether the PEA was acceptable - because if it were not, the FAA would not have published it and opened up the public comment period, but instead have gone back to SpaceX to revise it until it did satisfy them.
Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: tymo77 on 11/11/2021 04:34 am
Each component will also have some fraction of the overall system's angular momentum which my intuition says should result in each component having the same angular velocity vector as the combined system before separation, but to say that definitively is beyond what my current coffee saturation levels will allow.
This is correct. Itís important not to confuse angular momentum with angular velocity.
Camera views at separation should show purely axial motion initially, then sideways shear due to apparent Coriolis ďforcesĒ and actual thruster forces.

Seems like this point is settled, and not that anyone asked, but chiming in to say the way I think about this is via the fundamental theorem of rigid body dynamics:
All points on a rigid body have the same angular velocity.

If there's no additional forces in play, there's no reason that changes if you suddenly split it in to two.
Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: sferrin on 11/11/2021 11:09 am
Any chance the FAA grants a one time license for an experimental vehicle (ie: S21/B4) sometime this winter, before the EA is completed?
None.
Abiding by NEPA is the reason the FAA cannot issue a launch license yet. Until the requirements of NEPA are satisfied, the FAA cannot issue a launch license, no matter if it's 'one off' or not.

Unless the public comment period turned up something that the FAA missed and that the FAA thinks has a material impact on the current PEA, then approval of the final EA for publishing is likely sooner than some people think. Things like the USFWS letter were already received by the FAA long before they published the PEA, which means those had already been taken into account in the FAAs assessment of whether the PEA was acceptable - because if it were not, the FAA would not have published it and opened up the public comment period, but instead have gone back to SpaceX to revise it until it did satisfy them.


Would love it if it turns out this way.  Right now SpaceX isn't really being held up as there is so much to get ready.  Hopefully this is resolved by the time they're ready to fly. 
Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: OTV Booster on 11/11/2021 03:42 pm
Each component will also have some fraction of the overall system's angular momentum which my intuition says should result in each component having the same angular velocity vector as the combined system before separation, but to say that definitively is beyond what my current coffee saturation levels will allow.
This is correct. Itís important not to confuse angular momentum with angular velocity.
Camera views at separation should show purely axial motion initially, then sideways shear due to apparent Coriolis ďforcesĒ and actual thruster forces.
So, translating this into non engineer visualization, what should we expect to see?


They will spin in one piece with the shared CG somewhere around the (edit:) SS engines, or maybe a bit lower. At the moment of release the CG no longer shared. SH CG would be somewhere low in the bottom tank an SH somewhere near the common dome - I think. How would they move/spin at the moment of release from an outside frame of reference with the same V?


I'd try it with a piece of bamboo and an oak stick if I could figure out an easy latch.
Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: Eer on 11/11/2021 03:50 pm
Each component will also have some fraction of the overall system's angular momentum which my intuition says should result in each component having the same angular velocity vector as the combined system before separation, but to say that definitively is beyond what my current coffee saturation levels will allow.
This is correct. Itís important not to confuse angular momentum with angular velocity.
Camera views at separation should show purely axial motion initially, then sideways shear due to apparent Coriolis ďforcesĒ and actual thruster forces.
So, translating this into non engineer visualization, what should we expect to see?


They will spin in one piece with the shared CG somewhere around the engines, or maybe a bit lower. At the moment of release the CG no longer shared. SH CG would be somewhere low in the bottom tank an SH somewhere near the common dome - I think. How would they move/spin at the moment of release from an outside frame of reference with the same V?


I'd try it with a piece of bamboo and an oak stick if I could figure out an easy latch.

I managed to get a "pass" from college flunk-out physics, so I do NOT know what's going on with the angular momentum, but ...

I have to disagree with where the center of gravity of a (loaded with fuel and cargo) SH/SS stack will be after MECO of the SH - it's going to be well above the SS engines, I'd think, for the shared stack following MECO.

The CG of the SH stage (after most fuel is expended) will, as you say, be well down the stage towards its engines.  So the angular momentum I would think would cause the top of the stage (towards the pointy end) to rotate the top end away from the SS pretty quickly (because of a longer arm of rotation from the SH CG).

The CG of the SS will be well up towards the center of the stage (because of the full load of fuel, even before any cargo is there), so the rotation speed of its fiery bits will be relatively low velocity in comparison to that of the top of the SH.

Do I have that right?
Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: Hitech on 11/11/2021 04:12 pm

One needs to understand why grid fins were chosen in the first place. Being able to fold was a major reason. Now that folding is no longer necessary, that reason goes away. I suspect the trades are being done (or have been done) and a decision has been made. What it is, I donít know.

Iím just stating that I would not be shocked *IF* in a few weeks we see ďnormalĒ fins being delivered for BN6.
[/quote]

How about no fins?

I'm pretty sure that was an option mentioned by Elon during his interview with Tim Dodd.
I think the suggestion was that ullage gas thrusters could possibly be used instead....
[/quote]

IIRC grid fins are used because of their control authority at hyper- and supersonic speeds, not because of their ability to fold.  It made/makes sense to fold them on F9 because it made sense at the time, or their drag contribution to F9's total drag is pretty large, etc.  Apparently that contribution on SH is small enough to not be worth the added complexity of folding.
[/quote]
As another poster up thread noted, grid fins minimize the chord length perpendicular to the rotation axis. To get the same force from a conventional fin for the same deflection, the chord must be much longer: just check out the size of the fins on New Glenn. A larger chord means the rotation axis must be somewhere mid-chord (usually close to the aerodynamic center) to minimize actuator torque. This means the motors, levers and structural mounts could no longer be housed above the CH4 dome in the interstage region of the current design. Perhaps they could be mounted in faired external housings farther down the sides of the tank, but that may be a heavier solution. Big fins hanging farther down the sides also create complications for the catching interface with the tower chopsticks (Iím still anxious to see how theyíre solving that one for Starship and itís huge Elonerons). They also would lose the nice failsafe of landing on the grid fins if they somehow missed the grappling pins. It would probably wreck the grid fins and their mounting interface, but given how beefy that structure is, it would probably hold and prevent a crash. I doubt flat fins would be quite as strong.
Also, I doubt no fins will ever work, particularly with weak ullage pressure nozzles. They already tried that with stronger relative authority N2 thrusters on Falcon 9 and were unable to make it work, hence the advent of grid fins.
[/quote]

I think drag is the reason
Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: cdebuhr on 11/11/2021 04:14 pm
Each component will also have some fraction of the overall system's angular momentum which my intuition says should result in each component having the same angular velocity vector as the combined system before separation, but to say that definitively is beyond what my current coffee saturation levels will allow.
This is correct. Itís important not to confuse angular momentum with angular velocity.
Camera views at separation should show purely axial motion initially, then sideways shear due to apparent Coriolis ďforcesĒ and actual thruster forces.
So, translating this into non engineer visualization, what should we expect to see?


They will spin in one piece with the shared CG somewhere around the engines, or maybe a bit lower. At the moment of release the CG no longer shared. SH CG would be somewhere low in the bottom tank an SH somewhere near the common dome - I think. How would they move/spin at the moment of release from an outside frame of reference with the same V?


I'd try it with a piece of bamboo and an oak stick if I could figure out an easy latch.

I managed to get a "pass" from college flunk-out physics, so I do NOT know what's going on with the angular momentum, but ...

I have to disagree with where the center of gravity of a (loaded with fuel and cargo) SH/SS stack will be after MECO of the SH - it's going to be well above the SS engines, I'd think, for the shared stack following MECO.

The CG of the SH stage (after most fuel is expended) will, as you say, be well down the stage towards its engines.  So the angular momentum I would think would cause the top of the stage (towards the pointy end) to rotate the top end away from the SS pretty quickly (because of a longer arm of rotation from the SH CG).

The CG of the SS will be well up towards the center of the stage (because of the full load of fuel, even before any cargo is there), so the rotation speed of its fiery bits will be relatively low velocity in comparison to that of the top of the SH.

Do I have that right?
I think you're probably mostly right on most bits - not sure about the exact placement of the combined CG, but somewhere near SS engines seems about right.  Keep in mind though that the SH engines are a long way from SS, which will pull the CG down significantly.

While I understand the mechanics well enough I think, I'm still trying to work out specifics of the separation, especially with respect to the possibility of re-contact.  At the moment of separation, everything keeps the same angular velocity vector, which will result in the top of SH and the bottom of SS sliding off in opposite directions (in the original frame of the combined stack), while also moving apart due to the sudden loss of centripetal acceleration formerly provided by the staging clamps.  The rate of separation needs to be high enough to prevent the formerly mated ends from raking across each other (although it would be very SpaceX /Starlink to just make them rugged enough to take the bumps).  Intuitively, I don't think the actual angular velocity is material here - it only affects how fast it all happens.  I believe this is entirely a question of where, specifically, the respective CGs are in the separated vehicles.  If the CG's we're both very close the the mating surface (they aren't), then the rate of separation would be perhaps too low.  If they're too far away, then perhaps the rate of shear at the separation plane would be too high.  Do we actually have enough information on hand to do a cartoon model of this?  I'm sure SX has worked this out in detail, but I don't believe they've publicly shared the specifics.

Edit: Without have to model the whole thing in detail, it occurs to me that it would be sufficient to know if, in the boosters original rotating frame prior to separation, any part of the staging interface of either component of the full stack has a translational velocity vector that would carry it across the separation plane.   In other words, does the centrifugal pulling-away of SS and SH outpace the rotational tendency to sweep the trailing edges of the staging interface across the separation plane.  If so, then we're free and clear.  If not, we might still be OK, but more detailed modeling will be required.
Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: Alberto-Girardi on 11/11/2021 04:24 pm
Guys this is the protype thread, not the launch licence one.
Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: ETurner on 11/11/2021 06:38 pm
[...]
Edit: Without have to model the whole thing in detail, it occurs to me that it would be sufficient to know if, in the boosters original rotating frame prior to separation, any part of the staging interface of either component of the full stack has a translational velocity vector that would carry it across the separation plane.   In other words, does the centrifugal pulling-away of SS and SH outpace the rotational tendency to sweep the trailing edges of the staging interface across the separation plane.  If so, then we're free and clear.  If not, we might still be OK, but more detailed modeling will be required.
Keep in mind that both sides of the interface have the same linear velocity at the moment of separation, and there is no sideways force to cause a sheering motion. There is, however, axial acceleration due to release of the centripetal forces that had been transmitted by the interface. When the prototypeís cameras show us the glorious moment, we will see the ends pull straight apart at the moment of separation, and will see little sheer until the ends are well separated.
Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: cdebuhr on 11/11/2021 07:26 pm
[...]
Edit: Without have to model the whole thing in detail, it occurs to me that it would be sufficient to know if, in the boosters original rotating frame prior to separation, any part of the staging interface of either component of the full stack has a translational velocity vector that would carry it across the separation plane.   In other words, does the centrifugal pulling-away of SS and SH outpace the rotational tendency to sweep the trailing edges of the staging interface across the separation plane.  If so, then we're free and clear.  If not, we might still be OK, but more detailed modeling will be required.
Keep in mind that both sides of the interface have the same linear velocity at the moment of separation, and there is no sideways force to cause a sheering motion. There is, however, axial acceleration due to release of the centripetal forces that had been transmitted by the interface. When the prototypeís cameras show us the glorious moment, we will see the ends pull straight apart at the moment of separation, and will see little sheer until the ends are well separated.
Hmmm .... good points.  Right on all counts, I think, but I also think the rotating reference frame of the separation plane is screwing with my intuition here.  If I was still fluent in MATLAB (that was a looong time ago), I'd make a simple cartoon 2-d model (I think I could get it down to ~6 adjustable parameters to account for dimensions, masses, and COGs) and brute force it numerically, but for now I'll just have to wait and see how it all works out.  I'd love to see a proper numerical simulation of this, ideally a side-by-side animation showing both the rotating frame of the separation plane alongside an inertial view.
Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: equiserre on 11/12/2021 01:13 pm
[...]
Edit: Without have to model the whole thing in detail, it occurs to me that it would be sufficient to know if, in the boosters original rotating frame prior to separation, any part of the staging interface of either component of the full stack has a translational velocity vector that would carry it across the separation plane.   In other words, does the centrifugal pulling-away of SS and SH outpace the rotational tendency to sweep the trailing edges of the staging interface across the separation plane.  If so, then we're free and clear.  If not, we might still be OK, but more detailed modeling will be required.
Keep in mind that both sides of the interface have the same linear velocity at the moment of separation, and there is no sideways force to cause a sheering motion. There is, however, axial acceleration due to release of the centripetal forces that had been transmitted by the interface. When the prototypeís cameras show us the glorious moment, we will see the ends pull straight apart at the moment of separation, and will see little sheer until the ends are well separated.
Hmmm .... good points.  Right on all counts, I think, but I also think the rotating reference frame of the separation plane is screwing with my intuition here.  If I was still fluent in MATLAB (that was a looong time ago), I'd make a simple cartoon 2-d model (I think I could get it down to ~6 adjustable parameters to account for dimensions, masses, and COGs) and brute force it numerically, but for now I'll just have to wait and see how it all works out.  I'd love to see a proper numerical simulation of this, ideally a side-by-side animation showing both the rotating frame of the separation plane alongside an inertial view.

OK I got curious and here is my contribution, I hope I didnīt make any mistakes. Iīm rusty, so maybe I did.

I derived the trajectories of the center point of the bottom of Starship and the top of Superheavy, after separation with a given angular velocity (pitch up). So these two points (A in the diagram) are in the same spot before separation, and then I show how they go their separate ways.

Assumptions:
Starship
mass at sep 1360t,
Center of Mass 14.7m from the bottom (this was calculated with a detailed spreadsheet I keep)

Superheavy
200t empty + 230t propellant (assumed to be at the bottom of the tanks) = 430t.
Center of Mass 21.4m from the bottom

Stack Center of Mass is then 0.5m down from the interfase

The trajectories are referenced TO THE COMMON CENTER OF MASS, so you will see the initial position is Y=0, X=0.5m, because the interfase is 0.5m above the CM. Each ship, before sep, has only an angular velocity around the CM. After sep, each individual CM flies away with a tangential velocity perpendicular to the ships centerline, PLUS the same angular velocity, but now the rotation is around each ship`s CM. It works with any angular velocity, this example is with 23deg/s. I should do the same with points at the top and bottom of the ships, to check for any bumping, but got lazy.

Fire away!



Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: rsdavis9 on 11/12/2021 06:51 pm
I have a question.

Is there any water deluge on the S20 suborbital test stands?
I don't think there is.
So that means when they fire up on the big stand (OLP) with the water deluge and 29 engines it maybe quieter?
Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: StevenOBrien on 11/12/2021 07:04 pm
I have a question.

Is there any water deluge on the S20 suborbital test stands?
I don't think there is.
So that means when they fire up on the big stand (OLP) with the water deluge and 29 engines it maybe quieter?
There is. It's difficult to see with all of the vapors, but it starts up at about T-0:20.
Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: capoman on 11/12/2021 07:43 pm
I have a question.

Is there any water deluge on the S20 suborbital test stands?
I don't think there is.
So that means when they fire up on the big stand (OLP) with the water deluge and 29 engines it maybe quieter?
There is. It's difficult to see with all of the vapors, but it starts up at about T-0:20.

Yes, the deluge on the suborbital pad basically just sprays the pad to protect it from what Iíve seen. I donít think itís really intended to be sound suppression. On the orbital mount though, I think they would want to use it to also suppress the sound and protect the launch stand which means it will have come from high up on the launch stand.
Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: Overtone on 11/12/2021 08:30 pm


Assumptions:
Starship
mass at sep 1360t,
Center of Mass 14.7m from the bottom (this was calculated with a detailed spreadsheet I keep)

Superheavy
200t empty + 230t propellant (assumed to be at the bottom of the tanks) = 430t.
Center of Mass 21.4m from the bottom

Stack Center of Mass is then 0.5m down from the interfase

Umm, I'm not an engineer, but this seems off to me.  You have a 1360t mass and a 430t mass and you calculate the stack center of mass as being closer to the CG of the 430t mass than the CG of the 1360t mass...  what am I missing?

My quick scribbles suggest stack center of mass would be 33.4 m below the interface.  Booster CG at +21.4, interface at +70, ship CG at +84.7.  Adding the two moments and dividing by total mass gives stack CG at +36.6 meters, not far above the mid point of the booster.

Someone please correct me if I'm wrong!  If I'm right, I'd be very interested to see your updated plots.
Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: SteveU on 11/12/2021 08:40 pm


Assumptions:
Starship
mass at sep 1360t,
Center of Mass 14.7m from the bottom (this was calculated with a detailed spreadsheet I keep)

Superheavy
200t empty + 230t propellant (assumed to be at the bottom of the tanks) = 430t.
Center of Mass 21.4m from the bottom

Stack Center of Mass is then 0.5m down from the interfase

Umm, I'm not an engineer, but this seems off to me.  You have a 1360t mass and a 430t mass and you calculate the stack center of mass as being closer to the CG of the 430t mass than the CG of the 1360t mass...  what am I missing?

My quick scribbles suggest stack center of mass would be 33.4 m below the interface.  Booster CG at +21.4, interface at +70, ship CG at +84.7.  Adding the two moments and dividing by total mass gives stack CG at +36.6 meters, not far above the mid point of the booster.

Someone please correct me if I'm wrong!  If I'm right, I'd be very interested to see your updated plots.
Think you switched the masses. 1360t is the SS mass, 430t is SH mass.

SH almost empty, SS still fully loaded
Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: Overtone on 11/13/2021 02:08 am
thanks!
Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: Reynold on 11/13/2021 02:37 am
Interesting in seeing the different views in the Update thread that on the TPS tile side, there is no visible line of frost but there is on the bare side. Obviously the TPS provides good insulation, but hopefully that is also a sign that there will not be ice accumulation in those TPS tiles on launch that causes problems during ascent, especially considering SpaceX's fairly fast fueling procedure to keep the fuel supercooled for density.   
Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: su27k on 11/13/2021 02:50 am
Interesting trivia for S20:

https://twitter.com/DJSnM/status/1459225930707062790
Quote
In theory this test article has more thrust than any single rocket in the world, there are some multicore and SRB assisted vehicles, but this is a single vehicle. No guarantee they went to full thrust on this test, but even then the lower limit is blistering.
Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: baking on 11/13/2021 02:55 am
Interesting trivia for S20:
Quote
In theory this test article has more thrust than any single rocket in the world, there are some multicore and SRB assisted vehicles, but this is a single vehicle. No guarantee they went to full thrust on this test, but even then the lower limit is blistering.
This was mentioned on the NSF livestream at least a couple of hours before Scott's Tweet.
Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: Keldor on 11/13/2021 04:28 am
Interesting trivia for S20:

https://twitter.com/DJSnM/status/1459225930707062790
Quote
In theory this test article has more thrust than any single rocket in the world, there are some multicore and SRB assisted vehicles, but this is a single vehicle. No guarantee they went to full thrust on this test, but even then the lower limit is blistering.

Should be clear, this is only true for rockets in operation today.  We'll have to wait for Superheavy to do its first full static firing to beat Saturn V, for instance.

It's still pretty incredible for a second stage.
Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: rsdavis9 on 11/13/2021 12:16 pm


Assumptions:
Starship
mass at sep 1360t,
Center of Mass 14.7m from the bottom (this was calculated with a detailed spreadsheet I keep)

Superheavy
200t empty + 230t propellant (assumed to be at the bottom of the tanks) = 430t.
Center of Mass 21.4m from the bottom

Stack Center of Mass is then 0.5m down from the interfase

Umm, I'm not an engineer, but this seems off to me.  You have a 1360t mass and a 430t mass and you calculate the stack center of mass as being closer to the CG of the 430t mass than the CG of the 1360t mass...  what am I missing?

My quick scribbles suggest stack center of mass would be 33.4 m below the interface.  Booster CG at +21.4, interface at +70, ship CG at +84.7.  Adding the two moments and dividing by total mass gives stack CG at +36.6 meters, not far above the mid point of the booster.

Someone please correct me if I'm wrong!  If I'm right, I'd be very interested to see your updated plots.
Think you switched the masses. 1360t is the SS mass, 430t is SH mass.

SH almost empty, SS still fully loaded

So just to see if "I" have it right:
(33.4m*430t+85m*1360t)/(1360t+430t) = 72m
So just 2m into the ship?
Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: envy887 on 11/13/2021 12:46 pm
Interesting trivia for S20:

https://twitter.com/DJSnM/status/1459225930707062790
Quote
In theory this test article has more thrust than any single rocket in the world, there are some multicore and SRB assisted vehicles, but this is a single vehicle. No guarantee they went to full thrust on this test, but even then the lower limit is blistering.

Should be clear, this is only true for rockets in operation today.  We'll have to wait for Superheavy to do its first full static firing to beat Saturn V, for instance.

It's still pretty incredible for a second stage.

It also depends on the going definition of "rocket" and "in operation". The SLS SRBs produce more thrust in a single core, and have also been ground fired.
Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: 2megs on 11/13/2021 12:57 pm

So just to see if "I" have it right:
(33.4m*430t+85m*1360t)/(1360t+430t) = 72m
So just 2m into the ship?


Same thing I get from those numbers, but...

Considering that the weight of the raptors and the plumbing feeding them is an estimate, the number of raptors is changing, the amount of remaining S1 propellant is an assumption, and the payload masses will vary from launch to launch... "In the general vicinity of the separation line" is about as precise a statement as anyone can confidently make right now.
Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: AstroDave on 11/13/2021 01:04 pm
So just to see if "I" have it right:
(33.4m*430t+85m*1360t)/(1360t+430t) = 72m
So just 2m into the ship?

Not sure where your 33.4m is coming from.

Take origin at bottom of booster:
CG Booster = 21.4m from bottom
CG Starship = 14.7m from bottom of SS, so 70m + 14.7m = 84.7m

((21.4m*430t)*(84.7m*1360t))/(430t+1360t)=69.5m

With booster being 70m, system CG is 0.5m below booster/ship interface.

Open to corrections if I'm interpreting this incorrectly.
Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: equiserre on 11/13/2021 03:37 pm
So just to see if "I" have it right:
(33.4m*430t+85m*1360t)/(1360t+430t) = 72m
So just 2m into the ship?

Not sure where your 33.4m is coming from.

Take origin at bottom of booster:
CG Booster = 21.4m from bottom
CG Starship = 14.7m from bottom of SS, so 70m + 14.7m = 84.7m

((21.4m*430t)*(84.7m*1360t))/(430t+1360t)=69.5m

With booster being 70m, system CG is 0.5m below booster/ship interface.

Open to corrections if I'm interpreting this incorrectly.

that is how I did the numbers. Still, all this is a guesstimate, based on what we know of masses and dimensions. So we should take the numbers as approximate. But what we can conclude is that the combined CM will be close-ish to the interfase at separation.
Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: seb21051 on 11/13/2021 04:19 pm
Hope this is an acceptable thread to ask about the chopsticks. If not please redirect.

The location of the hydraulics: The actuators for the arms are pretty big. Someone on Nerdle mentioned their accumulators as being housed within the tower. Would this imply that there would be an umbilical containing flexible hydraulic hoses, plus AC for the tractor motors, and command/wiring wiring?

Would it not make more sense to locate all the hydraulics in the travelling assembly, and just umbilical the AC Power and Command/Control signals?
Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: cpushack on 11/13/2021 09:33 pm
Hope this is an acceptable thread to ask about the chopsticks. If not please redirect.

The location of the hydraulics: The actuators for the arms are pretty big. Someone on Nerdle mentioned their accumulators as being housed within the tower. Would this imply that there would be an umbilical containing flexible hydraulic hoses, plus AC for the tractor motors, and command/wiring wiring?

Would it not make more sense to locate all the hydraulics in the travelling assembly, and just umbilical the AC Power and Command/Control signals?

Good spot for that is here: https://forum.nasaspaceflight.com/index.php?topic=54355.780
Chopsticks being actively discussed there
Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: seb21051 on 11/13/2021 09:56 pm
Much appreciated!
Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: Fizrock on 11/14/2021 02:47 am
Mods feel free to remove, but the patch for the first orbital launch attempt has (allegedly) leaked to reddit:
https://www.reddit.com/r/SpaceXLounge/comments/qtfly1/starship_orbital_demo_patch_super_heavy_first/
Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: vaporcobra on 11/16/2021 12:56 am
Delivery.

Hmmm... first thing that comes to mind is spray bars for an orbital launch mount deluge system.
Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: cpushack on 11/16/2021 06:25 am
Appears they are working to insulate some components from the tank walls a bit

(image bocachicagal)

Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: Skyway on 11/16/2021 09:12 am
Appears they are working to insulate some components from the tank walls a bit

(image bocachicagal)

I was intrigued when I saw this picture from Mary. These orange cables looks like those typical of automotive electric motors and batteries, which by the position made me think it was something related to a solar panel or other energy source.

But aside from the fact that I think it's too early to see something like this in the prototypes, I don't know if these components were already part of the prototypes.

If anyone knows and can clarify if these components already existed there in the other prototypes, I would appreciate it.

Edit: Typo
Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: Vonbraun on 11/16/2021 10:14 am
I was intrigued when I saw this picture from Mary. These orange cables looks like those typical of automotive electric motors and batteries, which by the position made me think it was something related to a solar panel or other energy source.
Edit: Typo

These are most likely cables for the Tesla motors and batteries and have always existed in some shape and form. The placements change constantly. This insulation mat looks like some sort of high voltage compliancy thing, its not thick enough to be thermal insulation.
Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: Skyway on 11/16/2021 01:04 pm
I was intrigued when I saw this picture from Mary. These orange cables looks like those typical of automotive electric motors and batteries, which by the position made me think it was something related to a solar panel or other energy source.
Edit: Typo

These are most likely cables for the Tesla motors and batteries and have always existed in some shape and form. The placements change constantly. This insulation mat looks like some sort of high voltage compliancy thing, its not thick enough to be thermal insulation.

Thank you for the explanation. I did think of Tesla batteries and motors, but I remembered the battery only in the upper dome and the motors near the control surfaces. I didn't realize that they were already changing places.
Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: AU1.52 on 11/16/2021 02:50 pm
Delivery.

Hmmm... first thing that comes to mind is spray bars for an orbital launch mount deluge system.


Or transpiration cooling was the other thing that came to my mind. Probably not though.
Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: OTV Booster on 11/16/2021 04:56 pm
Delivery.

Hmmm... first thing that comes to mind is spray bars for an orbital launch mount deluge system.
That as my first take too. If the mount got six spray bar the bevel would 30deg. More segments would be a lesser angle. The cut looks like 45deg so as usual, I'm scratching my head.
Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: oiorionsbelt on 11/16/2021 05:00 pm
Delivery.

Hmmm... first thing that comes to mind is spray bars for an orbital launch mount deluge system.


Or transpiration cooling was the other thing that came to my mind. Probably not though.
Those "holes" do not look capable of suppling enough water fast enough.
 Compare with the water deluge system on 39A
Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: alugobi on 11/16/2021 05:28 pm
Those look more like French drain piping than anything designed for flowing water outward at any appreciable volume.
Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: grndkntrl on 11/16/2021 07:40 pm
Delivery.

Hmmm... first thing that comes to mind is spray bars for an orbital launch mount deluge system.


Or transpiration cooling was the other thing that came to my mind. Probably not though.
Those "holes" do not look capable of suppling enough water fast enough.
 Compare with the water deluge system on 39A

These are probably for something like a low volume water curtain portion of the deluge system, with a much higher volume portion yet to be assembled as well.
Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: edzieba on 11/16/2021 08:37 pm
I was intrigued when I saw this picture from Mary. These orange cables looks like those typical of automotive electric motors and batteries, which by the position made me think it was something related to a solar panel or other energy source.
Edit: Typo

These are most likely cables for the Tesla motors and batteries and have always existed in some shape and form. The placements change constantly. This insulation mat looks like some sort of high voltage compliancy thing, its not thick enough to be thermal insulation.

Thank you for the explanation. I did think of Tesla batteries and motors, but I remembered the battery only in the upper dome and the motors near the control surfaces. I didn't realize that they were already changing places.
The batteries at on the upper dome, and the motors are both above the batteries (in the nose) and below the batteries (mounted just below the aft dome inside the skirt), so there needs to be cabling run to link them all together. SpaceX currently run all that cabling externally rather than through the inside of the tanks.
The cables seen in the photos run from a cable grommet just below the aft dome to some coupling hardware near the main cable run that descends down the back of the vehicle, so are likely linked to the aft flap motors.
Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: chief on 11/16/2021 08:38 pm
Appears they are working to insulate some components from the tank walls a bit

(image bocachicagal)

This is the skirt section, aft of the thrust dome and so not a tank wall and not subject to cryogenic prop temperatures.
Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: edzieba on 11/16/2021 08:42 pm
Appears they are working to insulate some components from the tank walls a bit

(image bocachicagal)

This is the skirt section, aft of the thrust dome and so not a tank wall and not subject to cryogenic prop temperatures.
The skirt will however be subjected to radiant heating from the engine bells inside the skirt.
Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: samgineer on 11/16/2021 08:50 pm
Delivery.

Hmmm... first thing that comes to mind is spray bars for an orbital launch mount deluge system.

Or transpiration cooling was the other thing that came to my mind. Probably not though.
Those "holes" do not look capable of suppling enough water fast enough.
 Compare with the water deluge system on 39A

These are probably for something like a low volume water curtain portion of the deluge system, with a much higher volume portion yet to be assembled as well.

As I remember, they have at suborbital pads two rings at the top of the stand, right below skirt of ship and it seems to be fire extinguishing, as we never seen it working as deluge. One pipe for water, made out of normal steel and another one made out of stainless for liquid nitrogen to reduce volume of oxygen by displacing it with sprayed nitrogen to prevent methane from exploding as SN-4 did. Maybe these perforated stainless pipes are for similar purpose but instead deigned for OLP?
Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: chief on 11/16/2021 09:26 pm
Appears they are working to insulate some components from the tank walls a bit

(image bocachicagal)

This is the skirt section, aft of the thrust dome and so not a tank wall and not subject to cryogenic prop temperatures.
The skirt will however be subjected to radiant heating from the engine bells inside the skirt.

I did expect that, but the mat doesn't appear to be beneath the components attached so far, so perhaps it's the cables that need protection. Although - the bells are regen cooled, are they not? So how hot/cold would they really get?
Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: envy887 on 11/16/2021 10:47 pm
Appears they are working to insulate some components from the tank walls a bit

(image bocachicagal)

This is the skirt section, aft of the thrust dome and so not a tank wall and not subject to cryogenic prop temperatures.
The skirt will however be subjected to radiant heating from the engine bells inside the skirt.

From the plumes, yes. Not from the bells.
Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: niwax on 11/17/2021 10:49 pm
From Elon in the interview right now: Up to 12 flights next year, first customers by 2023.
Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: StevenOBrien on 11/18/2021 01:13 am
Feel free to move if there's a more appropriate thread:

The judge responsible for granting road closures in Boca Chica did a video interview today where he "talks candidly about the challenge of balancing the positive and negative effects of SpaceX on the community as a whole.  He also shares some of his one-on-one conversations with SpaceX founder, Elon Musk."

https://www.cameroncountytx.gov/spacex-effect-extra-judge-eddie-trevino-extended-interview/
Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: grndkntrl on 11/18/2021 01:48 am
Feel free to move if there's a more appropriate thread:

The judge responsible for granting road closures in Boca Chica did a video interview today where he "talks candidly about the challenge of balancing the positive and negative effects of SpaceX on the community as a whole.  He also shares some of his one-on-one conversations with SpaceX founder, Elon Musk."

https://www.cameroncountytx.gov/spacex-effect-extra-judge-eddie-trevino-extended-interview/

Interesting interview.

Probably best suited to the "Starbase, Texas" thread: https://forum.nasaspaceflight.com/index.php?topic=53216.0
Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: Hamish.Student on 11/18/2021 05:09 am
Notes by a user in /r/SpaceXLounge about Musk's talk today at SSG & BPA. 
 
Quote
Orbital launch site complete this month
First orbital flight of Starship in January
HLS Starship will help make a permanent base on the moon
Starship 90% funded by SpaceX so far
Carbon fiber abandoned because potentially ignite with LOX, and difficult to mold accurately
Stainless steel properties roughly equal to Carbon Fiber at cryogenic temperatures, easy to weld, tough resilient, cheap. Also resists high temperatures on reentry, so only partial heat shield required with lighter tiles
Starship radiation protection - check weather report before lunar launch, some clever ways to solve for Mars should be possible (mini-magnetosphere?)
Wants propellant production on the moon and Mars, then 100 tonnes payload to Europa possible
Should land 2 or 3 Starships on Mars first, without people, hopefully with NASA support and other countries
Big rockets really useful for asteroid defense, save a lot of lives
People on Mars would learn more than rovers, go anywhere they want, do whatever they want
Once we can explore solar system can send robot probes to other star systems
Tickets for Starship should be possible in two years (#Dearmoon?)
Testing operational payloads in 2023 (Starlink?)
Works closely with Vera Rubin Observatory to mitigate effects from Starlink
Docking with propellant depot should be easier than with ISS
Transferring biological material to Mars is inevitable should be limited to small area - big planet
Tesla should help transition to sustainable energy, SpaceX to ensure long term survival of humanity
Long term Neuralink allows symbiosis with AI (cant fight 'em join 'em!)
Creating a multiplanetary civilization allows us to overcome one of the Great Filters (re. Fermi Paradox)
Only a little of the sun's energy could power all human activity, 100 km square solar array could power all of United States, needs Solar + Battery. Clear path to sustainable energy future, we have all materials necessary (iron, lithium, silicon etc)
   
 
Additionally, he mentioned aiming for 12 Starship launches next year. 

https://www.reddit.com/r/SpaceXLounge/comments/qwbbpf/livestream_elon_musk_starship_presentation_at_ssg/hl1til8/
Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: seb21051 on 11/18/2021 05:52 pm
"Only a little of the sun's energy could power all human activity, 100 km square solar array could power all of United States, needs Solar + Battery. Clear path to sustainable energy future, we have all materials necessary (iron, lithium, silicon etc)"

Previously EM spoke of 100-150 square MILE Solar Array with batteries to supply the whole US.

Total U.S. electricity consumption in 2020 was about 3.8 trillion kWh.

From:

Use of electricity - U.S. Energy Information Administration (EIA)https://www.eia.gov õ energyexplained õ use-of-electricity

Edit:- A square 150 miles on each side equals 21,484 sq miles which equals roughly 13,750,000 acres.
Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: r8ix on 11/18/2021 07:43 pm

Edit:- A square 150 miles on each side equals 21,484 sq miles which equals roughly 13,750,000 acres.

22,500-->14,400,000

but I heard him say kilometers, so about 5.6 million acres.
Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: seb21051 on 11/18/2021 08:11 pm
According to this article, one would need 13,750,000 acres to house the 7.85 Billion panels required:

https://ecotality.com/how-many-solar-panels-to-power-the-us/#:~:text=About%207.86%20billion%20solar%20panels,4000%20billion%20kWh%20of%20electricity.
Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: r8ix on 11/19/2021 03:04 am
According to this article, one would need 13,750,000 acres to house the 7.85 Billion panels required:

https://ecotality.com/how-many-solar-panels-to-power-the-us/#:~:text=About%207.86%20billion%20solar%20panels,4000%20billion%20kWh%20of%20electricity.
but we're talking about what Elon said, not what "ecotality" saidÖ

And we're getting off topic! Back to the prototype!
Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: Tangilinear Interjar on 11/22/2021 02:58 pm
AFT8 INDUCTIVE INHIBIT ? Not really sure of that last word but what would an Inductive Inhibit be. Or could this be some form of non-contact data connection?

Zoomed from RGV Aerial Photography pic.
Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: niwax on 11/22/2021 03:12 pm
AFT8 INDUCTIVE INHIBIT ? Not really sure of that last word but what would an Inductive Inhibit be. Or could this be some form of non-contact data connection?

Zoomed from RGV Aerial Photography pic.

AFTS inhibitor

Presumably part of the AFTS saving process.
Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: beelsebob on 11/23/2021 06:14 pm
Presumably the flight termination system will be disallowed from working as long as a voltage is being induced in a circuit on the ship by the QD system.  That is - if the ship is still plugged in on the ground, and powered, the FTS won't go off.

I imagine that the ship will do all kinds of things that might confuse the FTS (like moving backwards because of sensor inaccuracies, or accelerating in odd, and sudden ways because of QD arms and hold downs disconnecting, or because someone forgot to turn it off before jostling things with a crane) while on the ground.
Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: dgkimpton on 11/23/2021 06:36 pm
Presumably part of the AFTS saving process.
I'm pretty sure that should be "AFTS Safing Process" - as in, the process of making the termination system safe, not the process of saving the termination system.
Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: Okie_Steve on 11/23/2021 07:43 pm
Presumably the flight termination system will be disallowed from working as long as a voltage is being induced in a circuit on the ship by the QD system.  That is - if the ship is still plugged in on the ground, and powered, the FTS won't go off.

I imagine that the ship will do all kinds of things that might confuse the FTS (like moving backwards because of sensor inaccuracies, or accelerating in odd, and sudden ways because of QD arms and hold downs disconnecting, or because someone forgot to turn it off before jostling things with a crane) while on the ground.

Yes, in the category of things learned the hard way. There was a spectacular historical case of FTS activating significantly after a launch abort due to rotation of the Earth, resulting in a very bad day.

Edit - See correction about LES below
Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: Hamish.Student on 11/23/2021 10:03 pm
Presumably the flight termination system will be disallowed from working as long as a voltage is being induced in a circuit on the ship by the QD system.  That is - if the ship is still plugged in on the ground, and powered, the FTS won't go off.

I imagine that the ship will do all kinds of things that might confuse the FTS (like moving backwards because of sensor inaccuracies, or accelerating in odd, and sudden ways because of QD arms and hold downs disconnecting, or because someone forgot to turn it off before jostling things with a crane) while on the ground.

Yes, in the category of things learned the hard way. There was a spectacular historical case of FTS activating significantly after a launch abort due to rotation of the Earth, resulting in a very bad day.
 
 
Minor correction, that was a LES activation, not FTS. Soyuz 7K-OK No.1   
 
Quote
During the attempted launch, the booster switched from external to internal power as it normally would do, which then activated the abort sensing system. The Earth's rotation caused the rate gyros to register an approximately 8į tilt 27 minutes after the aborted liftoff, which the abort sensing system then interpreted as meaning that the booster had deviated from its flight path, and thus it activated the LES.   
https://en.wikipedia.org/wiki/Soyuz_7K-OK_No.1
Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: cscott on 11/24/2021 05:42 pm
An inductive sensor is a big coil that can detect the presence of nearby metal.  I've got one on my 3d printer to detect (and zero against) the metal bed.

My guess is that the ball joint in the photo which secures the QD arm also has a vehicle-side inductive sensor in its socket, so that the AFTS is safed when the QD is connected.  The AFTS would automatically activate when the QD is pulled back and the ball disengages from it's socket.

I think there are more than one ball joint on the QD? I suspect only one of them is hooked up to the AFTS though, and so this label is just to let us know which one the "important" ball joint is.
Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: edzieba on 11/24/2021 06:06 pm
The 'ball joints' are ball-ended alignment pins, that insert into cone-tipped alignment sockets on the Starship-side QD plate.

The "AFTS Inductive Inhibit" label is directly below a nonconductive patch area (i.e. no electrical connection), so this is likely a 'window' for inductive communication. This could be anything from a simple permanent magnet (inhibit removed as QD retracts), an always-on active coil (to allow AFTS to arm in the event the QD plate is ripped from the launch mount but remains attached to Starship), or a one-way or two-way inductive communication channel to allow AFTS commanding and status updates without any electrical continuity between the AFTS system and the GSE (to avoid arcing e.g. from a lightning strike).
Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: StuffOfInterest on 11/24/2021 06:41 pm
For something as critical as AFTS I would hope there is some redundancy in the contact sensors.  You wouldn't want the AFTS to have a bad day because one sensor failed.
Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: Keldor on 11/24/2021 08:16 pm
For something as critical as AFTS I would hope there is some redundancy in the contact sensors.  You wouldn't want the AFTS to have a bad day because one sensor failed.

In all likelyhood, this IS a backup system.  Arming the AFTS would involve first sending a command to the computer, then disconnecting the inhibitor.  If only one or the other happened, the AFTS would remain safed, and the countdown would be aborted.  (We're assuming that the arm is detached shortly before liftoff, perhaps somewhere around T-1)
Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: StuffOfInterest on 11/24/2021 09:37 pm
For something as critical as AFTS I would hope there is some redundancy in the contact sensors.  You wouldn't want the AFTS to have a bad day because one sensor failed.

In all likelyhood, this IS a backup system.  Arming the AFTS would involve first sending a command to the computer, then disconnecting the inhibitor.  If only one or the other happened, the AFTS would remain safed, and the countdown would be aborted.  (We're assuming that the arm is detached shortly before liftoff, perhaps somewhere around T-1)

Isn't the whole idea of a "quick disconnect" to disconnect quickly at T-0? :)

If there is an abort at engine startup you still need to drain the tanks.
Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: Slothman on 11/24/2021 09:55 pm
For something as critical as AFTS I would hope there is some redundancy in the contact sensors.  You wouldn't want the AFTS to have a bad day because one sensor failed.

In all likelyhood, this IS a backup system.  Arming the AFTS would involve first sending a command to the computer, then disconnecting the inhibitor.  If only one or the other happened, the AFTS would remain safed, and the countdown would be aborted.  (We're assuming that the arm is detached shortly before liftoff, perhaps somewhere around T-1)

Isn't the whole idea of a "quick disconnect" to disconnect quickly at T-0? :)

If there is an abort at engine startup you still need to drain the tanks.

No, QD just means that you don't need a dude in a manlift to unbolt the connector. It quickly (relatively) disconnects itself. This does not require the arm to move out of harms way very quicky after the interface has quickly disconnected.
Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: robot_enthusiast on 11/24/2021 11:24 pm
For something as critical as AFTS I would hope there is some redundancy in the contact sensors.  You wouldn't want the AFTS to have a bad day because one sensor failed.

In all likelyhood, this IS a backup system.  Arming the AFTS would involve first sending a command to the computer, then disconnecting the inhibitor.  If only one or the other happened, the AFTS would remain safed, and the countdown would be aborted.  (We're assuming that the arm is detached shortly before liftoff, perhaps somewhere around T-1)

Isn't the whole idea of a "quick disconnect" to disconnect quickly at T-0? :)

If there is an abort at engine startup you still need to drain the tanks.
Unlike other quick disconnects, this one is also designed to be a quick connect. In the case of an abort after QD retract, they could simply extend it back out and reattach it.
Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: RocketLover0119 on 11/29/2021 12:42 pm
Just a note to the nsf editing team: the common dome flipped yesterday was indeed B6, however it was no flipped ďagainĒ as you claimed. Maybe be a little more careful with words next time  :)

The dome is capped which recommends that B6 wonít fly and rather be a test tank, or in my opinion be a mechazilla test lifter.
Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: su27k on 11/30/2021 02:18 am
This twitter handle just tweeted a video people may be interested in (but may not be appropriate to post here...):

https://twitter.com/SpaceX_Missions
Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: Herb Schaltegger on 11/30/2021 02:24 am
This twitter handle just tweeted a video people may be interested in (but may not be appropriate to post here...):

https://twitter.com/SpaceX_Missions

That video is going to someone fired and the owner of that Twitter handle sued.
Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: Fizrock on 11/30/2021 02:30 am
Space Explored obtained an internal email sent by Elon Musk to employees.   
https://spaceexplored.com/2021/11/29/spacex-raptor-crisis/ 
 
Here's the email, as it appears in the article. It primarily concerns Raptor, but it touches on a bunch of Starship-related stuff, so I'm posting it here. 
 
Quote
Unfortunately, the Raptor production crisis is much worse than it had seemed a few weeks ago. As we have dug into the issues following the exiting of prior senior management, they have unfortunately turned out to be far more severe than was reported. There is no way to sugarcoat this.

I was going to take this weekend off, as my first weekend off in a long time, but instead, I will be on the Raptor line all night and through the weekend.
 
Unless you have critical family matters or cannot physically return to Hawthorne, we will need all hands on deck to recover from what is, quite frankly, a disaster.

The consequences for SpaceX if we can not get enough reliable Raptors made is that we then canít fly Starship, which means we then canít fly Starlink Satellite V2 (Falcon has neither the volume nor the mass to orbit needed for satellite V2). Satellite V1, by itself, is financially weak, while V2 is strong.

In addition, we are spooling up terminal production to several million units per year, which will consume massive capital, assuming that satellite V2 will be on orbit to handle the bandwidth demand. These terminals will be useless otherwise.
 
What it comes down to, is that we face a genuine risk of bankruptcy if we canít achieve a Starship flight rate of at least once every two weeks next year.

Thanks,

Elon
Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: meekGee on 11/30/2021 03:10 am
This twitter handle just tweeted a video people may be interested in (but may not be appropriate to post here...):

https://twitter.com/SpaceX_Missions
I may have missed the significance - other than the unprecedented view, was there something there that wasn't known beforehand?  Am I missing something obvious?
Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: meekGee on 11/30/2021 03:14 am


Space Explored obtained an internal email sent by Elon Musk to employees.   
https://spaceexplored.com/2021/11/29/spacex-raptor-crisis/ 
 
Here's the email, as it appears in the article. It primarily concerns Raptor, but it touches on a bunch of Starship-related stuff, so I'm posting it here. 
 
Quote
Unfortunately, the Raptor production crisis is much worse than it had seemed a few weeks ago. As we have dug into the issues following the exiting of prior senior management, they have unfortunately turned out to be far more severe than was reported. There is no way to sugarcoat this.

I was going to take this weekend off, as my first weekend off in a long time, but instead, I will be on the Raptor line all night and through the weekend.
 
Unless you have critical family matters or cannot physically return to Hawthorne, we will need all hands on deck to recover from what is, quite frankly, a disaster.

The consequences for SpaceX if we can not get enough reliable Raptors made is that we then can’t fly Starship, which means we then can’t fly Starlink Satellite V2 (Falcon has neither the volume nor the mass to orbit needed for satellite V2). Satellite V1, by itself, is financially weak, while V2 is strong.

In addition, we are spooling up terminal production to several million units per year, which will consume massive capital, assuming that satellite V2 will be on orbit to handle the bandwidth demand. These terminals will be useless otherwise.
 
What it comes down to, is that we face a genuine risk of bankruptcy if we can’t achieve a Starship flight rate of at least once every two weeks next year.

Thanks,

Elon

Ouch.  Not mincing words.
Explains why he wants a redesign...

New things:
- Expected/desired flight rate (woah)
- SL v2 sats (we all expected that)


Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: [email protected] on 11/30/2021 03:20 am


Space Explored obtained an internal email sent by Elon Musk to employees.   
https://spaceexplored.com/2021/11/29/spacex-raptor-crisis/ 
 
Here's the email, as it appears in the article. It primarily concerns Raptor, but it touches on a bunch of Starship-related stuff, so I'm posting it here. 
 
Quote
Unfortunately, the Raptor production crisis is much worse than it had seemed a few weeks ago. As we have dug into the issues following the exiting of prior senior management, they have unfortunately turned out to be far more severe than was reported. There is no way to sugarcoat this.

I was going to take this weekend off, as my first weekend off in a long time, but instead, I will be on the Raptor line all night and through the weekend.
 
Unless you have critical family matters or cannot physically return to Hawthorne, we will need all hands on deck to recover from what is, quite frankly, a disaster.

The consequences for SpaceX if we can not get enough reliable Raptors made is that we then canít fly Starship, which means we then canít fly Starlink Satellite V2 (Falcon has neither the volume nor the mass to orbit needed for satellite V2). Satellite V1, by itself, is financially weak, while V2 is strong.

In addition, we are spooling up terminal production to several million units per year, which will consume massive capital, assuming that satellite V2 will be on orbit to handle the bandwidth demand. These terminals will be useless otherwise.
 
What it comes down to, is that we face a genuine risk of bankruptcy if we canít achieve a Starship flight rate of at least once every two weeks next year.

Thanks,

Elon

Ouch.  Not mincing words.
Explains why he wants a redesign...

New things:
- Expected/desired flight rate (woah)
- SL v2 sats (we all expected that)
Words that you totally expected from Elon's ever ambitious pursue (not a bad thing)
Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: baking on 11/30/2021 03:29 am
Quote
What it comes down to, is that we face a genuine risk of bankruptcy if we canít achieve a Starship flight rate of at least once every two weeks next year.

I am reading this as "achieve a Starship flight rate of at least once every two weeks [within the/by the end of] next year." instead of "26 launches in 2022" which would be impossible.
Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: meekGee on 11/30/2021 03:39 am
Quote
What it comes down to, is that we face a genuine risk of bankruptcy if we canít achieve a Starship flight rate of at least once every two weeks next year.

I am reading this as "achieve a Starship flight rate of at least once every two weeks [within the/by the end of] next year." instead of "26 launches in 2022" which would be impossible.
Agreed.  Still woah.
Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: su27k on 11/30/2021 04:00 am
This twitter handle just tweeted a video people may be interested in (but may not be appropriate to post here...):

https://twitter.com/SpaceX_Missions
I may have missed the significance - other than the unprecedented view, was there something there that wasn't known beforehand?  Am I missing something obvious?

Nothing obvious to me but I'm not good at analyzing these so...
Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: su27k on 11/30/2021 04:02 am
Space Explored obtained an internal email sent by Elon Musk to employees.   
https://spaceexplored.com/2021/11/29/spacex-raptor-crisis/ 

Besides the email, this article also mentioned the following:

Quote
These tiles have not survived the testing, and Starship 20 is expected to be destroyed on reentry. In order to combat this, and to get useful data from the flight, it is rumored that SpaceX will deploy a copy of the recorded telemetry from Starship during reentry Ė a black box of sorts.
Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: Craftyatom on 11/30/2021 04:22 am
Ouch.  Not mincing words.
At least, assuming they are his words.
Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: EspenU on 11/30/2021 04:51 am
It might be real, but at least for me it does not make sense.
As I understand it, although initial production is in Hawthorne, mass production will be at MacGregor. So everything hinging on the line at Hawthorne now seems strange.

Also, if I recall correctly the EIS has a limit of 5 launches per year. This has to be expanded in the future of course, but betting the whole company on that it can be expanded before a year has passed seems very stupid. Especially considering that they haven't been given a green light on the current one yet.
Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: yokem55 on 11/30/2021 05:28 am
My take: the issue is hitting the combination of production rate and reliability. They can spend a ton time getting each and every raptor perfect. Or they can get them out the door fast and hopefully catch the bad ones in acceptance testing on the test stand. But they aren't quite to the point of getting 99+% perfect raptors, at a high production rate.

We've seen the rapid increase in raptor SN's. What if that rapid incrementation is simply because too many aren't meeting spec?
Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: M.E.T. on 11/30/2021 05:33 am
Welcome to the opposite of gradatim ferociter.



Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: RoboGoofers on 11/30/2021 11:25 am
If it's truly an email from Elon, it rings a bit hollow. Sure, he wants to light a fire under everyone, but spacex's coffers are as full as Elon wants them to be. As if he'd let the company go bankrupt at this stage ::)
Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: [email protected] on 11/30/2021 11:35 am
If it's truly an email from Elon, it rings a bit hollow. Sure, he wants to light a fire under everyone, but spacex's coffers are as full as Elon wants them to be. As if he'd let the company go bankrupt at this stage ::)
If there's no such email, the employees will think everything is fine & not let their full efforts into it, making a slower progress
Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: etudiant on 11/30/2021 11:42 am
Don't think it 'rings hollow'.
Elon knows that the stock market is manic depressive, that any serious SS/SH disruption would have disproportionate impact.
Losing a couple of early launches because of engine issues would hurt very badly.
Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: SkyRate on 11/30/2021 11:56 am
They're not publicly traded and should be impervious to short-term market fluctuations.
Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: Spindog on 11/30/2021 12:11 pm
They are spending huge amounts of money and need to have a cash flow positive goal in sight. Elon is just lighting a fire to increase the urgency IMO.
Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: ZachF on 11/30/2021 01:53 pm
One launch every other week full of Starlink satellites is ~2,600 tonnes worth of satellites per year… about 5x the rest of the world combined. About the same amount as the Ariane family has lifted up over its entire existence.  :o Also more than the Chinese space industry’s cumulative lifetime total!

I’m betting the new v2 sats weigh 1-2 tonnes each.
Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: SimonFD on 11/30/2021 03:28 pm
Could this 'leaked' email be actually a rehash of a genuine email about Tesla production issues? I remember at the time Elon publicly talked about bankruptcy at Tesla if they couldn't get production running better.
Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: volker2020 on 11/30/2021 03:35 pm
I personally believe, that the e-mail is genuine. It has some unknown details in it (volume and mass requirements for starlink v2 satellites, that otherwise come of nowhere).
Yes, SpaceX has a rather well filled war chest, but if you assume for a second that the 1000$ per customer upfront is real and they currently scale for some millions of extra customers, the billions melt in an alarming way. And if you can not monetize that investment, because you need Starship up and running at this point, since the new better and more efficient satellites (I assume longer life + more bandwidth + laser links) can only be launched using starship, things can go downhill quite fast.

On the plus site. If all of the above it is true, any competitor will have an extremely hard time to play catch up with SpaceX. Not good for rest, but quite good for SpaceX and it's investors.
Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: meekGee on 11/30/2021 04:22 pm
Welcome to the opposite of gradatim ferociter.
Actually that's exactly Gradatim Ferociter.
Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: Reynold on 11/30/2021 04:40 pm
And if you can not monetize that investment, because you need Starship up and running at this point, since the new better and more efficient satellites (I assume longer life + more bandwidth + laser links) can only be launched using starship, things can go downhill quite fast.

On the plus site. If all of the above it is true, any competitor will have an extremely hard time to play catch up with SpaceX. Not good for rest, but quite good for SpaceX and it's investors.

Well, worst case is that they have to bite the bullet and launch V2s on the F9 for most of next year.  There is no way their V2 satellites are individually too heavy for an F9, you just may not be sending up 60/launch. maybe its 5 or 10.  The main risk there is that breakeven for Starlink revenue is probably pushed out by almost as long as Starship is delayed, and Elon may have to go back to the capital markets again with SpaceX, or sell of some of Tesla if he wants to keep control of SpaceX (which is what I would do, but full disclosure, I am not a billionaire). 

Going back to the capital markets should still be pretty easy though, given that even a purely F9 launched constellation is probably at least 5x cheaper to get going per GB served than any competing constellation. 
Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: volker2020 on 11/30/2021 04:46 pm
And if you can not monetize that investment, because you need Starship up and running at this point, since the new better and more efficient satellites (I assume longer life + more bandwidth + laser links) can only be launched using starship, things can go downhill quite fast.

On the plus site. If all of the above it is true, any competitor will have an extremely hard time to play catch up with SpaceX. Not good for rest, but quite good for SpaceX and it's investors.
...There is no way their V2 satellites are individually too heavy for an F9, you just may not be sending up 60/launch. ...

That is a bold claim. e.g. Assume that the v2 are flat 8m disks, stacked on one another. No way to get them into the F9 cargo bay.
Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: DanClemmensen on 11/30/2021 04:58 pm
And if you can not monetize that investment, because you need Starship up and running at this point, since the new better and more efficient satellites (I assume longer life + more bandwidth + laser links) can only be launched using starship, things can go downhill quite fast.

On the plus site. If all of the above it is true, any competitor will have an extremely hard time to play catch up with SpaceX. Not good for rest, but quite good for SpaceX and it's investors.
...There is no way their V2 satellites are individually too heavy for an F9, you just may not be sending up 60/launch. ...

That is a bold claim. e.g. Assume that the v2 are flat 8m disks, stacked on one another. No way to get them into the F9 cargo bay.
F9 uses fairings, so it does not have a cargo bay. Basically all single-stick launchers with a fairing can support an oversize fairing. I do not know if F9 has ever done this before, but is is a very standard practice in the industry and I (an uneducated outsider) know of no reason F9 could not do this.
Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: rakaydos on 11/30/2021 05:01 pm
And if you can not monetize that investment, because you need Starship up and running at this point, since the new better and more efficient satellites (I assume longer life + more bandwidth + laser links) can only be launched using starship, things can go downhill quite fast.

On the plus site. If all of the above it is true, any competitor will have an extremely hard time to play catch up with SpaceX. Not good for rest, but quite good for SpaceX and it's investors.
...There is no way their V2 satellites are individually too heavy for an F9, you just may not be sending up 60/launch. ...

That is a bold claim. e.g. Assume that the v2 are flat 8m disks, stacked on one another. No way to get them into the F9 cargo bay.
F9 uses fairings, so it does not have a cargo bay. Basically all single-stick launchers with a fairing can support an oversize fairing. I do not know if F9 has ever done this before, but is is a very standard practice in the industry and I (an uneducated outsider) know of no reason F9 could not do this.
The lead time for a 9m fairing for FH, and all the testing and redesign it would require, means that option is impractical as an alternative to getting the Starship operational in the first place.
Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: punder on 11/30/2021 05:09 pm
Might be a good time to make Tom Mueller an offer he canít refuse.
Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: Herb Schaltegger on 11/30/2021 05:11 pm
And if you can not monetize that investment, because you need Starship up and running at this point, since the new better and more efficient satellites (I assume longer life + more bandwidth + laser links) can only be launched using starship, things can go downhill quite fast.

On the plus site. If all of the above it is true, any competitor will have an extremely hard time to play catch up with SpaceX. Not good for rest, but quite good for SpaceX and it's investors.
...There is no way their V2 satellites are individually too heavy for an F9, you just may not be sending up 60/launch. ...

That is a bold claim. e.g. Assume that the v2 are flat 8m disks, stacked on one another. No way to get them into the F9 cargo bay.
F9 uses fairings, so it does not have a cargo bay. Basically all single-stick launchers with a fairing can support an oversize fairing. I do not know if F9 has ever done this before, but is is a very standard practice in the industry and I (an uneducated outsider) know of no reason F9 could not do this.


If I am not mistaken, a LENGTHENED fairing for NatSec F9/FH launches is in work. A widened fairing is not, and it would take years of lead time to get one designed, built and ready to fly.
Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: DanClemmensen on 11/30/2021 05:16 pm
And if you can not monetize that investment, because you need Starship up and running at this point, since the new better and more efficient satellites (I assume longer life + more bandwidth + laser links) can only be launched using starship, things can go downhill quite fast.

On the plus site. If all of the above it is true, any competitor will have an extremely hard time to play catch up with SpaceX. Not good for rest, but quite good for SpaceX and it's investors.
...There is no way their V2 satellites are individually too heavy for an F9, you just may not be sending up 60/launch. ...

That is a bold claim. e.g. Assume that the v2 are flat 8m disks, stacked on one another. No way to get them into the F9 cargo bay.
F9 uses fairings, so it does not have a cargo bay. Basically all single-stick launchers with a fairing can support an oversize fairing. I do not know if F9 has ever done this before, but is is a very standard practice in the industry and I (an uneducated outsider) know of no reason F9 could not do this.
The lead time for a 9m fairing for FH, and all the testing and redesign it would require, means that option is impractical as an alternative to getting the Starship operational in the first place.
True unless SpaceX already has the design for an oversize fairing/adapter/etc. on the shelf and ready to dust off and implement, perhaps because they wanted to be able to support a large F9/FH payload on request. Remember the scenario here: Elon says "crisis for Starlink". Desperate times call for desperate measures. SpaceX is its own customer in this case, so they are self-insured. The risk/benefit weighs the risk of a launch failure against the cost of non-delivery of Starlink capacity to customers. Clearly, they really really really prefer to use Starship and could and should put the efforts there. But if they determine early that it cannot be done on time, then implement the big F9/FH fairing if F9/FH cannot otherwise accommodate a Starlink V2.
Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: magicsound on 11/30/2021 05:24 pm
Don't confuse Starlink v2 (with laser links) and the Starlink "Gen2" proposed for some time in the future. I may have missed something, but I don't think the specs for Gen2 have been disclosed, or even fixed at this time. There was some mention of "three times as big" though that could be based on mass or volume, not largest dimension. So discussion of a 9-meter flat disc form factor is just speculation.
Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: sebk on 11/30/2021 06:06 pm
It might be real, but at least for me it does not make sense.
As I understand it, although initial production is in Hawthorne, mass production will be at MacGregor. So everything hinging on the line at Hawthorne now seems strange.

To start mass production you first need a design amenable to mass production.

Also, if I recall correctly the EIS has a limit of 5 launches per year. This has to be expanded in the future of course, but betting the whole company on that it can be expanded before a year has passed seems very stupid. Especially considering that they haven't been given a green light on the current one yet.

You're forgetting about Cape and LC-39a which already has EA (except for catching boosters on the pad), and this EA has an order of magnitude higher yearly limits.
Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: Herb Schaltegger on 11/30/2021 06:06 pm
And if you can not monetize that investment, because you need Starship up and running at this point, since the new better and more efficient satellites (I assume longer life + more bandwidth + laser links) can only be launched using starship, things can go downhill quite fast.

On the plus site. If all of the above it is true, any competitor will have an extremely hard time to play catch up with SpaceX. Not good for rest, but quite good for SpaceX and it's investors.
...There is no way their V2 satellites are individually too heavy for an F9, you just may not be sending up 60/launch. ...

That is a bold claim. e.g. Assume that the v2 are flat 8m disks, stacked on one another. No way to get them into the F9 cargo bay.
F9 uses fairings, so it does not have a cargo bay. Basically all single-stick launchers with a fairing can support an oversize fairing. I do not know if F9 has ever done this before, but is is a very standard practice in the industry and I (an uneducated outsider) know of no reason F9 could not do this.
The lead time for a 9m fairing for FH, and all the testing and redesign it would require, means that option is impractical as an alternative to getting the Starship operational in the first place.
True unless SpaceX already has the design for an oversize fairing/adapter/etc. on the shelf and ready to dust off and implement Ö
Itís not just the design. Itís the production tooling and the manufacturing time that is the long-pole in the ďdusting offĒ you propose. Composite structures of this size are not things you can just whip out of a shop in a few weeks once you know you need one.
Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: Reynold on 11/30/2021 06:29 pm
...There is no way their V2 satellites are individually too heavy for an F9, you just may not be sending up 60/launch. ...

That is a bold claim. e.g. Assume that the v2 are flat 8m disks, stacked on one another. No way to get them into the F9 cargo bay.

Well, I did say "too heavy", not "too large", but I'm even willing to stand by my claim in terms of size.  I would be really surprised if Musk approved a design for a satellite they want to be launching in the next few months that relies solely on a ship that has never been launched, or even been approved for launch by the FAA.   Starship also does not seem to have a prototype door for releasing cargo, or engines that have been tested in anything like an orbital profile, or a completed launch pad, or a tested way to "land" the rocket sections. 

While I absolutely believe SpaceX will solve all of these issues, all it needs is to have one take 6-9 months and there is a huge delay separate from engine manufacturability.  I would think he would at least want the back up option of an ability to launch working Starlink V2.0 prototypes on his existing launchers, which are STILL much cheaper than the competition has.  While I'm not a satellite design expert, I also don't know of any reason why you would need a really large size for these, its not like he is building thousands of space telescopes with big mirrors, and they've been fine with unfolding bulky solar panels on V1. 

If he were starting a clean sheet design of a Starlink V2.0 today, and expected to build the first ones in a year or so, and had some compelling design/cost reason for a really wide satellite, I could see him making the risky choice of a Starship only design.  If I had to bet, though, I'd bet on him designing them to fit one across in the F9, like the current Starlinks, somewhat thicker and heavier, but shaped so you could put 4 or 5 across inside the Starship fairing packed together like the engines, also stacked obviously, and have the best of both worlds backup-wise. 
Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: mmeijeri on 11/30/2021 06:41 pm
If I am not mistaken, a LENGTHENED fairing for NatSec F9/FH launches is in work. A widened fairing is not, and it would take years of lead time to get one designed, built and ready to fly.

The 5m longer lengthened ('extended') fairing is already mentioned in the latest version of the F9/FH user guide.
Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: Vultur on 11/30/2021 06:47 pm
Do we know what kind of test this week's closures are for?
Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: friendly3 on 11/30/2021 11:39 pm
Quote from: Elon Musk
I was going to take this weekend off, as my first weekend off in a long time, but instead, I will be on the Raptor line all night and through the weekend.

Could it simply be an elaborate trick by Elon so he can justify to his family that he won't be able to be with them this weekend? I did something similar when I was young to justify some truancy of mine, it worked well until I was caught.
Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: meekGee on 12/01/2021 12:17 am
What we're seeing is the opposite of "We have all the money in the world, we don't need to worry", and we know where THAT leads.

SpaceX is fine right now, but Musk is reminding them that that's not a god-given permanent status.  If they don't keep up the pressure, it can be gone in a year's time.
Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: su27k on 12/01/2021 12:30 am
Don't confuse Starlink v2 (with laser links) and the Starlink "Gen2" proposed for some time in the future. I may have missed something, but I don't think the specs for Gen2 have been disclosed, or even fixed at this time. There was some mention of "three times as big" though that could be based on mass or volume, not largest dimension. So discussion of a 9-meter flat disc form factor is just speculation.

The satellite with laser link is Starlink v1.5.

Elon Musk has confirmed v2 is the satellite optimized for launching on Starship.

From SpaceX FCC filing, Gen2 constellation will use "next-generation satellite" that launches on Starship. Most people assume Gen2 constellation will use V2 Starlink satellite, which I think it's a safe assumption.

Also from FCC filing, the satellite in Gen2 constellation (assumed to be V2) can be launched on Falcon 9, but SpaceX would prefer to launch it on Starship.

Gen2 constellation hasn't been approved yet, not sure when it can be approved. But I don't think there's anything preventing SpaceX from using V2 satellite in the current LEO constellation (the one with 4,400 satellites).

More details can be discussed in the Starlink thread (https://forum.nasaspaceflight.com/index.php?topic=48297.0).
Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: catdlr on 12/01/2021 02:05 am
SpaceX Starship/Superheavy Launch and Catch Animation

Quote
With the first Starship orbital flight attempt scheduled for early next year, we're now starting to look forward to one of the wildest parts of the Starship program to date: catching the Super Heavy booster instead of using landing legs. Very little is known about the exact catch sequence, so I decided to animate how I think it may look.

The actual first catch attempt will likely be on the second or third launch attempt, so the booster is shown as the upgraded 33-engine version.

https://youtu.be/_gLbV07eVls
Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: edzieba on 12/01/2021 12:35 pm
And if you can not monetize that investment, because you need Starship up and running at this point, since the new better and more efficient satellites (I assume longer life + more bandwidth + laser links) can only be launched using starship, things can go downhill quite fast.

On the plus site. If all of the above it is true, any competitor will have an extremely hard time to play catch up with SpaceX. Not good for rest, but quite good for SpaceX and it's investors.
...There is no way their V2 satellites are individually too heavy for an F9, you just may not be sending up 60/launch. ...

That is a bold claim. e.g. Assume that the v2 are flat 8m disks, stacked on one another. No way to get them into the F9 cargo bay.
F9 uses fairings, so it does not have a cargo bay. Basically all single-stick launchers with a fairing can support an oversize fairing. I do not know if F9 has ever done this before, but is is a very standard practice in the industry and I (an uneducated outsider) know of no reason F9 could not do this.


If I am not mistaken, a LENGTHENED fairing for NatSec F9/FH launches is in work. A widened fairing is not, and it would take years of lead time to get one designed, built and ready to fly.
Given the rather sturdy nature of the Starlink birds ('just stack them right on top of each other, and deploy them by spinning around and letting them bump together until they separate. Maybe stack some customer satellites on top of all that too, why not?') I would half expect SpaceX to just ditch the fairing altogether, stack an small nose on top of the topmost satellite(s) in the stack, and eat the aerodynamic losses from turbulence with excess performance. I would not be in the least surprised is tucked somewhere on SpaceX servers there is already a simulation of edge heating of exposed Starlinks during ascent.
Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: capoman on 12/01/2021 03:01 pm
I can't comment on whether this e-mail is legit or not, but I wouldn't be surprised if this is SpaceX's equivalent of "production hell".

Thing is, the situation as it stands is that SpaceX will be completing several boosters and ships by the time they are flying next year, and I wouldn't be surprised if Raptors are the bottleneck as production of vehicles seems to be going quite well. With throwing engines in the drink, a raptor production shortage is going really bog down the ability to even test vehicles, let alone launch Starlinks, slowing down the entire program, and they may need to slow down vehicle production until Raptor production ramps up. Everything is so interdependent, and the reason Elon appears to be focusing on Raptor, the current bottleneck. Aside from this e-mail, whether real not, Elon has mentioned this several times publicly that it's one of their biggest challenges and the reason they are looking to build a simpler version (as well as cost).
Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: tssp_art on 12/01/2021 03:44 pm
In light of the new focus on Raptor production issues, a conservative strategy to help preserve schedule might also include testing/flying/landing the SH booster in a separate campaign that precedes or parallels the orbital launch campaign. Sending a booster up a few hundred (or a few thousand) meters and catching it successfully would go along way to minimizing the loss of boosters - and the 33 raptors that go with each one. And if it were launched using only a few Raptors it might not require any special FAA permissions as it would stay within the existing EA and FAA guidelines. This may be a quick and (relatively) easy way to refine the positioning and landing algorithms of both the booster and "Stage 0", especially if the FAA orbital launch license is delayed in any way.
Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: philw1776 on 12/01/2021 04:03 pm
In light of the new focus on Raptor production issues, a conservative strategy to help preserve schedule might also include testing/flying/landing the SH booster in a separate campaign that precedes or parallels the orbital launch campaign. Sending a booster up a few hundred (or a few thousand) meters and catching it successfully would go along way to minimizing the loss of boosters - and the 33 raptors that go with each one. And if it were launched using only a few Raptors it might not require any special FAA permissions as it would stay within the existing EA and FAA guidelines. This may be a quick and (relatively) easy way to refine the positioning and landing algorithms of both the booster and "Stage 0", especially if the FAA orbital launch license is delayed in any way.

Yes
Another thing, Starship orbital and re-entry tests can be done using boosters with far less than 33 or 29 engines.
Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: Okie_Steve on 12/01/2021 04:06 pm
In light of the new focus on Raptor production issues, a conservative strategy to help preserve schedule might also include testing/flying/landing the SH booster in a separate campaign that precedes or parallels the orbital launch campaign. Sending a booster up a few hundred (or a few thousand) meters and catching it successfully would go along way to minimizing the loss of boosters - and the 33 raptors that go with each one. And if it were launched using only a few Raptors it might not require any special FAA permissions as it would stay within the existing EA and FAA guidelines. This may be a quick and (relatively) easy way to refine the positioning and landing algorithms of both the booster and "Stage 0", especially if the FAA orbital launch license is delayed in any way.

The problem is that testing landing also risks the only currently existing SS/SH launch facility and push to orbit seems to be the priority for Musk at this time.
Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: [email protected] on 12/01/2021 04:17 pm
In light of the new focus on Raptor production issues, a conservative strategy to help preserve schedule might also include testing/flying/landing the SH booster in a separate campaign that precedes or parallels the orbital launch campaign. Sending a booster up a few hundred (or a few thousand) meters and catching it successfully would go along way to minimizing the loss of boosters - and the 33 raptors that go with each one. And if it were launched using only a few Raptors it might not require any special FAA permissions as it would stay within the existing EA and FAA guidelines. This may be a quick and (relatively) easy way to refine the positioning and landing algorithms of both the booster and "Stage 0", especially if the FAA orbital launch license is delayed in any way.
The reason why the OIG schedule is actually more realistic is that they didn't bother with people insisting they need to fly the booster separately first. Real world data is important to be received quick
Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: clongton on 12/01/2021 04:53 pm
Could it simply be an elaborate trick by Elon so he can justify ...

If you knew anything about Elon you would know that that is not his style.
Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: friendly3 on 12/01/2021 05:25 pm
Could it simply be an elaborate trick by Elon so he can justify ...

If you knew anything about Elon you would know that that is not his style.

I was joking.
Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: tssp_art on 12/01/2021 05:31 pm
The reason why the OIG schedule is actually more realistic is that they didn't bother with people insisting they need to fly the booster separately first. Real world data is important to be received quick

Agree, but that planning was assuming that Raptor production would keep up - but it doesn't synch with the current rate of production. At the current rate, each Booster loss consumes almost 3 months of production. And my guess is that they will lose at least three in the current campaign plan for orbital testing. If testing the booster separately can reduce those losses that is a significant impact to the schedule.
Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: _MECO on 12/01/2021 05:40 pm
The reason why the OIG schedule is actually more realistic is that they didn't bother with people insisting they need to fly the booster separately first. Real world data is important to be received quick

Agree, but that planning was assuming that Raptor production would keep up - but it doesn't synch with the current rate of production. At the current rate, each Booster loss consumes almost 3 months of production. And my guess is that they will lose at least three in the current campaign plan for orbital testing. If testing the booster separately can reduce those losses that is a significant impact to the schedule.
Maybe that's the driver behind the ridiculous demand. How many Falcon 9s did SpaceX blow up again in the name of perfecting first stage recovery? Like seven or eight? For the sake of simple argument let's say that SpaceX's increased experience and the increased difficulty of catching a booster on giant robot arms cancels out. Including this launch which we know will have no booster recovery, that would mean we can expect the first several launches to return basically zero working engines back to the company. When you consider they now need Starship launches to construct phase two of their yet-to-be-money-making Starlink constellation it starts to make sense they would be sweating over expensive engines in the near term. At 33 engines a booster and 10 RUDded boosters that's already 330 engines expended hoisting Starships towards orbit.
Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: alugobi on 12/01/2021 06:36 pm
Quote
sweating over expensive engines
He's already said that they're going to make them at a pretty low cost.  Expense just confuses the issue. 

The need volume, not low cost-of-production.
Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: steveleach on 12/01/2021 07:54 pm
Quote
sweating over expensive engines
He's already said that they're going to make them at a pretty low cost.  Expense just confuses the issue. 

The need volume, not low cost-of-production.
While that's likely true, it is also likely that one of the reasons they need volume is to get the cost of production (per unit) down, and one of the reasons they need low unit cost is so that they can afford high volumes.
Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: djh on 12/01/2021 08:00 pm
In light of the new focus on Raptor production issues, a conservative strategy to help preserve schedule might also include testing/flying/landing the SH booster in a separate campaign that precedes or parallels the orbital launch campaign. Sending a booster up a few hundred (or a few thousand) meters and catching it successfully would go along way to minimizing the loss of boosters - and the 33 raptors that go with each one. And if it were launched using only a few Raptors it might not require any special FAA permissions as it would stay within the existing EA and FAA guidelines. This may be a quick and (relatively) easy way to refine the positioning and landing algorithms of both the booster and "Stage 0", especially if the FAA orbital launch license is delayed in any way.

The problem is that testing landing also risks the only currently existing SS/SH launch facility and push to orbit seems to be the priority for Musk at this time.


Taking a leaf out of the early Starhopper test campaign, they could do a simple 3ft/1m test hop (straight up off the launch table, hover, then catch and lower). Using the catching arms for the first hop just to test that the catch-and-release mechanism works, from such a small height (1m) should have very low risk of damaging Stage 0, and would also prove the technology. It would also help suggest improvements or tweaks that would go into the next iteration.


Yes, the higher tests would be much more risky, but just proving that the catching arms operate as expected should definitely increase trust in the system for when they are actually ready to do a real orbital catch. Plus, hopefully by that point, the second orbital launch pad and tower would have been constucted.
Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: flexbuffchest on 12/01/2021 09:56 pm
So this is kind of a dumb question, but what are the most common reasons why a static fire might be aborted? Presumably all these engines have been tested before and haven't they been hooked up to SN20 for a while now?

I'm kind of a rube to all of this.
Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: spacenut on 12/01/2021 10:01 pm
I don't think SpaceX will lose a booster on launch, or even getting Starship to orbit.  Landing at the launch mount is the kicker.  Also, the belly flop landing of the Starship has only had one 100% successful landing.  One other one did land, but the fire below it caused it to fall over. 

Current rate of Raptor production only gives you two boosters and about 12 Starships per year.  Enough for testing, but once the landings are mastered, Musk wants to ramp up production rapidly. 
Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: ulm_atms on 12/01/2021 10:06 pm
So this is kind of a dumb question, but what are the most common reasons why a static fire might be aborted? Presumably all these engines have been tested before and haven't they been hooked up to SN20 for a while now?

I'm kind of a rube to all of this.

There are so many things....pressure sensor (one of many) saying to high/low, temp sensor (one of many) saying to high/low, valve not reporting open/closed, valve not actually opening/closing, pumps spinning to fast/slow, GSE sensors showing leaking pipes, power bus reporting issues, and the list can go on and on....ALL of them common reasons!

For this SF as a quick example...sitting so long...a valve might of stuck on startup...only SpaceX can answer the real reason however.
Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: flexbuffchest on 12/01/2021 10:19 pm
So this is kind of a dumb question, but what are the most common reasons why a static fire might be aborted? Presumably all these engines have been tested before and haven't they been hooked up to SN20 for a while now?

I'm kind of a rube to all of this.

There are so many things....pressure sensor (one of many) saying to high/low, temp sensor (one of many) saying to high/low, valve not reporting open/closed, valve not actually opening/closing, pumps spinning to fast/slow, GSE sensors showing leaking pipes, power bus reporting issues, and the list can go on and on....ALL of them common reasons!

For this SF as a quick example...sitting so long...a valve might of stuck on startup...only SpaceX can answer the real reason however.

Thanks a million!
Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: OTV Booster on 12/01/2021 11:25 pm
I can't comment on whether this e-mail is legit or not, but I wouldn't be surprised if this is SpaceX's equivalent of "production hell".

Thing is, the situation as it stands is that SpaceX will be completing several boosters and ships by the time they are flying next year, and I wouldn't be surprised if Raptors are the bottleneck as production of vehicles seems to be going quite well. With throwing engines in the drink, a raptor production shortage is going really bog down the ability to even test vehicles, let alone launch Starlinks, slowing down the entire program, and they may need to slow down vehicle production until Raptor production ramps up. Everything is so interdependent, and the reason Elon appears to be focusing on Raptor, the current bottleneck. Aside from this e-mail, whether real not, Elon has mentioned this several times publicly that it's one of their biggest challenges and the reason they are looking to build a simpler version (as well as cost).
Sounds like a good reason to prioritize booster return. Luckily that can run parallel with everything else that has to be developed but it gives a focus on where to spend the money.
Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: baking on 12/02/2021 06:28 am
I can't comment on whether this e-mail is legit or not, but I wouldn't be surprised if this is SpaceX's equivalent of "production hell".

Thing is, the situation as it stands is that SpaceX will be completing several boosters and ships by the time they are flying next year, and I wouldn't be surprised if Raptors are the bottleneck as production of vehicles seems to be going quite well. With throwing engines in the drink, a raptor production shortage is going really bog down the ability to even test vehicles, let alone launch Starlinks, slowing down the entire program, and they may need to slow down vehicle production until Raptor production ramps up. Everything is so interdependent, and the reason Elon appears to be focusing on Raptor, the current bottleneck. Aside from this e-mail, whether real not, Elon has mentioned this several times publicly that it's one of their biggest challenges and the reason they are looking to build a simpler version (as well as cost).
Sounds like a good reason to prioritize booster return. Luckily that can run parallel with everything else that has to be developed but it gives a focus on where to spend the money.
Pretty sure they will be able to build 33 Raptors before the can build another orbital launch mount, tower, and tank farm.  Trade-off will be how much they can control BN4 before the drop it in the drink and whether they think they can risk catching BN5 or 6, etc.

Of course, if they can catch them then they won't need as many Raptors.  In a sense, the panic rush to build Raptors reflects a lack of faith in Mechazilla.
Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: samgineer on 12/02/2021 11:16 am
Of course, if they can catch them then they won't need as many Raptors.  In a sense, the panic rush to build Raptors reflects a lack of faith in Mechazilla.

I don't think lack of faith in Mechazilla is reason for Raptor production panic. Even if mechazilla can catch 100% of boosters, Raptor production must go as fast as possible and as reliable as possible. Launch every two weeks mean they must build fleet of at least 5-10 boosters and ships to keep such cadence.  No way they can reach two weeks turnaround time for one ship and booster immediately. It means they need hundreds of Raptors, they are not able and never will be, to build new ship and booster every 2 weeks... Lot more sense make to think they are targeting to sacrifice at least 2-5 boosters without catching and few Starships. Even in best case scenario, they will plan to catch and reuse B5 they still need lots and lots of Raptors and ramp-up economics of scale.
Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: schuttle89 on 12/02/2021 12:05 pm
Of course, if they can catch them then they won't need as many Raptors.  In a sense, the panic rush to build Raptors reflects a lack of faith in Mechazilla.

I don't think lack of faith in Mechazilla is reason for Raptor production panic. Even if mechazilla can catch 100% of boosters, Raptor production must go as fast as possible and as reliable as possible. Launch every two weeks mean they must build fleet of at least 5-10 boosters and ships to keep such cadence.  No way they can reach two weeks turnaround time for one ship and booster immediately. It means they need hundreds of Raptors, they are not able and never will be, to build new ship and booster every 2 weeks... Lot more sense make to think they are targeting to sacrifice at least 2-5 boosters without catching and few Starships. Even in best case scenario, they will plan to catch and reuse B5 they still need lots and lots of Raptors and ramp-up economics of scale.

I don't think they plan on building a new booster every two weeks but the goal has always been to build ships faster than 2 weeks. It's been a year or 2 but I remember Elon talking about having 2 a week or some crazy number like that.
Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: Mike_1179 on 12/02/2021 01:17 pm
So this is kind of a dumb question, but what are the most common reasons why a static fire might be aborted? Presumably all these engines have been tested before and haven't they been hooked up to SN20 for a while now?

I'm kind of a rube to all of this.

There are so many things....pressure sensor (one of many) saying to high/low, temp sensor (one of many) saying to high/low, valve not reporting open/closed, valve not actually opening/closing, pumps spinning to fast/slow, GSE sensors showing leaking pipes, power bus reporting issues, and the list can go on and on....ALL of them common reasons!

For this SF as a quick example...sitting so long...a valve might of stuck on startup...only SpaceX can answer the real reason however.

Could also be that they are testing different things on this static fire. Maybe changes to valve timing to reduce start-up stresses (see the crazy valve positions for SSME) based on what they saw a few weeks ago. If those are new or different, you can get an engine out of its start box and then it will abort.
Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: RoboGoofers on 12/02/2021 01:33 pm
If starlink is the priority, drop starship reuse for now and concentrate on payload deployment. No need for heat shield, fins, header tank, or Rvacs. Use that mass to deploy more starlink sats. (assuming they won't have any issues producing v2 sats fast enough, but they can worry about that next thanksgiving.)

once boosters are being reused reliably, they can bring back starship reuse.
Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: Robotbeat on 12/02/2021 01:37 pm
If starlink is the priority, drop starship reuse for now and concentrate on payload deployment. No need for heat shield, fins, header tank, or Rvacs. Use that mass to deploy more starlink sats. (assuming they won't have any issues producing v2 sats fast enough, but they can worry about that next thanksgiving.)

once boosters are being reused reliably, they can bring back starship reuse.
That means they have to make more engines.
Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: RoboGoofers on 12/02/2021 03:20 pm
If starlink is the priority, drop starship reuse for now and concentrate on payload deployment. No need for heat shield, fins, header tank, or Rvacs. Use that mass to deploy more starlink sats. (assuming they won't have any issues producing v2 sats fast enough, but they can worry about that next thanksgiving.)

once boosters are being reused reliably, they can bring back starship reuse.
That means they have to make more engines.
The yield of reliable raptors needs to be high enough for them to fill all flights they're allowed per year as expendable. Once they recover the boosters, they'll need significantly less as the boosters are the big driver of engine demand. They won't need more engines than that until they have the authority to launch more from Boca Chica (if that's even in the cards), or somewhere else to launch from.

They might even be able to use some marginal raptors on the booster, which should tolerate engine-outs better, correct?

How long will it take to fill up the propellant farm from tanker trucks, anyway?
Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: Vettedrmr on 12/02/2021 03:23 pm
If starlink is the priority, drop starship reuse for now and concentrate on payload deployment. No need for heat shield, fins, header tank, or Rvacs. Use that mass to deploy more starlink sats. (assuming they won't have any issues producing v2 sats fast enough, but they can worry about that next thanksgiving.)

once boosters are being reused reliably, they can bring back starship reuse.

I think you're making the assumption that assets being used for heat shield, etc. are assets that could also be used for Raptor manufacturing; I expect that's not the case.  You can do both.
Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: RoboGoofers on 12/02/2021 03:52 pm
If starlink is the priority, drop starship reuse for now and concentrate on payload deployment. No need for heat shield, fins, header tank, or Rvacs. Use that mass to deploy more starlink sats. (assuming they won't have any issues producing v2 sats fast enough, but they can worry about that next thanksgiving.)

once boosters are being reused reliably, they can bring back starship reuse.

I think you're making the assumption that assets being used for heat shield, etc. are assets that could also be used for Raptor manufacturing; I expect that's not the case.  You can do both.
I'm not saying anything about moving assets from one area to another, unless that asset is the mass budget. i'm saying that if starlink is the driver of revenue, best to get them in orbit in volume as soon as possible to 'avoid bankruptcy'. Follow the example of F9 and get booster recovery down first. the mass saved by removing recovery equipment can either be used to add more sats, or reduce engine count on the booster.

the biggest risk to the whole system, bellyflop gliding and the flip, are at least possible, so starship recovery can go on the backburner until they get booster recovery or their financial situation figured out.
Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: Vettedrmr on 12/02/2021 04:04 pm
the biggest risk to the whole system, bellyflop gliding and the flip, are at least possible, so starship recovery can go on the backburner until they get booster recovery or their financial situation figured out.

That's what I'm referring to.  You assume that the work associated with re-entry is going to slow down the launch cadence, and those development assets could presumably be used elsewhere.  All I'm saying is that's not necessarily the case, and based on my experience in fighter aircraft development, it's likely not the case.

Keep working on everything, but keep the long pole the engine manufacturing development, that way when that logjam breaks you're in position to start launching.  Get data on the other stuff with each launch.

Have a good one,
Mike
Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: RoboGoofers on 12/02/2021 04:26 pm
the biggest risk to the whole system, bellyflop gliding and the flip, are at least possible, so starship recovery can go on the backburner until they get booster recovery or their financial situation figured out.

That's what I'm referring to.  You assume that the work associated with re-entry is going to slow down the launch cadence, and those development assets could presumably be used elsewhere.  All I'm saying is that's not necessarily the case, and based on my experience in fighter aircraft development, it's likely not the case.

Keep working on everything, but keep the long pole the engine manufacturing development, that way when that logjam breaks you're in position to start launching.  Get data on the other stuff with each launch.

Have a good one,
Mike
No. Again, i said they're limited to the launches they're allowed. they should maximize starlink payload on each of those flights. one of those is already spoken for with 4/20 so 0 starlinks for 29+6 raptors. not a good start.
Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: Vettedrmr on 12/02/2021 04:33 pm
Ok, I see what you're saying now.  You're just saying that they need to have a payload on every launch, accepting the risk of loss of the payload on launch.  I'm not sure why stopping work on the tile system, testing the landing algorithms, etc. improves the ability to put payloads into orbit (other than the fact that the current version of SS doesn't have a way to deploy them).
Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: RoboGoofers on 12/02/2021 04:39 pm
Ok, I see what you're saying now.  You're just saying that they need to have a payload on every launch, accepting the risk of loss of the payload on launch.  I'm not sure why stopping work on the tile system, testing the landing algorithms, etc. improves the ability to put payloads into orbit (other than the fact that the current version of SS doesn't have a way to deploy them).
yeah payload door is one. a simple disposable second stage could just have a traditional fairing deployment (albeit, a stainless fairing, though you don't have to take it all the way to orbit.)

And the wings/heatshield are an extra ~20 tons (guessing) that you save, so fewer engines needed on the booster, reducing the raptor production demand.

and again, this is just while they're in a pinch for engines. As soon as they recover the boosters they can go back to regular old starship
Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: wannamoonbase on 12/02/2021 05:12 pm
Ok, I see what you're saying now.  You're just saying that they need to have a payload on every launch, accepting the risk of loss of the payload on launch.  I'm not sure why stopping work on the tile system, testing the landing algorithms, etc. improves the ability to put payloads into orbit (other than the fact that the current version of SS doesn't have a way to deploy them).
yeah payload door is one. a simple disposable second stage could just have a traditional fairing deployment (albeit, a stainless fairing, though you don't have to take it all the way to orbit.)

And the wings/heatshield are an extra ~20 tons (guessing) that you save, so fewer engines needed on the booster, reducing the raptor production demand.

and again, this is just while they're in a pinch for engines. As soon as they recover the boosters they can go back to regular old starship

With the construction techniques they have developed a simplified expendable starship based upper stage would be cheap and quick to build.  I bet they could do 1 a week.
Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: Robotbeat on 12/02/2021 05:14 pm
The expendable payload of Starship may be 200-250 tonnes.

Itís not a trivial thing to redesign the satellite, fairing, and payload adapter to handle a load twice as much. And 100 tons of Starslinks is ALREADY a lot to risk on a single launch.

So no, I donít think that theyíd buy much by making the early Starships expendable except being able to reduce the number of engines used perhaps. They wouldnít be able to increase the payload much without a lot of work or a lot of risk.
Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: DanClemmensen on 12/02/2021 05:22 pm
Ok, I see what you're saying now.  You're just saying that they need to have a payload on every launch, accepting the risk of loss of the payload on launch.  I'm not sure why stopping work on the tile system, testing the landing algorithms, etc. improves the ability to put payloads into orbit (other than the fact that the current version of SS doesn't have a way to deploy them).
yeah payload door is one. a simple disposable second stage could just have a traditional fairing deployment (albeit, a stainless fairing, though you don't have to take it all the way to orbit.)

And the wings/heatshield are an extra ~20 tons (guessing) that you save, so fewer engines needed on the booster, reducing the raptor production demand.

and again, this is just while they're in a pinch for engines. As soon as they recover the boosters they can go back to regular old starship

The other advantage of a cheap, simple, expendable SS is that it is familiar, so all of the long-timers on this forum (and apparently in the industry) seem to think that this is the only "real" way to launch heavy payloads. To extent that this is true, SpaceX will find it easier to market this SS version to this class of customers in the short term.  This is not an important consideration for solving the immediate 2022 V2 launch problem, but it does mean that the development cost for this SS version can be recovered.
Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: Robotbeat on 12/02/2021 05:24 pm
I actually do think they should start by using a smaller number of engines on the first stage. Starship has a pretty high T/W ratio for a large rocket, and I doubt they need the full 100 tons payload for early Starlink missions.

20 engines should be enough for Super Heavy if it is under-loaded in propellant.
Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: beelsebob on 12/02/2021 06:41 pm
The question is whether the log jam will break faster with an expendable, or a reusable first/second stage.  It may be that figuring out recovery and reuse results in fewer engines being used for more launches, and as a result takes the pressure off the engine team more than simply saying "we're going to stay profitable by throwing things up as fast as we can".

I'm sure Elon has figured out which is the optimal.
Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: wannamoonbase on 12/02/2021 07:27 pm
[quote
I actually do think they should start by using a smaller number of engines on the first stage. Starship has a pretty high T/W ratio for a large rocket, and I doubt they need the full 100 tons payload for early Starlink missions.

20 engines should be enough for Super Heavy if it is under-loaded in propellant.

I actually do think they should start by using a smaller number of engines on the first stage. Starship has a pretty high T/W ratio for a large rocket, and I doubt they need the full 100 tons payload for early Starlink missions.

20 engines should be enough for Super Heavy if it is under-loaded in propellant.

I've thought about that myself, since that was discussed earlier in development.

I assume they are going for the full load to help evaluate the design and loads on the vehicle.  Maybe the flight software as well.

This could help cut down the number of cycles from now until full functionality.
Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: OTV Booster on 12/03/2021 12:05 am
If starlink is the priority, drop starship reuse for now and concentrate on payload deployment. No need for heat shield, fins, header tank, or Rvacs. Use that mass to deploy more starlink sats. (assuming they won't have any issues producing v2 sats fast enough, but they can worry about that next thanksgiving.)

once boosters are being reused reliably, they can bring back starship reuse.
That means they have to make more engines.
The yield of reliable raptors needs to be high enough for them to fill all flights they're allowed per year as expendable. Once they recover the boosters, they'll need significantly less as the boosters are the big driver of engine demand. They won't need more engines than that until they have the authority to launch more from Boca Chica (if that's even in the cards), or somewhere else to launch from.

They might even be able to use some marginal raptors on the booster, which should tolerate engine-outs better, correct?

How long will it take to fill up the propellant farm from tanker trucks, anyway?
Here's some specs for an LNG tanker.
https://files.chartindustries.com/14722928_TransportTrailers.pdf (https://files.chartindustries.com/14722928_TransportTrailers.pdf)


The big one carries 61,702 liters or 26 tons. The same tanker with LOX would carry 70 tons. The pumps deliver 300 gpm or 54 minutes to transfer. I'm not sure about Texas weight limits. Most states would not allow anything near a 70 ton cargo. Texas does things it's own way.


Cryo transfer would need maybe 15 minutes longer while dribbling a thin stream to chill the plumbing, but that's only a guess. My experience with LN2 is liter volumes only. Hookup and disconnect would normally take ~10 minutes total but cryo would take more if only to allow the hoses to thaw. With pull-up and exiting, an hour and a half per truck would be a well oiled process but 1:45 seems more realistic.


That's the bad news. The good news is they may may have more than one fill point per fluid. I've got a gut feeling that transferring methane and O2 at the same time is not a good idea.


Some more bad news - Texas has a history of methane disruptions during cold snaps.
Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: Robotbeat on 12/03/2021 12:33 am
I pretty regularly fill 50-100 liter dewars once the line is chilled, you donít have to chill it down again if thereís someone behind you. So only the first truck of the day has to wait for the line to chill if the trucks are lined up.
Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: DanClemmensen on 12/03/2021 12:43 am

How long will it take to fill up the propellant farm from tanker trucks, anyway?
Here's some specs for an LNG tanker.
https://files.chartindustries.com/14722928_TransportTrailers.pdf (https://files.chartindustries.com/14722928_TransportTrailers.pdf)

The big one carries 61,702 liters or 26 tons. The same tanker with LOX would carry 70 tons. The pumps deliver 300 gpm or 54 minutes to transfer. I'm not sure about Texas weight limits. Most states would not allow anything near a 70 ton cargo. Texas does things it's own way.

Cryo transfer would need maybe 15 minutes longer while dribbling a thin stream to chill the plumbing, but that's only a guess. My experience with LN2 is liter volumes only. Hookup and disconnect would normally take ~10 minutes total but cryo would take more if only to allow the hoses to thaw. With pull-up and exiting, an hour and a half per truck would be a well oiled process but 1:45 seems more realistic.

That's the bad news. The good news is they may may have more than one fill point per fluid. I've got a gut feeling that transferring methane and O2 at the same time is not a good idea.

Some more bad news - Texas has a history of methane disruptions during cold snaps.
We saw a picture about a week ago that showed multiple fill points for LOX and multiple fill points for liquid CH4, the two sets separated by some space. I seem to recall about five in one set and 4 in the other, but not sure, and I don't know if the separation was big enough to permit simultaneous operation. You would also need to worry about the number of trucks available and the truck filling rate at the source.

Texas had a very nasty disruption in February 2021 for three(?) days affecting both NG and electricity. They had a smaller one in 2010. I'm not sure that's a "history". I would be more worried about my workers' families getting cold at home than about disrupted operations. The problem was exacerbated by icy roads in much of Texas, but I don't know if that affected Boca Chica or the roads the trucks will use.  Hurricanes are worse.
Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: OTV Booster on 12/03/2021 12:51 am
[quote
I actually do think they should start by using a smaller number of engines on the first stage. Starship has a pretty high T/W ratio for a large rocket, and I doubt they need the full 100 tons payload for early Starlink missions.

20 engines should be enough for Super Heavy if it is under-loaded in propellant.

I actually do think they should start by using a smaller number of engines on the first stage. Starship has a pretty high T/W ratio for a large rocket, and I doubt they need the full 100 tons payload for early Starlink missions.

20 engines should be enough for Super Heavy if it is under-loaded in propellant.

I've thought about that myself, since that was discussed earlier in development.

I assume they are going for the full load to help evaluate the design and loads on the vehicle.  Maybe the flight software as well.

This could help cut down the number of cycles from now until full functionality.
A breakaway fairing isn't on the critical path but a chomper or variant is. The first flight with one could have an SL payload but I seriously doubt it would be a full load. Probably a Falcon sized load or less.


They ran a full load (ignoring a couple of test sats) first time on Falcon but it was a ship they were intimately familiar with. We have no hard info but it's looking like a full SS load of the current sats would be equal to around seven Falcon loads. they could loose a Falcon load and it would be painful but not catastrophic. Loosing seven loads would be 3-4 months production at current rates and beyond painful.


Musk knows what risk level he's willing to face much better than we do but I doubt he's willing to risk that big a hole in the deployment schedule. After one small launch he might go for a full load or he may expand it incrementally. At that point he'll have some firm engineering data on SS and deployment.
Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: OTV Booster on 12/03/2021 12:58 am
I pretty regularly fill 50-100 liter dewars once the line is chilled, you donít have to chill it down again if thereís someone behind you. So only the first truck of the day has to wait for the line to chill if the trucks are lined up.
If they do it the same as gasoline each truck uses its own hoses. They have to be chilled down and after that it all depends on how good the insulation is and there's always some moron blocking you in. Well not always.


Trucks all lined up and ready to go does minimize it.
Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: DanClemmensen on 12/03/2021 01:02 am
Quote
I assume they are going for the full load to help evaluate the design and loads on the vehicle.  Maybe the flight software as well.

This could help cut down the number of cycles from now until full functionality.
A breakaway fairing isn't on the critical path but a chomper or variant is. The first flight with one could have an SL payload but I seriously doubt it would be a full load. Probably a Falcon sized load or less.


They ran a full load (ignoring a couple of test sats) first time on Falcon but it was a ship they were intimately familiar with. We have no hard info but it's looking like a full SS load of the current sats would be equal to around seven Falcon loads. they could loose a Falcon load and it would be painful but not catastrophic. Loosing seven loads would be 3-4 months production at current rates and beyond painful.

Musk knows what risk level he's willing to face much better than we do but I doubt he's willing to risk that big a hole in the deployment schedule. After one small launch he might go for a full load or he may expand it incrementally. At that point he'll have some firm engineering data on SS and deployment.

As I understand it, it's hard to use a single launch to put satellites in more than one plane, with the difficulty increasing as the planes diverge. Is this understanding correct?  A full SS is almost certainly too much for one plane or even three "reasonably close" planes. It may be more cost-effective to do one partially-filled launch per plane. This is even more likely when they get to "fully rapidly reusable".
Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: OTV Booster on 12/03/2021 01:28 am

How long will it take to fill up the propellant farm from tanker trucks, anyway?
Here's some specs for an LNG tanker.
https://files.chartindustries.com/14722928_TransportTrailers.pdf (https://files.chartindustries.com/14722928_TransportTrailers.pdf)

The big one carries 61,702 liters or 26 tons. The same tanker with LOX would carry 70 tons. The pumps deliver 300 gpm or 54 minutes to transfer. I'm not sure about Texas weight limits. Most states would not allow anything near a 70 ton cargo. Texas does things it's own way.

Cryo transfer would need maybe 15 minutes longer while dribbling a thin stream to chill the plumbing, but that's only a guess. My experience with LN2 is liter volumes only. Hookup and disconnect would normally take ~10 minutes total but cryo would take more if only to allow the hoses to thaw. With pull-up and exiting, an hour and a half per truck would be a well oiled process but 1:45 seems more realistic.

That's the bad news. The good news is they may may have more than one fill point per fluid. I've got a gut feeling that transferring methane and O2 at the same time is not a good idea.

Some more bad news - Texas has a history of methane disruptions during cold snaps.
We saw a picture about a week ago that showed multiple fill points for LOX and multiple fill points for liquid CH4, the two sets separated by some space. I seem to recall about five in one set and 4 in the other, but not sure, and I don't know if the separation was big enough to permit simultaneous operation. You would also need to worry about the number of trucks available and the truck filling rate at the source.

Texas had a very nasty disruption in February 2021 for three(?) days affecting both NG and electricity. They had a smaller one in 2010. I'm not sure that's a "history". I would be more worried about my workers' families getting cold at home than about disrupted operations. The problem was exacerbated by icy roads in much of Texas, but I don't know if that affected Boca Chica or the roads the trucks will use.  Hurricanes are worse.
Yeah, that's the history I was talking about. Texas does not deal with cold very well. I was trucking down there one time (probably 2010) and it was so bad the state had both salt trucks out.


Being about as far south as you can get and being on the coast, BC probably didn't have ice problems but can you imagine the uproar if Elon is filling his tank farm while people are without heat in temperatures below anything they've ever experienced?


IIRC Ars Technica had an article a month or two back that said that the infrastructure winterizing was not going all that well. If they get a repeat of last winter... Well, them folks down there got a lot of guns.
Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: rickyramjet on 12/03/2021 01:39 am

IIRC Ars Technica had an article a month or two back that said that the infrastructure winterizing was not going all that well. If they get a repeat of last winter... Well, them folks down there got a lot of guns.

Yep, we have a lot of guns, that's fer shure.  But, gosh, what do you think we are?  It ain't like it's still the wild west.  We only shoot varmits that really NEED shootin!
Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: OTV Booster on 12/03/2021 01:43 am
Quote
I assume they are going for the full load to help evaluate the design and loads on the vehicle.  Maybe the flight software as well.

This could help cut down the number of cycles from now until full functionality.
A breakaway fairing isn't on the critical path but a chomper or variant is. The first flight with one could have an SL payload but I seriously doubt it would be a full load. Probably a Falcon sized load or less.


They ran a full load (ignoring a couple of test sats) first time on Falcon but it was a ship they were intimately familiar with. We have no hard info but it's looking like a full SS load of the current sats would be equal to around seven Falcon loads. they could loose a Falcon load and it would be painful but not catastrophic. Loosing seven loads would be 3-4 months production at current rates and beyond painful.

Musk knows what risk level he's willing to face much better than we do but I doubt he's willing to risk that big a hole in the deployment schedule. After one small launch he might go for a full load or he may expand it incrementally. At that point he'll have some firm engineering data on SS and deployment.

As I understand it, it's hard to use a single launch to put satellites in more than one plane, with the difficulty increasing as the planes diverge. Is this understanding correct?  A full SS is almost certainly too much for one plane or even three "reasonably close" planes. It may be more cost-effective to do one partially-filled launch per plane. This is even more likely when they get to "fully rapidly reusable".
AIUI, lower orbits precess faster than high orbits and the technique is to raise orbit sequentially (getting them spaced properly) for the birds in one plane, then bide your time until the gaggle of birds precesses to the next plane of interest. Repeat as necessary.


It's a slow process but the only costs is some propellant when the orbit drops too low. It also gives an opportunity to insert replacements and backup birds into planes as the gaggle works past them.


Does anybody have numbers for rates of precession at orbit insertion altitude and working altitude?
Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: OTV Booster on 12/03/2021 01:52 am

IIRC Ars Technica had an article a month or two back that said that the infrastructure winterizing was not going all that well. If they get a repeat of last winter... Well, them folks down there got a lot of guns.

Yep, we have a lot of guns, that's fer shure.  But, gosh, what do you think we are?  It ain't like it's still the wild west.  We only shoot varmits that really NEED shootin!
Well yeah! I was thinkin politicians that don't fix the problem.


Young Texas lawyer to an old Texas lawyer: Why is it that we treat cattle rustlers more harshly than people who kill?


Old Texas lawyer: You ever seen a cow that looked like it needed stealing?
Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: CMac on 12/03/2021 08:57 am
There was a graph or two floating around about p recession rates with altitude. It was around the time of maybe the second or third starlink launch. I can't recall where I saw those graphs.
Edit: this paper describes it: https://strathprints.strath.ac.uk/71130/1/McGrath_Macdonald_JGCD_2020_General_perturbation_method_for_satellite_constellation_deployment.pdf (https://strathprints.strath.ac.uk/71130/1/McGrath_Macdonald_JGCD_2020_General_perturbation_method_for_satellite_constellation_deployment.pdf)
Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: DanClemmensen on 12/03/2021 03:48 pm
There was a graph or two floating around about p recession rates with altitude. It was around the time of maybe the second or third starlink launch. I can't recall where I saw those graphs.
Edit: this paper describes it: https://strathprints.strath.ac.uk/71130/1/McGrath_Macdonald_JGCD_2020_General_perturbation_method_for_satellite_constellation_deployment.pdf (https://strathprints.strath.ac.uk/71130/1/McGrath_Macdonald_JGCD_2020_General_perturbation_method_for_satellite_constellation_deployment.pdf)
Thanks! It appears that the tradeoff is that the satellites will need extra propellant and the deployment will take longer, with the cost rising as the plane change(s) get larger. The paper mentions the "very high cost" of each launch as the justification for using this maneuver. So this tradeoff must be re-evaluated for the dramatically cheaper launch. Should SpaceX use more launches in order to reduce deployment time and satellite propellant? Can they find rideshare customers that will accept the risks of  the relatively untried SS to fill up the payloads? It must be "interesting" to juggle such tradeoffs.
Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: billh on 12/03/2021 07:24 pm
What the heck is this thing? (Image credit: recent tweet from Cosmic Perspective)
Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: xvel on 12/03/2021 07:39 pm
haha
Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: beelsebob on 12/04/2021 02:49 pm
What the heck is this thing? (Image credit: recent tweet from Cosmic Perspective)
One of the guys working at the top cycled up there.
Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: Vonbraun on 12/04/2021 05:07 pm
What the heck is this thing? (Image credit: recent tweet from Cosmic Perspective)

Booster has not been moved for 6 months and is now considered a permanent housing structure at lot #172939 and the new regulations requires them to be handicap accessible.
Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: OTV Booster on 12/04/2021 05:43 pm
There was a graph or two floating around about p recession rates with altitude. It was around the time of maybe the second or third starlink launch. I can't recall where I saw those graphs.
Edit: this paper describes it: https://strathprints.strath.ac.uk/71130/1/McGrath_Macdonald_JGCD_2020_General_perturbation_method_for_satellite_constellation_deployment.pdf (https://strathprints.strath.ac.uk/71130/1/McGrath_Macdonald_JGCD_2020_General_perturbation_method_for_satellite_constellation_deployment.pdf)
Thanks! It appears that the tradeoff is that the satellites will need extra propellant and the deployment will take longer, with the cost rising as the plane change(s) get larger. The paper mentions the "very high cost" of each launch as the justification for using this maneuver. So this tradeoff must be re-evaluated for the dramatically cheaper launch. Should SpaceX use more launches in order to reduce deployment time and satellite propellant? Can they find rideshare customers that will accept the risks of  the relatively untried SS to fill up the payloads? It must be "interesting" to juggle such tradeoffs.
One trade might be to do a reduced payload and give the sats larger tanks. If the plan for the V2 is to use SS, this might be baked into the design. The launches would be filling a pipeline. Once filled, sats would start coming into service and the precession delay becomes a schedule hiccup not an ever extending delay.


Launching 6-7 planes at a crack might even be faster than than using F9, even with the hiccup. That gets me to wondering if we're gonna see stage 0 moving ahead at Kennedy as they learn lessions from BC GSE.
Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: Keldor on 12/05/2021 06:56 am
There was a graph or two floating around about p recession rates with altitude. It was around the time of maybe the second or third starlink launch. I can't recall where I saw those graphs.
Edit: this paper describes it: https://strathprints.strath.ac.uk/71130/1/McGrath_Macdonald_JGCD_2020_General_perturbation_method_for_satellite_constellation_deployment.pdf (https://strathprints.strath.ac.uk/71130/1/McGrath_Macdonald_JGCD_2020_General_perturbation_method_for_satellite_constellation_deployment.pdf)
Thanks! It appears that the tradeoff is that the satellites will need extra propellant and the deployment will take longer, with the cost rising as the plane change(s) get larger. The paper mentions the "very high cost" of each launch as the justification for using this maneuver. So this tradeoff must be re-evaluated for the dramatically cheaper launch. Should SpaceX use more launches in order to reduce deployment time and satellite propellant? Can they find rideshare customers that will accept the risks of  the relatively untried SS to fill up the payloads? It must be "interesting" to juggle such tradeoffs.
One trade might be to do a reduced payload and give the sats larger tanks. If the plan for the V2 is to use SS, this might be baked into the design. The launches would be filling a pipeline. Once filled, sats would start coming into service and the precession delay becomes a schedule hiccup not an ever extending delay.


Launching 6-7 planes at a crack might even be faster than than using F9, even with the hiccup. That gets me to wondering if we're gonna see stage 0 moving ahead at Kennedy as they learn lessions from BC GSE.

Remember, the sky has 360 degrees worth of planes whether you launch 1,000 satellites or 10,000.  This means that we won't be seeing any longer precession delays for V2 than we did for V1, we'll just see more satellites per plane (or more planes closer together).
Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: Slothman on 12/05/2021 12:19 pm
Booster alignment. How it works!
I hope you like it.
https://youtu.be/dJizM_AiQ8c

Ok but does the tower blast a neverending stream of obnoxious music all the time or why is that in the video?
I mean.. I wouldn't put it past Rave-Elon.
Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: ThatOldJanxSpirit on 12/05/2021 02:41 pm
Booster alignment. How it works!
I hope you like it.
https://youtu.be/dJizM_AiQ8c

Ok but does the tower blast a neverending stream of obnoxious music all the time or why is that in the video?
I mean.. I wouldn't put it past Rave-Elon.

You could always turn the sound down.

Thanks Owe for the awesome work!
Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: wannamoonbase on 12/05/2021 03:41 pm
Agreed, use the volume control on your device and enjoy the video.

I think itís a great video, canít wait to see it in use.
Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: DanClemmensen on 12/05/2021 03:43 pm
Remember, the sky has 360 degrees worth of planes whether you launch 1,000 satellites or 10,000.  This means that we won't be seeing any longer precession delays for V2 than we did for V1, we'll just see more satellites per plane (or more planes closer together).
Your observation may be true for Starlink or other extremely large constellations, but is not true in general. If it were, then the number of launches for a given constellation cannot go below a certain minimum, regardless of the launcher's max payload capacity. If I wish to launch an Earth observation constellation with 36 planes of 36 satellites each at 1200 km altitude, I would need 36 launches, whether I use an F9 or a Starship. With Starship I can launch bigger satellites or have the launcher carry them all the way up, but I still need 36 launches.

But it's not strictly true, because with Starship I can use 18 launches and have each satellite carry more fuel to do plane change maneuvers.

But the whole point of Starship (fully, quickly, and cheaply reusable) is that it is cheaper than any other launcher on a per-launch basis for any non-trivial payload, so I just might go ahead and buy 36 launches anyway.
Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: clongton on 12/05/2021 06:28 pm
Booster alignment. How it works!
I hope you like it.

Ok but does the tower blast a never-ending stream of obnoxious music all the time or why is that in the video?
I mean.. I wouldn't put it past Rave-Elon

You could always turn the sound down.

Thanks Owe for the awesome work!

It's an epidemic these days to background horrible, horrible sounds to otherwise exceptional videos such as this one. It's so distracting at times that as often as not I actually end the video mid-stream rather than subject myself to any further audio torture. P.S. I did not watch this all the way thru for that exact reason. I terminated it.

Content creators take note. I am *NOT* the only one that shuts off your videos part way thru because of the ill-conceived background noise!
Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: abaddon on 12/05/2021 07:27 pm
How hard is it to hit the mute?  Sheesh.
Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: meekGee on 12/05/2021 07:31 pm
How hard is it to hit the mute?  Sheesh.
It depends on how fast he's dodging.  They can be quite wily, quiet little buggers.
Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: punder on 12/05/2021 07:38 pm
How hard is it to hit the mute?  Sheesh.
It depends on how fast he's dodging.  They can be quite wily, quiet little buggers.
You are SO headed for a meeting with HR.
Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: alugobi on 12/05/2021 07:47 pm
How hard is it to hit the mute?  Sheesh.
It's not, and I do that.  But I'll second the vote to can the techno noise.  Is it something that they teach in CAD school?  Make a jaw-dropping presentation but then poison it with unnecessary, distracting screech?
Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: OTV Booster on 12/06/2021 12:09 am
There was a graph or two floating around about p recession rates with altitude. It was around the time of maybe the second or third starlink launch. I can't recall where I saw those graphs.
Edit: this paper describes it: https://strathprints.strath.ac.uk/71130/1/McGrath_Macdonald_JGCD_2020_General_perturbation_method_for_satellite_constellation_deployment.pdf (https://strathprints.strath.ac.uk/71130/1/McGrath_Macdonald_JGCD_2020_General_perturbation_method_for_satellite_constellation_deployment.pdf)
Thanks! It appears that the tradeoff is that the satellites will need extra propellant and the deployment will take longer, with the cost rising as the plane change(s) get larger. The paper mentions the "very high cost" of each launch as the justification for using this maneuver. So this tradeoff must be re-evaluated for the dramatically cheaper launch. Should SpaceX use more launches in order to reduce deployment time and satellite propellant? Can they find rideshare customers that will accept the risks of  the relatively untried SS to fill up the payloads? It must be "interesting" to juggle such tradeoffs.
One trade might be to do a reduced payload and give the sats larger tanks. If the plan for the V2 is to use SS, this might be baked into the design. The launches would be filling a pipeline. Once filled, sats would start coming into service and the precession delay becomes a schedule hiccup not an ever extending delay.


Launching 6-7 planes at a crack might even be faster than than using F9, even with the hiccup. That gets me to wondering if we're gonna see stage 0 moving ahead at Kennedy as they learn lessions from BC GSE.

Remember, the sky has 360 degrees worth of planes whether you launch 1,000 satellites or 10,000.  This means that we won't be seeing any longer precession delays for V2 than we did for V1, we'll just see more satellites per plane (or more planes closer together).
IIRC (probably don't) the current shell is near done, Vandy is doing the high inclination, and they're about ready to start a new shell out a bit higher. So that would be where SS would shine.


The chip shortage is slowing UT production. This might be a blessing in disguise. More customers, more birds needed. SS isn't on line for launches yet and there's no way to get that bandwidth up except in F9 increments. No customers irritated because of slow service. It hurts the business plan but not as much as a customer base that starts seeing StarLink as just another crummy service provider.


All for the want of a well balanced Raptor.

Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: TomH on 12/06/2021 01:02 am
I still worry that when SS lands, that even offset a bit it will still be too close to SH and that the exhaust plume may be able to damage the nearby SH.
Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: Tangilinear Interjar on 12/06/2021 02:58 pm
How hard is it to hit the mute?  Sheesh.
It's not, and I do that.  But I'll second the vote to can the techno noise.  Is it something that they teach in CAD school?  Make a jaw-dropping presentation but then poison it with unnecessary, distracting screech?

LOL, I like the music!

I guess to each his own.
Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: _MECO on 12/06/2021 03:06 pm
I, for one, proudly salute this mindless OT bickering!
Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: tesh90 on 12/07/2021 08:31 am
A quick question: are we cutting it fine for a Jan orbital attempt? We have a booster SF to carry out, stacking and then possibly a second SF of the booster (once fully stacked) and/or a full wet DR (i.e. everything but launch)...
Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: Hamish.Student on 12/07/2021 10:58 am
Booster 4 has been hooked up to the loadspreader, but it's currently nowhere near the orbital launch mount, so it's not clear what their plan is.
 
 
Lifting onto an SPMT for transport, either to the launch stand or the manufacturing site?
Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: samgineer on 12/07/2021 11:39 am
They can move booster with crawler crane to launch mount. LR 11000 is oriented with threads heading to the OLP, so I think it's likely and completely possible, no SPMT is required.
Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: schuttle89 on 12/07/2021 02:22 pm
A quick question: are we cutting it fine for a Jan orbital attempt? We have a booster SF to carry out, stacking and then possibly a second SF of the booster (once fully stacked) and/or a full wet DR (i.e. everything but launch)...
I'm wondering if they have to wait for the FAA approval to do the SH static fire.
Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: Vettedrmr on 12/07/2021 02:53 pm
An utter guess, but I think the FAA would accept any SF that didn't exceed the quantity of prop and oxidizer that the 15km hop flights used.
Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: Chris Bergin on 12/07/2021 04:38 pm
People annoyed this thread has been taken over by the photo discussion. As noted, PM me - but the decision has been made (after several previous and similar debates only made the matter worse). Please keep this on the thread subject.

(Saved the posts so they can be replied to by me later).
Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: edzieba on 12/08/2021 03:18 pm
Booster 5 is heading towards the old gas well site. Possibly to the parking area beside SN15 and SN16?

(Also, Friday closure cancelled. Next testing closure is now Monday, Dec 13)

Per NSF 24/7
Possibly to meet up with BN 2.1 and take its place on the 'can crusher' stand, now BN 2.1 has completed its test campaign.
Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: Alberto-Girardi on 12/08/2021 08:28 pm
A quick question: are we cutting it fine for a Jan orbital attempt? We have a booster SF to carry out, stacking and then possibly a second SF of the booster (once fully stacked) and/or a full wet DR (i.e. everything but launch)...
My personal thought is thet we will see a very hot February, with SLS and SS launching. I think that two months is not enough, there are many things to do, and there is always the risk of dalays. But good progres has been made, with the tests to the orbital farm. I cosnider them important because we are now very close with having the gse concluded.
Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: wannamoonbase on 12/08/2021 08:32 pm
A quick question: are we cutting it fine for a Jan orbital attempt? We have a booster SF to carry out, stacking and then possibly a second SF of the booster (once fully stacked) and/or a full wet DR (i.e. everything but launch)...
My personal thought is thet we will see a very hot February, with SLS and SS launching. I think that two months is not enough, there are many things to do, and there is always the risk of dalays. But good progres has been made, with the tests to the orbital farm. I cosnider them important because we are now very close with having the gse concluded.

I agree, February seems more likely, of course that all depends on the FAA.

There is a lot of ground testing to be done of the booster and starship, but also the OLS.  Tanking, detanking, multiple static fires. 

The first time using all that equipment and systems they are going to find out a lot things that need to be corrected in real time.  I won't be surprised if we see them do plenty of static fires of the booster to build confidence.  No one has ever made, fired and flown a booster this time.
Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: oldAtlas_Eguy on 12/09/2021 01:14 am
Just a small note is that 2 months from now is only 8 Feb.

Another note is about SLS and that is that it continues to be behind on it's schedules and may not make it's current NET 12 Feb date for launch. Another large difference between the two is how long it would take recycle after an abort once engines have started but yet to be released. SLS would take a couple of weeks. If the SH abort are similar to the situation for an SS aborts then the recycle time for SH is a mater of hours and at worst next day.

Such that getting to a success at the stack leaving the pad is not likely to be as difficult for SpaceX as NASA getting the SLS stack to leave the pad.
Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: tesh90 on 12/09/2021 10:02 am
A quick question: are we cutting it fine for a Jan orbital attempt? We have a booster SF to carry out, stacking and then possibly a second SF of the booster (once fully stacked) and/or a full wet DR (i.e. everything but launch)...
My personal thought is thet we will see a very hot February, with SLS and SS launching. I think that two months is not enough, there are many things to do, and there is always the risk of dalays. But good progres has been made, with the tests to the orbital farm. I cosnider them important because we are now very close with having the gse concluded.

I agree, February seems more likely, of course that all depends on the FAA.

There is a lot of ground testing to be done of the booster and starship, but also the OLS.  Tanking, detanking, multiple static fires. 

The first time using all that equipment and systems they are going to find out a lot things that need to be corrected in real time.  I won't be surprised if we see them do plenty of static fires of the booster to build confidence.  No one has ever made, fired and flown a booster this time.

Even if they slip into Q2 it would be great progress. I'm just amazed at the speed of the their progress - with so may different activities going on I dunno how they keep track of it all.
Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: sferrin on 12/09/2021 12:09 pm
A quick question: are we cutting it fine for a Jan orbital attempt? We have a booster SF to carry out, stacking and then possibly a second SF of the booster (once fully stacked) and/or a full wet DR (i.e. everything but launch)...
My personal thought is thet we will see a very hot February, with SLS and SS launching. I think that two months is not enough, there are many things to do, and there is always the risk of dalays. But good progres has been made, with the tests to the orbital farm. I cosnider them important because we are now very close with having the gse concluded.

I agree, February seems more likely, of course that all depends on the FAA.

There is a lot of ground testing to be done of the booster and starship, but also the OLS.  Tanking, detanking, multiple static fires. 

The first time using all that equipment and systems they are going to find out a lot things that need to be corrected in real time.  I won't be surprised if we see them do plenty of static fires of the booster to build confidence.  No one has ever made, fired and flown a booster this time.

Even if they slip into Q2 it would be great progress. I'm just amazed at the speed of the their progress - with so may different activities going on I dunno how they keep track of it all.


I would hate to be the guy responsible for version control.  :o
Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: Oersted on 12/09/2021 02:45 pm
I am a bit surprised that Starship hasn't flown lots of times while they get the heat-shield and ground equipment in order. Just lots of hops up to whichever altitude is feasible with only the ship. Would give lots of interesting data points characterizing landing behaviour. The only reasons I can think of for that not happening are 1) insufficiently reliable Raptors and perhaps 2) FAA bureaucracy.   
Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: xvel on 12/09/2021 03:01 pm
I am a bit surprised that Starship hasn't flown lots of times while they get the heat-shield and ground equipment in order. Just lots of hops up to whichever altitude is feasible with only the ship. Would give lots of interesting data points characterizing landing behaviour. The only reasons I can think of for that not happening are 1) insufficiently reliable Raptors and perhaps 2) FAA bureaucracy.

or maybe they want to make progress in design, production and ground infrastructure instead of playing around?
Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: Confusador on 12/09/2021 03:01 pm
I am a bit surprised that Starship hasn't flown lots of times while they get the heat-shield and ground equipment in order. Just lots of hops up to whichever altitude is feasible with only the ship. Would give lots of interesting data points characterizing landing behaviour. The only reasons I can think of for that not happening are 1) insufficiently reliable Raptors and perhaps 2) FAA bureaucracy.

3) Disruption of construction activities at the launch site.
4) No spare Starships because they spent all summer building GSE tanks instead.

If they get to the point where the launch site and S21 are ready to go but the FAA isn't done with the PEA, then sure, I could see them doing more hops with S20.  But for now, they've learned everything they need to on the suborbital flights, and the FAA is almost ready to go.  Better to spend the time prepping for orbital(-ish) attempts.
Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: Hamish.Student on 12/10/2021 11:42 am
Sure miss Mary's photos on this thread.   :(
 
 
Not an update, but the question is valid. What's happened to all the photos recently?
Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: edzieba on 12/10/2021 11:54 am
Sure miss Mary's photos on this thread.   :(
 
 
Not an update, but the question is valid. What's happened to all the photos recently?
See Chris' update in the Update thread:
Side by side attached.

Also per the 200-300mb of hi res photos that were uploaded into here, we did warn people that we could not continue to allow mass hotlinking on Reddit, etc. Also the amount of harvesting by Twitter folk (usually removing the watermark and @elon clout chasing, heh) minutes after the uploads were getting worse by the week. So we're now uploading the full sets of both Mary and Nic into a dedicated L2 thread, and then the selection (as previous) that fit the video go into the daily vid.

If an engineering thread requires a specific hi-res photo of the mount or something then it can be requested and we'll upload it.

(Sorry, remember this is still an update only thread. Any questions, fire me a PM on the forum!)
Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: Hamish.Student on 12/11/2021 01:07 am
Sure miss Mary's photos on this thread.   :(
 
 
Not an update, but the question is valid. What's happened to all the photos recently?
See Chris' update in the Update thread:
Side by side attached.

Also per the 200-300mb of hi res photos that were uploaded into here, we did warn people that we could not continue to allow mass hotlinking on Reddit, etc. Also the amount of harvesting by Twitter folk (usually removing the watermark and @elon clout chasing, heh) minutes after the uploads were getting worse by the week. So we're now uploading the full sets of both Mary and Nic into a dedicated L2 thread, and then the selection (as previous) that fit the video go into the daily vid.

If an engineering thread requires a specific hi-res photo of the mount or something then it can be requested and we'll upload it.

(Sorry, remember this is still an update only thread. Any questions, fire me a PM on the forum!)
 
 
Well that's disappointing, though slightly understandable. Thanks.
Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: alugobi on 12/11/2021 03:55 pm
Video shows a lot of crane weights moved to the launch site.  Booster lift on the way?
Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: Andy DC on 12/11/2021 04:44 pm
Video shows a lot of crane weights moved to the launch site.  Booster lift on the way?

My thinking was a potential test of the new crane hooking up, then counterweights, then lift.

But the hope is lift on the SPMT, roll to OLS and then chopstick lift on to the mount. I just don;t think the chopsticks are ready yet.

What do you all think?
Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: seb21051 on 12/11/2021 05:02 pm
It would seem B5 has been relegated to the garden gnome section.

Does this imply a problem with the engines?

Does this mean it will not fly?

Can it fly with any Raptors other than V.1?

SX has produced more than 100 V.1 engines. Are they so unreliable?
Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: xvel on 12/11/2021 05:15 pm
There is still scaffolding on the tower, so the chopsticks cannot move
Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: xvel on 12/11/2021 05:21 pm
It would seem B5 has been relegated to the garden gnome section.

Does this imply a problem with the engines?

Does this mean it will not fly?

Can it fly with any Raptors other than V.1?

SX has produced more than 100 V.1 engines. Are they so unreliable?

It has to wait its turn somewhere.

Maybe.

I think it will.

I don't think so.

This is a common misconception, serial number does not equal the number of engines produced, just as the starship serial number does not equal the number of prototypes produced.
Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: jadebenn on 12/11/2021 05:54 pm
Just a small note is that 2 months from now is only 8 Feb.

Another note is about SLS and that is that it continues to be behind on it's schedules and may not make it's current NET 12 Feb date for launch. Another large difference between the two is how long it would take recycle after an abort once engines have started but yet to be released. SLS would take a couple of weeks. If the SH abort are similar to the situation for an SS aborts then the recycle time for SH is a mater of hours and at worst next day.

Such that getting to a success at the stack leaving the pad is not likely to be as difficult for SpaceX as NASA getting the SLS stack to leave the pad.
Honestly, a scrub that deep into the launch sequence might be closer to a month for SLS, especially with its launch crews still climbing up the learning curve and the launch window constraints imposed by ICPS. The latter is especially important to understand, because anything that pushes SLS out of its 15 day Lunar window instantly pushes it back a month for the next.

There are a few more dynamics to understand as well. According to Philip Sloss's article, the 39B clean pad means that NASA basically gets 7 days of opportunity after a rollout. For Artemis I, with the new LH2 sphere mostly-built but not coming online until Artemis II, the fueling turnaround gives them 3 launch opportunities. So in other words, they have 3 launch opportunities about every month.

It's very possible that general slippage is going to push them March, especially depending on how the engine controller situation is resolved (if they need to pull the RS-25... big delay). Even if they're ready in time for the February window, if they'd only have partial availability, it may be prudent to wait. Then you have to roll the dice and see if 3 launch attempts will be enough, or that's another month. (On the plus side, we may get a day launch).

It seems very unlikely that 6 launch attempts wouldn't be sufficient, so absent any further nasty surprises, which one is first is really a question of whether you think Starship will go orbital before mid-year.
Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: seb21051 on 12/12/2021 01:25 am
It would seem B5 has been relegated to the garden gnome section.

Does this imply a problem with the engines?

Does this mean it will not fly?

Can it fly with any Raptors other than V.1?

SX has produced more than 100 V.1 engines. Are they so unreliable?

It has to wait its turn somewhere.

Maybe.

I think it will.

I don't think so.

This is a common misconception, serial number does not equal the number of engines produced, just as the starship serial number does not equal the number of prototypes produced.

Spacex had produced 100 Raptors by July of this year:

https://www.tesmanian.com/blogs/tesmanian-blog/100-raptor
Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: xvel on 12/12/2021 01:36 am
They also produced 20 prototype starships.

Except that half of them were scrapped before they were completed.
Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: alugobi on 12/12/2021 04:09 am
From the video, I wonder if they're repouring the slab in front of the GSE tanks because the crane that had been parked and lifting there cracked or weakened it.
Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: Hyperus on 12/12/2021 08:34 am
This is a common misconception, serial number does not equal the number of engines produced, just as the starship serial number does not equal the number of prototypes produced.

However, their production rate as of May 2021 was about 1 Raptor every 48 hours, They have pretty much all raptors required for B4 for a couple of months now. I think the reason that B5 doesn't have engines yet can not be pinpointed on engine production alone.
Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: beelsebob on 12/12/2021 11:31 am
Who says B5 doesn't have all its engines anyway?  I mean, we know with some reasonable confidence that they're not at Boca Chica, but that doesn't mean they don't exist.  There's only limited space for all the activities there, even if they are constantly expanding.

That said, I do think the most likely explanation is that it's taken so long for the FAA to sign off on launching any boosters at all, that B4/5 are obsolete.  They probably are thinking that they'll launch booster 4/ship 20, because it's all basically ready anyway, and they have no reason not to do it.  There's lots to learn from B4 in terms of control electronics, confirming aerodynamic models, confirming that stage 0 works, etc. Beyond that though, there's no reason to finish off B5 if they won't learn much from it, and a raptor 2 based booster is going to be ready in short order.

It may or may not be that they underestimated how long said raptor 2 based booster would take to be ready though.
Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: Vettedrmr on 12/12/2021 11:57 am
Based on SpaceX's record, I don't think there's much of any chance that B4/S20 will fly.  They've shown quite a willingness to take perfectly flyable vehicles and scrap them at a moment's notice, and I've never heard of SpaceX having any hint of regret at doing so.

Also "test as you fly" doesn't really apply to flying versions that are already obsolete.

Have a good one,
Mike
Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: Okie_Steve on 12/12/2021 01:29 pm
Based on SpaceX's record, I don't think there's much of any chance that B4/S20 will fly.  They've shown quite a willingness to take perfectly flyable vehicles and scrap them at a moment's notice, and I've never heard of SpaceX having any hint of regret at doing so.

Also "test as you fly" doesn't really apply to flying versions that are already obsolete.

Have a good one,
Mike

^What Mike said. If anything I would expect them to fly B5/S21 instead of B4/S20 since B6 is a test tank, B7 was cancelled and B8 will be a while building. B5 is the most recent extant air frame if they want to fly a ship orbital-ish in the near term assuming FAA approval is pending sooner rather than later.
Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: Genial Precis on 12/12/2021 01:51 pm
Conversely, if they've partially built and scrapped B7 it might indicate some relatively important improvement. If they launch in Jan I would expect them to use B5 but if they slip into Feb I would expect the booster to be B8. Or maybe they'll finish B8 sooner and launch B8 in Jan. S21 has been around long enough that I expect them to launch it or even a later article.

B4 and S20 are probably overtaken by events--they might have launched it if the tower and mount and approval had been ready by now, but in the mean time they've built new stuff that probably makes B4 and S20 look like old clunkers. Imagine if some tiles popped off S20 on launch--it would be a much more useful test if they actually got to re-entry before the TPS started breaking or not breaking.
Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: rakaydos on 12/12/2021 01:54 pm
This is a common misconception, serial number does not equal the number of engines produced, just as the starship serial number does not equal the number of prototypes produced.

However, their production rate as of May 2021 was about 1 Raptor every 48 hours,
That's what Elon was told, anyway. Wasnt the person in charge of that fired?
Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: wannamoonbase on 12/12/2021 02:21 pm
Based on SpaceX's record, I don't think there's much of any chance that B4/S20 will fly.  They've shown quite a willingness to take perfectly flyable vehicles and scrap them at a moment's notice, and I've never heard of SpaceX having any hint of regret at doing so.

Also "test as you fly" doesn't really apply to flying versions that are already obsolete.

Have a good one,
Mike

^What Mike said. If anything I would expect them to fly B5/S21 instead of B4/S20 since B6 is a test tank, B7 was cancelled and B8 will be a while building. B5 is the most recent extant air frame if they want to fly a ship orbital-ish in the near term assuming FAA approval is pending sooner rather than later.

Except that, B4 and S20 are at the launch site and have the engines installed.  I think they will fly unless there is a mechanical/structural reason for them not to fly.

B5 and S21 may wait and see if B4/S20 need to stand down, or if they fly and show there is a benefit to more flights.

If we are waiting for B8 and Raptor 2 weíd be waiting a long time for Raptor 2 testing and 33 engines for B8.

May as well fly the B4 and B5 sets.

Edit: If B4 doesnít fly, there is plenty of use for it to prove out the ground systems and some static fires.
Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: capoman on 12/12/2021 02:59 pm
This is a common misconception, serial number does not equal the number of engines produced, just as the starship serial number does not equal the number of prototypes produced.

However, their production rate as of May 2021 was about 1 Raptor every 48 hours,
That's what Elon was told, anyway. Wasnt the person in charge of that fired?

That may be the case with Raptor 1, but it sounds like they are trying to ramp up V2 which changes everything. We donít have a lot of public detail on this, though.
Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: Hyperus on 12/12/2021 03:10 pm
That's what Elon was told, anyway. Wasnt the person in charge of that fired?
I doubt thats what he was told, he would know how many are being built first hand.
Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: Chris Bergin on 12/12/2021 06:57 pm
This is a common misconception, serial number does not equal the number of engines produced, just as the starship serial number does not equal the number of prototypes produced.

However, their production rate as of May 2021 was about 1 Raptor every 48 hours,
That's what Elon was told, anyway. Wasnt the person in charge of that fired?

If it helps, as much as a number of folk departed, Lee Rosen was absolutely not fired. He came to the natural end of his 10 year stint after deciding on 10 years when he left the Air Force in 2011.
Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: Robotbeat on 12/12/2021 07:41 pm
This is a common misconception, serial number does not equal the number of engines produced, just as the starship serial number does not equal the number of prototypes produced.

However, their production rate as of May 2021 was about 1 Raptor every 48 hours,
That's what Elon was told, anyway. Wasnt the person in charge of that fired?

If it helps, as much as a number of folk departed, Lee Rosen was absolutely not fired. He came to the natural end of his 10 year stint after deciding on 10 years when he left the Air Force in 2011.
Man, thatís super helpful. A rumor goes around the world before the truth gets its trousers onÖ
Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: meekGee on 12/12/2021 08:39 pm
This is a common misconception, serial number does not equal the number of engines produced, just as the starship serial number does not equal the number of prototypes produced.

However, their production rate as of May 2021 was about 1 Raptor every 48 hours,
That's what Elon was told, anyway. Wasnt the person in charge of that fired?

If it helps, as much as a number of folk departed, Lee Rosen was absolutely not fired. He came to the natural end of his 10 year stint after deciding on 10 years when he left the Air Force in 2011.
Thanks.  And people also forget that R2 is still part of the current Raptor dynasty.
Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: Nescio Erucis on 12/12/2021 09:05 pm
Apart from the general environmental review that's ongoing, don't they need special FAA approval for each launch? And isn't that approval based on the particulars of the hardware that's being used?
In which case, once they are close to getting approval on a specific flight, it seems it may be worth their while to not change up the hardware too much, thereby causing the FAA people to start the whole launch/flight assessment all over again.
Not sure if this applies to B4 or 5 necessarily, but I don't think SpaceX can just bring out a new Booster prototype and launch it whenever they want (assuming the environmental assessment is OK) -- all the hardware details have to be analyzed by the FAA, which is going to take a certain amount of time.
Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: DecoLV on 12/12/2021 09:31 pm
It's one thing to progressively advance the state of the art. But it is something else to rush pell-mell at such speed that a new interation of hardware is declared obsolete before it is finished. Why is all the time and expense on Raptor 1 engines being discarded? Why bother to fly  Booster 4 if before it flies SpaceX has already decided the Raptor 1 engine design won't be used going forward? At this rate Raptor 2 will also never fly because Raptor 3 will be invented first. And the moment 3 starts being designed Elon will announce 4, then 5, and then 6, with new engines and boosters every week, then every day. Hardware is already being built and discarded, such as Ship 16 and Booster 3. This is insanity!! Starship system is not even proven yet. If I were a prospective customer, such as the USG, I might back away from SpaceX due to not knowing what I was buying. This is crazy.
Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: WiresMN on 12/12/2021 10:02 pm
It's one thing to progressively advance the state of the art. But it is something else to rush pell-mell at such speed that a new interation of hardware is declared obsolete before it is finished. Why is all the time and expense on Raptor 1 engines being discarded? Why bother to fly  Booster 4 if before it flies SpaceX has already decided the Raptor 1 engine design won't be used going forward? At this rate Raptor 2 will also never fly because Raptor 3 will be invented first. And the moment 3 starts being designed Elon will announce 4, then 5, and then 6, with new engines and boosters every week, then every day. Hardware is already being built and discarded, such as Ship 16 and Booster 3. This is insanity!! Starship system is not even proven yet. If I were a prospective customer, such as the USG, I might back away from SpaceX due to not knowing what I was buying. This is crazy.

You don't fly raptor 1 if you know or strongly suspect there is a problem and fixing it will take longer than bringing raptor 2 online. SpaceX is not one yo fall for sunk cost fallacy. SpaceX is also not one for perfect when good enough will do. Do I have no fear of ghem waiting until raptor x.

Note I have no insider information and am only suggesting why you may not fly raptor 1 a d wait for raptor 2.
Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: meekGee on 12/12/2021 10:10 pm
It's one thing to progressively advance the state of the art. But it is something else to rush pell-mell at such speed that a new interation of hardware is declared obsolete before it is finished. Why is all the time and expense on Raptor 1 engines being discarded? Why bother to fly  Booster 4 if before it flies SpaceX has already decided the Raptor 1 engine design won't be used going forward? At this rate Raptor 2 will also never fly because Raptor 3 will be invented first. And the moment 3 starts being designed Elon will announce 4, then 5, and then 6, with new engines and boosters every week, then every day. Hardware is already being built and discarded, such as Ship 16 and Booster 3. This is insanity!! Starship system is not even proven yet. If I were a prospective customer, such as the USG, I might back away from SpaceX due to not knowing what I was buying. This is crazy.

I so wish that the company I work at would have had the ability to discard the current prototype line and move already to what we know is the next step.

What you're so alarmed about is exactly precisely the sunk cost fallacy.  "We invested so much in Rev 1.0, we can't just discard it without first flying it".

Musk's thinking is: "Rev 1.0 taught us enough to already establish rev 2.0, so it has served its purpose.  Best is to shift all resources to rev 2.0 and learn from it".

I'm glad he has the financial backing to accomplish that - partly a result of having followed this same line of thinking before.
Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: Coastal Ron on 12/12/2021 10:21 pm
It's one thing to progressively advance the state of the art. But it is something else to rush pell-mell at such speed that a new interation of hardware is declared obsolete before it is finished.

First of all, SpaceX is not trying to "advance the state of the art", they are trying to build a first generation fully reusable space transportation system. And they perfectly fine in using technology that is NOT new, but for what they are doing there is no roadmap, so they have to make a bunch of guesses and try them out.

However even though Starship production is fast compared to other large flying things, it is slow enough that sometimes significant changes will obsolete what they have in production. This happens a lot in the manufacturing world (where I've been a factory scheduling manager), but the scale of what SpaceX is doing makes obsolescence more noticeable.

Quote
Why is all the time and expense on Raptor 1 engines being discarded?

Obviously the knowledge gained with Raptor 1 engines is not being discarded, but again, when you are building something new it is not unusual to have to scrap a bunch of early prototypes - SpaceX just does that on a larger scale.

Quote
Why bother to fly  Booster 4 if before it flies SpaceX has already decided the Raptor 1 engine design won't be used going forward?

Not sure we know for sure if Booster 4 will actually fly, but it is likely they will use it for testing. And testing is VERY important, so it is not like they won't get any use out of Booster 4, but it could be that significant changes have been made on Booster 5 (and beyond) that make it clear flying Booster 4 will not be worth the time and money.

Quote
At this rate Raptor 2 will also never fly because Raptor 3 will be invented first.

Let's give Elon Musk and the SpaceX employees a little credit, huh? This is NOT their first rocket development program, so they understand what their goals are, and what their challenges are. We only see what makes it into public view, which is likely only a very small part of the picture.

Quote
This is insanity!! Starship system is not even proven yet. If I were a prospective customer, such as the USG, I might back away from SpaceX due to not knowing what I was buying. This is crazy.

Calm down, NASA and other potential customers know what SpaceX is doing, and they are more likely thrilled than concerned. Why thrilled? Because of the rapid pace of development that doesn't cost customers like NASA any money, yet could yield a space transportation system that will truly be revolutionary.

So we all need to be more like observers rather than critics, since we don't see everything that SpaceX is dealing with, we only see the aftermath of their decisions and guesses. And as a taxpayer, none of what they are doing costs me any money, so I tend to view it as entertainment...  :D
Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: DanClemmensen on 12/12/2021 10:27 pm
It's one thing to progressively advance the state of the art. But it is something else to rush pell-mell at such speed that a new interation of hardware is declared obsolete before it is finished. Why is all the time and expense on Raptor 1 engines being discarded? Why bother to fly  Booster 4 if before it flies SpaceX has already decided the Raptor 1 engine design won't be used going forward? At this rate Raptor 2 will also never fly because Raptor 3 will be invented first. And the moment 3 starts being designed Elon will announce 4, then 5, and then 6, with new engines and boosters every week, then every day. Hardware is already being built and discarded, such as Ship 16 and Booster 3. This is insanity!! Starship system is not even proven yet. If I were a prospective customer, such as the USG, I might back away from SpaceX due to not knowing what I was buying. This is crazy.

You don't fly raptor 1 if you know or strongly suspect there is a problem and fixing it will take longer than bringing raptor 2 online. SpaceX is not one yo fall for sunk cost fallacy. SpaceX is also not one for perfect when good enough will do. Do I have no fear of ghem waiting until raptor x.

Note I have no insider information and am only suggesting why you may not fly raptor 1 a d wait for raptor 2.

If essentially everything including the Raptors will be scrapped, then it might make sense to go ahead and fly SN20/BN4, if there is anything at all to be learned and if there is a reasonable chance that it will at least clear the pad. Having the SS and the SH land in nice deep water may be cheapest way to scrap them.
Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: Okie_Steve on 12/12/2021 10:37 pm
All the GSE, what Musk calls "Stage 0", needs testing. I do not know, but even if they have decided that B4 will not fly it ought to make a dandy ground test item up to and possiby including static firing all 29(?) Booster engines to collect data on things like how well the water deluge works compared to modeling as a baseline.

Assuming the QDC is not one of the things that changed with B5 or later of course.
Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: WiresMN on 12/12/2021 10:42 pm
It's one thing to progressively advance the state of the art. But it is something else to rush pell-mell at such speed that a new interation of hardware is declared obsolete before it is finished. Why is all the time and expense on Raptor 1 engines being discarded? Why bother to fly  Booster 4 if before it flies SpaceX has already decided the Raptor 1 engine design won't be used going forward? At this rate Raptor 2 will also never fly because Raptor 3 will be invented first. And the moment 3 starts being designed Elon will announce 4, then 5, and then 6, with new engines and boosters every week, then every day. Hardware is already being built and discarded, such as Ship 16 and Booster 3. This is insanity!! Starship system is not even proven yet. If I were a prospective customer, such as the USG, I might back away from SpaceX due to not knowing what I was buying. This is crazy.

You don't fly raptor 1 if you know or strongly suspect there is a problem and fixing it will take longer than bringing raptor 2 online. SpaceX is not one yo fall for sunk cost fallacy. SpaceX is also not one for perfect when good enough will do. Do I have no fear of ghem waiting until raptor x.

Note I have no insider information and am only suggesting why you may not fly raptor 1 a d wait for raptor 2.

If essentially everything including the Raptors will be scrapped, then it might make sense to go ahead and fly SN20/BN4, if there is anything at all to be learned and if there is a reasonable chance that it will at least clear the pad. Having the SS and the SH land in nice deep water may be cheapest way to scrap them.

No you don't. If they learned what they needed or will learn from with ground testing.  Anything else is a distraction to the main goal. A rapid fully reusable system.
Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: AC in NC on 12/12/2021 10:51 pm
It's one thing to progressively advance the state of the art. But it is something else to rush pell-mell at such speed that a new interation of hardware is declared obsolete before it is finished. Why is all the time and expense on Raptor 1 engines being discarded? Why bother to fly  Booster 4 if before it flies SpaceX has already decided the Raptor 1 engine design won't be used going forward? At this rate Raptor 2 will also never fly because Raptor 3 will be invented first. And the moment 3 starts being designed Elon will announce 4, then 5, and then 6, with new engines and boosters every week, then every day. Hardware is already being built and discarded, such as Ship 16 and Booster 3. This is insanity!! Starship system is not even proven yet. If I were a prospective customer, such as the USG, I might back away from SpaceX due to not knowing what I was buying. This is crazy.
There is literally nothing about this post that is informed by an understanding of how SpaceX operates or why iterations become obsolete.  100% FUD.
Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: xvel on 12/12/2021 10:55 pm
It's one thing to progressively advance the state of the art. But it is something else to rush pell-mell at such speed that a new interation of hardware is declared obsolete before it is finished. Why is all the time and expense on Raptor 1 engines being discarded? Why bother to fly  Booster 4 if before it flies SpaceX has already decided the Raptor 1 engine design won't be used going forward? At this rate Raptor 2 will also never fly because Raptor 3 will be invented first. And the moment 3 starts being designed Elon will announce 4, then 5, and then 6, with new engines and boosters every week, then every day. Hardware is already being built and discarded, such as Ship 16 and Booster 3. This is insanity!! Starship system is not even proven yet. If I were a prospective customer, such as the USG, I might back away from SpaceX due to not knowing what I was buying. This is crazy.

I will ask one question: Why not?
Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: Redclaws on 12/12/2021 11:07 pm
It's one thing to progressively advance the state of the art. But it is something else to rush pell-mell at such speed that a new interation of hardware is declared obsolete before it is finished. Why is all the time and expense on Raptor 1 engines being discarded? Why bother to fly  Booster 4 if before it flies SpaceX has already decided the Raptor 1 engine design won't be used going forward? At this rate Raptor 2 will also never fly because Raptor 3 will be invented first. And the moment 3 starts being designed Elon will announce 4, then 5, and then 6, with new engines and boosters every week, then every day. Hardware is already being built and discarded, such as Ship 16 and Booster 3. This is insanity!! Starship system is not even proven yet. If I were a prospective customer, such as the USG, I might back away from SpaceX due to not knowing what I was buying. This is crazy.
There is literally nothing about this post that is informed by an understanding of how SpaceX operates or why iterations become obsolete.  100% FUD.

I donít think itís FUD; but I do think itís silly - itís exactly the logical trap that Elon works so hard to avoid.  Sunk cost fallacy, and fear of throwing away progress in search of something better (which isnít quite the same thing).

Itís shocking to watch sometimes, and if you havenít followed SpaceX, it could look like the kind of ADD style behavior that results in nothing shipping or is even the modus operandi of a certain style of (basically) scam startup.

But none of these apply to SpaceX.  Theyíve delivered a *lot*, and NASA expects them to continue doing so.  Which is pretty incredible if you think about it - reaching constantly for more while still making tangible progress is a pretty remarkable feat.
Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: Herb Schaltegger on 12/12/2021 11:13 pm
Fortunately, the only people Elon has to answer to about SpaceX are his investors, his customers, and US government regulators, not randos on internet forums.
Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: AC in NC on 12/12/2021 11:14 pm
I donít think itís FUD; but I do think itís silly - itís exactly the logical trap that Elon works so hard to avoid.  Sunk cost fallacy, and fear of throwing away progress in search of something better (which isnít quite the same thing).
If it were just Sunk Cost Fallacy you might be right.  You can tell it's 100% FUD with the hyperventilating and the nonsense about nothing ever flying because they are iterating new Raptors and Boosters on weekly and then daily basis.
Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: Surfdaddy on 12/12/2021 11:26 pm
It's one thing to progressively advance the state of the art. But it is something else to rush pell-mell at such speed that a new interation of hardware is declared obsolete before it is finished. Why is all the time and expense on Raptor 1 engines being discarded? Why bother to fly  Booster 4 if before it flies SpaceX has already decided the Raptor 1 engine design won't be used going forward? At this rate Raptor 2 will also never fly because Raptor 3 will be invented first. And the moment 3 starts being designed Elon will announce 4, then 5, and then 6, with new engines and boosters every week, then every day. Hardware is already being built and discarded, such as Ship 16 and Booster 3. This is insanity!! Starship system is not even proven yet. If I were a prospective customer, such as the USG, I might back away from SpaceX due to not knowing what I was buying. This is crazy.

Of course the mostly opposite of that is the Space Shuttle which was significantly unchanged for 30 years due to the Waterfall method of HW development and timidity to change, versus the Agile method of development. And we know what a seriously flawed vehicle the Shuttle was. Imagine if they could have iterated a bit to improve all of the weak areas before astronauts died.
Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: Kazioo on 12/13/2021 02:10 am
It's one thing to progressively advance the state of the art. But it is something else to rush pell-mell at such speed that a new interation of hardware is declared obsolete before it is finished. Why is all the time and expense on Raptor 1 engines being discarded? Why bother to fly  Booster 4 if before it flies SpaceX has already decided the Raptor 1 engine design won't be used going forward? At this rate Raptor 2 will also never fly because Raptor 3 will be invented first. And the moment 3 starts being designed Elon will announce 4, then 5, and then 6, with new engines and boosters every week, then every day. Hardware is already being built and discarded, such as Ship 16 and Booster 3. This is insanity!! Starship system is not even proven yet. If I were a prospective customer, such as the USG, I might back away from SpaceX due to not knowing what I was buying. This is crazy.
There is literally nothing about this post that is informed by an understanding of how SpaceX operates or why iterations become obsolete.  100% FUD.

I donít think itís FUD; but I do think itís silly - itís exactly the logical trap that Elon works so hard to avoid.  Sunk cost fallacy, and fear of throwing away progress in search of something better (which isnít quite the same thing).

The funny thing is none of the examples he mentioned are sunk cost or a waste and he failed to point out an actual blunder SpaceX made: the carbon fiber prototype work. They had a big expensive mandrel and they wasted time and millions of dollars on it. That was the sunk cost fallacy Elon didn't want to make.

BUT Raptor 1, Ship 16 and Booster 3 not flying were NOT wasted resources. This is where OP doesn't understand how prototyping or research and development work. Raptor especially generated tons of data. He would probably be shocked that electronics companies can sometimes make  large amounts of prototypes of eg. a new type of gaming controller. And some are discarded very early without even being properly tested.

OP also doesn't understand that production system of Starship is one of the biggest challenges (Elon even claims that it's more difficult than making Starship work), so the methods of building hardware are part of the prototyping progress, which means that even trashing a fresh hardware right after making it, without even testing, is NOT necessarily a waste if it resulted in changes in the build system. And we have photos and videos documenting that this happens often at Starbase.

A good analogy might be injection molding for plastic products - releasing a well made design often requires multiple iterations of expensive changes to the molds. Sometimes the mold has to be replaced with a different one and the old ones are discarded before the actual production even starts. They are declared obsolete before the prototype turns into final product. Insanity!
Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: su27k on 12/13/2021 03:24 am
This is a common misconception, serial number does not equal the number of engines produced, just as the starship serial number does not equal the number of prototypes produced.

However, their production rate as of May 2021 was about 1 Raptor every 48 hours,
That's what Elon was told, anyway. Wasnt the person in charge of that fired?

If it helps, as much as a number of folk departed, Lee Rosen was absolutely not fired. He came to the natural end of his 10 year stint after deciding on 10 years when he left the Air Force in 2011.

I think it should also be pointed out that Lee Rosen is VP of mission and launch operations. Just goes by his title, he's probably not in charge of Raptor in any shape or form.

The person rakaydos may be referring to is Will Heltsley, VP of propulsion. Per CNBC (https://www.cnbc.com/2021/11/22/elon-musks-spacex-leadership-shakes-up-as-two-vps-depart.html,) "Heltsley was taken off Raptor engine development due to a lack of progress."
Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: Chris Bergin on 12/13/2021 12:30 pm
Just because I was getting DMs....the rumor on reddit about Booster 4 not flying and being just for ground testing is from someone who works at Nextspaceflight, not NASASpaceflight (and not even Michael Baylor at nextspaceflight). I think the whole "NSF" thing got confused. I have no data on how reliable that poster is, although a number say he's hit and miss, so YMMV.

Hardly beyond the realm of the possible path forward too, but not us, per the reason for the post. Something we'll likely know for sure in the weeks to come.

PS Blame that Chris B for picking the site name. Should have gone with ShuttleSpaceFlight.con ;) (Nearly did, oof!)
Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: Florian F on 12/13/2021 02:16 pm
On 12/13/21, at 05:22-05:24, on Rover Cam, you can see the QD "socket" retract and the hood close.
Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: alugobi on 12/13/2021 03:57 pm
^^^Note that that is the UTC time stamp, not Texas time.
Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: clongton on 12/13/2021 04:10 pm
Why is all the time and expense on Raptor 1 engines being discarded?

It is absolutely NOT being discarded. They know how to do what they need to do for Raptor 2 BECAUSE of the time and expense of Raptor 1.
Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: seb21051 on 12/13/2021 04:40 pm
I suspect they may be concentrating on making the engines more reliable and manufacturable, even if it means stepping back on performance. This may impact B5, since it probably only has a 29 engine thrustpuck, and they may need to increase the number of engines to 31 or 33 to have sufficient TWR to lift the stack reliably and with enough redundancy. Thus it would not surprise me if they are building B6 with a different thrustpuck.
Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: xvel on 12/13/2021 04:48 pm
I suspect they may be concentrating on making the engines more reliable and manufacturable, even if it means stepping back on performance. This may impact B5, since it probably only has a 29 engine thrustpuck, and they may need to increase the number of engines to 31 or 33 to have sufficient TWR to lift the stack reliably and with enough redundancy. Thus it would not surprise me if they are building B6 with a different thrustpuck.

For starship to work it needs 33 230t engines which are fast to manufacture reliable and cheap, they have no margins to work around, that's the whole point.
Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: daveglo on 12/13/2021 07:12 pm
https://twitter.com/BocaChicaGal/status/1470456662083477510

Observationally, I'd say the chopsticks are NOT going to be in play for this testing iteration on Booster 4.  Unless they pick the booster back up and swing out of the way to allow the east (right?) chopstick to get on the correct side of the booster.
Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: seb21051 on 12/13/2021 07:19 pm
May just be an optical illusion, but the QD arm seems somewhat low to be able to connect to SS on this photo.
Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: eriblo on 12/13/2021 07:26 pm
[...]
Observationally, I'd say the chopsticks are NOT going to be in play for this testing iteration on Booster 4.  Unless they pick the booster back up and swing out of the way to allow the east (right?) chopstick to get on the correct side of the booster.
Once the scaffolding is removed and the chopsticks are ready to move they can go up and over B4.
Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: eriblo on 12/13/2021 07:32 pm
May just be an optical illusion, but the QD arm seems somewhat low to be able to connect to SS on this photo.
That is just the angle, check the long distance views - it is quite clear that the grabby arms will go beneath the grid fins and that the Starship/GSE QD sits well above the Superheavy/Starship interface.
Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: wannamoonbase on 12/13/2021 07:58 pm
I am very excited for SpaceX to kick off the ground testing for Superheavy.

This is the booster the world has needed for decades.

Even if B4 doesn't fly, there is a lot of testing and system proving out the OLS and the booster.

Just learning how to fuel Heavy, and later a full stack with Starship is no small challenge. 

Hopefully we get into a series of static fires soon-ish too. 
Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: Lars-J on 12/13/2021 07:59 pm
May just be an optical illusion, but the QD arm seems somewhat low to be able to connect to SS on this photo.

The booster was still hanging quite a bit above the launch mount in this picture. That - and the perspective - makes it seem further down than it is. The QD arm will connect at the SH and SS connection point.
Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: Lars-J on 12/13/2021 08:09 pm
The addition of an engine skirt (not yet complete) was expected, it does change the look quite a bit. (I attached a pre- and post-skirt photo for comparison)
Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: Lars-J on 12/13/2021 08:14 pm
For those that are wondering how in the world the booster sits on the pad, I highlighted the assumed load bearing points in red, with a quick outline of how the support structure holds it. (The 22 20 arms retract at liftoff)
Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: daavery on 12/13/2021 08:31 pm
For those that are wondering how in the world the booster sits on the pad, I highlighted the assumed load bearing points in red, with a quick outline of how the support structure holds it. (The 22 arms retract at liftoff)

only 20 arms
Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: WiresMN on 12/13/2021 08:37 pm
OceanCam on you tube had a great video of it and from an angle I had not seen. You also get a good view of the outer ring engine start up attachment.
I have attached a snip from the video.

Source: OceanCam on YouTube. See Link below:
https://youtu.be/lnv_27mCr1c (https://youtu.be/lnv_27mCr1c)
Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: OTV Booster on 12/13/2021 09:17 pm
It's one thing to progressively advance the state of the art. But it is something else to rush pell-mell at such speed that a new interation of hardware is declared obsolete before it is finished. Why is all the time and expense on Raptor 1 engines being discarded? Why bother to fly  Booster 4 if before it flies SpaceX has already decided the Raptor 1 engine design won't be used going forward? At this rate Raptor 2 will also never fly because Raptor 3 will be invented first. And the moment 3 starts being designed Elon will announce 4, then 5, and then 6, with new engines and boosters every week, then every day. Hardware is already being built and discarded, such as Ship 16 and Booster 3. This is insanity!! Starship system is not even proven yet. If I were a prospective customer, such as the USG, I might back away from SpaceX due to not knowing what I was buying. This is crazy.
There are at least two different types of improvement. Tech and process. The technical differences between BN 4&5 are most probably minimal. Most tech improvements come from testing. BN4 hasn't flown so what would they change?


Process changes are how it's built. Things like (speculative examples here) the installation order of internal bits. Maybe more carefully thought out aero covers. Maybe some repositioning of engine bay hardware the facilitate engine install/removal. The first one built informs the second without flying.


If 5 has process changes over 4, and they're both available for flight, why fly the old one? Same holds for SS.


Elon said SN24 would have major changes. This may (speculation) slip to 25 or 26. Again speculating, this would be things like repositioned front fins or mountings for Raptor 2 and iterative lessons from all launches leading up to it. This is all tech and well thought out within the limits of fast iteration.


Something to look for is R2. The assumption seems to be that it will be a forklift. Doesn't have to be. Maybe start with the outer ring on BN, then, as production ramps up, do the gymbal version and start with three on SS.


Stay tuned and DON'T PANIC.
Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: OTV Booster on 12/13/2021 09:30 pm
The addition of an engine skirt (not yet complete) was expected, it does change the look quite a bit. (I attached a pre- and post-skirt photo for comparison)
Ummm, a lot of plumbing still sticking out. Any chance there will be Art Deco blisters over the plumbing? It really is Elon's style.
Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: Lars-J on 12/13/2021 09:36 pm
The addition of an engine skirt (not yet complete) was expected, it does change the look quite a bit. (I attached a pre- and post-skirt photo for comparison)
Ummm, a lot of plumbing still sticking out. Any chance there will be Art Deco blisters over the plumbing? It really is Elon's style.

Yes, there will presumably be covers over the remaining visible piping.
Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: oldAtlas_Eguy on 12/13/2021 10:05 pm
The addition of an engine skirt (not yet complete) was expected, it does change the look quite a bit. (I attached a pre- and post-skirt photo for comparison)
Ummm, a lot of plumbing still sticking out. Any chance there will be Art Deco blisters over the plumbing? It really is Elon's style.

Yes, there will presumably be covers over the remaining visible piping.
Doesn't have to be. The frame is for a solid cover across the bottom to protect the engines from the return back into the atmosphere engine end first. That bottom cover flares out such that not much air flow impinges on that piping. Meaning covers are not required. Also the engine start quick disconnects have to attach to the engines and a cover causes problems with that.
Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: Lars-J on 12/13/2021 10:08 pm
The addition of an engine skirt (not yet complete) was expected, it does change the look quite a bit. (I attached a pre- and post-skirt photo for comparison)
Ummm, a lot of plumbing still sticking out. Any chance there will be Art Deco blisters over the plumbing? It really is Elon's style.

Yes, there will presumably be covers over the remaining visible piping.
Doesn't have to be. The frame is for a solid cover across the bottom to protect the engines from the return back into the atmosphere engine end first. That bottom cover flares out such that not much air flow impinges on that piping. Meaning covers are not required. Also the engine start quick disconnects have to attach to the engines and a cover causes problems with that.
Are you just playing devils advocate, or would actually bet on no covers? I personally believe there is no chance it will fly without covers of the exposed piping.

I assume you have seen how recirculation affects the engine section during ascent, and how toast the engine section sides look after landing. No Merlin piping is exposed.
Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: oldAtlas_Eguy on 12/13/2021 10:44 pm
The addition of an engine skirt (not yet complete) was expected, it does change the look quite a bit. (I attached a pre- and post-skirt photo for comparison)
Ummm, a lot of plumbing still sticking out. Any chance there will be Art Deco blisters over the plumbing? It really is Elon's style.

Yes, there will presumably be covers over the remaining visible piping.
Doesn't have to be. The frame is for a solid cover across the bottom to protect the engines from the return back into the atmosphere engine end first. That bottom cover flares out such that not much air flow impinges on that piping. Meaning covers are not required. Also the engine start quick disconnects have to attach to the engines and a cover causes problems with that.
Are you just playing devils advocate, or would actually bet on no covers? I personally believe there is no chance it will fly without covers of the exposed piping.

I assume you have seen how recirculation affects the engine section during ascent, and how toast the engine section sides look after landing. No Merlin piping is exposed.
Unfortunately it is only a guess at this point but is based on the fact we have yet to see any covers anywhere at Starbase. Also equating one vehicle air flow conditions to another is not a good thing to assume. Always model extensively and as well test to validate models. Shapes between SH and F9 are very different at the engine section so any assumptions made based on another vehicle are highly likely wrong.
Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: cdebuhr on 12/14/2021 12:04 am
The addition of an engine skirt (not yet complete) was expected, it does change the look quite a bit. (I attached a pre- and post-skirt photo for comparison)
Ummm, a lot of plumbing still sticking out. Any chance there will be Art Deco blisters over the plumbing? It really is Elon's style.

Yes, there will presumably be covers over the remaining visible piping.
Doesn't have to be. The frame is for a solid cover across the bottom to protect the engines from the return back into the atmosphere engine end first. That bottom cover flares out such that not much air flow impinges on that piping. Meaning covers are not required. Also the engine start quick disconnects have to attach to the engines and a cover causes problems with that.
Are you just playing devils advocate, or would actually bet on no covers? I personally believe there is no chance it will fly without covers of the exposed piping.

I assume you have seen how recirculation affects the engine section during ascent, and how toast the engine section sides look after landing. No Merlin piping is exposed.
Unfortunately it is only a guess at this point but is based on the fact we have yet to see any covers anywhere at Starbase. Also equating one vehicle air flow conditions to another is not a good thing to assume. Always model extensively and as well test to validate models. Shapes between SH and F9 are very different at the engine section so any assumptions made based on another vehicle are highly likely wrong.
I'm pretty sure I remember an Elon quote a while back talking about "close out covers" to be installed over the exposed bits, So I assume were going to see covers.
Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: Yiosie on 12/14/2021 02:02 am
The addition of an engine skirt (not yet complete) was expected, it does change the look quite a bit. (I attached a pre- and post-skirt photo for comparison)
Ummm, a lot of plumbing still sticking out. Any chance there will be Art Deco blisters over the plumbing? It really is Elon's style.

Yes, there will presumably be covers over the remaining visible piping.
Doesn't have to be. The frame is for a solid cover across the bottom to protect the engines from the return back into the atmosphere engine end first. That bottom cover flares out such that not much air flow impinges on that piping. Meaning covers are not required. Also the engine start quick disconnects have to attach to the engines and a cover causes problems with that.
Are you just playing devils advocate, or would actually bet on no covers? I personally believe there is no chance it will fly without covers of the exposed piping.

I assume you have seen how recirculation affects the engine section during ascent, and how toast the engine section sides look after landing. No Merlin piping is exposed.
Unfortunately it is only a guess at this point but is based on the fact we have yet to see any covers anywhere at Starbase. Also equating one vehicle air flow conditions to another is not a good thing to assume. Always model extensively and as well test to validate models. Shapes between SH and F9 are very different at the engine section so any assumptions made based on another vehicle are highly likely wrong.
I'm pretty sure I remember an Elon quote a while back talking about "close out covers" to be installed over the exposed bits, So I assume were going to see covers.

Yup, in this tweet:

https://twitter.com/elonmusk/status/1460813037670219778
Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: gsa on 12/14/2021 01:00 pm
The addition of an engine skirt (not yet complete) was expected, it does change the look quite a bit. (I attached a pre- and post-skirt photo for comparison)
Ummm, a lot of plumbing still sticking out. Any chance there will be Art Deco blisters over the plumbing? It really is Elon's style.

Yes, there will presumably be covers over the remaining visible piping.
Doesn't have to be. The frame is for a solid cover across the bottom to protect the engines from the return back into the atmosphere engine end first. That bottom cover flares out such that not much air flow impinges on that piping. Meaning covers are not required. Also the engine start quick disconnects have to attach to the engines and a cover causes problems with that.
Are you just playing devils advocate, or would actually bet on no covers? I personally believe there is no chance it will fly without covers of the exposed piping.

I assume you have seen how recirculation affects the engine section during ascent, and how toast the engine section sides look after landing. No Merlin piping is exposed.
Unfortunately it is only a guess at this point but is based on the fact we have yet to see any covers anywhere at Starbase. Also equating one vehicle air flow conditions to another is not a good thing to assume. Always model extensively and as well test to validate models. Shapes between SH and F9 are very different at the engine section so any assumptions made based on another vehicle are highly likely wrong.
Please look at the photo from this tweet:
https://twitter.com/StarshipGazer/status/1451591311312789515
When viewing at full resolution you can see series of holes along the vertical edge of the cover. Couldn't find any publicly available hi-res with all covers installed but these holes exist along all edges. I assume they are for closeout panels.
Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: JimTheBeet on 12/14/2021 01:24 pm
I was sort of expecting 1 large aero cover for all the engines, but looking at the holes around each exposed section, it seems there'll be many smaller sections. I have a hunch it'll make it look pretty cool - no clue as to the advantages/disadvantages aerodynamically though. Looking at the conical (is that the right word?) skirt and the two-tiered engine layout, I can't help but think of another similar rocket... hopefully B4 fares much better!  ;)
Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: Oersted on 12/14/2021 01:59 pm
They're going to go with this style (Waco engine cowling) and it is going to look fabulous:

(Credit: https://www.flickr.com/photos/brraveheart/2263638075)

Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: mpusch on 12/14/2021 03:14 pm
Interesting thought.  Per @_brendan_lewis, progress on B7 has been minimal over the last month, and we have seen SpaceX do this with SN16/SN17 after SN15's success.  It would not be surprising for SpaceX to use the most up to date build specs for the orbital launch test vehicle.  Though it would definitely make a launch by February less likely

https://twitter.com/Matt_Lowne/status/1470371712407687175

He's just repeating information that was bouncing around on Reddit (which may or may not be correct). I doubt Matt has any actual updates himself.
Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: Tangilinear Interjar on 12/14/2021 03:15 pm
[...]
Observationally, I'd say the chopsticks are NOT going to be in play for this testing iteration on Booster 4.  Unless they pick the booster back up and swing out of the way to allow the east (right?) chopstick to get on the correct side of the booster.
Once the scaffolding is removed and the chopsticks are ready to move they can go up and over B4.

I think BE is going to be on the pad for a long time. Even though they didn't use the chopsticks to lift it they need a Booster to calibrate the chopsticks attachment systems as well as practice with. However there's a significant amount of work still to be done on the tower before they can do that.

I have been wondering why all the scaffolding on the tower but it might simply be for painting. I didn't think they would do that but I can't imagine why they need so much scaffolding; they haven't cleaned up the weld points yet so maybe a full coat of paint is to be applied.

The upper arm needs to be calibrated and practiced with. Not nearly as complex of a process as the chopsticks but I would imagine a handful of approach and withdrawal operations.

Also test attachment and detachment from all GSE, there's a lot of that!

However I do suspect that B4 will be removed at least once more before a test fire because I think they still have a good amount of shielding and painting to be done to the launch table as well as painting. I also think they wouldn't test the deluge system with the Booster in place.
Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: baking on 12/14/2021 03:30 pm
I was sort of expecting 1 large aero cover for all the engines, but looking at the holes around each exposed section, it seems there'll be many smaller sections. I have a hunch it'll make it look pretty cool - no clue as to the advantages/disadvantages aerodynamically though. Looking at the conical (is that the right word?) skirt and the two-tiered engine layout, I can't help but think of another similar rocket... hopefully B4 fares much better!  ;)
I can see a number of advantages.  For one, the skirt had to be set back at the top for the supports/hold-downs.  Also, individual covers allow for maintenance of the engines without taking big sections of the skirt off.

Of course, if B4 never flies we might not see covers on it, and if B8 is first to fly who knows what the design will be for that one.
Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: jstrotha0975 on 12/14/2021 04:05 pm
They're going to go with this style (Waco engine cowling) and it is going to look fabulous:

(Credit: https://www.flickr.com/photos/brraveheart/2263638075)

This is what I thought too. It will look 1930's retro.
Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: edzieba on 12/15/2021 08:24 am
I have been wondering why all the scaffolding on the tower but it might simply be for painting. I didn't think they would do that but I can't imagine why they need so much scaffolding; they haven't cleaned up the weld points yet so maybe a full coat of paint is to be applied.
Painting the tower (and other tall structures) a mutually agreed colour is part of the Section 106 MOA (https://www.faa.gov/space/environmental/nepa_docs/spacex_texas_eis/media/SpaceX_Texas_Launch_Site_MOA.pdf) that has been mentioned in some of the FAA Written Reevaluations and in the PEA.
Quote
In accordance with the MOA (Stipulation I.C), SpaceX will paint all structures above 30 feet tall a color agreed upon by the National Park Service and Texas State Historic Preservation Officer.
Even if the sections were pre-painted, touch-up would be required for weather resistance at the welded joints and any other areas where the paint was damaged in handling and installation.

There may also be some non-destructive testing going on on the columns themselves after they were filled with concrete (e.g. checking for voids).
Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: samgineer on 12/15/2021 08:46 am
I think scaffolding is there for chopstick rail calibration mainly. It  is only on rail equipped columns.
Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: Horasio on 12/15/2021 01:33 pm
Hi,

Ship 21's nosecone has a sort of mustache on its front (belly), just over the weld between the cylindrical part and the fairing: a sort of metal bar, perhaps 30cm high (≈1 foot) and 2 meters long. It's been there since the beginning and currently prevents some tiles to be installed.

Any idea of what its purpose is?

Thanks!
Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: WiresMN on 12/15/2021 01:43 pm
Hi,

Ship 21's nosecone has a sort of mustache on its front (belly), just over the weld between the cylindrical part and the fairing: a sort of metal bar, perhaps 30cm high (≈1 foot) and 2 meters long. It's been there since the beginning and currently prevents some tiles to be installed.

Any idea of what its purpose is?

Thanks!

I believe it is a weight hanger to balance the lifting load. There has  been a counter balance weight on the nose cone for the final mating lift for a while. 
Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: cdebuhr on 12/15/2021 03:17 pm
On the latest daily updates video, it seemed they were removing the lifting points from Ship 20 on the suborbital pad.  I thought the plan of record was eventually stack onto B4 for the orbital test, but without lifting points, it seems the only way to get it off the pad (in one piece anyway) is under thrust.  Anyone here have any thoughts about this? 

Edit:  For screenshots of what I'm talking about see this post: https://forum.nasaspaceflight.com/index.php?topic=54439.msg2321234#msg2321234
Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: xvel on 12/15/2021 03:22 pm
On the latest daily updates video, it seemed they were removing the lifting points from Ship 20 on the suborbital pad.  I thought the plan of record was eventually stack onto B4 for the orbital test, but without lifting points, it seems the only way to get it off the pad (in one piece anyway) is under thrust.  Anyone here have any thoughts about this? 

Edit:  For screenshots of what I'm talking about see this post: https://forum.nasaspaceflight.com/index.php?topic=54439.msg2321234#msg2321234

It has to have lifting point for lifting with chopsticks, crane they have is too short anyway to stack it on superheavy so maybe they will lift it from current pad by those lifting points with some sort of jig for the crane
Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: Vettedrmr on 12/15/2021 03:35 pm
Or, just as likely, they're done with SS20 and getting ready for SS21.
Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: cdebuhr on 12/15/2021 03:37 pm
On the latest daily updates video, it seemed they were removing the lifting points from Ship 20 on the suborbital pad.  I thought the plan of record was eventually stack onto B4 for the orbital test, but without lifting points, it seems the only way to get it off the pad (in one piece anyway) is under thrust.  Anyone here have any thoughts about this? 

Edit:  For screenshots of what I'm talking about see this post: https://forum.nasaspaceflight.com/index.php?topic=54439.msg2321234#msg2321234

It has to have lifting point for lifting with chopsticks, crane they have is too short anyway to stack it on superheavy so maybe they will lift it from current pad by those lifting points with some sort of jig for the crane
Yeah - the chopstick lifting points are still there of course, but without the crane lift points on the nose ... I guess they could use some sort of a lifting frame, but that really seems like doing it the hard way, as that's not something they should routinely need anyway.  It seems like it would have been much simpler to put this thing on a transport stand first, so it could get carted off via SPMT when the time came, no cranes required. 
Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: cdebuhr on 12/15/2021 03:40 pm
Or, just as likely, they're done with SS20 and getting ready for SS21.
Which would be all the more reason to not remove the nose lifting points.  They even seem to be patching the gaps in the TPS where the lift points were.  Unless they're planning on leaving it a permanent decoration on the suborbital pad, they need a way to pick it up ... unless they're planning a suborbital flight for Ship 20.
Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: WiresMN on 12/15/2021 04:33 pm
Or, just as likely, they're done with SS20 and getting ready for SS21.
Which would be all the more reason to not remove the nose lifting points.  They even seem to be patching the gaps in the TPS where the lift points were.  Unless they're planning on leaving it a permanent decoration on the suborbital pad, they need a way to pick it up ... unless they're planning a suborbital flight for Ship 20.

I could see them going for another hop or two if the FAA environmental assessment comes back with more work for SpaceX. Perhaps they are getting ready for that. Otherwise, they just want to to look all dressed up for the company holiday party.  :D
Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: Okie_Steve on 12/15/2021 04:52 pm
Could be as simple as wanting to practice ship "close out" while they have the time and opportunity too.
Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: StuffOfInterest on 12/15/2021 05:25 pm
Another idea, maybe they've come up with a lifting rig that can hook under the chopsticks lift points and then provide a sling for crane pickup.  Crane picks up a cross bar, ends of cross bar have long cables, and those cables end on "J" shaped hooks that go around the top fins and hook under the lift points.  This would remove the need to have tiles missing on the nose this late in the manufacturing process while still allowing them to move the Starship around without the chopsticks.
Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: xvel on 12/15/2021 05:27 pm
Another idea, maybe they've come up with a lifting rig that can hook under the chopsticks lift points and then provide a sling for crane pickup.  Crane picks up a cross bar, ends of cross bar have long cables, and those cables end on "J" shaped hooks that go around the top fins and hook under the lift points.  This would remove the need to have tiles missing on the nose this late in the manufacturing process while still allowing them to move the Starship around without the chopsticks.
it's what I said

but really we can expect anything now
Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: EL_DIABLO on 12/15/2021 07:45 pm
Does anyone have better photos of this bottom edge? Wondering if there are tiles there?
Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: eriblo on 12/15/2021 11:27 pm
Does anyone have better photos of this bottom edge? Wondering if there are tiles there?
Nic does:
https://www.twitter.com/NicAnsuini/status/1470454169723191301
Yes, there are tiles there and on the fin edges as well. This is not the case for S20.
Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: Lars-J on 12/16/2021 12:26 am
Does anyone have better photos of this bottom edge? Wondering if there are tiles there?

Here is a brightened version of @NicAnsuini's image above - Yes, there are tiles there. Except for one gap by the hinge, but that might be filled in before flight.
Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: psherriffs on 12/16/2021 12:54 am
Another idea, maybe they've come up with a lifting rig that can hook under the chopsticks lift points and then provide a sling for crane pickup.  Crane picks up a cross bar, ends of cross bar have long cables, and those cables end on "J" shaped hooks that go around the top fins and hook under the lift points.  This would remove the need to have tiles missing on the nose this late in the manufacturing process while still allowing them to move the Starship around without the chopsticks.

Good point. Could this also be a sign that they intend to have the chopsticks ready to stack S20?
Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: cdebuhr on 12/16/2021 02:02 am
Another idea, maybe they've come up with a lifting rig that can hook under the chopsticks lift points and then provide a sling for crane pickup.  Crane picks up a cross bar, ends of cross bar have long cables, and those cables end on "J" shaped hooks that go around the top fins and hook under the lift points.  This would remove the need to have tiles missing on the nose this late in the manufacturing process while still allowing them to move the Starship around without the chopsticks.

Good point. Could this also be a sign that they intend to have the chopsticks ready to stack S20?

Not unless the tower can take a walk over to the suborbital pad.  Thats not to say the chopsticks couldn't pick up Ship 20, but they've got to get it off the suborbital pad and over by the OLP first.  Theres only four options I can see (open to others, of course), in no particular order:
1) This was practice, and they'll rip off the tiles and reattach the nose lifting points before bringing in the crane.
2) They have (or will have) an as-yet unseen lifting frame that engages the "catch" hard points under the fins.   Considering this has to reach around and under the fins, stay in balance during the lift, and not destroy the TPS during attachment, I'm having a hard time visualizing this in full structural detail.
3) They're planning another hop (high enough to give the TPS a bit of a workout? ... maybe?).
4) That suborbital pad is being retired and they wanted to leave this in place as a decoration.

I have a hard time seeing option 4, but as for 1-3, damned if I know.
Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: dgkimpton on 12/16/2021 08:52 am
... options ...
I suppose it is also possible they may be planning to lift it from the non-tiled side only. Like sticking a long handle on the back of a can of coke - as long as it's pressurised and strong enough there isn't any reason that it has to be lifted from the top, it could be lifted from one side with some leverage. I don't think they're going this way, but I also don't see any reason why they couldn't.
Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: sferrin on 12/16/2021 10:55 am
Anybody know what the giant purple and orange ropes are for? (Specifically.)
Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: Yggdrasill on 12/16/2021 11:04 am
Probably they are extended down, and attached to a mechanism that can slowly tighten them down, applying in the ballpark of a total of 6000 tons of force. (While the tank is pressurized.)

If the tank can't handle the force, the design of Super Heavy can't handle the weight of a Starship with full propellant load while accelerating at up to 4G.

There seems to be around 30 ropes. So each rope will have to handle around 200 tons. (Maybe someone has an idea what they are likely rated for.)
Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: samgineer on 12/16/2021 11:13 am
Anybody know what the giant purple and orange ropes are for? (Specifically.)
They will be tied down to already installed hydraulic pistons and pulled down by pistons simulating axial load on fuselage. This is reason why this test stand is named "can crusher" it will literally crush can (booster). We may see in future even full scale booster tested like this. NASA done similar testing with SLS hydrogen tank two years ago but they used instead strong ropes fancy tower.
https://www.nasa.gov/exploration/systems/sls/multimedia/marshall-engineers-break-sls-test-tank-on-purpose-to-test-extreme-limits.html (https://www.nasa.gov/exploration/systems/sls/multimedia/marshall-engineers-break-sls-test-tank-on-purpose-to-test-extreme-limits.html)
Edit: now link works
Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: haywoodfloyd on 12/16/2021 12:05 pm
Anybody know what the giant purple and orange ropes are for? (Specifically.)
They will be tied down to already installed hydraulic pistons and pulled down by pistons simulating axial load on fuselage. This is reason why this test stand is named "can crusher" it will literally crush can (booster). We may see in future even full scale booster tested like this. NASA done similar testing with SLS hydrogen tank two years ago but they used instead strong ropes fancy tower.
https://www.nasa.gov/exploration/systems/sls/multimedia/marshall-engineers-break-sls-test-tank-on-purpose-to-test-extreme-limits.htmle (https://www.nasa.gov/exploration/systems/sls/multimedia/marshall-engineers-break-sls-test-tank-on-purpose-to-test-extreme-limits.htmle)
You might want to remove the "e"  from the end of your link to make it work.
Thanks
Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: sferrin on 12/16/2021 01:00 pm
Anybody know what the giant purple and orange ropes are for? (Specifically.)
They will be tied down to already installed hydraulic pistons and pulled down by pistons simulating axial load on fuselage. This is reason why this test stand is named "can crusher" it will literally crush can (booster). We may see in future even full scale booster tested like this. NASA done similar testing with SLS hydrogen tank two years ago but they used instead strong ropes fancy tower.
https://www.nasa.gov/exploration/systems/sls/multimedia/marshall-engineers-break-sls-test-tank-on-purpose-to-test-extreme-limits.htmle (https://www.nasa.gov/exploration/systems/sls/multimedia/marshall-engineers-break-sls-test-tank-on-purpose-to-test-extreme-limits.htmle)


Any idea why they're not using wire rope or solid rod?  Something with a little less stretch.
Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: baking on 12/16/2021 01:03 pm
Anybody know what the giant purple and orange ropes are for? (Specifically.)
They will be tied down to already installed hydraulic pistons and pulled down by pistons simulating axial load on fuselage. This is reason why this test stand is named "can crusher" it will literally crush can (booster). We may see in future even full scale booster tested like this. NASA done similar testing with SLS hydrogen tank two years ago but they used instead strong ropes fancy tower.
https://www.nasa.gov/exploration/systems/sls/multimedia/marshall-engineers-break-sls-test-tank-on-purpose-to-test-extreme-limits.htmle (https://www.nasa.gov/exploration/systems/sls/multimedia/marshall-engineers-break-sls-test-tank-on-purpose-to-test-extreme-limits.htmle)
Any idea why they're not using wire rope or solid rod?  Something with a little less stretch.
The tension will be more gradual.
Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: Doom2pro on 12/16/2021 01:06 pm
The ship quick disconnect rig at production site really has me thinking they are going to modify Pad B to support hopping newer ships with side panels... Remember Pad A and Pad B have the QD hardware underneath, and they had to Jerry rig a non quick disconnect (lol) to allow testing. They may hop Ship 20 afterall... Not sure how it will land without legs, unless they do a late addition, or sacrifice it with a hypersonic flight?
Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: Nescio Erucis on 12/16/2021 02:26 pm
The ship quick disconnect rig at production site really has me thinking they are going to modify Pad B to support hopping newer ships with side panels... Remember Pad A and Pad B have the QD hardware underneath, and they had to Jerry rig a non quick disconnect (lol) to allow testing. They may hop Ship 20 afterall... Not sure how it will land without legs, unless they do a late addition, or sacrifice it with a hypersonic flight?
Don't they usually install the legs last anyway?
I like the idea of a hop but I'm not getting my 'hops' up.
Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: Tangilinear Interjar on 12/16/2021 03:03 pm
Anybody know what the giant purple and orange ropes are for? (Specifically.)
They will be tied down to already installed hydraulic pistons and pulled down by pistons simulating axial load on fuselage. This is reason why this test stand is named "can crusher" it will literally crush can (booster). We may see in future even full scale booster tested like this. NASA done similar testing with SLS hydrogen tank two years ago but they used instead strong ropes fancy tower.
https://www.nasa.gov/exploration/systems/sls/multimedia/marshall-engineers-break-sls-test-tank-on-purpose-to-test-extreme-limits.htmle (https://www.nasa.gov/exploration/systems/sls/multimedia/marshall-engineers-break-sls-test-tank-on-purpose-to-test-extreme-limits.htmle)


Any idea why they're not using wire rope or solid rod?  Something with a little less stretch.

Probably Dyneema rope. Super strong, flexible, low stretch, actually lighter than water (floats), and is what ships use for mooring and tugs for towing.

Solid rods would be very impractical and wire rope would be harder to use and more dangerous in the case of a failure. When they snap there's a lot of energy stored up that tends to do a lot of damage.
Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: Tangilinear Interjar on 12/16/2021 03:15 pm
The ship quick disconnect rig at production site really has me thinking they are going to modify Pad B to support hopping newer ships with side panels... Remember Pad A and Pad B have the QD hardware underneath, and they had to Jerry rig a non quick disconnect (lol) to allow testing. They may hop Ship 20 afterall... Not sure how it will land without legs, unless they do a late addition, or sacrifice it with a hypersonic flight?

They won't hop S20, that makes no sense. They would have to make so many modifications that it would have to be removed from the stand to accomplish them. Plus it doesn't give much new useful data.

No matter what it has to be removed from the stand therefore there's a lifting rig that works from the crane but we would expect something like that for use in the high bay anyway.

The SS was designed to be lifted up onto the Booster with the chopsticks via the four hardpoints that we can see, it seems pretty simple to design a load spreader for a crane that attaches to the same points.
Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: rsdavis9 on 12/16/2021 04:07 pm
... options ...
I suppose it is also possible they may be planning to lift it from the non-tiled side only. Like sticking a long handle on the back of a can of coke - as long as it's pressurised and strong enough there isn't any reason that it has to be lifted from the top, it could be lifted from one side with some leverage. I don't think they're going this way, but I also don't see any reason why they couldn't.

That was my guess(asymmetrical lift) before we saw the armpit lift points. Now I think option 2 above makes sense.(some sort of rig for the armpit lift points and then to crane).
Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: OTV Booster on 12/16/2021 05:28 pm
In Nicks pic of the fresh delivered thrust puck I'm seeing only 13 engine mounting points. Those flat plates are where engines have traditionally been mounted. Is there an alternative mounting arrangement?
Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: niwax on 12/16/2021 05:37 pm
In Nicks pic of the fresh delivered thrust puck I'm seeing only 13 engine mounting points. Those flat plates are where engines have traditionally been mounted. Is there an alternative mounting arrangement?

Put another 18 in a ring around this and you got the full 31.
Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: baking on 12/16/2021 05:43 pm
In Nicks pic of the fresh delivered thrust puck I'm seeing only 13 engine mounting points. Those flat plates are where engines have traditionally been mounted. Is there an alternative mounting arrangement?
Put another 1820 in a ring around this and you got the full 3133.
FTFY
Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: cdebuhr on 12/16/2021 06:32 pm
In Nicks pic of the fresh delivered thrust puck I'm seeing only 13 engine mounting points. Those flat plates are where engines have traditionally been mounted. Is there an alternative mounting arrangement?

Put another 18 in a ring around this and you got the full 31.
The "old" SH thrust puck (like on Booster 3 & 4) only had nine mounts (one in the middle surrounded by eight) but was otherwise quite similar to this one.  This is the new design that stuffs 4 more engines under the booster.  The remaining 20 engines are supported on the outer ring attached directly to the skin of the booster.  Note that (as near as I can tell anyway) the outer ring is now locked in at 20 engines (not 18) as changing that at this point would require massive rework of the launch table.  Total engine count was 29, now 33 with the new puck design.
Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: eriblo on 12/16/2021 11:55 pm
It is worth noting that the latest puck is more machined/optimized compared to the previous one and now has consistent fuel feed hole sizing.
Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: Pete on 12/17/2021 10:42 am
What is mindboggling is that this is the device that will be all that stands between 3000tonnes of thrust, and 13 raptors flying through the tanks. It looks almost too... elegant... for that role.
Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: sferrin on 12/17/2021 11:06 am
What is mindboggling is that this is the device that will be all that stands between 3000tonnes of thrust, and 13 raptors flying through the tanks. It looks almost too... elegant... for that role.


It's not unsupported on the opposite side when installed.
Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: geza on 12/17/2021 11:30 am
Beyond the two propellant holes per engine, there are two large holes: one in the outer ring and one in the inner one. What are they?
Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: WiresMN on 12/17/2021 12:50 pm
What is mindboggling is that this is the device that will be all that stands between 3000tonnes of thrust, and 13 raptors flying through the tanks. It looks almost too... elegant... for that role.


It's not unsupported on the opposite side when installed.

Not questioning your statement, but have we seen the backside when it is installed? I remember people coming up with different support structures. Have any of those ever been verified?
Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: eriblo on 12/17/2021 12:57 pm
It will be interesting to see if the larger thrust puck will lead to the inner Raptors being level (or at least more in line) with the outer ones or if they move the aft dome down to compensate.
Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: cdebuhr on 12/17/2021 01:11 pm
Beyond the two propellant holes per engine, there are two large holes: one in the outer ring and one in the inner one. What are they?
I believe those are almost certainly holes for the fill/drain lines for LOX and LCH4.  As for which is which, I'd think it more logical that the more central one is for LCH4, as it will feed into the bottom of the LCH4 downcomer, but without a look at the interior plumbing I'm really just guessing here.
Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: dhHopkins on 12/17/2021 01:23 pm
Ok - I didn't see if anyone had this thought - but . . .  What if they are closing up the nosecone hard points on S20, in order to do a first catch attempt with the chopsticks - with S20?  Those open areas right behind/below the forward fins - are they about where lifting/landing points would go on SS, or is that something else.  Might be safer to risk a first catch with a smaller vehicle, and S21 is right behind in processing.  Or, alternatively, attach a cradle/load spreader/lifting jig - to attach to S20 hardpoints under fins - to lift onto SPMT - transport over to OLM?Then have chopsticks pick up S20, to mount to booster.  Incredibly fun to speculate!  Can't wait to see what happens!
Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: eriblo on 12/17/2021 01:29 pm
Beyond the two propellant holes per engine, there are two large holes: one in the outer ring and one in the inner one. What are they?
I believe those are almost certainly holes for the fill/drain lines for LOX and LCH4.  As for which is which, I'd think it more logical that the more central one is for LCH4, as it will feed into the bottom of the LCH4 downcomer, but without a look at the interior plumbing I'm really just guessing here.
The fill and drain lines for the propellants are conveniently placed on the side at the SH QD with internal lines going down to the bottom. There could be propellant sumps to access the last little bit of residuals but it would be simpler to just let them boil off (a benefit of all cryogenic propellants). The only time you need to empty things at the bottom is if you use cleaners that leave residuals but these could probably be manually wiped up.

The holes could be access ports but the tank already has one on the side so why the need for two more? Any external access will also be severely hampered by the presens of engines and heat shields in the engine compartment. The only reason I can think of is to install/access something that would be blocked by the propellant manifold and other structures in the tank.
Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: cdebuhr on 12/17/2021 02:34 pm
Beyond the two propellant holes per engine, there are two large holes: one in the outer ring and one in the inner one. What are they?
I believe those are almost certainly holes for the fill/drain lines for LOX and LCH4.  As for which is which, I'd think it more logical that the more central one is for LCH4, as it will feed into the bottom of the LCH4 downcomer, but without a look at the interior plumbing I'm really just guessing here.
The fill and drain lines for the propellants are conveniently placed on the side at the SH QD with internal lines going down to the bottom. There could be propellant sumps to access the last little bit of residuals but it would be simpler to just let them boil off (a benefit of all cryogenic propellants). The only time you need to empty things at the bottom is if you use cleaners that leave residuals but these could probably be manually wiped up.

The holes could be access ports but the tank already has one on the side so why the need for two more? Any external access will also be severely hampered by the presens of engines and heat shields in the engine compartment. The only reason I can think of is to install/access something that would be blocked by the propellant manifold and other structures in the tank.
Good point - I had assumed the LOX/LCH4 F/D ports were far enough below the level of the lower bulkhead weld line to allow for routing of these beneath the lower dome, but upon reviewing the pictures, I see that these lines come in above the weld line and seem to directly enter the lower tank.  I have to update my guess as to what these holes are to "damned if I know".  That's what I get for commenting from memory without looking at the pictures first!
Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: mandrewa on 12/17/2021 05:06 pm
Beyond the two propellant holes per engine, there are two large holes: one in the outer ring and one in the inner one. What are they?
I believe those are almost certainly holes for the fill/drain lines for LOX and LCH4.  As for which is which, I'd think it more logical that the more central one is for LCH4, as it will feed into the bottom of the LCH4 downcomer, but without a look at the interior plumbing I'm really just guessing here.
The fill and drain lines for the propellants are conveniently placed on the side at the SH QD with internal lines going down to the bottom. There could be propellant sumps to access the last little bit of residuals but it would be simpler to just let them boil off (a benefit of all cryogenic propellants). The only time you need to empty things at the bottom is if you use cleaners that leave residuals but these could probably be manually wiped up.

The holes could be access ports but the tank already has one on the side so why the need for two more? Any external access will also be severely hampered by the presens of engines and heat shields in the engine compartment. The only reason I can think of is to install/access something that would be blocked by the propellant manifold and other structures in the tank.

Could it be that these holes are for a methane loop that supplies the outer 20 engines?  The benefit of doing things this way is that this removes 20 methane supply lines that would otherwise have to be going through the oxygen tank to supply methane to the outer 20 engines.  For the outer 20 engines you only need a single short pipe per engine to connect to the oxygen tank directly above to the needed LOX, since these engines will never be restarted, and likewise, a single loop of methane going through the thrust puck twice and then out to the outer engines.  It would have to be quite a big supply line which sort of matches the big holes.
Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: OTV Booster on 12/17/2021 06:02 pm
In Nicks pic of the fresh delivered thrust puck I'm seeing only 13 engine mounting points. Those flat plates are where engines have traditionally been mounted. Is there an alternative mounting arrangement?

Put another 18 in a ring around this and you got the full 31.
DuH!  Just tuned in and looked at it again. Came to the same conclusion.
Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: OTV Booster on 12/17/2021 06:10 pm
It is worth noting that the latest puck is more machined/optimized compared to the previous one and now has consistent fuel feed hole sizing.
Yup. That's a consistent path. Even the individual pieces are prototypes. Everything gets more polished with each iteration.


Maybe that's the magic sauce that keeps the project in a state of high wonder. Old space, anybody can look at the drawing done three years ago and know what's coming up tomorrow. Borrrringggg.
Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: OTV Booster on 12/17/2021 06:18 pm
Ok - I didn't see if anyone had this thought - but . . .  What if they are closing up the nosecone hard points on S20, in order to do a first catch attempt with the chopsticks - with S20?  Those open areas right behind/below the forward fins - are they about where lifting/landing points would go on SS, or is that something else.  Might be safer to risk a first catch with a smaller vehicle, and S21 is right behind in processing.  Or, alternatively, attach a cradle/load spreader/lifting jig - to attach to S20 hardpoints under fins - to lift onto SPMT - transport over to OLM?Then have chopsticks pick up S20, to mount to booster.  Incredibly fun to speculate!  Can't wait to see what happens!
Catching 20 is an interesting thought. They have enough experience smacking them in hard to have a feel for what they can get away with on a catch abort.
Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: rsdavis9 on 12/17/2021 07:24 pm
Ok - I didn't see if anyone had this thought - but . . .  What if they are closing up the nosecone hard points on S20, in order to do a first catch attempt with the chopsticks - with S20?  Those open areas right behind/below the forward fins - are they about where lifting/landing points would go on SS, or is that something else.  Might be safer to risk a first catch with a smaller vehicle, and S21 is right behind in processing.  Or, alternatively, attach a cradle/load spreader/lifting jig - to attach to S20 hardpoints under fins - to lift onto SPMT - transport over to OLM?Then have chopsticks pick up S20, to mount to booster.  Incredibly fun to speculate!  Can't wait to see what happens!
Catching 20 is an interesting thought. They have enough experience smacking them in hard to have a feel for what they can get away with on a catch abort.

I can't weight for catching 22...  :)
Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: Nevyn72 on 12/17/2021 09:28 pm
... options ...
I suppose it is also possible they may be planning to lift it from the non-tiled side only. Like sticking a long handle on the back of a can of coke - as long as it's pressurised and strong enough there isn't any reason that it has to be lifted from the top, it could be lifted from one side with some leverage. I don't think they're going this way, but I also don't see any reason why they couldn't.

That was my guess(asymmetrical lift) before we saw the armpit lift points. Now I think option 2 above makes sense.(some sort of rig for the armpit lift points and then to crane).

This is only really an issue for the current Ship versions, 20, 21 and maybe 22.

Once the forward flaps are moved toward the leeward side, from Ship 24 I believe, there will be a straight vertical path for a lifting jig to be attached to the chopstick catch sockets.
Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: AC in NC on 12/18/2021 04:47 am
Super Heavy: 13 + 20
Starship: 3 + 6

All roads lead to 42
Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: baking on 12/18/2021 12:53 pm
https://mobile.twitter.com/elonmusk/status/1472052839316963329
I'm having a difficult time imagining 4 more raptors in there.  3 in the center and 10 in the ring.

Also, it just occurs to me that the outer ring of 20 won't be relit for landing (or catching.)
Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: Crispy on 12/18/2021 01:46 pm
https://mobile.twitter.com/elonmusk/status/1472052839316963329
I'm having a difficult time imagining 4 more raptors in there.  3 in the center and 10 in the ring.

Also, it just occurs to me that the outer ring of 20 won't be relit for landing (or catching.)
A 10+3 thrust puck just got delivered the other day so you barely even have to use your imagination!
Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: baking on 12/18/2021 02:32 pm
I'm having a difficult time imagining 4 more raptors in there.  3 in the center and 10 in the ring.

Also, it just occurs to me that the outer ring of 20 won't be relit for landing (or catching.)
A 10+3 thrust puck just got delivered the other day so you barely even have to use your imagination!
I was referring to that.  I meant with raptors attached and moving around while steering.  Seems tight.

EDIT:  Yes, if all the engines move in coordination, you can do it.  But what about during shut-down landing/catch? 
Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: StuffOfInterest on 12/18/2021 02:57 pm
I'm having a difficult time imagining 4 more raptors in there.  3 in the center and 10 in the ring.

Also, it just occurs to me that the outer ring of 20 won't be relit for landing (or catching.)
A 10+3 thrust puck just got delivered the other day so you barely even have to use your imagination!
I was referring to that.  I meant with raptors attached and moving around while steering.  Seems tight.

EDIT:  Yes, if all the engines move in coordination, you can do it.  But what about during shut-down landing/catch? 

Using this video as a reference, hopefully Owe (https://www.youtube.com/channel/UCRqNQqEW4nKlZ9A0Lpfxo6g) will do a simulation comparing the 29 engine arrangement to the 33 engine arrangement so we can see how the range of motion will work.
Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: DanClemmensen on 12/18/2021 04:25 pm
I'm having a difficult time imagining 4 more raptors in there.  3 in the center and 10 in the ring.

Also, it just occurs to me that the outer ring of 20 won't be relit for landing (or catching.)
A 10+3 thrust puck just got delivered the other day so you barely even have to use your imagination!
I was referring to that.  I meant with raptors attached and moving around while steering.  Seems tight.

EDIT:  Yes, if all the engines move in coordination, you can do it.  But what about during shut-down landing/catch?
How many raptors at full thrust are needed to land a nearly-empty SH? Current estimates are SH < 200 t dry, and Raptor 1 thrust is 185 tf and can be throttled as low as 40%. So, for shutdown/landing/catch you light three Raptors (for redundancy) and immediately shut one down if all three light, before throttling back to 40% on the other two to land. All of the gimballed engines could swing together, but only two are lit. Maybe play games with differential thrust if you need it and your control algorithms are set up to use it, but with only two engines lit this is not very flexible. If the engines cannot be independently gimballed at all, then some other mechanism is needed to rotate about the long axis if needed to align with the chopsticks.
Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: baking on 12/18/2021 05:09 pm
I'm having a difficult time imagining 4 more raptors in there.  3 in the center and 10 in the ring.

Also, it just occurs to me that the outer ring of 20 won't be relit for landing (or catching.)
A 10+3 thrust puck just got delivered the other day so you barely even have to use your imagination!
I was referring to that.  I meant with raptors attached and moving around while steering.  Seems tight.

EDIT:  Yes, if all the engines move in coordination, you can do it.  But what about during shut-down landing/catch?
How many raptors at full thrust are needed to land a nearly-empty SH? Current estimates are SH < 200 t dry, and Raptor 1 thrust is 185 tf and can be throttled as low as 40%. So, for shutdown/landing/catch you light three Raptors (for redundancy) and immediately shut one down if all three light, before throttling back to 40% on the other two to land. All of the gimballed engines could swing together, but only two are lit. Maybe play games with differential thrust if you need it and your control algorithms are set up to use it, but with only two engines lit this is not very flexible. If the engines cannot be independently gimballed at all, then some other mechanism is needed to rotate about the long axis if needed to align with the chopsticks.
So what if you "park" the ring of ten to give the inner three maximum room to maneuver independently for the landing/catch burn.  This assumes you have some individual control and the hydraulics aren't just always synched up.  The video shows that the engines have different orientations so there must be independent controls of each engine even when they are synched.
Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: billh on 12/18/2021 06:23 pm
Six vacuum Raptors on the Starship mean no more cargo lockers at the base...which was one of the features called out by the recent white paper by Heldmann et al. But in trade you'll get higher total payload capacity, presumably, along with perhaps fewer tanker flights for deep space missions.
Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: Lars-J on 12/18/2021 07:05 pm
Six vacuum Raptors on the Starship mean no more cargo lockers at the base...which was one of the features called out by the recent white paper by Heldmann et al. But in trade you'll get higher total payload capacity, presumably, along with perhaps fewer tanker flights for deep space missions.
Yes the biggest benefit of this change would be increased tanker load.

I do wonder if dedicated space variants like HLS would still have 6 engines? (3 extra Vac Raptors offer no benefit beyond LEO) But this is where commonality may win over efficiency.

One interesting thought is that thrust balance is possible with 2, 3, 4, and 6 Vac Raptors, if there is a future need to trade engines for cargo space or deep space efficiency.
Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: baking on 12/18/2021 07:56 pm
Did I miss something?  Why are we talking about >3 Vac Raptors?  Did they suddenly get smaller?  I thought the size of the bells precluded more than 3 in a 9m rocket.
Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: samgineer on 12/18/2021 08:07 pm
Did I miss something?  Why are we talking about >3 Vac Raptors?  Did they suddenly get smaller?  I thought the size of the bells precluded more than 3 in a 9m rocket.

Do you think there is not enough space for three more? Yes it will be tight with SL Raptors, but it will fit.
https://www.flickr.com/photos/spacex/51371124479/ (https://www.flickr.com/photos/spacex/51371124479/)
Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: russianhalo117 on 12/18/2021 08:12 pm
Did I miss something?  Why are we talking about >3 Vac Raptors?  Did they suddenly get smaller?  I thought the size of the bells precluded more than 3 in a 9m rocket.

Do you think there is not enough space for three more?
https://www.flickr.com/photos/spacex/51371124479/ (https://www.flickr.com/photos/spacex/51371124479/)

The vehicle was always designed with the potential to add 3 more RVac's for certain missions and/or versions. They downsized to 3 early on for at least the test programme. It is all about tradeoffs.

We are all seeing this with the booster at the moment. Tradeoffs as to how many you want to gimbal and how many you want to stay fixed. Personally IMO 4 center gimballing and 30 fixed is what I see as optimal as it allows a 4 engine deceleration burn switching to 2 complete the landing sequence.
Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: billh on 12/18/2021 08:37 pm
Did I miss something?  Why are we talking about >3 Vac Raptors?  Did they suddenly get smaller?  I thought the size of the bells precluded more than 3 in a 9m rocket.

Do you think there is not enough space for three more?
https://www.flickr.com/photos/spacex/51371124479/ (https://www.flickr.com/photos/spacex/51371124479/)

The vehicle was always designed with the potential to add 3 more RVac's  for certain missions and/or versions. The downsized to 3 early on for at least the test programme. It is all about tradeoffs.

We are all seeing this with the booster at the moment. Tradeoffs as to how many you want to gimbal and how many you want to stay fixed. Personally IMO 4 center gimballing and 30 fixed is what I see as optimal as it allows a 4 engine deceleration burn switching to 2 complete the landing sequence.
It was definitely the plan at one time to land on Mars with six engines, and the vehicle was portrayed as having three cargo compartments under the vehicle skirt (from which it would be much easier to unload "smaller" cargo items). Image is from SpaceX website.
Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: Oersted on 12/18/2021 11:18 pm
The flexibility of this ship is simply amazing. What a tremendous architecture. Just adding or subtracting engines according to the mission needs. Hitherto unheard of in spaceflight, I believe.
Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: Lars-J on 12/18/2021 11:19 pm
Here is the original ITS (12m diameter) engine layout… look familiar?
Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: TrueBlueWitt on 12/19/2021 02:25 am
Six vacuum Raptors on the Starship mean no more cargo lockers at the base...which was one of the features called out by the recent white paper by Heldmann et al. But in trade you'll get higher total payload capacity, presumably, along with perhaps fewer tanker flights for deep space missions.
Yes the biggest benefit of this change would be increased tanker load.

I do wonder if dedicated space variants like HLS would still have 6 engines? (3 extra Vac Raptors offer no benefit beyond LEO) But this is where commonality may win over efficiency.

One interesting thought is that thrust balance is possible with 2, 3, 4, and 6 Vac Raptors, if there is a future need to trade engines for cargo space or deep space efficiency.

This also makes it possible to test higher ER engines on a flight with a lot less risk..
Use 4 of the base SL startable Rap Vac to ensure you can make orbit and then add 2 smaller throat, High ER engines to test.  Low level abort would be the only reason to keep some SL start capable Vac Raptors right?
Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: rsdavis9 on 12/19/2021 11:17 am
It also allows musk to claim 42 engines on the combined vehicle.
33+9=42
Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: rsdavis9 on 12/19/2021 11:50 am
Six vacuum Raptors on the Starship mean no more cargo lockers at the base...which was one of the features called out by the recent white paper by Heldmann et al. But in trade you'll get higher total payload capacity, presumably, along with perhaps fewer tanker flights for deep space missions.
Yes the biggest benefit of this change would be increased tanker load.

I do wonder if dedicated space variants like HLS would still have 6 engines? (3 extra Vac Raptors offer no benefit beyond LEO) But this is where commonality may win over efficiency.

One interesting thought is that thrust balance is possible with 2, 3, 4, and 6 Vac Raptors, if there is a future need to trade engines for cargo space or deep space efficiency.

This also makes it possible to test higher ER engines on a flight with a lot less risk..
Use 4 of the base SL startable Rap Vac to ensure you can make orbit and then add 2 smaller throat, High ER engines to test.  Low level abort would be the only reason to keep some SL start capable Vac Raptors right?

Isn't the VacRaptor at ER=107 ?
Elon commented that VacRaptor R+D was a lot of work for not a lot of isp.
So does he really need to go beyond 107?
Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: OTV Booster on 12/19/2021 02:16 pm
Six vacuum Raptors on the Starship mean no more cargo lockers at the base...which was one of the features called out by the recent white paper by Heldmann et al. But in trade you'll get higher total payload capacity, presumably, along with perhaps fewer tanker flights for deep space missions.
Yes the biggest benefit of this change would be increased tanker load.

I do wonder if dedicated space variants like HLS would still have 6 engines? (3 extra Vac Raptors offer no benefit beyond LEO) But this is where commonality may win over efficiency.

One interesting thought is that thrust balance is possible with 2, 3, 4, and 6 Vac Raptors, if there is a future need to trade engines for cargo space or deep space efficiency.
Commonality is good but so is tailoring to needs. Avoiding the extremes of either is best.


Doggedly adhering to exact dupes on the line gives great production efficiency but loosing a crew because there is no LES has an inefficiency all its own.


OTOH having different mounting systems and plumbing for different engine counts is inefficient if it's possible to have one design that works for three or six vac engines. It then becomes a matter of not using what's not needed for a three engine build.


There's an inverse relationship between ease of production tweaks and unit cost and production volume. A line producing 12 cheap widgets a minute can't be stopped to turn out one with a different finish - unless it's for the pointy haired bosses wife. Cars do it different. Each is accompanied by a build sheet and can get different engines, seats, paint, electronics...  Still the same basic car but customized.


At two a week and relatively high cost, a lot of customization can be done with little inefficiency as long as the line is designed to accommodate it. Atmospheric entry package. Dirt landing package. Six Vrap package. Stretch tank package. Crew packages accommodating from 2 to 20. Chomper package. Human steerage package. 





Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: livingjw on 12/19/2021 03:13 pm
Six vacuum Raptors on the Starship mean no more cargo lockers at the base...which was one of the features called out by the recent white paper by Heldmann et al. But in trade you'll get higher total payload capacity, presumably, along with perhaps fewer tanker flights for deep space missions.
Yes the biggest benefit of this change would be increased tanker load.

I do wonder if dedicated space variants like HLS would still have 6 engines? (3 extra Vac Raptors offer no benefit beyond LEO) But this is where commonality may win over efficiency.

One interesting thought is that thrust balance is possible with 2, 3, 4, and 6 Vac Raptors, if there is a future need to trade engines for cargo space or deep space efficiency.

This also makes it possible to test higher ER engines on a flight with a lot less risk..
Use 4 of the base SL startable Rap Vac to ensure you can make orbit and then add 2 smaller throat, High ER engines to test.  Low level abort would be the only reason to keep some SL start capable Vac Raptors right?

Isn't the VacRaptor at ER=107 ?
Elon commented that VacRaptor R+D was a lot of work for not a lot of isp.
So does he really need to go beyond 107?

- You can see the trend in the Isp vs ER chart. You can gain a few seconds, but remember you have to extend the engine compartment to fit the longer engine. There is obviously a limit to the Raptor exit diameter that can fit as well.

- Graph accuracy probably about +- 2 s Isp.

John
Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: meekGee on 12/19/2021 03:56 pm
Six vacuum Raptors on the Starship mean no more cargo lockers at the base...which was one of the features called out by the recent white paper by Heldmann et al. But in trade you'll get higher total payload capacity, presumably, along with perhaps fewer tanker flights for deep space missions.
Yes the biggest benefit of this change would be increased tanker load.

I do wonder if dedicated space variants like HLS would still have 6 engines? (3 extra Vac Raptors offer no benefit beyond LEO) But this is where commonality may win over efficiency.

One interesting thought is that thrust balance is possible with 2, 3, 4, and 6 Vac Raptors, if there is a future need to trade engines for cargo space or deep space efficiency.
Commonality is good but so is tailoring to needs. Avoiding the extremes of either is best.


Doggedly adhering to exact dupes on the line gives great production efficiency but loosing a crew because there is no LES has an inefficiency all its own.


OTOH having different mounting systems and plumbing for different engine counts is inefficient if it's possible to have one design that works for three or six vac engines. It then becomes a matter of not using what's not needed for a three engine build.


There's an inverse relationship between ease of production tweaks and unit cost and production volume. A line producing 12 cheap widgets a minute can't be stopped to turn out one with a different finish - unless it's for the pointy haired bosses wife. Cars do it different. Each is accompanied by a build sheet and can get different engines, seats, paint, electronics...  Still the same basic car but customized.


At two a week and relatively high cost, a lot of customization can be done with little inefficiency as long as the line is designed to accommodate it. Atmospheric entry package. Dirt landing package. Six Vrap package. Stretch tank package. Crew packages accommodating from 2 to 20. Chomper package. Human steerage package.
I think emphasis on commonality at the vehicle level went out with the transition to stainless construction.

Subsystem commonality (engines, rings, most domes, interfaces) - that will be what matters.
Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: beelsebob on 12/20/2021 11:04 am
I also don't really see what the issue with commonality and an extra 3 engines really is.  What different parts would actually be needed?

Potentially:

ē The thrust puck
ē Adding an extra ring or two to the tanks
ē The downcomer
ē The plumbing from the downcomer to the thrust puck.
ē The software

The thrust puck can be trivially adapted with blanking plates.  If an engine bolted to it can hold the required pressure, then so can a blanking plate.  Adding an extra ring or two is trivial for them with steel construction.  The downcomer is an easy modification.  Thu plumbing, I don't think is even an issue by the time that you have a new downcomer in there, and blanking plates over the engine pickups.  The software needs to be able to handle a different number of engines, but I'd be very surprised if SpaceX hadn't designed the software so that it can handle any combination of engines in different positions (within reason).  Otherwise they'd have to hand craft new software for each configuration of booster/ship.

Look at how smoothly the transition from 29 to 33 engines on the booster is happening.  I don't see any reason why having some ships with 6 engines, and some with 9 would be more complex.
Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: aboveallofit on 12/20/2021 08:14 pm
How much tank stretch will the current launch tower support?
Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: DanClemmensen on 12/20/2021 08:22 pm
How much tank stretch will the current launch tower support?
The limit appears to be the height above the platform of the lift points on the Starship that are "caught" by the chopsticks. The Starship could in theory be stretched above those lift points up to point where the center of mass becomes too high. I'm sure there are other considerations that would limit the stretch. and of course the stretched version would need to be engineered to be lifted from these lift points.
Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: Hamish.Student on 12/22/2021 03:52 am
I miss the daily update posts by Mary. It's not the same without them, much harder to follow things.
Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: woods170 on 12/22/2021 08:49 am
I miss the daily update posts by Mary. It's not the same without them, much harder to follow things.

Yeah, we can understand that. But the blame for this situation squarely rests with a bunch of **** who ran with the images from this part of the forum and presented them as their own without giving credit to Mary or NSF.
Chris B. rightfully put a stop to that.



**** insert expletive here
Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: edzieba on 12/22/2021 10:00 am
I miss the daily update posts by Mary. It's not the same without them, much harder to follow things.
Many of the images are incorporated into the daily update videos as full-res pans (as they have been for quite some time). 
Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: Herb Schaltegger on 12/22/2021 12:14 pm
I miss the daily update posts by Mary. It's not the same without them, much harder to follow things.
Many of the images are incorporated into the daily update videos as full-res pans (as they have been for quite some time).

A poor replacement, at best. It's not the same.  :-\

This has been hashed, rehashed and hashed again. The solution is pay for the content you value - join L2. 
Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: wannamoonbase on 12/22/2021 12:42 pm
I miss the daily update posts by Mary. It's not the same without them, much harder to follow things.
Many of the images are incorporated into the daily update videos as full-res pans (as they have been for quite some time).

A poor replacement, at best. It's not the same.  :-\

Join L2, itís worth it, Iíve been here since F1, maybe before the F1, itís been so long I forget.

Edit: Just looked it up, been a member since April 10, 2006.  Love this site, itís my first stop every morning!
Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: beelsebob on 12/22/2021 01:35 pm
Does anyone have good ideas on whatís going on with B4?

Are we seeing them being cautious and increasing the tests but by bit while checking that everything is working correctly?  Are we seeing something not working correctly, and them repeatedly going back to try it again after making an adjustment?
Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: SDSmith on 12/22/2021 01:57 pm
Does anyone have good ideas on whatís going on with B4?

Are we seeing them being cautious and increasing the tests but by bit while checking that everything is working correctly?  Are we seeing something not working correctly, and them repeatedly going back to try it again after making an adjustment?
I would say a little bit of both. The GSE is new so a bit a of a learning curve.
Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: Rossco on 12/22/2021 02:26 pm
Does anyone have good ideas on whatís going on with B4?

Are we seeing them being cautious and increasing the tests but by bit while checking that everything is working correctly?  Are we seeing something not working correctly, and them repeatedly going back to try it again after making an adjustment?
I would say a little bit of both. The GSE is new so a bit a of a learning curve.

I wondered the same when they tested SS - maybe they're tanking/de-tanking, testing all the various pipes, valves, joints and systems both to and from the GSE farm.
Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: Nescio Erucis on 12/22/2021 02:30 pm
Very interesting seeing them gradually "show off" some of the different capabilities of B4 (e.g., what seem to be the ullage thrusters for settling prop).
Have we ever seen the grid fins moving yet? I remember reading a lot of speculation about their range of motion a couple months ago (basically, that they wouldn't be capable of folding) but don't recall seeing them ever being tested. It seems like such a simple thing to do (wouldn't even require any GSE) that it would be weird if it hadn't been done.
Thanks, and sorry if I've missed it somehow.
Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: StuffOfInterest on 12/22/2021 03:17 pm
It makes sense that they are going slow on the testing.  Remember that they lost prototypes due to GSE failure and procedure failure.  Here they have a new vehicle and new ground support equipment.  We definitely don't want to see a Nitrogen powered launch of the SuperHeavy due to a stuck valve.
Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: wannamoonbase on 12/22/2021 03:39 pm
It makes sense that they are going slow on the testing.  Remember that they lost prototypes due to GSE failure and procedure failure.  Here they have a new vehicle and new ground support equipment.  We definitely don't want to see a Nitrogen powered launch of the SuperHeavy due to a stuck valve.

Agreed, the entire new ground side takes some time.  Just being able to fill and drain the vehicle a few times will teach them alot.

I think as they work up to starting engines we will see them proceed very slowly at first, stepping up slowly.  I won't be surprised to see a single engine start as they build confidence.

A natural split will be engines in the outer ring with ground side start support and the inner engines with on board support. 

It's going to a fun testing cycle.

Also, looking forward to the chopsticks stacking SS20 and seeing that testing begin as well. 
Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: tssp_art on 12/22/2021 05:29 pm

A natural split will be engines in the outer ring with ground side start support and the inner engines with on board support. 

Agree, and that works for the inner 9 engines on Booster 4. The outer ring as a complete set, and maybe the 13 engine inner set, will have to wait for FAA approval of Super Heavy launches. The current limitation is based on the (already approved) Falcon Heavy launch which is, I think, equal to about a dozen Raptor 1.5s.

Hopefully, all that will be taken care of in the next couple of weeks.  (Please Santa, I've been a good boy all year, really...well mostly...)
Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: wannamoonbase on 12/22/2021 05:56 pm

A natural split will be engines in the outer ring with ground side start support and the inner engines with on board support. 

Agree, and that works for the inner 9 engines on Booster 4. The outer ring as a complete set, and maybe the 13 engine inner set, will have to wait for FAA approval of Super Heavy launches. The current limitation is based on the (already approved) Falcon Heavy launch which is, I think, equal to about a dozen Raptor 1.5s.

Hopefully, all that will be taken care of in the next couple of weeks.  (Please Santa, I've been a good boy all year, really...well mostly...)

Epic tanking test going on today.

The live stream said there is no methane in the tank farm, so that could be a limitation.

However, any static fire before 2022 would be huge, even if it's just 1 engine.

It's a start and shows they can load everything needed to stage up from there.
Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: Robotbeat on 12/22/2021 06:42 pm

A natural split will be engines in the outer ring with ground side start support and the inner engines with on board support. 

Agree, and that works for the inner 9 engines on Booster 4. The outer ring as a complete set, and maybe the 13 engine inner set, will have to wait for FAA approval of Super Heavy launches. The current limitation is based on the (already approved) Falcon Heavy launch which is, I think, equal to about a dozen Raptor 1.5s.

Hopefully, all that will be taken care of in the next couple of weeks.  (Please Santa, I've been a good boy all year, really...well mostly...)
They could also test at a slightly reduced throttle to stay within FH thrust levels. I think the outer engines have SOME throttle capability.
Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: Lars-J on 12/22/2021 07:10 pm

A natural split will be engines in the outer ring with ground side start support and the inner engines with on board support. 

Agree, and that works for the inner 9 engines on Booster 4. The outer ring as a complete set, and maybe the 13 engine inner set, will have to wait for FAA approval of Super Heavy launches. The current limitation is based on the (already approved) Falcon Heavy launch which is, I think, equal to about a dozen Raptor 1.5s.

Hopefully, all that will be taken care of in the next couple of weeks.  (Please Santa, I've been a good boy all year, really...well mostly...)
They could also test at a slightly reduced throttle to stay within FH thrust levels. I think the outer engines have SOME throttle capability.

They do, they can throttle to assist in steering.

Source: https://twitter.com/elonmusk/status/1411545837172269058
Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: Robotbeat on 12/22/2021 07:16 pm
If they can throttle to 60%, they should be able to fire up all 20 outer engines.
Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: Robotbeat on 12/22/2021 07:23 pm
Current status: LOX tank has been holding full for about 20 minutes, CH4 tank has been holding at about 10% full.

Currently holding around 2,000 metric tonnes of LN2, if my back-of-the-envelope math is anywhere near accurate.
Note that LOx is 1.14kg/liter and LN2 is 0.808kg/liter, both at boiling point. Methane is 0.42kg/liter.
So to get the same force, you only need to fill the methane tank to about 50%. The hoop loading distribution also is a bit different than with methane. LN2 is also colder, so the steel should be stronger (but more brittle).

Oxygen is closer in density and boiling point. 112K CH4 vs 90K O2 vs 77K N2. So you can fill it all the way up with LN2 and you still havenít reached the same loading. But fairly close.

The colder temperature of LN2 does help simulate subcooling of the propellants.
Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: beelsebob on 12/22/2021 09:07 pm
Today's test looked hard to argue with the success of it.  A full O2 tank, and half full CH4 tank, and as noted above, that's basically the whole enchilada 'full' in terms of mass.  It hasn't all come crashing down (yet), so it looks like it's holding the requisite mass, at some level of pressure (whether a suitable one is a different matter, but I imagine they're not too concerned about that).  Hopefully onwards to dry firing a bunch of motors now to check that the plumbing plumbs.
Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: Chris Bergin on 12/23/2021 12:54 pm
Lovely view this morning!
Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: wannamoonbase on 12/23/2021 01:35 pm
Lovely view this morning!

Whoa that looks like a landscape painting.
Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: webdan on 12/23/2021 01:43 pm
Lovely view this morning!

Wow, I thought the thumbnail looked like a Chesley Bonestell painting of a SpaceX tanking facilities on Mars.

Gotta clean my glasses...
Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: beelsebob on 12/24/2021 10:48 am
Does anyone have any thoughts on how SN20 is going to get moved to the pad?  I assume that it's going to get lifted onto the booster via the chopsticks, but without the lifting points on the top any more, how is it going to get onto an SMPT?
Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: edzieba on 12/24/2021 11:25 am
Does anyone have any thoughts on how SN20 is going to get moved to the pad?  I assume that it's going to get lifted onto the booster via the chopsticks, but without the lifting points on the top any more, how is it going to get onto an SMPT?
It's still sat on the old suborbital stand. This stand still has the old vertical QD assembly underneath, and the side 'QD panel' is just a static frame holding the connectors in place that would not work for a suborbital launch (no way to retract the QD panel before launch) with flex hoses just routed from there to the old vertical QD assembly. 
Roll the SPMTs underneath, unbolt/gas-axe the mount off of the foundations, roll it over to the chopsticks. Then roll the new side-QD suborbital launch mount that has been assembled at the build site to the cleared foundations and bolt/weld it on.

::EDIT:: Through the latest images of the tiles over the lifting point covers shows they have been 'drilled out' over the mounting pegs in the same way tiles undergoing replacement are. The covers may just have been installed and tiled over as a fit-check, and are going to be removed before a normal crane lift.
Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: awests on 12/24/2021 03:43 pm
Does anyone have any thoughts on how SN20 is going to get moved to the pad?  I assume that it's going to get lifted onto the booster via the chopsticks, but without the lifting points on the top any more, how is it going to get onto an SMPT?
Use a jig designed to lift SN20 by the hard points off the suborbital stand with one of the many mobile cranes onto SMPTs, roll over to chopsticks, lift from there.
Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: Wolfram66 on 12/24/2021 05:50 pm
Lovely view this morning!

This would make an awesome jigsaw puzzle! Not like we havenít been doing a lot more of there during this pandemic
Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: geza on 12/25/2021 07:14 pm
Does anyone have any thoughts on how SN20 is going to get moved to the pad?  I assume that it's going to get lifted onto the booster via the chopsticks, but without the lifting points on the top any more, how is it going to get onto an SMPT?
Use a jig designed to lift SN20 by the hard points off the suborbital stand with one of the many mobile cranes onto SMPTs, roll over to chopsticks, lift from there.

Readiness of the chopsticks seems to be the weak point. They have never been tested in motion. Their motion remains impossible until the scaffolding higher on the tower is removed.
Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: Robotbeat on 12/27/2021 09:33 pm
They moved somewhat already I think. Not very much and not very fast. But they wonít be used for recovery for the first launch anyway.
Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: sferrin on 12/28/2021 01:53 am
Have they used the, "can crusher" yet?  ???
Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: livingjw on 12/29/2021 02:51 pm
Mate time!

https://twitter.com/NASASpaceflight/status/1475477858315345927

Have we seen that mating jig before? First time for me.

John
Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: grndkntrl on 12/29/2021 04:19 pm
Mate time!

https:// twitter.com/NASASpaceflight/status/1475477858315345927

Have we seen that mating jig before? First time for me.

John

Yep, it's new.

Seen resting at ground level, stored on a low black jig/stand, on 12th/13th December in pics from @StarshipGazer, and maybe pics from another non-NSF photog, also appears briefly in a few of the NSF daily update videos.

This is the first time it's been seen in use, and seems like a big improvement over the previous individually welded on, temporary locating fingers.
Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: rsdavis9 on 12/29/2021 04:29 pm
Mate time!

https:// twitter.com/NASASpaceflight/status/1475477858315345927

Have we seen that mating jig before? First time for me.

John

Yep, it's new.

Seen resting at ground level, stored on a low black jig/stand, on 12th/13th December in pics from @StarshipGazer, and maybe pics from another non-NSF photog, also appears briefly in a few of the NSF daily update videos.

This is the first time it's been seen in use, and seems like a big improvement over the previous individually welded on, temporary locating fingers.

So I assume we are talking about all the sloped spikes sticking up that ensure the top half goes over and outside of the bottom half?

If it is a reusable jig how do they get it out of the tank after mating?
Possibilities:
1. Its bolted together and they unbolt it and take it out the top.
2.  ?
Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: grndkntrl on 12/29/2021 05:58 pm
Mate time!

https:// twitter.com/NASASpaceflight/status/1475477858315345927

Have we seen that mating jig before? First time for me.

John

Yep, it's new.

Seen resting at ground level, stored on a low black jig/stand, on 12th/13th December in pics from @StarshipGazer, and maybe pics from another non-NSF photog, also appears briefly in a few of the NSF daily update videos.

This is the first time it's been seen in use, and seems like a big improvement over the previous individually welded on, temporary locating fingers.

So I assume we are talking about all the sloped spikes sticking up that ensure the top half goes over and outside of the bottom half?

If it is a reusable jig how do they get it out of the tank after mating?
Possibilities:
1. Its bolted together and they unbolt it and take it out the top.
2.  ?

Yep, it's split into many sections - with four loosely bolted "fingers" on each jig section.

You can see 3 workers putting the jig sections into place in the daily update video from yesterday (28th Dec.) at the 3:55 (235s) mark:

https:// youtu.be/wgz77JLUe0A&t=235s (inserted space to prevent forum breaking the timestamping)

see also attached screengrabs from that video.

They are small enough to fit lengthways through an access hatch - if used when joining a closed tank - or just removed from top or bottom of open barrel sections.

Not sure if they bolt the sections together before welding starts, or just slot them into the open ends of the internal stringers or other internal features we can't see, for a solid enough temporary fit.
Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: Yeknom-Ecaps on 12/29/2021 10:45 pm
Sorry this is a repeat but I can't find the answer with the searches I tried.

When and why was "Starship 20" changed to "Ship 20" and is the designation SN20 or S20 or both?
Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: Oersted on 12/29/2021 11:02 pm
Those jigs look much better than the previous, somewhat improvised ones. Damn' it's cool to see SpaceX incrementally improve their production methods. And its only by actually cutting metal and producing stuff that you get improvements like that.
Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: Wolfram66 on 12/30/2021 12:53 am
Any word on how many Raptors were fired in todayís static fire?
3 - 6?
Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: Hamish.Student on 12/30/2021 01:19 am
Sorry this is a repeat but I can't find the answer with the searches I tried.

When and why was "Starship 20" changed to "Ship 20" and is the designation SN20 or S20 or both?
 
 
About 6-12 months ago now, because Elon decided to confuse us some more. S20 is the correct form.
Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: StevenOBrien on 12/30/2021 01:45 am
Sorry this is a repeat but I can't find the answer with the searches I tried.

When and why was "Starship 20" changed to "Ship 20" and is the designation SN20 or S20 or both?

Ship 20 (S20) and Booster 3 (B3) were the first to get the new naming scheme (around June 2021). Both were originally SN20 and BN3.

As best as I understand it:

SN8 originally stood for "Serial Number 8". The PA announcements and the SpaceX livestream commentary would usually read it as "Starship serial number X". Raptors were also referred to as "Raptor SN50" etc.

When they started building boosters in early 2021, they began by calling them "BN1, BN2", etc. standing for Booster Number X. (Presumably because "Starship SN20 and Booster SN4" would be confusing?)

I can only assume they then changed everything over because they wanted to simplify the naming scheme and make it consistent.

The labels put on newer barrel sections by SpaceX after SN15's flight began to read "S-22" "B-7" etc. (though nobody outside of SpaceX seems to use the hyphens) and Raptor designations became "RC60", "RB1", "RV2" etc.

Elon recently used "Booster 4 and Ship 20" so presumably that's how you're supposed to pronounce them. I think because the whole system is technically supposed to be "Starship", but the booster is not a ship, and the ship is not a booster?

https://twitter.com/elonmusk/status/1472072191483256834

Personally I still prefer "SN20" and "BN4". The "N" just gives it that extra zing, you know? Feels more like a solidly engineered aerospace system. "S20" is just wimpy and sounds like an ingredient you'd read off the back of a shampoo bottle.
Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: Slothman on 12/30/2021 04:35 am
Sorry this is a repeat but I can't find the answer with the searches I tried.

When and why was "Starship 20" changed to "Ship 20" and is the designation SN20 or S20 or both?

Ship 20 (S20) and Booster 3 (B3) were the first to get the new naming scheme (around June 2021). Both were originally SN20 and BN3.

As best as I understand it:

SN8 originally stood for "Serial Number 8". The PA announcements and the SpaceX livestream commentary would usually read it as "Starship serial number X". Raptors were also referred to as "Raptor SN50" etc.

When they started building boosters in early 2021, they began by calling them "BN1, BN2", etc. standing for Booster Number X. (Presumably because "Starship SN20 and Booster SN4" would be confusing?)

I can only assume they then changed everything over because they wanted to simplify the naming scheme and make it consistent.

The labels put on newer barrel sections by SpaceX after SN15's flight began to read "S-22" "B-7" etc. (though nobody outside of SpaceX seems to use the hyphens) and Raptor designations became "RC60", "RB1", "RV2" etc.

Elon recently used "Booster 4 and Ship 20" so presumably that's how you're supposed to pronounce them. I think because the whole system is technically supposed to be "Starship", but the booster is not a ship, and the ship is not a booster?

https://twitter.com/elonmusk/status/1472072191483256834

Personally I still prefer "SN20" and "BN4". The "N" just gives it that extra zing, you know? Feels more like a solidly engineered aerospace system. "S20" is just wimpy and sounds like an ingredient you'd read off the back of a shampoo bottle.

Hey I commonly take the S4 metro line into the city. Maybe some day we can say "I'll take the S500 to the moon later and be with you at 6"
Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: Johnnyhinbos on 12/30/2021 02:05 pm
Looks like they just attached guide ropes to base of B4. A lift could be imminent…

My thinking is they will remove B4 from launch mount and put it on a transport stand next to the mount. They will then test out the ability to maneuver booster between chopstick arms and place it so that the lifting points line up with track mechanism on top of arms within tolerance.

Few notes:
- The staging at top arm carriage where the arm attaches to drag chain has been removed, implying major work at the interface is done.

- The staging up tower is still in place, but there is enough clear space above arms to do a small lift for testing.

- the arm hoist rope leading down to deadhead at base of tower runs through a small standoff just before dropping through the roof of the hoisting room. It looks like the rope angles coming out of this standoff. I’d expect this standoff to be removed before any lifting action as it doesn’t look like it’s designed for any lateral loading. Suspect it’s a temporary clamp during construction.
Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: Tangilinear Interjar on 12/30/2021 09:26 pm
I'm pretty sure we will see the tower painted before any real lifting happens. That's the most likely reason for all the scaffolding.

There's still a bunch of deluge work and testing to be done on the launch mount so they won't want the booster around for that.

Also the chopsticks are a crane so need to be proof tested and certified and I'm very confident that won't be done using a booster. When we see them loading up a big pile of counter weights under the chopsticks that will mean they are getting serious.
Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: Johnnyhinbos on 12/31/2021 10:53 am
Tower scaffolding started coming down EOD yesterday.
Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: WiresMN on 12/31/2021 01:06 pm
I'm pretty sure we will see the tower painted before any real lifting happens. That's the most likely reason for all the scaffolding.

There's still a bunch of deluge work and testing to be done on the launch mount so they won't want the booster around for that.

Also the chopsticks are a crane so need to be proof tested and certified and I'm very confident that won't be done using a booster. When we see them loading up a big pile of counter weights under the chopsticks that will mean they are getting serious.

Booster 5 is waiting in the wings for a chance to fly. I could see them using it for the first lift tests with weight. I expect the first movements will be empty.
Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: Hamish.Student on 12/31/2021 03:56 pm
Tower scaffolding started coming down EOD yesterday.
   
 
EOD?
Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: Johnnyhinbos on 12/31/2021 04:24 pm
Tower scaffolding started coming down EOD yesterday.
   
 
EOD?
End of Day
Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: clongton on 12/31/2021 06:10 pm
SpaceX removed Booster 4 from the Orbital Launch Mount after recently undergoing cryo proof tests. B4 was later moved to the landing pad. Meanwhile, the new High Bay continued to rise and Ship 24;s common dome was spotted outside the production tents.<snip>

I am curious how SpaceX will automate the lowering and circular orientation of a booster being loaded. They obviously can't continue with crews of ironworkers like that pushing, shoving and spinning the booster to get it in the right place.
Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: DanClemmensen on 12/31/2021 06:25 pm
SpaceX removed Booster 4 from the Orbital Launch Mount after recently undergoing cryo proof tests. B4 was later moved to the landing pad. Meanwhile, the new High Bay continued to rise and Ship 24;s common dome was spotted outside the production tents.<snip>

I am curious how SpaceX will automate the lowering and circular orientation of a booster being loaded. They obviously can't continue with crews of ironworker like that pushing, shoving and spinning the booster to get it in the right place.

I think the chopsticks have provision for adjusting the position of the booster in six dimensions (X, Y, Z, pitch, roll, yaw), all to a fine degree. Coarse X,Y,Z positioning is done with the drawworks and the big hydraulics that swing the arms. Roll is done by fine positioning of the pins along the arms. Pitch and yaw are done by the hydraulics on the lower stabilizer arms that hang from the arms and connect to the lower stabilization points on the SH (or SS) and possibly by differential height adjustment by the hydraulics that raise and lower the tracks that carry the pins. If I am correct that all these actuators exist, then the fine control will require feedback from cameras or other sensors.
Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: Nevyn72 on 01/03/2022 08:39 pm
Interesting image today from BocaChicaGal (legend) of the S24 common dome sleeve.

You can clearly see on the side a heavy duty protrusion that would have to most likely be a 'catch pin' for use by the chopsticks during stacking and landing operations.

Given it would end up roughly in line with the common dome that puts it quite low on the Ship overall but still works from a centre of gravity perspective on a mostly empty ship and well clear of both sets of flaps.

What do you all think?
Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: awests on 01/03/2022 09:25 pm
I think they typically cap the open pipe ends that penetrate through the side wall during stacking and sleeving. Once they are ready to run exterior plumbing they remove the welded cap and run the exterior lines.

TLDR: Most likely through tank wall penetration, not catching part.
Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: cpushack on 01/03/2022 09:49 pm
I think they typically cap the open pipe ends that penetrate through the side wall during stacking and sleeving. Once they are ready to run exterior plumbing they remove the welded cap and run the exterior lines.

TLDR: Most likely through tank wall penetration, not catching part.

There is some interesting welds a meter or 2 on each side of it, seems like a pretty long reinforcing plate supports that on the inside of the tank wall. 
Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: DigitalMan on 01/03/2022 10:06 pm
Chris's post in the updates thread about the methane header moving to the nose makes me happy in that the mechanism previously used had some characteristics that I didn't think were very helpful for reliability, now they are gone.

A side thought: Elon had previously said that for certain areas, it might be necessary to use some technique, such as transpiration cooling, rather than tiles (such as particular areas around the fins). Has anyone seen evidence of this?
Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: NH22077 on 01/03/2022 10:11 pm
Interesting image today from BocaChicaGal (legend) of the S24 common dome sleeve.

You can clearly see on the side a heavy duty protrusion that would have to most likely be a 'catch pin' for use by the chopsticks during stacking and landing operations.

Given it would end up roughly in line with the common dome that puts it quite low on the Ship overall but still works from a centre of gravity perspective on a mostly empty ship and well clear of both sets of flaps.

What do you all think?

I think it will be higher up.

https://twitter.com/elonmusk/status/1432276054664744961

Quote
I remember you saying that Mechazilla will
 catch Super Heavy booster + ship, wondering
how the ship will caught using the Mechazilla?
In other words, what will the Mechazilla
latch on to for catching the Ship, will it be
upper flap wings? As for Super Heavy booster
there's fins

Booster has 2 pins for lifting & catching,
although maybe itís better to modify grid
fins to take more load.
Something will need to flip out from leeward
side of top of ship to do same there. Maybe
itís part of fwd flaps, but prob not.
Diff solutions for diff load paths."
Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: Nevyn72 on 01/04/2022 02:09 am
Chris's post in the updates thread about the methane header moving to the nose makes me happy in that the mechanism previously used had some characteristics that I didn't think were very helpful for reliability, now they are gone.

A side thought: Elon had previously said that for certain areas, it might be necessary to use some technique, such as transpiration cooling, rather than tiles (such as particular areas around the fins). Has anyone seen evidence of this?

I suspect the move may also be needed to help balance the additional weight of 3 more Raptor Vac engines at the other end.
Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: Nevyn72 on 01/04/2022 02:10 am
I think they typically cap the open pipe ends that penetrate through the side wall during stacking and sleeving. Once they are ready to run exterior plumbing they remove the welded cap and run the exterior lines.

TLDR: Most likely through tank wall penetration, not catching part.

Taking a closer look at the zoomed image, I think you may be right.
Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: raivo45 on 01/07/2022 10:29 am
Has this been discussed yet? Looks like the B2.1 test tank crumpled a bit with the testing, there's a crease in the thrust section just above the stiffener ring they added.(Thanks to u/ClayWatney for mentioning it on Reddit.),(Pic is from Dec 21 update video.)
Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: sferrin on 01/07/2022 11:40 am
Has this been discussed yet? Looks like the B2.1 test tank crumpled a bit with the testing, there's a crease in the thrust section just above the stiffener ring they added.(Thanks to u/ClayWatney for mentioning it on Reddit.),(Pic is from Dec 21 update video.)


I haven't seen any discussion of this setup at all.  I too am interested.  I'd love to know if this was a test to failure or if it failed requirements.
Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: beelsebob on 01/07/2022 05:46 pm
Has this been discussed yet? Looks like the B2.1 test tank crumpled a bit with the testing, there's a crease in the thrust section just above the stiffener ring they added.(Thanks to u/ClayWatney for mentioning it on Reddit.),(Pic is from Dec 21 update video.)


I haven't seen any discussion of this setup at all.  I too am interested.  I'd love to know if this was a test to failure or if it failed requirements.
Unfortunately, that's something we're unlikely to know by any means other than whether we see things flying and failing.  Similarly, we don't know for sure if the tanks hold the requisite pressures for actually flying things, or if they're just strong enough to test just now.  We never see the actual numbers, just things going boom or not.

For me, it's rather unclear from that image if there is a failure or not.  There's a lot of complex geometry at that area of the vehicle, and a lot of complex reflections.  It could be a reflection, ambient light occlusion, etc.
Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: raivo45 on 01/07/2022 07:18 pm
In Dec 22 update video it can be clearly seen that it's not "straight" anymore. My guess is that their calculations/simulations showed that it would fail there(at the force they wanted to test it with) and they tried to strenghten it by adding the stiffener ring but it wasn't enough...

Of course there's no way for us to know what loads it was tested at but I'd like to point out that B4 has the same thrust section design.

The new booster design has the entire outside of the thrust section covered with stringers.(Can be seen in the Dec 22 update video.)
Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: Oersted on 01/08/2022 11:13 pm
2021 Overview vid. 26 mins, multiday edit - very cool!

https://www.youtube.com/watch?v=iVqjh3JH4cU

https://twitter.com/thejackbeyer/status/1478065794353283072

This is such a great overview of 2021! - Can't believe that this video hasn't gotten more likes. What a huge editing job and also sterling commentary. Kudos to all involved and many many thanks for your effort. 
Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: DanClemmensen on 01/09/2022 04:12 pm
Something being lowered into the chopsticks.

You can actually see what look like the same little nubbins present on Super Heavies on both sides. The only plausible explanation I can think of: mass sim meant for testing the booster conveyor system :)
My guess: alignment jig. It allows precise calibration of the sensors and actuators for the movable pin portions of the two arms relative to each other in several dimensions. Also to calibrate the squeezing force relative to the commands to the actuators.
Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: Sciencefan on 01/09/2022 07:17 pm
Not just alignment. There is also black pins to loop cables around. Most likely we will see soon how the tower lift some load on that bar.
Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: TheGull on 01/11/2022 05:00 pm
In Dec 22 update video it can be clearly seen that it's not "straight" anymore. My guess is that their calculations/simulations showed that it would fail there(at the force they wanted to test it with) and they tried to strenghten it by adding the stiffener ring but it wasn't enough...

Of course there's no way for us to know what loads it was tested at but I'd like to point out that B4 has the same thrust section design.

The new booster design has the entire outside of the thrust section covered with stringers.(Can be seen in the Dec 22 update video.)

I always watch those update videos but regarding this detail I passed through. Nice observation, raivo45.
I capture the images you refered on Dec 22 update videos and tryied to post them here. Credits: NSFlight
(http://Screenshot_dec_22_reinforcement.jpg)
(http://Screenshot_dec_22_crease.jpg)
Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: brice on 01/12/2022 06:17 pm
Are those "ballast" bags custom for SpaceX or do they have another use in industry? Does anyone know the general name for them? Google is failing me.
Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: tleski on 01/12/2022 06:29 pm
Google the following:
load test water weight bags
Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: AJW on 01/12/2022 06:36 pm
Ninja'd... Google 'Water Weight Load Testing'    These are brought in to verify load strength on overhead lifts, cranes, walkways and even boats to test how susceptible they are to listing and heeling.  You don't have to bring weights, they can be filled from regular hydrants, and they are environmentally friendly.

https://www.youtube.com/watch?v=zt8yjQTM2JE&ab_channel=LiftsafeGroupofCompanies
Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: equiserre on 01/12/2022 07:03 pm
OK, my pixel counting is there are 2x 6.2m diam + 1x 4.3m diam bags per side. Considering a water volume of 70% of a sphere per bag when full, there would be 200t per side, 400t (metric) total

Or, has anyone seen labels on the bags indicating capacity?

FWIW
Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: gsa on 01/13/2022 10:06 am
OK, my pixel counting is there are 2x 6.2m diam + 1x 4.3m diam bags per side. Considering a water volume of 70% of a sphere per bag when full, there would be 200t per side, 400t (metric) total
Or, has anyone seen labels on the bags indicating capacity?
Yes, see the latest daily video. The big ones are 100t. Apparently, the small ones are 50t, but I haven't seen any labels on them.
So, your calculations are pretty much correct. Yet they don't fill all bags at once. My estimation is 300t. Ish. :)
Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: capoman on 01/13/2022 01:22 pm
Ninja'd... Google 'Water Weight Load Testing'    These are brought in to verify load strength on overhead lifts, cranes, walkways and even boats to test how susceptible they are to listing and heeling.  You don't have to bring weights, they can be filled from regular hydrants, and they are environmentally friendly.

https://www.youtube.com/watch?v=zt8yjQTM2JE&ab_channel=LiftsafeGroupofCompanies

Another advantage is if there is a failure and they get dropped. Dropped water bags will cause far less damage (such as the OLM) if for some reason they get dropped than a solid mass simulator.
Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: Sciencefan on 01/14/2022 02:16 pm
Worth of mentioning that the filled bags was moved forward with help of actuators on the chopsticks and back later.

How it was in the middle position:
(https://pbs.twimg.com/media/FI2atnqUYAEd3s0?format=jpg&name=small)
Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: Slothman on 01/14/2022 06:40 pm
Worth of mentioning that the filled bags was moved forward with help of actuators on the chopsticks and back later.

How it was in the middle position:
(https://pbs.twimg.com/media/FI2atnqUYAEd3s0?format=jpg&name=small)

They're literally in the same position in both images
Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: Sciencefan on 01/14/2022 07:39 pm
They're literally in the same position in both images

The bar with bags moved several meters forward. The default position is between the vertical beams that should hold Starship exactly over the center of the launch mount.
Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: edzieba on 01/15/2022 12:05 pm
They're literally in the same position in both images

The bar with bags moved several meters forward. The default position is between the vertical beams that should hold Starship exactly over the center of the launch mount.
That can't be inferred from those images, as they show the catch arms at two different angles with respect to the camera, and the two objects you are comparing are at different Z-depths.
Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: Slothman on 01/15/2022 12:41 pm
They're literally in the same position in both images

The bar with bags moved several meters forward. The default position is between the vertical beams that should hold Starship exactly over the center of the launch mount.
That can't be inferred from those images, as they show the catch arms at two different angles with respect to the camera, and the two objects you are comparing are at different Z-depths.

My comment was based on the vertical straps that hold the water bags, which seem to be in both pictures at nearly exactly the point where the 3rd strut meets the bottom beam of the chopstick. That seems to be the same location in both images, 3rd strut from the front.

Of course I didn't observe the whole day so it could have moved or the movement was just a few centimeters, which isn't quite discernable, but at least based on those 2 images the load seems to be in pretty much the same place.
Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: Sciencefan on 01/15/2022 12:55 pm
That can't be inferred from those images, as they show the catch arms at two different angles with respect to the camera, and the two objects you are comparing are at different Z-depths.

Obvious that on the second image the bags not in the plane with the vertical bars. There is plenty of shots of first day of testing where bags exactly between bars when they tested movement around the launch mount. On the second day they tested sliders. Apparently, all tests was ok.
Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: Sciencefan on 01/15/2022 02:56 pm
With some pixel hunting and the assumption of 30 meters length of the chopstick i got that the bags was moved 1.5 meters forward.
Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: su27k on 01/16/2022 11:13 am
Not sure if these has been posted, reddit says the black hexagon on the booster is Starlink antenna.
Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: EnricoR on 01/16/2022 01:44 pm
Does anyone know what the orange cylinders are?
Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: cdebuhr on 01/16/2022 03:10 pm
Does anyone know what the orange cylinders are?
I Second the question.  One thought that comes to mind ... jettisonable data recorders?  I didn't say it was a great thought, its just all I've got at the moment.  I think I remember an Elon tweet a while back saying they were thinking about this for the test flight, and it seems like a good idea to be sure you capture all the data without having the rely on wireless telemetry.  They're also the right shade of "black-box orange", and look like they're attached in a way that would support in-flight deployment.
Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: cpushack on 01/17/2022 06:53 am
Does anyone know what the orange cylinders are?
I Second the question.  One thought that comes to mind ... jettisonable data recorders?  I didn't say it was a great thought, its just all I've got at the moment.  I think I remember an Elon tweet a while back saying they were thinking about this for the test flight, and it seems like a good idea to be sure you capture all the data without having the rely on wireless telemetry.  They're also the right shade of "black-box orange", and look like they're attached in a way that would support in-flight deployment.

It is very much what they look like, Commercial off the shelf ones are available (often water activated, usually for ships, but wouldn't be bad for a starship landing in the ocean
Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: Okie_Steve on 01/17/2022 01:47 pm
https://mobile.twitter.com/RGVaerialphotos/status/1482439093707591682/photo/1

RGV Aerial Photography posted this pic of the rocket garden at the bend in Remedios.

Are those aero covers beside B5 like the ones recently installed on B4?
Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: Tangilinear Interjar on 01/18/2022 05:05 pm
I've a theory on why the crane was hooked up to the Starship.

I suspect that they don't want to leave an unpressurized vehicle sitting unsupported on the mounts.

They need to remove the umbilical connections in order to install the aero covers, therefore they need to support the ship with the crane so they can depressurize.

To me this indicates continuing intension to use S20 for the first launch.
Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: meekGee on 01/18/2022 08:07 pm
May have to clear some portapotties off the road before reopening.

Per LabPadre Rover 2.0
It's a lot easier to clean up when frozen.  I know.
Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: Slothman on 01/18/2022 08:51 pm
I wonder, previously (after a few test tank takeoffs I think) they strapped down the test tanks to their stands. Any known reason why they didn't do that now?
Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: wannamoonbase on 01/18/2022 08:52 pm
I wonder, previously (after a few test tank takeoffs I think) they strapped down the test tanks to their stands. Any known reason why they didn't do that now?

Only reason I can guess is that they didn't want any interference on the loads.
Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: alugobi on 01/18/2022 08:52 pm
I've a theory on why the crane was hooked up to the Starship.

I suspect that they don't want to leave an unpressurized vehicle sitting unsupported on the mounts.

They need to remove the umbilical connections in order to install the aero covers, therefore they need to support the ship with the crane so they can depressurize.

To me this indicates continuing intension to use S20 for the first launch.
Or to steady it in case part of the now-burst test tank flew over and whacked it.
Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: Slothman on 01/18/2022 08:55 pm
I wonder, previously (after a few test tank takeoffs I think) they strapped down the test tanks to their stands. Any known reason why they didn't do that now?

Only reason I can guess is that they didn't want any interference on the loads.

Sorry just took a better look and it seems there were ropes.
Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: Oersted on 01/18/2022 09:13 pm
I have been missing SpaceX blowing up stuff at Boca Chica. Quite a satisfying pop, though of course far from the triumphal Starship conflagrations.
Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: Sciencefan on 01/18/2022 09:31 pm
Sorry just took a better look and it seems there were ropes.

Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: AstroDave on 01/18/2022 09:32 pm
  With all the high tech accomplishments going on in Boca Chica, seeing the Porta-Potty wall get taken out by the nitrogen tsunami really entertained the juvenile part of my brain today.
  Check out StevenOBrien's post on the update thread:
https://forum.nasaspaceflight.com/index.php?topic=54984.msg2332226#msg2332226
https://forum.nasaspaceflight.com/index.php?topic=54984.msg2332238#msg2332238

  Many thanks to LabPadre for having a remote camera going, and NSF as always for having the live feed up. Watch the NSF feed at the time stamp shown to see the tsunami take out the porta-pottys.
Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: Robotbeat on 01/18/2022 09:40 pm
LOL that is hilarious!
Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: atsf90east on 01/18/2022 10:00 pm
It's probably a good thing for all involved that the Porta-Potties were flash frozen before they were blown against the white pickup truck, or the truck may have instantly gained a new color scheme :-)

LOL that is hilarious!
Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: Oersted on 01/18/2022 10:03 pm
Are the portapotties part of SpaceX' environmentally friendly methane production effort?
Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: envy887 on 01/18/2022 10:03 pm
GSE-4 test today it would appear. Not as fun as the old "pop/splosh" days. ;)

Uh, as were you saying?

Someone better remind Chris not to say how boring things are when the actual launch comes around  ;D
Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: Chris Bergin on 01/18/2022 10:22 pm
Yep, I jinxed it like I jinxed the New York Jets when our discord told me to pick a NFL team :D
Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: abaddon on 01/19/2022 12:05 am
Yep, I jinxed it like I jinxed the New York Jets when our discord told me to pick a NFL team :D
You can't jinx terrible.
Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: Nomadd on 01/19/2022 12:51 am
 It's my fault. Things tend to blow up wherever I visit. They're lucky they didn't have a volcano go off.
Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: Vultur on 01/19/2022 01:10 am
I wonder what happened? Seems like their welding and such has been pretty practiced...
Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: clongton on 01/19/2022 01:42 am
Can just about see the remains of GSE4 now on the NSF feed.

And Michael Baylor has the NSF Live clip on Twitter:

The GSE-4 test tank has popped!

My guess is that's why Ship 20 was lifted and suspended.
Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: robot_enthusiast on 01/19/2022 01:48 am
I wonder what happened? Seems like their welding and such has been pretty practiced...
Destructive testing to determine exact failure points is one of the primary purposes for building test tanks. Considering that this is the same design as all the other GSE tanks which were successfully cryo tested and have been happily storing cryo fluids (including those used for this test) ever since, we know that the GSE tanks have enough margin to be used operationally. Exactly how much margin that is was most likely the main question they were hoping to answer with this test.
Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: xyv on 01/19/2022 03:49 am
And why were they destructively testing now? Hmmm?  Think it might have something to do with ongoing discussion of GSE tank separation distance?  A safety analysis is probabilistic in nature.  I wonder if they are demonstrating that one of the coefficients in the model is really better (or worse - we don't know the expected versus demonstrated failure point  ;D)
Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: awests on 01/19/2022 04:01 am
There are some twitter threads showing close ups of a test tank. It appears that the can crusher tests may have structurally compromised the sidewall. It looks like the tank failed today at the location that the tank was deformed during the crusher tests.

EDIT: Apparently I need to spend more time tank watching...
Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: cdebuhr on 01/19/2022 04:09 am
There are some twitter threads showing close ups of SN4. It appears that the can crusher tests may have structurally compromised the sidewall. It looks like the tank failed today at the location that the tank was deformed during the crusher tests.
That was a different tank.
Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: abaddon on 01/19/2022 04:29 am
It's my fault. Things tend to blow up wherever I visit. They're lucky they didn't have a volcano go off.
How did you like Tonga?
Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: awests on 01/19/2022 04:37 am
There are some twitter threads showing close ups of SN4. It appears that the can crusher tests may have structurally compromised the sidewall. It looks like the tank failed today at the location that the tank was deformed during the crusher tests.
That was a different tank.

Oops, you are correct. My mistake.
Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: su27k on 01/19/2022 05:08 am
An interesting twitter thread about the difference between B4 and B7 (the first tweet is hyperbole and can be ignored):

https://twitter.com/csi_starbase/status/1483158431506657281
Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: CameronD on 01/19/2022 06:35 am
I wonder what happened? Seems like their welding and such has been pretty practiced...
Destructive testing to determine exact failure points is one of the primary purposes for building test tanks. Considering that this is the same design as all the other GSE tanks which were successfully cryo tested and have been happily storing cryo fluids (including those used for this test) ever since, we know that the GSE tanks have enough margin to be used operationally. Exactly how much margin that is was most likely the main question they were hoping to answer with this test.

Looks to me like maybe the safety valve(s) iced over?  Pressure vessels are designed to fail pretty-much exactly the way that one did, dissipating the energy vertically by splitting around the circumference.. but..

WOW!!!  Seeing those vehicles get engulfed in liquid nitrogen tells me that perhaps that "test" didn't entirely go to plan.  Inflated rubber tires (and porta-potti poo seals!) generally don't handle LN2 so well - they usually fragment immediately - so the clean-up/repair bill from this could be rather expensive (and messy).
 
Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: woods170 on 01/19/2022 09:24 am
An interesting twitter thread about the difference between B4 and B7 (the first tweet is hyperbole and can be ignored):

https://twitter.com/csi_starbase/status/1483158431506657281 (https://twitter.com/csi_starbase/status/1483158431506657281)

That first tweet is much less hyperbole than you want to make everyone believe.
Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: OTV Booster on 01/19/2022 03:46 pm
I wonder what happened? Seems like their welding and such has been pretty practiced...
I've gotta wonder if it had something to do with the number of pressure cycles. Alternatively, they intentionally tested to destruction only after running all the other tests they had in mind.


Has anybody kept track of how many times it was cycled? How does that relate to other tanks?
Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: StuffOfInterest on 01/19/2022 04:08 pm
I wonder what happened? Seems like their welding and such has been pretty practiced...
I've gotta wonder if it had something to do with the number of pressure cycles. Alternatively, they intentionally tested to destruction only after running all the other tests they had in mind.

If the intent was to test to destruction, perhaps the tank held together longer than expected resulting in much higher pressure being released when it finally did blow.  Since there were ropes in place, they were prepared for the top of the tank to be liberated.  I think it just exceeded their expectations a bit.
Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: SteveU on 01/19/2022 04:20 pm
I wonder what happened? Seems like their welding and such has been pretty practiced...
I've gotta wonder if it had something to do with the number of pressure cycles. Alternatively, they intentionally tested to destruction only after running all the other tests they had in mind.

If the intent was to test to destruction, perhaps the tank held together longer than expected resulting in much higher pressure being released when it finally did blow.  Since there were ropes in place, they were prepared for the top of the tank to be liberated.  I think it just exceeded their expectations a bit.
There was discussion that they were having difficulty getting the vertical LCH4 tanks certified.  Could this be a test to destruction for that certification ?
Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: CameronD on 01/19/2022 11:10 pm
I wonder what happened? Seems like their welding and such has been pretty practiced...
I've gotta wonder if it had something to do with the number of pressure cycles. Alternatively, they intentionally tested to destruction only after running all the other tests they had in mind.

If the intent was to test to destruction, perhaps the tank held together longer than expected resulting in much higher pressure being released when it finally did blow.  Since there were ropes in place, they were prepared for the top of the tank to be liberated.  I think it just exceeded their expectations a bit.
There was discussion that they were having difficulty getting the vertical LCH4 tanks certified.  Could this be a test to destruction for that certification ?

"Test to destruction"... so that's the latest Rocketspeak for any kind of RUD?!??

In that case, their first Hopper flight wasn't a failure at all, but was really a "test to destruction".  I like it!  8)
Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: jpo234 on 01/19/2022 11:14 pm


"Test to destruction"... so that's the latest Rocketspeak for any kind of RUD?!??
Depends on the intention. If the goal of the test is the destruction, then it is by definition not a RUD.
Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: xvel on 01/19/2022 11:16 pm
I wonder what happened? Seems like their welding and such has been pretty practiced...
I've gotta wonder if it had something to do with the number of pressure cycles. Alternatively, they intentionally tested to destruction only after running all the other tests they had in mind.

If the intent was to test to destruction, perhaps the tank held together longer than expected resulting in much higher pressure being released when it finally did blow.  Since there were ropes in place, they were prepared for the top of the tank to be liberated.  I think it just exceeded their expectations a bit.
There was discussion that they were having difficulty getting the vertical LCH4 tanks certified.  Could this be a test to destruction for that certification ?

"Test to destruction"... so that's the latest Rocketspeak for any kind of RUD?!??

In that case, their first Hopper flight wasn't a failure at all, but was really a "test to destruction".  I like it!  8)

https://en.wikipedia.org/wiki/Destructive_testing

Even nasa is doing it sometimes:
https://www.nasa.gov/exploration/systems/sls/nasa-engineers-break-sls-test-tank-on-purpose-to-test-extreme-limits.html

We have no confirmation that the last test was destructive on purpose, but it probably was.
Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: Ben Baley on 01/20/2022 06:30 am
An interesting twitter thread about the difference between B4 and B7 (the first tweet is hyperbole and can be ignored):

https://twitter.com/csi_starbase/status/1483158431506657281 (https://twitter.com/csi_starbase/status/1483158431506657281)

That first tweet is much less hyperbole than you want to make everyone believe.

What indicators are there that point to B4 not being used for the Orbital flight test?

The last tweet from Musk on the subject indicates they were still planning on using B4, and SpaceX has continued to work on bringing B4 to flight readiness recently installing aerocovers. Plans can always change especially if we see more regulatory delays but from all indications I have seen the current plan is to use B4.
Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: woods170 on 01/20/2022 08:30 am
An interesting twitter thread about the difference between B4 and B7 (the first tweet is hyperbole and can be ignored):

https://twitter.com/csi_starbase/status/1483158431506657281 (https://twitter.com/csi_starbase/status/1483158431506657281)

That first tweet is much less hyperbole than you want to make everyone believe.

What indicators are there that point to B4 not being used for the Orbital flight test?

The last tweet from Musk on the subject indicates they were still planning on using B4, and SpaceX has continued to work on bringing B4 to flight readiness recently installing aerocovers. Plans can always change especially if we see more regulatory delays but from all indications I have seen the current plan is to use B4.

Emphasis mine.
Indicators come directly from my own sources at SpaceX. B4 will see ground testing, but nothing else.
Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: Lampyridae on 01/20/2022 11:21 am
Emphasis mine.
Indicators come directly from my own sources at SpaceX. B4 will see ground testing, but nothing else.

I can believe that. Might even try for a catch the first time around. What about Ship 20?
Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion
Post by: LouScheffer on 01/20/2022 12:52 pm
SpaceX has continued to work on bringing B4 to flight readiness recently installing aerocovers.
It's not clear that installing aerocovers on B4 implies it is on the path to flight readiness.  You want to check the fit of every part, and practice every possible installation procedure, before you need to do it on your flight vehicle.  You'll need to practice un-installing it, too, as for sure many of the repair and refurbishment procedures start with "First, remove the aerocover..."
Title: Re: SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion