SpaceX Starship : Texas Prototype(s) Thread 23 : Discussion

[Lee Jay]

The new platform effectively makes it ground level when it's raised.  The various camera views show dudes walking around in that space as though they were on the floor. 

I've spent many thousands of hours working at height and many thousands more supporting others working at height.

General rule of thumb - whatever it takes for you to do it on the ground, multiply by 5 when doing it at height.

Depending on the "at height" situation, reasons could include:

Time it takes to get to the height.
Dropped tools falling to the ground and you have to go get them (this is real fun when it's a small allen wrench that lands in the gravel).
Forgotten or not anticipated tools or supplies.  Have to go back down and get them.
Having to go down and back up for bathroom breaks and/or food breaks.
Having to tie-off (depending on the situation).
Limited space for people.
Limited space for equipment.
Working around weather contraints.
Being in the sun and high heat rather than indoors.

All this just makes it slower to do stuff compared with in a lab/highbay/whatever on the ground.

[tgr9898]

To Lee's excellent list above I'd add that we know the platform can support a number of people. It most likely can support a Raptor or two.
13 might be a bit much weight.

[alugobi]

Don't have to put all 13 up at once. 

The floor is lowered and raised in a few minutes.  It's not that high; there are stairs. Whether on the ground or on the platform, it's the same space in the engine bay.  And it's out of the weather. 

Lee's list is a good one, but not, in toto, a strong case for not installing engines at the site.  Up on the high bay scaffolding, not doubt about it.  But the OLM?  Not so much in my estimation.

[Sohl]

Any ideas why so much dust was kicked up with the 20 second static fire?  I would think that most of the available nearby loose dust would be cleared in a few seconds, but it kept billowing and billowing through the burn.  It's kind of awesome but makes it darn hard to see that even-more-awesome exhaust plume!

[lykos]

Don't have to put all 13 up at once. 

The floor is lowered and raised in a few minutes.  It's not that high; there are stairs. Whether on the ground or on the platform, it's the same space in the engine bay.  And it's out of the weather. 

Lee's list is a good one, but not, in toto, a strong case for not installing engines at the site.  Up on the high bay scaffolding, not doubt about it.  But the OLM?  Not so much in my estimation.

It's not only the 13 Raptors, the shielding arround the inner engines and at the outside of the 20 has to be mounted too!

[alugobi]

It's not only the 13 Raptors, the shielding arround the inner engines and at the outside of the 20 has to be mounted too!

Excellent point about the outside of the 20, a step that I had forgotten about.  That in itself may be sufficient reason to take it down.

[[email protected]]

"So in good old Elon fashion, SpaceX decided "best part is no part" and went for "no water deluge is the best water deluge" -- a decision that if I remember right was commented on by Musk on Twitter too along the lines of "might have been a mistake, we shall see.."

I think that comment was regarding a flame diversion trench.

You are right, I misremembered.

That being said, I can't remember seeing any water deluge being used on the OLM ever. Only on pad A and B. The former landing pad had one of these remote controlled fire suppression cannons.

Also for real water deluge you'd need a tall tower for some head pressure and volume. I don't see any such infrastructure anywhere near the Orbital pad.. Compare with the thickness of water pipes on Pad 39A or in Vandenberg SFB.

Or a regular water tank with big pump, which is what they're using on Starbase. Doesn't have to be 39A-style water tower (SLC-40 doesn't have one either)

They're not using deluge simply because they're firing one engine in a stand that's designed for 33 engines

[kdhilliard]

... They're not using deluge simply because they're firing one engine in a stand that's designed for 33 engines

But have you ever seen *any* indication of a deluge test at the Orbital Launch Mount?

One of the criticisms I recall of the FAA Programmatic Environmental Assessment was that it didn't cover a deluge system and its associate retention ponds, so that if SpaceX decides one is necessary they will have to go through a lengthy process with the U.S. Army Corps of Engineers to get it permitted.

[tacoLover7916]

Have they had a mariner notice like this before for static fires? In the past I was thinking they only did this notice for the test flights? Might this indicate a larger prop load or more engines than previous static fires?

Austin

https://forum.nasaspaceflight.com/index.php?topic=56074.msg2395916#msg2395916

[chopsticks]

... They're not using deluge simply because they're firing one engine in a stand that's designed for 33 engines

But have you ever seen *any* indication of a deluge test at the Orbital Launch Mount?

One of the criticisms I recall of the FAA Programmatic Environmental Assessment was that it didn't cover a deluge system and its associate retention ponds, so that if SpaceX decides one is necessary they will have to go through a lengthy process with the U.S. Army Corps of Engineers to get it permitted.

Did you see the video linked upthread a bit?

[StevenOBrien]

Have they had a mariner notice like this before for static fires? In the past I was thinking they only did this notice for the test flights? Might this indicate a larger prop load or more engines than previous static fires?

Austin

https://forum.nasaspaceflight.com/index.php?topic=56074.msg2395916#msg2395916

Yes, they've been issued for almost every week since about July.

[GmP]

Did I miss a road closure announcement? Or is that not needed anymore for a quick run between the two sites? No road closures on Fridays (and the weekends)?

[[email protected]]

Did I miss a road closure announcement? Or is that not needed anymore for a quick run between the two sites? No road closures on Fridays (and the weekends)?

Yes, rollout closure no longer needed to be listed in county website. No Friday closures cause it's currently summer, expect them to reappear after that

[kdhilliard]

... They're not using deluge simply because they're firing one engine in a stand that's designed for 33 engines

But have you ever seen *any* indication of a deluge test at the Orbital Launch Mount?

One of the criticisms I recall of the FAA Programmatic Environmental Assessment was that it didn't cover a deluge system and its associate retention ponds, so that if SpaceX decides one is necessary they will have to go through a lengthy process with the U.S. Army Corps of Engineers to get it permitted.

Did you see the video linked upthread a bit?

This post.  Yes, and I know that video from April calls it a water deluge test, but are you telling me there is any consensus here that it was deluge system they just trickled a little water into and not a fire suppression misting system?  (Whenever I watch it I expect to hear the recorded thunder some grocery stores play before their automatic produce misters activate. )

I think there are a lot of people, me included, who can't believe they would try to launch a 33 engine Superheavy booster without a substantial deluge, but I'm still seeing no evidence of such a system.

[JamesH65]

Don't have to put all 13 up at once. 

The floor is lowered and raised in a few minutes.  It's not that high; there are stairs. Whether on the ground or on the platform, it's the same space in the engine bay.  And it's out of the weather. 

Lee's list is a good one, but not, in toto, a strong case for not installing engines at the site.  Up on the high bay scaffolding, not doubt about it.  But the OLM?  Not so much in my estimation.

It's always better to work in a workshop than outside. That's why they built all the hangers....

Bringing that platform up and down thirteen times, with the associated delays as stuff is moved on and off, would seen a compelling enough reason to get back to the high bay, where they can work on multiple engines at one.

The real proof should be that SpaceX did, indeed, take the booster back to install the engines.

[aboveallofit]

I may have missed something...

Is the recent static fire of the outer ring engine the first successful use of the OLM to initiate a raptor startup?

Is there a similar test rig at McGregor for this?

Would it be true that outer ring engines could not be static fired at the sub-orbital pads?

[russianhalo117]

I may have missed something...

Is the recent static fire of the outer ring engine the first successful use of the OLM to initiate a raptor startup?

Is there a similar test rig at McGregor for this?

Would it be true that outer ring engines could not be static fired at the sub-orbital pads?

Off of memory.
The outer ring of engines could not be fired on B3 because the suborbital pads do not support their ability to be fired because the booster adapter and launch mount was in the way.

[DanClemmensen]

I may have missed something...

Is the recent static fire of the outer ring engine the first successful use of the OLM to initiate a raptor startup?

Is there a similar test rig at McGregor for this?

Would it be true that outer ring engines could not be static fired at the sub-orbital pads?

This was not just a test of the engine. The engines are tested at McGregor.

This was a test of the ability to start an outer-ring engine using the OLM and the related functionality of the booster, both of which are very different than the hardware used by the booster to start the other 13 engines.

[BT52]

So you are also thinking that outer rim start-up sequence is done by OLM and not BY booster right? We know those engines are not restartable so i m toying with this idea for long time. Engineers really wanna lose any unnecessarily hardware from booter and transfer it to the olm as much as possible. I can see any helium purging, preheating(i mean prechilling mainly) and spin-up anchielery storage is totally separated and transferred to the OLM.

[aboveallofit]

My understanding, is that to save weight, the start-up hardware for the outer engines has been transferred to the OLM.  Therefore, is the static fire of an outer ring B7 engine a technical first?  I'm not sure I understand how the OLM to Booster transfer works. 

For a 20 second static fire, are initial propellants provided by the OLM and then propellant feed is transferred to the Booster?  Or does the OLM only provide pressurized gas to spin-up Raptor, but propellant is always provided by the Booster?

I don't know whether the startup software/controllers for the outer ring Raptors is on the booster, or the OLM...but in either event, has a previous rocket system technically proven this capability...or has this static fire been a first time demonstration?

I suspect that some sort of testing rig for this exists at McGregor, but I don't know its configuration or how it relates to the OLM configuration.