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

[kevinof]

Also some of the engines are marked in green and others in white.

The green engines are gimballed while the white are fixed.

Landing engines? Would they be using that many on the booster for landing?

[Durham Park]

I think green are engines shipped. You'll notice one of the inner three starship engines is white.

[NL-SpaceNews]

This has been posted in another thread

It shows  what appears to be a countdown to the orbital test launch and the engine configuration of the rockets.
Also some of the engines are marked in green and others in white.

Looks Like Elon is pushing for a pre - July 20th launch 

regards
Serge

[DavP]

I think green are engines shipped. You'll notice one of the inner three starship engines is white.

Yes. Engines shipped. That appears on the screen.

That countdown could be the deadline to have  all the needed engines  shipped

[envy887]

All of this could be understand with a bit of time in Kerbal Space Program, even in the tuturials, but the real answer is whether starship will need to do a deorbit burn? If so, it was orbital, if it was going to decay on the first trip around the earth without a deorbit burn, it's not orbital.

Why not? That's purely a function of ballistic coefficient. If Starship would remain in orbit for 1.01 revs in the nose-prograde low-drag orientation, but changes to the nose-up high-drag orientation and decays in 0.99 revs, how is that intentional change in drag different from an intentional deorbit burn?

[envy887]

All of this could be understand with a bit of time in Kerbal Space Program, even in the tuturials, but the real answer is whether starship will need to do a deorbit burn? If so, it was orbital, if it was going to decay on the first trip around the earth without a deorbit burn, it's not orbital.

Not sure about that..

Since there's no such thing as a gravitational decay in a two body classical system, then you're talking about aerodynamic decay, and then no, decay during the first orbit doesn't mean you weren't orbital, not any more than if you actively de-orbited.

I think we are really discussing the difference between the behaviour of Spherical Cows orbiting Billiard Balls and Real Rockets orbiting Planets.

The best definition is whether at insertion you had enough energy to ballistically go around the earth.

For the Cow, this will mean you stay in orbit forever. For the Rocket, you will immediately experience aerodynamic drag and effectively begin your deorbit manoeuvre. You are now in a region where you must balance drag and boost if you wish to maintain orbital velocity.

If you want to stay in orbit around your Planet you have to go higher to reduce the drag to a manageable level. The ISS is near the top of this region and is effectively deorbiting all the time and left to its own devices would re-enter. It is only kept there by regular orbit boosting burns.

SpaceX are deliberately exploiting the bottom edge of this region to allow for a controlled and predictable flight profile that does not require additional burns and all the complexities that entails. This allows them to maximise the chance of getting permits and also of being able to test high speed re-entry with a passive deorbit system.

So, yes, Starship will be orbital momentarily (English meaning) but will immediately start to deorbit so will not go all the way around.

I don't think they're trying to naturally decay within one-half of an orbit - I think they specifically said they'll do a de-orbit burn.

They want to a) demonstrate orbital velocity and b) hit a specific landing zone.

Besides, natural decay within one-half of an orbit is really difficult and serves no useful purpose.

It's not difficult at all to decay in 1/2 an orbit. Just set your perigee to around 70 km or so.

[aero]

What would that test beyond proving that they can program the guidance system?

They already know that they can start the engines (sort of) and guide to a designated target landing zone.

[DBMandrake]

I think green are engines shipped. You'll notice one of the inner three starship engines is white.

Yes. Engines shipped. That appears on the screen.

That countdown could be the deadline to have  all the needed engines  shipped

I wonder if "shipped" means the engines left Hawthorne for testing in McGregor, or whether it means they've completed testing and certification at McGregor and have been shipped to Boca Chica...

[cwr]

I think green are engines shipped. You'll notice one of the inner three starship engines is white.

Yes. Engines shipped. That appears on the screen.

That countdown could be the deadline to have  all the needed engines  shipped

I wonder if "shipped" means the engines left Hawthorne for testing in McGregor, or whether it means they've completed testing and certification at McGregor and have been shipped to Boca Chica...

Throughout my career, every manufacturing facility that I've known considered
"leaving our loading dock" as "shipped".

I've seen instances of the cargo part of a 6 wheeler loaded and pushed into the
parking lot to await it's front part and that was considered shipped!

So I would expect shipped meant left Hawthorne loading dock.

Carl

[billh]

I think green are engines shipped. You'll notice one of the inner three starship engines is white.

Yes. Engines shipped. That appears on the screen.

That countdown could be the deadline to have  all the needed engines  shipped

I wonder if "shipped" means the engines left Hawthorne for testing in McGregor, or whether it means they've completed testing and certification at McGregor and have been shipped to Boca Chica...

Just spitballing here, but I would guess "shipped" means "shipped" - i.e., finished manufacturing and left the factory. This display is in Hawthorne, after all.

[OTV Booster]

I think green are engines shipped. You'll notice one of the inner three starship engines is white.

Yes. Engines shipped. That appears on the screen.

That countdown could be the deadline to have  all the needed engines  shipped

I wonder if "shipped" means the engines left Hawthorne for testing in McGregor, or whether it means they've completed testing and certification at McGregor and have been shipped to Boca Chica...

Throughout my career, every manufacturing facility that I've known considered
"leaving our loading dock" as "shipped".

I've seen instances of the cargo part of a 6 wheeler loaded and pushed into the
parking lot to await it's front part and that was considered shipped!

So I would expect shipped meant left Hawthorne loading dock.

Carl

If the invoice says FOB (Freight On Board) it's considered shipped when it's loaded on the trailer. FOB is nearly, but not quite universal. Pushing a piece into the parking lot might make the internal paperwork look good but if the invoice is FOB and there is an issue, it will quickly becomes a bigger issue.

It's not just about shipping. Under FOB terms ownership and liability shifts to the receiver when it ships. This is covered in either the 'drayage' (maybe 'cartage') or 'warehousing' chapters of the Universal Commercial Code.

Please, oh please, don't ask for a tighter reference. The UCC is truly mind numbing.


Edit: The engines would be an internal transfer so ownership issues don't apply. I've done a lot of this type of move but never payed attention to the shipping terms.

[DBMandrake]

I think green are engines shipped. You'll notice one of the inner three starship engines is white.

Yes. Engines shipped. That appears on the screen.

That countdown could be the deadline to have  all the needed engines  shipped

I wonder if "shipped" means the engines left Hawthorne for testing in McGregor, or whether it means they've completed testing and certification at McGregor and have been shipped to Boca Chica...

Just spitballing here, but I would guess "shipped" means "shipped" - i.e., finished manufacturing and left the factory. This display is in Hawthorne, after all.

I agree. I guess my point was shipped from Hawthorne doesn't necessarily mean that it has arrived at Boca Chica and is ready and waiting because it first has to go to McGregor for test firings and validation, then ship from there to Boca Chica if the test firings are satisfactory.

While we would hope that all the engines sent to McGregor now are passing their tests and being forwarded on that might not be the case, some may need to go back for rework or have replacements sent.

In short while that picture gives a good idea of the production rate of engines it doesn't really tell us how many engines are ready and waiting at Boca Chica.

[oldAtlas_Eguy]

Yes the expected production rate (shipped out the door from Hawthorn) as evidence from the poster is 24 engines in just less than 26 days!!!!

The real question are they hitting that expected or is it closer to the 1 engine every 2 days from a Elon tweet.

So if that video dates back to end of April first week of May. A much slower production rate of 24 engines in 50 days would be end of June first week of July. Currently the tea leaves are all saying that the first set will all be at Boca Chica by mid July. So the status info and production rate expectation and actual all add up to that the engines will be ready for install on flight vehicles in mid /late July.

Now still need the GSE and the FAA launch license + FCC approvals for the mission/flight experiment.

[capoman]

Yes the expected production rate (shipped out the door from Hawthorn) as evidence from the poster is 24 engines in just less than 26 days!!!!

The real question are they hitting that expected or is it closer to the 1 engine every 2 days from a Elon tweet.

So if that video dates back to end of April first week of May. A much slower production rate of 24 engines in 50 days would be end of June first week of July. Currently the tea leaves are all saying that the first set will all be at Boca Chica by mid July. So the status info and production rate expectation and actual all add up to that the engines will be ready for install on flight vehicles in mid /late July.

Now still need the GSE and the FAA launch license + FCC approvals for the mission/flight experiment.

I suspect everything will be ready long before the FAA approves of the orbital flight. This might cause a window to allow another flight of Starship which will likely be easier to get approval for.

[Lockne]

Now still need the GSE and the FAA launch license + FCC approvals for the mission/flight experiment.

FCC approval has been granted. I don't think this has been posted in the update thread yet:
https://fcc.report/ELS/Space-Exploration-Technologies-Corp-SpaceX/0748-EX-ST-2021/275207

I suspect everything will be ready long before the FAA approves of the orbital flight. This might cause a window to allow another flight of Starship which will likely be easier to get approval for.

That's what I think too. I suspect that is why SN15 and SN16 are on hold, still hooked up to pressure lines, and not scrapped. The most important goal is getting the launch site ready. But if it is ready and the launch license for the full stack isn't there yet, they could resume testing SS rather quickly. The current license should allow for a max q test...I think they have the license for up to 30km suborbital flights with Starship? Of course they'll probably need a new launch clearance, I doubt the 'blanket clearance' for SN15-17 in case of a successful SN15 landing would apply to a different flight profile. But getting a launch clearance for such a test should be possible even without the environmental review being completed.

Also, I believe some SH testing should be possible with the current license too. Maybe not a 29 engine static fire, but possibly cryo or smaller cluster static fires, hot gas thruster tests, etc. So they could still proceed getting SH ready and taking the tank farm online. As long as they have their launch mount and GSE ready, they can continue working towards the orbital launch, while possibly resuming Starship testing. And once they got their launch license, they can proceed with that ASAP.

[wannamoonbase]

Also, I believe some SH testing should be possible with the current license too. Maybe not a 29 engine static fire, but possibly cryo or smaller cluster static fires, hot gas thruster tests, etc. So they could still proceed getting SH ready and taking the tank farm online. As long as they have their launch mount and GSE ready, they can continue working towards the orbital launch, while possibly resuming Starship testing. And once they got their launch license, they can proceed with that ASAP.

Given the all new GSE, generators, electrical infrastructure, new launch structure and vehicles, they could probably tank and detain 10 to 20 times before getting things figured out to be smooth and efficient.

They have a lot of operational procedures to go through and refine, even for SpaceX it's going to take several months.

Then think about the fuel tank yard.  All the liquid methane and Lox next to each other.  Yikes!

[dgkimpton]

If we needed any more proof that SpaceX is running multiple development paths in parallel,

Scott Manley @DJSnM
Starship test flights have all used compressed nitrogen for reaction control thrusters, this looks likely to be the hit has version. Little rocket motors using pressure fed Methalox in gas form - pressurized gas makes them easier to turn in and off for accurate control.

https://twitter.com/DJSnM/status/1407754444884742152?s=20

Elon Musk @elonmusk
Cool, but an unnecessary complication for now. These are being removed to speed up time to orbital launch.

https://twitter.com/elonmusk/status/1407969457411067905?s=20

It's cool they're developing the hot gas thrusters, it's even more cool they aren't going to let that development get in the way of testing the rest of the booster.

[Comga]

If we needed any more proof that SpaceX is running multiple development paths in parallel,

Scott Manley @DJSnM
Starship test flights have all used compressed nitrogen for reaction control thrusters, this looks likely to be the hit has version. Little rocket motors using pressure fed Methalox in gas form - pressurized gas makes them easier to turn in and off for accurate control

https://twitter.com/DJSnM/status/1407754444884742152?s=20

Elon Musk @elonmusk
Cool, but an unnecessary complication for now. These are being removed to speed up time to orbital launch.

https://twitter.com/elonmusk/status/1407969457411067905?s=20

It's cool they're developing the hot gas thrusters, it's even more cool they aren't going to let that development get in the way of testing the rest of the booster.

Proof?
Whatever is being said is fairly garbled.
"...the hit has version"?
What's a guess as to what Manley meant?

And what, specifically is that "unnecessary complication"?
RCS engines burning "methalox", which would actually be gaseous methane and oxygen?
And what is that complex bit of plumbing photographed by Kenniston?

[freddo411]

If we needed any more proof that SpaceX is running multiple development paths in parallel,

Scott Manley @DJSnM
Starship test flights have all used compressed nitrogen for reaction control thrusters, this looks likely to be the hit has version. Little rocket motors using pressure fed Methalox in gas form - pressurized gas makes them easier to turn in and off for accurate control

https://twitter.com/DJSnM/status/1407754444884742152?s=20

Elon Musk @elonmusk
Cool, but an unnecessary complication for now. These are being removed to speed up time to orbital launch.

https://twitter.com/elonmusk/status/1407969457411067905?s=20

It's cool they're developing the hot gas thrusters, it's even more cool they aren't going to let that development get in the way of testing the rest of the booster.

Proof?
Whatever is being said is fairly garbled.
"...the hit has version"?
What's a guess as to what Manley meant?

And what, specifically is that "unnecessary complication"?
RCS engines burning "methalox", which would actually be gaseous methane and oxygen?
And what is that complex bit of plumbing photographed by Kenniston?

Hot gas.   Not “hit has”. Stupid auto correct

[Lockne]

Proof?
Whatever is being said is fairly garbled.
"...the hit has version"?
What's a guess as to what Manley meant?

And what, specifically is that "unnecessary complication"?
RCS engines burning "methalox", which would actually be gaseous methane and oxygen?
And what is that complex bit of plumbing photographed by Kenniston?

He's talking about RCS thrusters. 'Hit has version' = 'hot gas version'

The unnecessary complication Elon is referring to are the hot gas thrusters. Cold gas thrusters are a lot more simple and have been used on Starship so far. So after initially pushing for a first test of the hot gas thrusters during the first orbital attempt, it seems like they have now decided to play it safe and use cold gas thrusters instead, eliminating one unknown.

Yeah, the hot gas thrusters are often called methalox, even though that doesn't make much sense if they are indeed using gaseous oxygen. That said, I don't know if it's actually confirmed that they'll be using gaseous methane and oxygen. Cryogenic pressure-fed hot gas thrusters are a thing too.

The picture shows a SH forward dome, and the complex plumbing attached to it is an assembly of three hot gas RCS thrusters, one nozzle pointing left, one right, one towards the camera.