totm nov 2023 SpaceX Discussion Thread

[DAL59]

 

[tater]

Booster 10 on the move, but to rocket garden.

[darthgently]

4 hours ago, Ultimate Steve said:

The 33 don't count for this analysis, this is just about restarting in flight, which is a significantly different environment than ground start.

Only the outer engines start differently from stage 0.  All the others start the same mostly, whether on launch or in flight.  Unless I'm wrong

[JoeSchmuckatelli]

2 hours ago, DAL59 said:

 

... well, if it does (but not too much) I will still be too far away to see anything.  Except this time, instead of a good internet connection, I'll likely be on a paddleboard fending off sharks.

[tater]

50 minutes ago, darthgently said:

Only the outer engines start differently from stage 0.  All the others start the same mostly, whether on launch or in flight.  Unless I'm wrong

The outer 20 only start on stage 0, no restart at all.

[darthgently]

17 minutes ago, tater said:

The outer 20 only start on stage 0, no restart at all.

Right, I didn't write that the outers restarted. Only that they started.  But all 33 ran like champs so I was questioning the idea that it was a Raptor issue rather than fuel issue

[CatastrophicFailure]

3 hours ago, DAL59 said:

 

IFT-3 should have a race with Vulcan-1. 

Or a dance-off. 

[SunlitZelkova]

5 hours ago, CatastrophicFailure said:

IFT-3 should have a race with Vulcan-1. 

Or a dance-off. 

These races are kinda lame IMO. I remember how during SLS' multiple failed launch attempts, everybody was so excited (confident?) SLS was about to be buried in history by Starship, which started development six years after SLS but would fly before the long delayed old space rocket. Starship flew five months later.

Stuff like that just seems like it will be silly in the historical record, kinda like how Soviet estimates for how much time it would take for them to beat Apollo are almost joke material in the present day.

I think they should take their time and make sure it works, not pit a medium lift rocket against a super heavy lift launch vehicle for the memes. Rushing to meet a certain date causes disasters. If the Soviets hadn't been so eager to return to crewed flight ahead of the 50th anniversary of the October Revolution, Vladimir Komarov might be still with us.

[Nuke]

flying is a lot different than flying and not exploding. just because someone has a fusion reactor on the drawing board or even a test reactor, doesn't mean you should demolish all your fission plants.

starship i think will make it in the long run, how long really depends on how much time the regulators and detractors waste. sls is an adequate mr. backup.

[tater]

5 hours ago, SunlitZelkova said:

These races are kinda lame IMO. I remember how during SLS' multiple failed launch attempts, everybody was so excited (confident?) SLS was about to be buried in history by Starship, which started development six years after SLS but would fly before the long delayed old space rocket. Starship flew five months later.

Stuff like that just seems like it will be silly in the historical record, kinda like how Soviet estimates for how much time it would take for them to beat Apollo are almost joke material in the present day.

I think they should take their time and make sure it works, not pit a medium lift rocket against a super heavy lift launch vehicle for the memes. Rushing to meet a certain date causes disasters. If the Soviets hadn't been so eager to return to crewed flight ahead of the 50th anniversary of the October Revolution, Vladimir Komarov might be still with us.

Races and rankings of most everything are lame (and generally subjective).

That said, the path to the first SLS flight is actually longer than even that claim (some dev was Shuttle, some Constellation). And you don't have to go too far back to have Berger's quote from NASA Administrator Golden saying:

“Let’s be very honest. We don’t have a commercially available heavy-lift vehicle. The Falcon 9 Heavy may some day come about. It’s on the drawing board right now. SLS is real.”

So the original "race" in the context of SpaceX was FH, not SS, but the finish line was moved after FH flew. Again, a silly race at some level, but when mission architectures are being planned, it's certainly worth considering vehicles that are in development, particularly when the baseline vehicle—in this case SLS—is completely incapable of doing the mission in question even if it was already in operational service.

Edited December 6, 2023 by tater

[RCgothic]

2 hours ago, Nuke said:

flying is a lot different than flying and not exploding. just because someone has a fusion reactor on the drawing board or even a test reactor, doesn't mean you should demolish all your fission plants.

starship i think will make it in the long run, how long really depends on how much time the regulators and detractors waste. sls is an adequate mr. backup.

We have a perfectly operational falcon 9 and falcon heavy, and with appropriate mission architectures *those* make a nonsense of SLS.

For the same expenditure as 1 SLS mission it would be possible to purchase 40 centre-core expended falcon heavy missions for about 2000t to LEO pure payload.

Moreover that's commercial sale price, so those missions would generate enough profit for SpaceX to launch more Starlink missions and progress Starship. Whereas funds spent on SLS are not redeveloped.

The only thing keeping SLS going at this point is stubbornness.

Edited December 6, 2023 by RCgothic

[CBase]

23 hours ago, RCgothic said:

Propellant transfer is a milestone

Just curious, but how do you demostrate propellant transfer with a single vehicle ? Any idea what we could observe during IFT-3 ?

My kerbal conception would have been rendeveaus of two spacecraft, docking and fuel transfer via docking port. But I doubt we see this with IFT-3, so there must be something else to expect.

 

[darthgently]

14 minutes ago, CBase said:

Just curious, but how do you demostrate propellant transfer with a single vehicle ? Any idea what we could observe during IFT-3 ?

My kerbal conception would have been rendeveaus of two spacecraft, docking and fuel transfer via docking port. But I doubt we see this with IFT-3, so there must be something else to expect.

 

I would think that the two big wrinkles involved would be

1) Refuel connecting.  Which could be done in the payload area

2) and "ullage" during fuel transfer, or keeping the xfer pumps from sucking air

Short of some kind of spin gravity I'm not sure how the "ullage" would be done.

I wonder if some kind of steerable fuel pickup could be automatically kept within the mass of fuel wherever it was within the source tank

Edited December 6, 2023 by darthgently

[tater]

53 minutes ago, CBase said:

Just curious, but how do you demostrate propellant transfer with a single vehicle ? Any idea what we could observe during IFT-3 ?

Maybe as @darthgently says you put 2 tanks in nose. There can be a valve, and also a connector. They can test the connector, and if that fails just open the valve. Settle props (moving them from top to bottom tank) with RCS? The valve offering a way to at least test the transfer if the linkage fails.

[darthgently]

1 minute ago, tater said:

Maybe as @darthgently says you put 2 tanks in nose. There can be a valve, and also a connector. They can test the connector, and if that fails just open the valve. Settle props (moving them from top to bottom tank) with RCS? The valve offering a way to at least test the transfer if the linkage fails.

Well, if they just want to test limited aspects they could xfer to/from the header tank using the additions you note

[darthgently]

One could also use a required maneuver to xfer via inertia so the RCS, or whatever thrust, would have been done anyway

[tater]

7 minutes ago, darthgently said:

One could also use a required maneuver to xfer via inertia so the RCS, or whatever thrust, would have been done anyway

There's enough room and margin that they could plausibly put a couple options in there to try out as well.

[CatastrophicFailure]

8 hours ago, SunlitZelkova said:

These races are kinda lame IMO. I remember how during SLS' multiple failed launch attempts, everybody was so excited (confident?) SLS was about to be buried in history by Starship, which started development six years after SLS but would fly before the long delayed old space rocket. Starship flew five months later.

Stuff like that just seems like it will be silly in the historical record, kinda like how Soviet estimates for how much time it would take for them to beat Apollo are almost joke material in the present day.

I think they should take their time and make sure it works, not pit a medium lift rocket against a super heavy lift launch vehicle for the memes. Rushing to meet a certain date causes disasters. If the Soviets hadn't been so eager to return to crewed flight ahead of the 50th anniversary of the October Revolution, Vladimir Komarov might be still with us.

You saw the bit about the dance-off, right? 

[CatastrophicFailure]

11 minutes ago, tater said:

There's enough room and margin that they could plausibly put a couple options in there to try out as well.

From what I’ve gleaned it’s just a transfer between main and header tanks. Little to no change to vehicle, plumbing’s already there (to fill header in the first place), zero additional risk to mission. 

[darthgently]

Copied and corrected from an X post:

"...Big news out of SpaceX recently: 

- Looking to certify F9 boosters for up to 30 flights! 

- Eyeing 50 launches from Vandenberg in 2024 and 100 in 2025! 

- First SLC-6 launched F9 from Vandenberg in mid-2025!

First FH from Vandenberg in 2026!..."

 

https://www.noozhawk.com/spacex-launch-rate-at-vandenberg-sfb-could-soar-to-100

 

 

Edited December 6, 2023 by darthgently

[Nuke]

4 hours ago, RCgothic said:

We have a perfectly operational falcon 9 and falcon heavy, and with appropriate mission architectures *those* make a nonsense of SLS.

For the same expenditure as 1 SLS mission it would be possible to purchase 40 centre-core expended falcon heavy missions and about 2000t to LEO pure payload.

Moreover that's commercial sale price, so those missions would generate enough profit for SpaceX to launch more Starlink missions and progress Starship. Whereas funds spent on SLS are not redeveloped.

The only thing keeping SLS going at this point is stubbornness.

existing platforms are adequate for maintaining a status quo in the space industry. sls falls into this trap, but so does falcon. falcon did however raise the bar and everyone else is playing catchup, and that's good for the industry as a whole. the consequence of starship failing is we have a new status quo, and spend decades merely maintaining it. worst case scenario it bankrupts the company and we lose falcon. a better space future requires starship, and i would really like it to see sls made completely obsolete. but so long as sls does things that falcon cant, there is a reason for its existence.

though if were being honest i think that sh could be quickly retrofitted to a disposable config and still out perform sls in the costs department. the booster performed excellent to the point of staging. stick a bare starship up top and run it disposable. 

Edited December 6, 2023 by Nuke

[SunlitZelkova]

5 hours ago, tater said:

That said, the path to the first SLS flight is actually longer than even that claim (some dev was Shuttle, some Constellation). And you don't have to go too far back to have Berger's quote from NASA Administrator Golden saying:

“Let’s be very honest. We don’t have a commercially available heavy-lift vehicle. The Falcon 9 Heavy may some day come about. It’s on the drawing board right now. SLS is real.”

So the original "race" in the context of SpaceX was FH, not SS, but the finish line was moved after FH flew. Again, a silly race at some level, but when mission architectures are being planned, it's certainly worth considering vehicles that are in development, particularly when the baseline vehicle—in this case SLS—is completely incapable of doing the mission in question even if it was already in operational service.

Yeah, SLS has plenty to be made fun of too.

2 hours ago, CatastrophicFailure said:

You saw the bit about the dance-off, right? 

In a thread where people discuss landing boosters on Caribbean islands and then fueling them for a suborbital hop back to Starbase in complete seriousness, it is hard to differ between sarcasm and a serious idea with some humor mixed in.

[darthgently]

20 minutes ago, SunlitZelkova said:

Yeah, SLS has plenty to be made fun of too.

In a thread where people discuss landing boosters on Caribbean islands and then fueling them for a suborbital hop back to Starbase in complete seriousness, it is hard to differ between sarcasm and a serious idea with some humor mixed in.

Hey, that hurt.  Watch where you point that rapier wit, will ya?  Lol

[sevenperforce]

On 12/5/2023 at 4:35 PM, Exoscientist said:

On 12/5/2023 at 4:16 PM, Geonovast said:

On 12/5/2023 at 4:11 PM, Exoscientist said:

SpaceX still has not demonstrated the Raptor can be restarted in flight

What did SN8, SN9, SN10, SN11, and SN15 use for their landing attempts, then?

 If you review the Starship landing tests, it has happened multiple times a Raptor engine has leaked fuel and caught fire. This was  only with one or at most 3 engines. Imagine this with 33 engines.

 I’m positing the Raptor is no more reliable now than on those landing tests on relights.

You said "restarted in flight". The high-altitude hop tests demonstrated in-flight restarts.

You may certainly opine that SpaceX cannot reliably restart the Raptor in flight (although all of those were Raptor 1 and there have been no demonstrated refiring/restart issues with Raptor 2), but you cannot deny that those Raptors did in fact restart in flight. And you still have no evidence beyond speculation that Raptor 2 has any startup issues at all, given that (a) the lack of completed Superheavy startups for OFT-1 was likely associated with sensor excursions and no actual engine failures, (b) the subsequent shutoffs on OFT-1 were associated with leaks from a hydraulic TVC system that no longer exists, and (c) IFT-2 had no difficulty keeping all 33 engines firing from ground to staging.

I don't know why you're on about the engines. Engines are an area where SpaceX seems to have the most success. There are more issues with propellant slosh, maneuvers, the survivability of tile failures on re-entry, and so forth.

[sevenperforce]

4 hours ago, CatastrophicFailure said:

5 hours ago, CBase said:

Just curious, but how do you demostrate propellant transfer with a single vehicle ? Any idea what we could observe during IFT-3 ?

From what I’ve gleaned it’s just a transfer between main and header tanks. Little to no change to vehicle, plumbing’s already there (to fill header in the first place), zero additional risk to mission. 

I believe I had read that they would have a separate actual tank in the payload bay and would test transfer between it and the vehicle tank, rather than transfer in and out of headers. The connections would already be in place and it would simply be a matter of opening the valves and using a small ullage burn to nudge the props from one tank to the other.